Abstracts

Abstracts are listed alphabetically by the last name of the first author.

 


Subsurface Characterization of the Lower to Middle Miocene Monterey Formation-Equivalent Strata of Long Beach Oil Field: Los Angeles Basin, California

Ayodeji Aina, California State University, Long Beach
Richard Behl, California State University, Long Beach

Abstract: In spite of being the most prolific petroleum producing basin per square foot in the world, the Monterey-equivalent strata from the deep Los Angeles Basin has been poorly explored and large volumes of technically recoverable petroleum may remain undiscovered. A report from the U.S. Geological Survey estimates that between 1.4 and 5.6 billion barrels of recoverable conventional oil remains in place in the Los Angeles Basin. Little is known about unconventional potential. This study will create a detailed characterization of the Monterey-equivalent, lower to middle Miocene rocks of the Long Beach Oil Field in the Los Angeles Basin.

Most conventional production from the Long Beach Field has been from upper Miocene to lower Pleistocene sandstones but the lower to middle Miocene rocks equally have tangible contributions to the petroleum system of the field. Consequently, the study will analyze both modern and legacy well data for regional stratigraphic correlation and to provide a stratigraphic framework of the older and deeper Miocene Monterey-equivalent rocks. A detailed petrophysical analysis will provide lithological units and define lateral variations that may be due to original depositional facies or structural offset. Lithologic, mineralogic and geochemical analysis of cores and cuttings from the greatest penetration wells will provide the data necessary to characterize the deep lithostratigraphy of the Long Beach Oil Field. Integration of petrographic and petrophysical analysis with regional studies of the basin will help define the lateral distribution of reservoir facies and give us insight into the tectonic and sedimentary history of the early stages of the formations within the Los Angeles Basin.

In the light of the development of the unconventional plays in North America, understanding these deep Miocene rocks are critically important both for their source and reservoir potential.

Presentation Format: Poster
Session: General

 


Mantle structure beneath the Alboran Sea from shear wave splitting

Lisa Alpert, Aera Energy LLC
Thorsten Becker, Jackson School of Geosciences , University of Texas, Austin
Meghan S Miller, Research School of Earth Sciences, Australian National University
Amir Allam, University of Utah, Department of Geology & Geophysics

Abstract: Earthquake patterns and seismic tomography in the western Mediterranean are insufficient to precisely resolve the density structure beneath the Alboran Sea reflected in the complex surface tectonics. Here, we use seismic anisotropy to test a range of suggested structures. We show that SKS splitting observations in the region are best reproduced by mantle flow models that include a continuous, deeply extending, slab structure beneath the Alboran Sea, elongate along the Iberian margin from Granada to Gibraltar, where it curves southward toward the High Atlas. Detached slabs, slabs with spatial gaps, and drip-like features produced results inconsistent with the splitting observations, suggesting delamination processes are unlikely. We also find that the absolute reference frame choice when prescribing surface velocities is crucial due to the opposing surface flow orientation in this region between two end-member absolute plate motion models, Nuvel-1A in the no-net-rotation and HS3 reference frames. Allowing for high net rotations and forcing the associated shear into the upper mantle with a no-slip core-mantle boundary generates a south-directed shear within the Alboran domain that predicts splitting orientations most similar to the patterns observed along Gibraltar,without invoking slab rollback. Slab viscosities of ~250 times that of the upper mantle produce the best match to the observations by providing a balance between radial flow induced by buoyant downwelling and toroidal flow induced by stiff slabs. Splitting orientations and delay times in the Atlas Mountains are best matched with the addition of a stiff continental keel in NW Africa, which deflects flow northward, generating EW fast axes. Our results show that predictions of LPO and SKS splitting orientations from mantle flow models, when compared with observations, can be useful in distinguishing the spatial and depth extent of regional density structure that is otherwise ambiguous.

Presentation Format: Oral
Session: SEG

 


Offshore in the West

Joan R. Barminski, Bureau of Ocean Energy Management, Department of the Interior

Abstract: BOEM manages the responsible exploration and development of offshore energy and marine mineral resources on the U.S. Outer Continental Shelf (OCS). BOEM is currently developing a new National OCS Oil and Gas Leasing Program. The Draft Proposed Program, the first of three required phases, analyzed potential leasing in 25 OCS planning areas around the country. The next step is publication of the Proposed Program and Draft Programmatic Environmental Impact Statement. The Proposed Program will describe which planning areas will continue to be considered for potential leasing. On the west coast, oil and gas resources and reserves on 34 active federal leases offshore Southern California are in BOEM’s purview. Twenty-three platforms have produced over 1.35 billion barrels of oil and 1.85 trillion cubic feet of natural gas since production started in 1968. Due to the 2015 onshore rupture of the Plains All American Pipeline, six facilities ceased production and remain shut-in. In 2018, nine leases were relinquished or expired; discussions are ongoing regarding decommissioning the five platforms on these leases. However, interest in enhanced recovery in this mature province continues, as evidenced by pursuit of a geological and geophysical survey permit in the Beta Unit field offshore Long Beach. The survey would provide subsurface imaging of the formations lying 3,000 to 5,000 feet below the seafloor within the field. The enhanced imaging of the subsurface geology will enable more efficient recovery of the remaining natural resources within the field. The survey will be used to map the subsurface geology to locate remaining oil and gas resources, thereby reducing the number of wells required to recover the hydrocarbons.

New to the region is the potential development of offshore renewable energy from wind energy. In California, work is in progress to assess wind energy areas offshore both the North coast and the Central coast with the goal of competitively issuing leases for future development projects. Collaboration with the state is a hallmark of the BOEM process, exemplified by a Federal-State intergovernmental task force established in 2016. Extensive public involvement and tribal engagement occurs all along the way, through Federal Register notices, public meetings, webinars, consultation, and other communication mechanisms.

Presentation Format: Oral
Session: The Future of CA: Alternative Energy Opportunities

 


Geochemical and Petrographic Characterization of Barite deposits in the Devonian Slaven Chert of Nevada

Harpreet Batther, California State University at Chico
Jochen Nuester, California State University at Chico
Russell Shapiro, California State University at Chico

Abstract: Barite (BaSO4) deposits are crucial to economic geology, paleoceanographic, and paleotectonic studies, yet the genesis of the megaton-scale beds is still being debated. The mineral is an economic commodity because its inert properties, low solubility, and high specific gravity of 4.5 g/cm3 allow it to act as a weighting agent in drilling fluid. In addition, the isotopic compositions recorded in barite could be used to demonstrate chemical and biological changes in seawater over time. My study is focused on large barite beds and limestone deposits located at the Clipper, Northumberland, Greystone, Dana, Mountain Springs, and Shasta open pit mines of the Roberts Mountain Allochthon in north-central Nevada. These deposits formed on a continental slope along an active tectonic margin before the Antler orogeny. Preliminary data support a model where barium is removed from seawater as organic flux to the sea bed, buried and remobilized in organic-rich and highly reducing sediments, transported by methane flow, and precipitated as barite at and below the seafloor. Evidence of methane seepage is based on anomalous limestone lenses with depleted d13C values (-27.31 to -31.65‰; n=13) and fossils of Dzieduszyckia—a brachiopod known to have inhabited seeps. Preliminary sulfur isotope data (n=34) show elevated d34S values up to 20‰ above contemporaneous Devonian seawater (23‰). The low d13C of seep associated limestone point to a carbon source that is influenced by subsurface anaerobic oxidation of methane, while the enriched sulfur isotope signals of barite indicate a sulfate source linked to bacterial sulfate reduction. Initial petrographic analysis shows a variety of barite fabrics ranging from 1.1-3.4 mm rosettes of euhedral acicular crystals to inequigranular xenotopic mosaics (76 µm avg). Poikilotopic frameworks of subhedral barite (.8 mm avg) enclosing smaller euhedral crystals (22 µm avg) are also common. The limestone is composed of small to large subhedral calcite crystals with extensive thin twinning. Brachiopod shells are recognizable and some shell fabric is preserved. Ongoing research is aimed at linking the geographical and stratigraphic occurrences of barite and limestone with specific petrofabrics and isotopic trends. The goal of this project is to detail the various pathways by which the barium, carbon, and sulfur cycles influenced barite formation and drove the localized chemosynthetic ecosystems across the continental slope in the Devonian.

Presentation Format: Poster
Session: General

 


90 ANTICLINES AND COUNTING: A Mostly Unmapped Fold Belt Between the San Andreas Fault and The Coast Range Thrust in Northern California

William R. Berry II, Buckskin Petroleum of California LLC, Miocene Minerals Inc. & PayZone Inc.

Abstract: Using viewing and navigational tools provided in Google Earth Pro over 90 anticlines have been identified in the extensively deformed fold belt which is north of the San Francisco Bay and bounded by major strike-slip and thrust fault features. Geomorphological features such as stream patterns, flat irons, and vegetation offer clues to major and sometimes more subtle structures throughout this trend. Some of these features are in excess of 30 miles in length and have length to width ratios in the range of three to ten. Most of the anticlines are breached and quite difficult to recognize without detailed analysis of stream patterns and flat iron orientation. The axis orientation of most of these folds lies parallel to subparallel with the San Andreas, Maacama, Rogers Creek, Bartlett Springs, Coast Range Thrust, Little Salmon, South Humboldt, and Russ Faults. However, there is an anomalous axis trend that is more or less perpendicular to the San Andreas and Maacama Fault traces extending from just south of Fort Bragg to about 25 miles north of Fort Bragg.

Several tools and techniques were developed to aid in identification of the structural features. Stream patterns were digitized and organized into major and subordinate drainage systems that can be individually turned on and off while viewing the terrain in both vertical and oblique orientations. Vertical relief can be exaggerated by up to a factor of 3:1, thus aiding in recognition of flat irons and other features when viewed in oblique orientation. Feature recognition can, in some cases, be aided by drafting lines along stream divides. This process is also greatly aided by oblique viewing and varying the elevation exaggeration.

There are numerous reasons why this extensive fold belt has not been recognized. The terrain is quite rugged, road access is very limited, and there have been only minimal efforts to do any detailed field mapping. Dibblee mapped some portions of the trend and the daunting nature of the topography is evidenced by the concentration of his strike and dip measurements along the more accessible stream beds with very little in between.

The entire trend east of the San Andreas Fault up to the Mendocino triple junction and beyond is a mix of ophiolite terranes. The convergent subduction and accretionary process resulted in chaotic bedding and low temperature metamorphism, all of which combine to reflect small scale deformational features when viewed in the field. All of this small-scale deformation occurred long before the advent of strike-slip movement along the San Andreas and other major faults throughout the trend. The strike-slip and compressional deformation commenced with or after the failure of subduction south of the triple junction. The very large anticlinal features now recognized overprint the older small-scale structures. However, most of these anticlines are of such great size that they are literally the forest that is hidden by the trees. The Kettleman Hills North Dome, Middle Dome and South Dome trend on the west margin of the San Joaquin Valley is about 30 miles in length. Many of the mapped anticlines in this trend are that size or bigger. Some of the features have been mapped as anticlinoriums with included closures having axial lengths of 8-10 miles.

Several anticlines in the area just north of San Francisco Bay are annotated in Bulletin 149 (Geology and Mineral Deposits of the Area North of San Francisco Bay, California, 1949). The Alton and Grizzly Bluff anticlines on the southern edge of the Eel River Tertiary basin have been mapped (Bulletin 164). However, for most of the twentieth century there were no anticline symbols between those features on published maps. The older Santa Rosa Quadrangle (having no anticlines indicated) was revised in 1988 and one anticline was annotated north west of the Geysers Geothermal Field at Pine Mountain. The author has found no other indications that a great number of anticlines exist in the trend.

The geomorphological features that are evident on the Pine Mountain structure can be seen throughout the trend when viewed with the tools used in this study. In a larger sense, this study also illustrates the value of using tools such as Google Earth to visualize and identify geomorphological features as an aid in structural mapping on a regional scale.

Presentation Format: Oral
Session: Regional Interpretations with potential Exploration: Petroleum System Consequences

 


Application of Machine Learning and Deep Learning for Complex Fault Network Characterization on the North Slope, Alaska

Shuvajit Bhattacharya, University of Alaska Anchorage

Abstract: The deep subsurface geology on the North Slope, Alaska is structurally complex and pervasively fractured. Faults/fractures control fluid flow (hydrocarbon and water) through rocks. Although seismic data is generally used to “manually” identify faults in the subsurface, the extreme nature of these discontinuities, such as their numbers per square miles and complexities, do not allow geoscientists to fully understand the multi-phase fault development history of northern Alaska over geologic time. Physics-based seismic attributes such as 3D curvature can be used to detect faults. However, this process is computationally intensive and requires a detailed understanding of the limits of the attributes in specific geologic settings and the quality of the data. In this study, a large 3D seismic survey over an area of 270 square miles on the North Slope was used for detailed fault characterization. Curvature attribute-assisted horizon mapping revealed the presence of three major extensional fault network along NW-SE, N-S, and E-W directions, many of which affect multiple source and reservoirs such as the Shublik, Sag River, and Kuparuk formations. Next, Multi-layer Perceptron Neural Network (MLPNN) and Convolutional Neural Network (CNN) were used to classify and predict faults in the seismic survey automatically. The results show that both MLPNN and CNN can be used for fault classification with high accuracy (>85%) in limited time; however, CNN-based fault classification does not require any seismic attributes as input to the neural network model as opposed to the MLPNN. The original seismic data with labeled faults can be directly used in the CNN model for automated fault classification, thereby, bypassing the traditional way of seismic attribute-assisted fault detection.

Presentation Format: Poster
Session: SEG

 


Hydrocarbon Potential of the Nanushuk and Torok Formations on the North Slope, Alaska: Implications for Supersized Oilfield Development

Shuvajit Bhattacharya, University of Alaska Anchorage

Abstract: Exploration of the Cretaceous sandstone reservoirs in the Nanushuk and Torok formations on the North Slope of Alaska is a hot topic and presents opportunities to oil and gas community because of their shallow depth, vast extent, and scope of development, etc. The consecutive discoveries of the hydrocarbon reservoirs in the Nanushuk and Torok formations by Repsol, Armstrong, and ConocoPhillips in 2015, 2016, and 2017 have only reconfirmed the presence of the vast recoverable resources present at shallow depth on the North Slope, which needs detailed geologic and geophysical characterization. The goal of the project was to characterize the Nanushuk and Torok formations integrating multiple 3D seismic surveys and well-log data. The Nanushuk Formation is expressed as topset reflections, whereas the Torok Formation is expressed as foresets and bottomsets on the seismic data. Seismic-attribute-assisted mapping revealed the presence of prograding shelf-edges, low-stand and high-stand deltas, feeder channels, and basin floor fans, all with significant amplitude anomalies. The shelf-edges continue for 10s-100s of miles. Some of these reservoirs are also bound by faults at places. The internal characters of these reservoirs delineated by well-logs show the presence of four sequences- coarsening upward, fining upward, aggradation, and transgression. Porosity and permeability values in the Nanushuk Formation range from 5% to 35% and 0.1 mD to 1,000 mD, respectively. Although the deltas are predominantly wave-dominated, there is evidence of fluvial influence.

Presentation Format: Oral
Session: Regional Interpretations with potential Exploration: Petroleum System Consequences

 


A path to a carbon-neutral oil industry in California

Steven Bohlen, Lawrence Livermore National Laboratory

Abstract: The California (CA) oil industry faces several huge challenges – oil reserves that are carbon intensive and costly to produce, low commodity prices, extensive environmental regulation, and a subset of environmental advocates who seek to have CA be ground zero for the “leave it in the ground” movement. However, the love affair between CA and the automobile will likely demand a continued supply of gasoline and diesel well into midcentury even as the uptake of batteries or fuel cells deepens. Recent amendments to the Low Carbon Fuel Standard (LCFS) extended eligibility for credits to some carbon capture and sequestration (CCS) projects. Hence, the LCFS could provide sufficient financial incentives to build a robust CCS industry in the State, with the oil and gas industry supplying geologic repositories and the technical know-how to store millions of tons of CO2 a year underground – and make a profit doing so. Development of this industry would preserve oil industry jobs and turn them to helping the state meet its aggressive carbon goals. The LCFS sets the stage for CA to create a first-of-its-kind carbon-neutral oil industry by the end of the next decade.

Presentation Format: Oral
Session: The Future of CA: Alternative Energy Opportunities

 


Determining Structure and Velocities in the Los Angeles Basin Using Passive Seismic with Dense Oil-Company Arrays

Robert W. Clayton, California Institute of Technology

Abstract: In this talk I show that you can use the ambient noise recorded by modern node arrays to measure the near-surface shear-wave velocities, the P-wave velocities down to 3 km depth, and the structural boundaries of the Los Angeles Basin and crust. Correlations between each pair of geophones used in the survey produce a “virtual” source that can be use much like an active source but without the problems associated with a vibrator. Surface waves are used to determine the shallow Vs velocities which are important for seismic hazard. P-waves can be extracted and used to determine the Vp velocities, and autocorrelations produce stacked seismic sections for imaging the structure.

Examples will be shown for arrays in Long Beach, Seal Beach, Rosecrans and Santa Fe Springs. In addition, the correlations with the regional earthquake network (SCSN) allows the results to be extended be beyond the original surveys.

Presentation Format: Oral
Session: SEG

 


A Preliminary Characterization and Kinematic Analysis of Fractures within the Miocene Vaqueros and Topanga Formation, Point Mugu Rock, Ventura County, California

John P. Detring, Department of the Interior, Bureau of Safety and Environmental Enforcement (BPELSG)

Abstract: A complex, transpressive kinematic history exists within the Transverse Ranges. Deformation is observed to be consistent with roughly N-S shortening. The structural trends and fracture patterns are in response to this deformation. This study analyzes the kinematic indicators, structural geometries and fracture patterns within California’s western Transverse Ranges. Fracture systems provide permeability as well as create traps in petroleum reservoirs. An understanding of the orientation and timing of fracture systems can test current tectonic models and allow for predictions of subsurface fracture orientation and permeability. This data will increase the understanding of regional fracture sets and identify fractures which may be ideal fluid pathways for the transmission of hydrocarbons.

Data from minor fault stations (4) and joint stations (2) were systematically collected throughout the area within the Topanga and Vaqueros Formations to obtain average joint orientations and to calculate the ideal σ 1 orientations of minor faults. Shear sense was determined using Petit’s (1987) RO criteria. When possible, cross-cutting relationships were observed so that timing relationships between different faulting events could be assessed. Joint surfaces were discriminated from faults by lack of gouge, slicks, or cataclasite, and whether plumose structures (hackles, ribs, or arrest lines) were present. The full data set was systematically analyzed to reveal kinematic relationships. Stereonet software was used to create plots of the data split by type of measurement or calculation (i.e. joint or fault plane, slickenline, or σ 1), and type of fracture (i.e. Mode I, II, or slip sense). Rose plots, rounded with a smoothing increment of 10 degrees, of average σ 1 trend, average slickenline trend, average joint strike, and average shearband trend were created using kinematic analysis software. The angle used for the calculation of the ideal σ 1 for preliminary analyses was assumed to be 25 degrees in accordance with Byerlee (1978).

Preliminary analyses of minor faults are underway. Joint measurements are bimodal in distribution, with average strikes of N0E and N78E. Abutting relationships suggest that the N0E-striking joints are primary (J1) and the N78E-striking joints are secondary (J2). Calcite mineralization is present along J1 joint planes suggesting fluid flow. Shearbands, fault zones and intrusive diabase dikes are found parallel to both J1 and J2.

Presentation Format: Oral
Session: Specific Data Sourced Studies

 


3-d mapping of groundwater total dissolved solids at the Midway-Sunset Oil Field using borehole geophysics and historical produced water geochemistry

David Finney, California State University, Sacramento
David Shimabukuro, California State University, Sacramento

Abstract: Mapping the distribution of groundwater salinity can help us make better groundwater management decisions. Salinity mapping efforts using borehole geophysics and produced water geochemistry have been successful at many oil fields in California’s San Joaquin Basin. Estimates of total dissolved solids (TDS) are calculated using the resistivity-porosity (RP) method, based on Archie’s equation, which uses deep resistivity, porosity and temperature to calculate groundwater TDS from geophysical logs. These estimates can be tuned with TDS measurements from produced water geochemical records.

At the Midway-Sunset oil field, there are challenges to applying the RP method. Decades of enhanced oil recovery operations have led to significant variations in the geothermal gradient, and detrital diatomite in sands causes geophysical porosity logs to overestimate total porosity. This is a problem because TDS calculations require resistivity, temperature, and porosity data. In addition, produced water samples collected near preexisting wastewater injection wells may be contaminated, and thus do not represent formation water salinity.

To solve these challenges, we avoid resistivity logs likely affected by steaming using a spatiotemporal algorithm that discards resistivity logs located near preexisting injection wells. We used the same spatiotemporal algorithm to discard produced water geochemical TDS measurements located closest to preexisting injection wells. To correct for geophysical porosity tool mismeasurements, three different porosity models were explored. Selected estimates of TDS and geochemical measurements were then kriged to generate 3-d volume models of TDS. In the northern portion of the field, the TDS maps and cross sections reveal that the depth to the 10,000 parts per million (ppm) TDS boundary extends to deeper than 1500 feet below sea level, while in the southern region the boundary is much shallower, with a maximum depth of ~150 feet elevation. From our model, we conclude that stratigraphy, faults, and freshwater recharge are the most likely factors contributing to the existing salinity trend.

Presentation Format: Poster
Session: General

 


Pre-1977 injection volumes from water flood and water disposal wells in Kern County, California

Michael Flowers, California State University, Sacramento
Haley Courser, California State University, Sacramento
David Shimabukuro, California State University, Sacramento

Abstract: Water is injected into the subsurface in and near oil fields in Kern County, California as water flood wells and water disposal wells for purposes of enhanced oil recovery and disposal of produced water. Location and volume of these injection process from 1977 onward are available in public databases hosted by the California Division of Oil, Gas, and Geothermal Resources (DOGGR). Injection data prior to 1977 are only available in yearly format in the published DOGGR Summary of Operations and as monthly reports from oil and gas producers. The undigitized nature of this pre-1977 data makes it difficult to understand the water injection history in and around oil fields during this period.

In an effort to understand this pre-1977 history, water injection volumes were manually extracted from the DOGGR Summary of Operations. These records contain injected volume, subdivided annual by field, area, and pool between 1956 and 1976 for water flood and water disposal wells in DOGGR District 4 of California. Data was compiled, then joined with post-1977 data to understand the long-term history of water injection in this area.

The data shows water injection rates in Kern County were relatively low until the late 1960s and then rapidly increase. Fields on the eastside of the San Joaquin Valley, such as Mount Poso, Round Mountain, and Kern River, collectively had the highest cumulative injection pre-1977; however, rates of injection were much lower post-1977 injection. Fields in southern and central regions, such as North Coles Levee, Rosedale Ranch, and Wheeler Ridge were most notable for their injection rates pre-1977 relative to post-1977. North Coles Levee and Mount Poso stand out because their cumulative injection was the highest at 264 and 233 MMbbls of injection respectively, compared to the next highest field, Round Mountain, with a total of 155 MMbbls. North Coles Levee also had the most extreme changes in water injection rates pre-1977. Water injection rates in North Coles Levee from 1969-1977 increased from 9.1 MMbbls/yr to 42.4 MMbbls/yr, and then decreases to 15.2 MMbbls/yr; injection rates decrease to a steady rate of 1-2 MMbbls/yr in 1988. Future work will involve determining the volume and depth of injection in select fields on a well-by-well basis.

Presentation Format: Poster
Session: General

 


Chemostratigraphic and lithostratigraphic variability of the Eocene Kreyenhagen Formation in the Kettleman Area, San Joaquin Basin, California

Leo G. Giannetta, California State University Long Beach
Richard J. Behl, California State University Long Beach

Abstract: The Eocene Kreyenhagen Formation is a widespread siliceous, organic-rich mudstone of the San Joaquin Basin (SJB). However, in comparison to the highly studied siliceous Monterey Formation, studies of the Kreyenhagen are limited. This study completes a stratigraphic characterization of the Kreyenhagen with emphasis on chemostratigraphy to understand its compositional variability and depositional history.

The Kreyenhagen was subdivided into 8 zones (A-H) and correlated across 128 wells to define its stratigraphic framework in the Kettleman area. Cross-sections and isopach maps show an eastward thinning from 1,100 to less than 600 feet. Petrophysical estimates of TOC and clay volume were coupled with bulk and trace elemental geochemistry as proxies of detrital input, paleo-productivity, and benthic redox conditions. The lower Kreyenhagen (H-E) does not display significant enrichment in any major compositional components. The middle Kreyenhagen (E-C) is the most distinctive, encompassing the zone of greatest TOC and enrichment in elemental proxies for anoxia (D). Also distinct in the middle Kreyenhagen is an upward trend of decreasing detritus and increasing biogenic quartz content. Lastly, the upper Kreyenhagen (B-A) cycles between low and moderately high values of detritus, biogenic quartz, and redox proxy character. Regional gridding of compositional data reveals a trend of high TOC sub-parallel to the present-day basin axis and an eastward increase in detritus.

The Kreyenhagen succession records at least one major transgressive-regressive cycle. The middle interval likely represents the period of highest sea-level, indicated by high TOC and enrichment of trace elemental proxies for anoxia. Additionally, the vertical increase in biogenic components may reflect an increase in primary productivity associated with known middle-late Eocene climatic cooling events. Lateral compositional trends may indicate that 1) some terrigenous sediment was delivered from the east from the Sierran Magmatic Arc, and 2) a northwest trending oxygen deficient environment, potentially caused by restricted ocean circulation associated with the uplifted Franciscan subduction complex.

Findings reveal spatial and temporal changes in benthic environments within the northern SJB during the Eocene. Further, relationships between geochemical proxies and lithofacies demonstrate the depositional controls on composition in siliceous, organic-rich mudstones.

Presentation Format: Poster
Session: General

 


Assessing Remediation Efforts at the former New Idria Mercury Mine, California

Rachel Hohn, California State University Northridge
Priya M. Ganguli, California State University Northridge
Scott Hauswirth, California State University Northridge
Kimberly Newton, California State University Northridge
Danielle Bram, California State University Northridge

Abstract: Mercury (Hg), which is mined from cinnabar (HgS), is an economic resource used extensively in California to extract gold and silver. Because Hg binds to carbon, fossil fuel combustion is a significant source of Hg globally. Although Hg is no longer mined in the US, abandoned mines continue to impact watersheds throughout California. In fact, the two largest Hg producers in North America were located in the California Coast Range Mountains: the New Almaden Mine near San Jose and the New Idria Mine, ~170 km SE of San Jose. Both are Superfund Sites, with extensive remediation completed at New Almaden. Cleanup at New Idria has been more challenging, due in part to its remote location. Our study is designed to evaluate water and sediment quality downstream from New Idria following initial remediation activities, which were completed in 2015.

The cinnabar deposit at New Idria is located within a metamorphosed region of the Coast Ranges. The ore occurs in altered shale and sandstone which sit stratigraphically above a serpentine diapir. Fractures created preferential pathways for hydrothermal fluids and cinnabar was deposited in fracture veins. Pyrite (FeS2) associated with this cinnabar enabled the generation of acid mine drainage (AMD). Initial remediation actions rerouted the AMD, but > 40 acres of mining waste remain exposed. Only one peer reviewed study conducted in the 1990s has quantified water quality impacts from the New Idria Mine. This work suggests the waste piles are the primary source of Hg to San Carlos Creek, which flows through the site. To our knowledge, no published studies have explored Hg transport beyond this creek. We conducted a preliminary sampling event in Jan 2019 to assess the effectiveness of the remediation efforts. Water upstream from the mine contained ~100 pM Hg, similar to previously reported values. About 0.3 km downstream from the site, concentrations jumped about 100-fold, exceeding 10,000 pM, then dropped to ~5,500 pM downstream 2.5 km, presumably due to Hg settling out with iron precipitated from the AMD. Hg in waters near the Mendota Wildlife Area (~100 km downstream) were < 20 pM, indicating Hg from the mine is not currently reaching this habitat. Our results indicate that remediation efforts to date have not reduced the flux of Hg from New Idria. Future work will include quantifying the concentration of bioaccumulative organic Hg in our field area and evaluating the importance of groundwater as a Hg source.

Presentation Format: Poster
Session: General

 


A High Density Seismic Hazard Survey in the Los Angeles Basin

Dan Hollis, Sisprobe SAS
Robert W. Clayton, California Institute of Technology
Eric Campbell, LA Seismic

Abstract: We are finalizing plans for a large-scale seismic hazard survey of the Los Angeles sedimentary basin for the purposes of determining near-surface (0 to 4 km) velocities, basin structure, microseismicity, and the structure of the underlying crust. The survey will be valuable for creating densely sampled micro-zonation maps of seismic hazards for infrastructure resiliency and for providing better velocity models for strong motion modeling. The survey may reveal structures that show some hydrocarbon potential as well has image the aquifer system in the basin.

This large number of sensors (Large-N) passive seismic survey will sample the basin at 10 sensors per square kilometer, which is about an order of magnitude less dense that a standard industry 3D survey, but would provide ample coverage for determining the basin structure and the 3D velocity variations. The survey will have about 18,000 receiver positions that will be occupied by a rolling grid of 5000 sensors, each occupying a given position for 30 days of passive recording. It will take approximately 4 months for this array to traverse the basin. There will be a fixed array of 200 three-component nodes that will record for the entire duration of the survey. In addition, we are planning on 60-70 deep hole (50m +/-) explosive charges to help determine the shallow P-wave velocities, and to look for possible reflections.

Data products resulting for the survey will be a shear-wave (Vs) model from surface to 2 to 3 km (to be used for Vs100 and deeper Vs for ground motion prediction modeling), P-wave (Vp) model from surface to 4 to 5 km, passive and active reflection imaging, seismicity, sedimentary basement and Moho imaging using receiver functions, and more. Initially, the raw data will be shared with researchers, government, and supporters before being made public.

Presentation Format: Oral
Session: SEG

 


Data Geoscience: Skills, Collaboration, and Open Source Approaches to creating value

Nathaniel Jones, California Resources Corporation

Abstract: Data science has made significant impacts in terms of technology, automation, and efficiency in many industries and is making inroads into the energy industry. Many of the advances in data science have come through the development and application of powerful, community driven open source software packages. California Resources Corporation has adopted open source software into its developing data science program and implemented new training and collaboration efforts centered around hackathons and sprints. Open source software has propelled data science efforts around capital workovers, seismic cluster analysis, core photography analysis, petrophysics, and more. This presentation will show how we use open source software in our projects and showcase ongoing community efforts to build out a more complete and powerful open source geoscience software stack.

Presentation Format: Oral
Session: Evaluating Data in a New Light

 


Monterey Formation as a Groundwater Resource

Jordan Kear, Kear Groundwater
Menso deJong, UC Santa Barbara

Abstract: Extensive data, publications, and field examples exist regarding the Monterey Formation and its petroleum capacity, fluid flow, fractured porosity and permeability. Recent demands for drought- and regulatory-compliant water resource development has steered significant investment in groundwater exploration in bedrock formations, specifically the Monterey. Given the history of exploration for petroleum, several new projects have relied on detailed, though often antiquated, notes of oil drilling and development in the Monterey Formation to justify the exploration of the groundwater resource. While results of production rates and groundwater quality can vary, deeper fractured sections of Monterey that have correlative exposures to recharge areas, have a history of "lost circulation" in petroleum exploration, and have geophysical log data that suggest a freshwater-bearing target have been most successful. Methods of feasibility assessment include research for the above, and case studies in the South Mountain (Ventura County) area and Lompoc (Santa Barbara County), among others, offer recent prime examples of melding petroleum geology exploration history and modern groundwater exploration and development.

Presentation Format: Oral
Session: Fluid Flow

 


Detrital Zircon Geochronology and Sediment Transport of the Miocene Stevens Sandstone; Characterizing Turbidite Channel and Fan Complexes of the San Joaquin Valley, California

Mark Korte-Nahabedian, San Diego State University
David Kimbrough, San Diego State University

Abstract: The Upper Miocene Stevens turbidite sandstones are prolific petroleum reservoirs in the southern San Joaquin Basin of California and were deposited as a series of submarine fan systems and deep water channels sourced from paleodrainages emanating from the Sierra Nevada, Techachapi Mtns., and the Salinian block across the proto-San Andreas fault system. The stratigraphy of Stevens channel-fan complexes is complicated by syn-depositional faulting and folding in a deep marine basin, and correlating the discontinuous sand bodies is not easily resolved with conventional electric logs or other methods. A combined detrital zircon U-Pb age and garnet composition provenance study is reported here with the goal of identifying regional-scale sources and sediment-dispersal patterns across the full spatial and temporal distribution of the Stevens, and provides a statistical framework that enables detailed correlation of producing sand reservoirs widely across the region. Provenance shifts resulting in significant differences in detrital zircon and garnet populations are particularly significant in the southwestern portion of the basin where the Salinian block sediment sources were being transported to the northwest across on the San Andreas fault plate boundary during the late upper Miocene. By collecting detrital zircon populations from existing core and outcrop data, we hope to establish links between individual channel and fan complexes together based on the composition of their provenance, challenge long-held paradigms about Stevens sedimentary distribution, and provide a new correlation tool to supplement conventional electric log correlation. This technique has implications for the exploration of new Stevens oil pools, and supplements detailed characterization of other reservoirs in existing oilfields by providing a new potentially high resolution correlation tool in the San Joaquin Basin.

Presentation Format: Poster
Session: General

 


Relations of groundwater chemistry to oil development in different hydrogeologic settings – Preliminary results from California regional groundwater monitoring near oil fields

Matthew K. Landon, U.S. Geological Survey
Peter B. McMahon, U.S. Geological Survey
Tracy A. Davis, U.S. Geological Survey
Michael T. Wright, U.S. Geological Survey
Kimberly T. Taylor, U.S. Geological Survey
Michael J. Stephens, U.S. Geological Survey
Janice M. Gillespie, U.S. Geological Survey
David Shimabukuro, Dept. of Geology California State University-Sacramento
Justin T. Kulongoski, U.S. Geological Survey

Abstract: In cooperation with the California State Water Resources Control Board’s Regional Monitoring Program (RMP) of Water Quality in Areas of Oil and Gas Production, the U.S. Geological Survey has been assessing: 1) the location and characteristics of protected groundwater in proximity to oil production; 2) evidence of oil and gas fluids mixing with protected groundwater, and, if present, determining the processes potentially responsible; and 3) how oil production has affected groundwater quality relative to other processes. A comparison of results to date from the eastside and westside of the San Joaquin Valley indicates that hydrogeologic setting influences the occurrence of oil-field fluids in groundwater. In the Fruitvale study area on the eastside, groundwater above oil-bearing zones is heavily used, with vertical separation of water and oil well perforations > 670 meters (m). This area has relatively high recharge from the Kern River that determines regional groundwater quality. Oil-field fluids were infrequently detected as minor local deviations from regional conditions. These detections sometimes occurred in water wells near areas of high produced water injection and high density of oil wells, some of which may provide pathways for oil-field gases and solutes to reach groundwater. On the westside, protected groundwater is primarily east (and downgradient) of the Lost Hills, South and North Belridge oil fields. Adjacent to these fields, many groundwater samples from wells currently used for irrigation or industrial supply showed no evidence of mixing with oil-field fluids, but some samples indicated mixing with produced waters, likely from historic disposal in surface ponds. There are currently limited data to assess lateral movement of produced water injected for disposal into adjacent groundwater. Within the fields, multiple lines of geochemical evidence indicated overlying groundwater is mixing with oil-field fluids. This result may be expected considering the vertical (< 140 m) and lateral proximity of sampled wells to oil-bearing formations and production activities. Conceptual models for relations of the occurrence of oil-field fluids in groundwater with hydrogeologic setting and potential risk factors are being evaluated in additional RMP study areas.

Presentation Format: Oral
Session: Fluid Flow

 


High-Resolution Seismic Imaging for Managing Natural Resources and Hazards in the Southern California Coastal Zone

Mark R. Legg, Legg Geophysical
Mike Barth, Subsea Systems
Laura Cathcart-Dodge, Spectrum Geophysics
Hany Elwany, EcoSystems Management Associates

Abstract: The Coastal Zone is one of the most important regions of human occupation and development where coastal communities rely on the ocean for food, water, energy and commerce. Natural hazards along the California coast threaten human existence and productivity with storm surge and tsunami, sea level rise, active faulting, earthquakes, liquefaction and landslides, and sea water intrusion that corrupts inland groundwater basins. High-resolution seismic methods provide important subsurface data that cross the transition from sea to land where coastal hazards may affect infrastructure and human activities. In the shallow water along the coast, multichannel seismic reflection profiles are needed to attenuate the water bottom multiple and increase image depth for geologic interpretation. These images combined with coastal zone wells and boreholes provide data to decipher the geologic history and tectonic evolution necessary for understanding coastal hazards and resources. Examples of important coastal features identified and mapped along the southern California coast include filled Pleistocene river channels that provide alluvial basins with coarse materials suitable for subsurface seawater intake systems, yet also represent direct pathways for seawater intrusion across coastal fault barriers into nearshore groundwater basins. The major coastal fault systems which represent earthquake hazards are imaged and mapped in the subsurface where displaced and deformed coastal sedimentary sequences exist to provide timing of activity. Vertical deformation of these sequences may indicate prehistoric uplift or subsidence associated with tectonic activity and tsunami potential. Future deformation may disrupt major utilities and other infrastructure that cross the coastal zone from land to sea. Major active and ancient geologic structures identified include strike-slip faults associated with Pacific-North America transform plate boundary tectonics, oblique-reverse faults and folds associated with inverted Miocene rift basins subjected to Plio-Pleistocene transpression, and major extensional faults active along the coastal breakaway of the Transverse Ranges during the Neogene Inner Borderland rifting episode. High-resolution coastal zone geophysical imaging provides an important “Rosetta Stone” for understanding the natural resources, hazards and tectonic evolution of the southern California region.

Presentation Format: Oral
Session: SEG

 


Quantitative Compositional Characterization of the Biosiliceous Miocene Lark Formation, Danish North Sea and Norwegian Margin

Megan R. Mortimer-Lamb, California State University Long Beach
Richard J. Behl, California State University Long Beach

Abstract: Biogenic silica, composed of the tests of diatoms and other siliceous algae, is a major constituent of marginal and equatorial oceanic sediments. Highly siliceous mudstones, like the Monterey Formation in California, are important source and reservoir rocks for oil and gas exploration. The proportion of biogenic silica to detritus has large controls on reservoir quality including porosity, permeability, and diagenetic phase. However, quantification of biosilica is challenging as two of the diagenetic phases, opal-A and opal-CT, are crystallographically amorphous or poorly ordered. Consequently, traditional methods of quantification of minerals, like x-ray diffraction (XRD) via peak height, must be calibrated and tested against other techniques, such as ICP-MS or XRF geochemical analysis, Fourier Transform-Infrared Spectroscopy (FT-IR), and wet-alkaline digestions of the biosilica.

This study advances biosilica quantification methods by evaluating and comparing the effectiveness of these four techniques. Analysis of 45 mudstone core samples from three different wells in the Miocene Lark Formation of the North Sea show that the Lark is remarkably homogenous and has a much lower SiO2:Al2O3 ratio (2.1) than the Monterey Formation (3.5) due to a high percentage of mixed layer clay and illite. Biogenic silica proportions derived from normative calculations using ICP-MS geochemistry are in agreement with Full Pattern Matching via XRD, which is suitable for amorphous materials as it does not rely on peak height or area measurement. Alkaline digestions of biogenic silica were inconclusive due to a weak diagenesis of opal-A diatoms to less soluble opal-A’. FT-IR results are yet to be processed. Information provided by this work tests the robustness and applicability of each quantification technique, and has developed an excess silica equation that can be applied to the Miocene Norwegian Margin and Danish North Sea. Based upon an empirically derived biosilica to detritus ratio, the excess silica equation will be used to estimate how much silica was biogenic in nature, even in highly diagenetically altered rocks.

Presentation Format: Poster
Session: General

 


The San Joaquin Basin – A California Super Basin

Kurt Neher, Berry Petroleum Company

Abstract: The concept that breakthroughs and innovation are achieved by applying new ideas and technologies is nothing new, nor is it unique to any industry or business. One of the most spectacular technology revolutions in recent decades occurred in the energy sector with the rise in oil and gas production from mature basins, principally in the United States, from low porosity-permeability unconventional reservoirs. This has transformed the worldwide energy industry, and indeed global politics by disrupting the conventional oil and gas supply relationships that have existed for decades. The upstream sector is focused now on those mature basins worldwide with rich petroleum systems, utilizing technologies such as horizontal drilling and multistage hydraulic fracturing to recover oil and gas from stratigraphic horizons that just a few years ago were considered non-reservoir due to their low porosity and permeability. The concentration of investment in extracting hydrocarbons in low-risk, mature, hydrocarbon-rich basins, now known as super basins, comes at the expense of traditional higher-risk exploration.

To classify as a super basin, a petroleum producing basin must have produced 5 billion BOE to date, have 5 billion BOE remaining potential, have two or more source rock intervals, have adequate infrastructure and markets, have an adequate service and supple sector, and have favorable, or at least non-restrictive petroleum laws and regulations. California’s mature San Joaquin basin meets all these criteria and classifies as a super basin. The richness of the basin is driven predominantly by the world-class Monterey formation source rock. Production, however, has declined over the last decade and has not seen the resurgence that other onshore producing areas have experienced like the Permian and Williston basins. California was the third largest producing state for many years, and only recently has slid to seventh as production surged in the other US onshore petroleum provinces. The San Joaquin basin has the rich petroleum systems, the service and support sectors, in-place infrastructure and a ready market in California to support the investments required to turn the production decline around and make the state a leading oil producer again. Both Industry and the state of California need to recognize this opportunity.

Presentation Format: Oral
Session: Wrap-up of Creativity and Opportunities Session

 


The BV Nose Field: from Discovery to Development (San Joaquin Basin, California)

Manuel Paz, California Resources Corporation (CRC)
Sam Afifi, California Resources Corporation (CRC)
Roman Omelchenko, California Resources Corporation (CRC)
Monica Carlsen, California Resources Corporation (CRC)
Bruno Ghiggeri, California Resources Corporation (CRC)
Keith Meyerholtz, California Resources Corporation (CRC)
Brandon Nguyen, California Resources Corporation (CRC)

Abstract: The BV Nose field was discovered in 2012 and is the most significant Stevens sands oil discovery in the last 30 years in the San Joaquin basin. These new resources were found by integrating a fine-tuned stratigraphic framework with the 3D seismic data, and by mapping the stratigraphic sequences throughout the seismic volume. BV Nose is not only significant in size but also because it was discovered in the relatively mature Stevens sand play.

The Stevens sandstones are a series of Miocene deep marine turbidite sands encased within the Monterey formation shales. The San Joaquin basin was surrounded by highlands whose erosion supplied the sediment for the deep marine Stevens turbidites. All the present-day major structures in the southern part of the basin were already tectonically active, so the sand distribution was controlled by those paleo bathymetric sea floor highs. Almost every major anticline in the southern San Joaquin basin has a Stevens oil field formed by the pinch-out of the sands against both structural plunging noses. BV Nose is one of those accumulations.

After an initial phase of exploration and appraisal mode between 2012 and 2014, the field started a new phase of full primary development in 2017. Development of the field is undertaken from a detailed Stevens sands geological model, used 3D seismic interpreted surfaces to define the top and base interval, and isochore mapping from well control and seismic-guided trends to define the internal subzones architecture of the sands. Sand and shale facies were geostatistically distributed within the main channel belts with influence from azimuthal sand channel trends. To capture the variations from cleaner to thin-bedded sands, the facies were then populated with sand quality types. Petrophysical properties were conditioned to and distributed within each sand quality type.

Waterflooding initial results are showing the potential for full field implementation. Early stage development planning, depletion strategy optimization and facilities sizing have been crucial to optimize primary production operations while generating waterflood development plans.

The development of the BV Nose field demonstrates CRC’s differentiating value-driven strategy in action whereby our multi-disciplinary reservoir characterization approach has been integrated with optimized and efficient development planning to maximize the value of existing infrastructure and assets.

Presentation Format: Oral
Session: Continuing Success & Development of Recent Discovery

 


Unconventional Opportunity in SJB

John Porter, California Resources Corporation (CRC)

Abstract: TO BE ADDED SOON.

Presentation Format: Oral
Session: Regional Interpretations with potential Exploration: Petroleum System Consequences

 


Contingent Resources in the Pacific Outer Continental Shelf

Renee Richards, Bureau of Safety and Environmental Enforcement (BSEE)
Bobby Kurtz, Bureau of Safety and Environmental Enforcement (BSEE)

Abstract: The National Outer Continental Shelf (OCS) Leasing Program for oil and gas development establishes a schedule of lease sales proposed for planning areas of the U.S. Outer Continental Shelf (OCS). In April 2017, the Secretary of the Interior issued guidance to the Bureau of Ocean Energy Management (BOEM) to develop a new National OCS 5-year Leasing Program for 2019-2024 to replace the current 2017-2022 plan. The program includes all four Pacific Outer Continental Shelf (POCS) planning areas: Washington-Oregon, Northern, Central, and Southern California. The Pacific OCS has over four decades of production and development history with over 1.35 billion barrels of oil in cumulative production. Many undeveloped fields in previously explored basins are situated within reach of existing offshore OCS infrastructure. To fully constrain the Pacific OCS resource potential that could be developed utilizing current platforms, BOEM and Bureau of Safety and Environmental Enforcement (BSEE) staff have re-evaluated 3D seismic reflection data, historic well, engineering and production data, and analog field data in the offshore Santa Maria and Santa Barbara Channel.

Presentation Format: Poster
Session: General

 


The integrated application of chemostratigraphy and biostratigraphy to the North Slope, Alaska

David Riley, Future Geoscience Ltd
John Gregory, Future Geoscience Ltd
Tim Pearce, Future Geoscience Ltd

Abstract: The objective of this study is to establish a comprehensive stratigraphic framework for Brookian sequences from the Eastern Beaufort Sea from the North Slope of Alaska. This area is under explored with few wells, but recent drilling has led to number of number discoveries reinforcing the area as emerging petroleum province on the North Slope. Few studies have focused on the region and stratigraphic correlation remains challenging in part influenced by poor biostratigraphic control.

The aim of this study is to establish a new integrated stratigraphic framework for the Brookian succession based on the acquisition of new quantitative biostratigraphic data, high resolution chemostratigraphy (ICP-OES+ICP-MS) and C-O isotope curve. The biostratigraphic workflow includes palynological, micropalaeontology and a limited number of nannofossils to address the variety of depositional environments. Chemostratigraphy involves the characterisation and correlation of strata based on inorganic geochemical data that relate to variations in the mineralogy, linked changes in sediment provenance, diagenesis and paleoclimate. The C-O isotope data when integrated with global reference data provides an independent chronostratigraphy. The multidisciplinary approach provides a chronostratigraphic framework that can cope with the facies diversity associated with the Brookian progradation cycles and provide a framework for subsequent provenance and reservoir quality studies.

The study focuses on 10 wells and DSDP 302 4A. Data are presented on Aurora-1 to highlight the workflow. Aurora was drilled to a total depth of 18,325 ft, and penetrates clastics sequences mainly shales, claystone’s and a few interbedded sandstone and siltstone. The chemostratigraphy of the Aurora-1 well subdivides the stratigraphy into three chemostratigraphic sequences, and 15 packages which can be correlated with other Beaufort Sea wells in the study. This zonation is matched by new biostratigraphic data but differs dramatically from the published interpretations for Aurora-1. The conflict between the two schemes arises over the Eocene and Cretaceous intervals, and the new data suggest thicker Cretaceous succession with the top Cretaceous boundary being coincident with a major change in sediment provenance detected chemostratigraphically. Other dramatic changes in the stratigraphy are apparent in the study and overall, this workflow will revolutionise the stratigraphy of the Eastern Beaufort Sea.

Presentation Format: Oral
Session: Specific Data Sourced Studies

 


A re-look at borehole images: What are we missing?

Jon Schwalbach
Tom Hauge, Hauge Geoscience
John Harris, Numeric Solutions LLC
Eric White, Numeric Solutions LLC

Abstract: Borehole Image (BHI) logs have been in the geoscientist’s tool kit for over 30 years. But despite being seen as a mostly mature technology, they are generally underutilized by geologists both for basic geological interpretations and reservoir characterization. This is surprising because BHI logs provide nearly the “ground truth” resolution of cores, and in certain aspects provide superior data. The most common applications focus on fracture characterization, stress field analysis, and structural interpretation. Much more information, however, can be gathered from a BHI data set. We review examples that highlight novel applications in structural analysis, sedimentologic and stratigraphic studies, and reservoir evaluation.

A structural analysis of Ventura Avenue Field illustrates how BHI logs delineate a specific deformational style leading to a new interpretation of fault geometry. Image logs also reveal the heterogeneous character of a major fault and associated damage zone along a four-mile transect. This heterogeneity impacts the interpretation of fault seal and reservoir pressure compartments.

BHI logs are most underutilized in sedimentologic and stratigraphic studies. The best interpretations are developed in conjunction with core calibration, but even in the absence of cores BHI logs enable the interpretation of sedimentary structures, diagenetic features, significant stratigraphic surfaces, and the stacking patterns of associated facies. These observations are critical for developing stratigraphic frameworks and depositional models. We illustrate with examples from both fine-grained sediments and coarser-grained clastic systems.

Our final examples highlight reservoir characterization and productivity studies integrating core, image logs, and well test data. These integrated data sets can reveal the distribution of fluid saturation in the reservoir, mechanical stratigraphy related to fracturing, and fluid entry into the wells. BHI logs are not necessarily standalones in these applications, but are a critical element in the interpretation.

BHI logs are commonly acquired for many wells, but the available data are often underutilized. Re-examining the role of image logs in both academic and industry evaluations has significant potential for more robust understanding of subsurface geology and improved integrated interpretations.

Presentation Format: Oral
Session: Evaluating Data in a New Light

 


Mapping volume balance of injected and produced fluids in and around Kern County oil fields

David H. Shimabukuro, Department of Geology, CSU Sacramento
Michael J. Stephens, USGS California Water Science Center
Aren Crandall-Bear, Department of Geology, CSU Sacramento (now at Nevada Bureau of Mines and Geology)
Janice M. Gillespie, USGS California Water Science Center
Emily A. Haugen, Department of Geology, CSU Sacramento (now at USGS California Water Science Center)
Will Chang, Hypergradient LLC

Abstract: The potential migration pathways of underground injection control fluids (UIC) from water disposal, water flood, steam flood, and cyclic steam processes in and around oil fields are governed by the subsurface hydraulic gradient field, which is often determined with reservoir pressure measurements. Because public data on these pressures are difficult to obtain, other techniques must be used to estimate the gradients that govern fluid flow. In support of the State Water Resources Control Board’s Regional Monitoring Program of Water Quality in Areas of Oil and Gas Production, we present an approach which uses publicly-available well data to map the net difference in injected and produced fluid volume in select oil fields, and identifies possible fluid migration pathways.

To do this, we use California Division of Oil, Gas, and Geothermal Resources UIC injection and produced-water production volume records to create a volume-balance map for select oil fields in Kern County from 1977 to the present. Monthly injection volumes for each individual well are summed, then spread outward from the well location. The same method is used to map the spatial distribution of monthly production volumes. The maps for injection and production volumes are then superimposed, with the difference yielding the net volume balance and a proxy for pressure gradients. Because this method is based on individual wells, net volume balance can also be mapped by field or pool (formation).

We find that in some pools in western Kern County oil fields, injection volumes greatly exceeded production volumes, implying fluid gradients that may have driven migration of injected fluids away from the pool. High net injection volumes also are present near the border of some fields suggesting displacement of saline fluids already present in the reservoir, possibly into aquifers outside of the field. In other areas, production volumes exceed injection volumes and correspond to the well-documented surface subsidence determined using geodetic methods.

Presentation Format: Poster
Session: General

 


Rifting and Inversion Along the Palos Verdes Fault Zone, San Pedro Shelf, Offshore Southern California

Peter A. Shimer, Roux Associates

Abstract: This study examines the relationship of the Palos Verdes Fault Zone (PVFZ), an important fault zone in the Inner Borderland (IB), to the Palos Verdes Anticlinorium, Wilmington Graben, and other structures through detailed mapping of the fault zone constructed from high resolution 2D and 3D seismic reflection data and well logs. The data reveal a Mohnian-Delmontian trough, controlled by rifting and predating Palos Verdes Anticlinorium uplift, along the western PVFZ boundary. Sediment growth in the trough, the bulk of which occurred during the Mohnian, locally persisted into the Repettian. The western PVFZ boundary fault then transitioned to a transpressional regime beginning during the Repettian, inverting trough sediments. Typical of transpressional restraining bends along strike-slip faulting, varying degrees of inversion occur along the fault, with moderate inversion occurring on the central shelf with areas of little to no inversion to the north and south, all bounded by extreme inversion in the Palos Verdes Peninsula to the north and Lasuen Knoll to the south.

The present location and geometry of the PVFZ with its various restraining and releasing bends, is potentially a product of the early rifting episode, which is related to other sub-parallel major IB rifts, such as San Pedro Basin, San Diego Trough, and Los Angeles Basin. At roughly 65 km long, 1-7 km wide, and 1-1.5 km deep, the PVFZ trough is much narrower than the other IB basins, except the San Diego Trough.

Presentation Format: Oral
Session: Regional Interpretations with potential Exploration: Petroleum System Consequences

 


Tracking structural changes in the Maniobra Basin to determine tectonic history and depositional setting

Hanah Sloan, California State University Northridge
Richard Heermance, California State University Northridge
Andrew Barajas, California State University Northridge
Isabel Pina, California State University Northridge

Abstract: The Maniobra Formation is composed of Eocene marine strata located on the northeastern flank of Orocopia Mountains in Southern California. The formation lies unconformably above Cretaceous granitic rocks and below the non-marine Miocene Diligencia Formation. Previous work described the lithofacies and interpreted these strata as a southwest trending submarine canyon formed along the continental margin forarc basin ~50 m.y. ago. The proximity of these sedimentary deposits to the Orocopia schist and Orocopia and Clemens Well detachments systems, combined with normal faulting of the basin units, suggests that there may be a causal relationship between exhumation of the the Orocopia Schist and basin formation represented by the Maniobra deposits. To test the hypothesis that the Maniobra Formation was deposited in a supra-detachment basin during the Eocene, we present new geologic mapping, detrital zircon geochronology, and magnetostratigraphy from the Maniobra Formation.

Three sections in the western portion of the study area have been measured and correlated with a total stratigraphic thickness of 450 meters. The lithologies are sedimentary ranging from fine grained shale to boulder conglomerate. Key lithologies within the measured section have been mapped, units were chosen based on distinguishing attributes such as fossils, color, and overall appearance. Sample collection for magnetostratigraphy has been done throughout the measured sections. These samples will be used to determine reversals in the section. Detrital zircon samples have been collected at the base, middle and top of the entire study area. The detrital zircon data will be used to calculate ages of the section. If normal faulting from a supra-detachment basin has occurred, a combination of mapping, magnetostratigraphy, and detrital zircon data should support that theory.

Our results will provide new constraints on the timing and provenance of basin stratigraphy, and support or refute our hypothesis that these strata represent deposition within a hyper-extending basin during the Eocene.

Presentation Format: Poster
Session: General

 


Machine Learning for Simple Petrophysical Analyses

Kevin Smith, Bureau of Ocean Energy Management (BOEM)
Chima Ojukwu, Bureau of Ocean Energy Management (BOEM)
Mark Leung, Bureau of Ocean Energy Management (BOEM)
Regan Mass, California State University Northridge (CSUN) Center for Geospatial Science and Technology (CGST)
Danielle Bram, California State University Northridge (CSUN) Center for Geospatial Science and Technology (CGST)
Danielle Demello, California State University Northridge (CSUN) Center for Geospatial Science and Technology (CGST)

Abstract: The Bureau of Ocean Energy Management (BOEM) has initiated machine learning (ML) tests in collaboration with the California State University Northridge’s Center for Geospatial Science and Technology (CGST) using small data sets from wells on the Southern California Outer Continental Shelf. Work is in progress to create larger and more accessible data sets as further ML testing is conducted. This talk will describe what has been accomplished so far and explain the short term goals to exploit this new technology. BOEM’s first ML test was able to distinguish between sands and claystones using a decision tree classifier trained with about 100 sidewall core descriptions and wireline logs. However, the accuracy was only about 75%. Subsequently CGST used a larger dataset to see which ML algorithm was most effective in distinguishing between sands and claystones. The best results, with an accuracy of about 80%, were obtained by a gradient-boosting classifier in single-well tests. Current work is focused on making a larger analytical dataset that can be filtered spatially and by geologic formation. The intention is to continue testing ML applications for lithological classification and permeability estimation.

Presentation Format: Oral
Session: Evaluating Data in a New Light

 


Exploring New Energy Frontiers with Petroleum Geoscience Talent and Technology

Edith Newton Wilson, Rock Whisperer, LLC

Abstract: The energy landscape is evolving from petroleum dominance to a widening array of renewable, lowcarbon components. Along with wind, hydro, and geothermal, solar has reached an economic threshold that fosters market growth. Storage requirements for electric vehicles and renewable baseload are spurring increased demand for lithium, graphite, cobalt, vanadium and nickel. Geologists who explore for and extract these metals will use skills honed in the oil and gas industry as well as familiar datasets, such as borehole records, surface geologic maps, rock mineralogy, and size statistics. Predictive models of ore accumulation rely on mass transport calculations at assumed heat, pressure, brine composition and mineral equilibria, and are comparable those used to understand oil generation, migration and trapping. Three dimensional geologic models to explore for and assess reserves of metals will benefit from enhanced geophysical techniques, including 3D seismic, as well as the application of play fairway analysis to better predict exploration corridors. Defining the heat resource, drilling, fracking, and circulating brines are also key components to the successful exploitation of geothermal energy. Structural geology and sedimentology studies remain crucial to proper siting, monitoring, and remediation of hydro-electric projects. Geoscientists can also maximize energy efficiency for development of renewable components via the use of low carbon energy resources, and we can apply our environmental experience to minimize the footprint of mines and manufacturing sites. Solar and wind design and construction are fertile ground for the application of geography and GIS skills. In parallel to development of new forms of renewable energy, a shift from heavy to light hydrocarbons for transportation and electricity generation requires traditional petroleum technology to define and extract stranded global gas resources. And, of course, we can always work to green the oilfield by introducing solar pumps and vapor recovery units. As geoscientists and engineers, we have opportunities to transfer our expertise in exploration, development, extraction and remediation to processes associated with cleaner energy production. We can utilize our strengths in creativity, risk assessment, and environmental stewardship to become leaders in sustainable energy development.

Presentation Format: Oral
Session: The Future of CA: Alternative Energy Opportunities

 


High Resolution Biostratigraphy of the Phillips Petroleum OCS-P-396-#1 Well, Offshore Santa Maria, California

Walter W. Wornardt, Ph.D., MICRO-STRAT, INC.

Abstract: A total of 507cuttings samples, 153-sidewall core and 34 conventional cores were analyzed in the Phillips Petroleum OCS-P-396-#1 Well, Offshore Santa Maria, California, from 760-7738.6 feet using detailed analysis of nannofossils, foraminifers, diatoms and silicoflagellates. The upper unit 760—3010’ is assigned to the early Pleistocene to middle Pliocene, early Hallian to Venturian Facies based on Foraminifera and were deposited in an open marine, upper to middle bathyal environment. Nannofossils suggest a Cn14a, 13b? and CN13a Zones.

The middle unit from 3010-7120 feet is assigned to early Pliocene to middle Miocene Luisian Stage. Foraminifera and Nannofossils are barren in this interval. Diatoms present through this interval with first occurrence of Nitzschia reinholdii at 3670-3730 feet and first occurrence of Thalassiosira oestrupii at 3424.0 feet. The interval from 3424.0 feet to 3010 feet is correlated to lower diatomaceous sediments on Harris Grade Road; Capistrano Formation, Newport Beach, California; and the sample near Lompoc, California, CAS 1736 (originally assigned to late Miocene, with contaminated Monterey Shale diatoms).

Sediments from 3670-4339 feet are assigned to Delmontian. The interval from 5710-6820 feet is interpreted as Mohnian (undifferentiated) based on Foraminifera deposited in Bathyal environment.

Middle Miocene Luisian Foraminifera are present from 6820-6880 feet in this well.

The lower unit, 7120-7743 feet, yielded Foraminifera of late Paleocene, Late Ynezian to early Bulitian Age, from 7330-7510 feet.

Presentation Format: Poster
Session: General

 


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