Gas Total Petroleum System—Neogene Nonassociated Gas Assessment Unit of the San Joaquin Basin Province 1

Petroleum Systems and Geologic Assessment of Oil and Gas in the San Joaquin Basin Province, California

Chapter 22 Neogene Gas Total Petroleum System—Neogene Nonassociated Gas Assessment Unit of the San Joaquin Basin Province

By Allegra Hosford Scheirer1 and Leslie B. Magoon

Traps Elongate gentle domes and strati- Contents graphic traps. Migration Locally from adjacent kerogen-rich Summary------1 mudstone into sandstone lenses. Description------1 Source Rocks------2 Timing Traps formed during as Maturation and Migration------2 gas was forming. Reservoir Rocks------2 Primary Fields Bowerbank, Buttonwillow, Coles Traps and Seals------2 Levee North, Coles Levee South, Exploration Status and Resource Potential------2… Dudley Ridge, Harvester, Paloma, References Cited------3 Figures------5 Rio Bravo, Semitropic, Ten Sec- Table------14 tion, Trico, Trico Northwest. Appendixes (.pdf files) Secondary Fields Canal, Garrison City, Los Lobos, Semitropic, Shafter Southeast, Strand. Summary Exploration Status Moderately explored (0.3 well per square mile and 23 percent of all Boundaries Extent of on sections have at least one explor- the north and east; limit of struc- atory well). tural deformation or petroleum Resource Potential Potential for undiscovered fields in system on the west; White Wolf subtle structural and stratigraphic Fault on the south; topographic traps. surface to base of Etchegoin Formation. Source Rocks Pliocene marine, kerogen-rich, Description mudstone of the Etchegoin and San Joaquin Formations. The Neogene Nonassociated Gas Assessment Unit (AU) Reservoir Rocks Pliocene shallow-water marine of the Neogene Total Petroleum System consists of nonassoci- sandstones of the Etchegoin and ated gas accumulations in Pliocene marine and brackish-water San Joaquin Formations and sandstone located in the south and central San Joaquin Basin deltaic and nonmarine Province (Rudkin, 1968). Traps consist mainly of stratigraphic sandstone lenses of the Tulare lenses in low-relief, elongate domes that trend northwest-south- Formation. east. Reservoir rocks typically occur as sands that pinch out at shallow depths (1,000 to 7,500 feet) within the Etchegoin and San Joaquin Formations. 1Now at: Department of Geological and Environmental Sciences, Stanford University, Braun Hall, 450 Serra Mall, Stanford, Calif., 94305; allegras@ Map boundaries of the assessment unit are shown in stanford.edu figures 22.1 and 22.2; this assessment unit replaces the Pliocene 2 Petroleum Systems and Geologic Assessment of Oil and Gas in the San Joaquin Basin Province, California

Nonassociated Gas play 1001 (shown by purple line in fig. the time of deposition of the reservoir rock. Biogenic gas forms 22.1) considered by the U.S. Geological Survey (USGS) in its from organic matter at low temperatures by microbial action at 1995 National Assessment (Beyer, 1996). The AU is drawn to the surface to a depth of few thousand feet (Rice and Claypool, include all existing fields containing nonassociated gas accumu- 1981). Typically this gas vents to the atmosphere, but under lations in the Pliocene to Pleistocene section, as was done in the certain conditions it becomes trapped in adjacent sand lenses 1995 assessment, but it was greatly expanded to include adja- that are sealed by mudstone and is buried to greater depths. cent areas believed to contain similar source and reservoir rock This burial improves seal integrity and increases the pressure of relationships. Stratigraphically, the AU extends from the topo- the entrapped gas, setting the stage for a possible commercial graphic surface to the base of the Etchegoin Formation (figs. accumulation. In this AU, from late Pliocene time, low-relief 22.3 and 22.4). The boundaries of the AU explicitly exclude gas anticlinal traps formed and regional up-to-the-northeast tilting accumulations in Neogene rocks on the severely deformed west occurred after burial had already compacted fine-grained cap- side of the basin and gas accumulations in underlying ping beds (Bartow, 1991; Beyer, 1996). rocks; these resources, which primarily consist of a mixture of mostly thermogenic and some biogenic gas, are included in two other assessment units. Lillis and others (this volume, chapter Reservoir Rocks 10) discuss the geochemical characteristics of biogenic gas in the San Joaquin Basin Province. Hydrocarbon reservoir rocks in this AU consist of Pliocene Primary fields in the assessment unit are defined as those shallow-water marine sandstones of the Etchegoin and San containing hydrocarbon resources greater than the USGS Joaquin Formations that generally unconformably overlie upper minimum threshold for assessment—3 billion cubic feet (BCF) Miocene rocks; these are overlain by Pleistocene deltaic and of gas; secondary fields contain smaller volumes of gas but con- nonmarine sand in the (figs. 22.4 and 22.5). stitute a significant show of hydrocarbons. Although 12 fields nonmarine deposits overlie the Tulare Formation. meet the 3 BCF criterion for inclusion in the AU, only 5 fields Individual reservoir rocks range from about 5 to 30 feet thick were considered at the time of assessment. (CDOGGR, 1998). Porosities of these poorly compacted res- ervoir rocks are reported to range from about 20 to 35 percent (CDOGGR, 1998). Detailed depositional histories of these Source Rocks reservoir rocks are discussed by Miller (1999), Reid (1995), and Loomis (1988), among others. In general, source rock units for natural gas are difficult to identify with confidence, because the composition of natural gas is too simple to correlate with organic matter in the source rock Traps and Seals and the carbon isotopic composition of biogenic methane from all source rocks is similar (generally less than -55 per mil; Rice Traps of known biogenic gas accumulations are mostly and Claypool, 1981). Geochemical analysis of five gas samples lenses of sandstone encased in a seal rock associated with elon- identified as biogenic in origin reveals that gas within the AU gate gentle domes. Seal rocks are fine-grained, low-permeability contains low carbon dioxide and nitrogen (less than 0.5 and 0.3 claystone, mudstone, and tightly cemented sandstone. Depths percent, respectively) and low d13C methane (–56 to –70 per of the 18 discovered accumulations range from about 1,000 mil) (Lillis and others, this volume, chapter 10). Thus, nonas- to 7,500 feet, with one accumulation at about 1,000 feet deep sociated, biogenic gas in the central and southern San Joaquin (Dudley Ridge field) and two at about 7,500 feet deep (Semi- Basin is most likely produced from microbial decomposition of tropic and Ten Section fields). marine organic matter within thick, Pliocene marine mudstone and claystone within the boundaries of the AU (fig. 22.5). Although Rock-Eval pyrolysis and organic carbon (TOC) Exploration Status and Resource data are lacking from organic intervals within the Pliocene section, the is the suspected source rock Potential for the biogenic gas in the AU because about 85 percent of the gas in the AU by volume resides in sand lenses that pinch out The AU has been intensely drilled by 1,694 exploratory stratigraphically against mud and claystone of the San Joaquin wells throughout its geographic extent, except for a handful of Formation. townships where only a few wells exist (fig. 22.2). However, we believe the number of wells in the AU overstate its explora- tion maturity; because these wells were drilled at times when natural gas wasn’t economic to produce, industry likely drilled Maturation and Migration for deeper oil targets, bypassing shallower gas sands. Although most of the obvious structures have been drilled in the AU, it From early Pliocene time, both stratigraphic trap develop- seems likely that additional gas deposits in small sand stringers ment and gas charge in this AU probably occurred at or about like the ones at Buttonwillow field (fig. 22.6) exist. Future dis- Neogene Gas Total Petroleum System—Neogene Nonassociated Gas Assessment Unit of the San Joaquin Basin Province 3 coveries of stratigraphically trapped biogenic gas likely reside in Geologists, v. 19, no. 8, p. 1192-1204. thin sand lenses that may have already been drilled through on Bartow, J.A., 1991, The evolution of the San Joaquin the gentle east flank of the basin, away from already-identified Valley, California: U.S. Geological Survey Professional structures to the west. There may also be additional biogenic gas Paper 1501, 40 p. in the Etchegoin and San Joaquin Formations above existing oil Berryman, W.M., 1973, Lithologic characteristics of Pliocene fields of the San Joaquin Basin; about half of the gas accumula- rocks cored at Elk Hills, Kern County, California: U.S. tions assigned to this assessment unit are associated with deeper, Geological Survey Bulletin 1332-D, 56 p. prolific oil pools. Beyer, L.A., 1996, San Joaquin Basin Province, in Gautier, Undiscovered gas composition probably is similar to D.L., Dolton, G.L., Takahashi, K.I., and Varnes, K.L., that of discovered gas, which generally is 97 percent or more eds., 1995 National assessment of United States oil and methane with average heating value of about 1,015 BTU/CFG. gas resources—Results, methodology, and supporting Depths of undiscovered accumulations are most likely in the data: U.S. Geological Survey Digital Data Series DDS-30, range of discovered reservoirs (1,000 to 7,000 feet). Undiscov- release 2. ered gas accumulations may exist in stratigraphic traps similar Bishop, C.C., 1970, Upper Cretaceous stratigraphy on the to those already discovered, primarily in the erratic sands in the west side of the Northern San Joaquin Valley, Stanislaus Mya sand zone of Berryman (1973) of the San Joaquin Forma- and San Joaquin counties, California: California Division tion. To find these, a thorough understanding of reservoir sands of Mines and Geology Special Report 104, 29 p. and depositional systems, combined with three-dimensional Callaway, D.C., 1964, Distribution of uppermost Cretaceous seismic surveys, is essential. sands in the Sacramento-Northern San Joaquin Basin The 12 primary fields larger than 3 BCF and the 5 used in of California: Selected Papers Presented to San Joaquin this assessment within the Neogene Nonassociated Gas Assess- Geological Society, v. 2, p. 5-18. ment Unit, in order of decreasing gas volume, are shown in CDOGGR, 1998, California oil and gas fields: Sacramento, table 22.1 and figure 22.8; all 18 gas fields are shown in figure Calif., California Department of Conservation, Division of 22.2. Trico field (fig. 22.7) accounts for about 50 percent, or Oil, Gas, and Geothermal Resources Publication No. CD-1, 200 billion cubic feet (BCF), of the total biogenic gas produced 1472 p. in the San Joaquin Basin. The remaining population of accu- CDOGGR, 2003, 2002 Annual Report of the State Oil and mulations ranges from a few to tens of BCF in size. Thus, an Gas Supervisor: California Department of Conservation, additional 200 BCF accumulation is probably unlikely. Division of Oil, Gas, and Geothermal Resources, All assessment results and supporting documentation for Publication No. PR06, 263 p. [also available at the Neogene Nonassociated Gas Assessment Unit of the San ftp://ftp.consrv.ca.gov/pub/oil/annual_reports/2002/]. Joaquin Basin Province are available in filesc100501.pdf (data Eckis, R., 1940, The Stevens sand, southern San Joaquin form for conventional assessment unit), d100501.pdf (summary Valley, California [abs.]: Bulletin of the American of discovery history), em100501.pdf (probabilistic estimates), Association of Petroleum Geologists, v. 24, no. 12, p. 2195- g100501.pdf (graphs of exploration and discovery data for 2196. grown volumes), and k100501.pdf (graphs of exploration and Edwards, E.C., 1943, Kern Front area of the Kern River discovery data for known volumes). Klett and Le (this volume, oil field, in Jenkins, O.P., ed., Geologic formations chapter 28) summarize the contents of these files. Using five and economic development of the oil and gas fields of known accumulations, the November 2003 assessment team California: San Francisco, Calif., State of California, estimated that the number of undiscovered accumulations Department of Natural Resources, Division of Mines greater than 3 BCF ranges from one to seven, with the likeli- Bulletin No. 118, p. 571-574. est number similar to the number of discovered accumulations. Goudkoff, P.P., 1943, Correlation of oil field formations on The total estimated gas resource in this assessment unit thus west side of San Joaquin Valley, in Jenkins, O.P., ed., ranges from 4 to 88 BCF, with a mean of 29 BCF. Geologic formations and economic development of the oil Since the 2003 assessment, the authors have determined and gas fields of California: San Francisco, Calif., State of that 12 known accumulations listed in table 22.1 should have California, Department of Natural Resources, Division of been assigned to the AU. Thus, the discovery history of gas Mines Bulletin No. 118, p. 247-252. accumulations, as illustrated in files d100501.pdf, g100501.pdf, Graham, S.A., and Williams, L.A., 1985, Tectonic, and k100501.pdf, shows fewer accumulations of biogenic gas in depositional, and diagenetic history of the AU. (Miocene), central San Joaquin Basin, California: American Association of Petroleum Geologists Bulletin, v. 69, no. 3, p. 385-411. Hoffman, R.D., 1964, Geology of the northern San Joaquin References Cited Valley: Selected Papers Presented to San Joaquin Geological Society, v. 2, p. 30-45. Atwill, E.R., 1935, Oligocene Tumey Formation of California: Kaplow, E.J., 1940, Gas fields of the southern San Bulletin of the American Association of Petroleum Joaquin Valley, in Summary of operations, California 4 Petroleum Systems and Geologic Assessment of Oil and Gas in the San Joaquin Basin Province, California

oil fields: San Francisco, Calif., Annual Report of the Francisco, Calif., Annual Report of the State Oil and Gas State Oil and Gas Supervisor, v. 24, no. 1, p. 30-50 Supervisor, v. 22, no. 4, p. 5-36 [also available in California [also available in California Division of Oil and Gas, Division of Oil and Gas, Summary of Operations, 1915- Summary of Operations, 1915-1999: California Division 1999: California Division of Conservation, Division of of Conservation, Division of Oil, Gas, and Geothermal Oil, Gas, and Geothermal Resources, Publication No. Resources, Publication No. CD-3, and at ftp://ftp.consrv. CD-3, and at ftp://ftp.consrv.ca.gov/pub/oil/Summary_of_ ca.gov/pub/oil/Summary_of_Operations/1938/]. Operations/1937/]. Kasline, F.E., 1942, Edison oil field, in Summary of Noble, E.B., 1940, Rio Bravo oil field, Kern County, operations, California oil fields: San Francisco, Calif., California: Bulletin of the American Association of Annual Report of the State Oil and Gas Supervisor, v. Petroleum Geologists, v. 24, no. 7, p. 1330-1333. 26, p. 12-18 [also available in California Division of Oil Reid, S.A., 1995, Miocene and Pliocene depositional systems and Gas, Summary of Operations, 1915-1999: California of the southern San Joaquin basin and formation of Division of Conservation, Division of Oil, Gas, and sandstone reservoirs in the Elk Hills area, California, in Geothermal Resources, Publication No. CD-3, and at ftp:// Fritsche, A.E., ed., Cenozoic paleogeography of the western ftp.consrv.ca.gov/pub/oil/Summary_of_Operations/1940/]. United States—II: Pacific Section, Society of Economic Loken, K.P., 1959, Gill Ranch gas field, in Summary of Paleontologists and Mineralogists, p. 131-150. operations, California oil fields: San Francisco, Calif., Rice, D.D., and Claypool, G.E., 1981, Generation, Annual Report of the State Oil and Gas Supervisor, v. 45, accumulation, and resource potential of biogenic gas: no. 1, p. 27-32 [also available in California Division of Oil American Association of Petroleum Geologists Bulletin, v. and Gas, Summary of Operations, 1915-1999: California 65, no. 1, p. 5-25. Division of Conservation, Division of Oil, Gas, and Rudkin, G.H., 1968, Natural gas in San Joaquin Valley, Geothermal Resources, Publication No. CD-3, and at California, in Beebe, B.W., and Curtis, B.F., eds., ftp://ftp.consrv.ca.gov/pub/oil/Summary_of Operations/ Natural gases of North America: Tulsa, Okla., American 1959/]. Association of Petroleum Geologists Memoir 9, p. 113-134. Loomis, K.B., 1988, Paleoenvironmental and paleoclimatic Sullivan, J.C., 1963, Guijarral Hills oil field, in Summary interpretation of upper Miocene-Pliocene lithofacies and of operations, California oil fields: San Francisco, Calif., macrobiota of the Etchegoin Group, Jacalitos Canyon, Annual Report of the State Oil and Gas Supervisor, v. 48, San Joaquin Valley, California, in Graham, S.A., and no. 2, p. 37-51 [also available in California Division of Oil Olson, H.C., eds., Studies of the geology of the San Joaquin and Gas, Summary of Operations, 1915-1999: California Basin: Los Angeles, Pacific Section, Society of Economic Division of Conservation, Division of Oil, Gas, and Paleontologists and Mineralogists, book 60, p. 303-318. Geothermal Resources, Publication No. CD-3, and at ftp:// McMasters, J.H., 1948, Oceanic sand [abs.]: Bulletin of the ftp.consrv.ca.gov/pub/oil/Summary_of_Operations/1962/]. American Association of Petroleum Geologists, v. 32, no. Wilkinson, E.R., 1960, Vallecitos field, in Summary of 12, p. 2320. operations, California oil fields: San Francisco, Calif., Miller, D.D., 1999, Sequence stratigraphy and controls on Annual Report of the State Oil and Gas Supervisor, v. 45, deposition of the upper Cenozoic Tulare Formation, San no. 2, p. 17-33 [also available in California Division of Oil Joaquin Valley, California: Stanford, Calif., Stanford and Gas, Summary of Operations, 1915-1999: California University, Ph.D. dissertation, 179 p. Division of Conservation, Division of Oil, Gas, and Miller, R.H., and Bloom, C.V., 1939, Mountain View oil Geothermal Resources, Publication No. CD-3, and at ftp:// field, in Summary of operations, California oil fields: San ftp.consrv.ca.gov/pub/oil/Summary_of_Operations/1959/]. Neogene Gas Total Petroleum System—Neogene Nonassociated Gas Assessment Unit of the San Joaquin Basin Province 5

Figures 6 Petroleum Systems and Geologic Assessment of Oil and Gas in the San Joaquin Basin Province, California

38˚N 38˚N miles

0 25 2003 Assessment Unit 1995 Play Boundary

37˚N 37˚N

36˚N 36˚N

35˚N 35˚N

Figure 22.1. Location map121˚W of the San Joaquin Valley, illustrating120˚W San Joaquin Basin Province boundary119˚W (bold black line), county boundaries (thin gray lines), Neogene Nonassociated Gas Assessment Unit boundary (blue line), play boundary from previous USGS assessment (purple line), and oil (green) and gas (red) fields in the province. Neogene Gas Total Petroleum System—Neogene Nonassociated Gas Assessment Unit of the San Joaquin Basin Province 7

37˚00'N 37˚00'N 11S/19E miles 0 10

15S/23E

36˚30'N 36˚30'N

A

20S/14E

36˚00'N 22S/15E 36˚00'N DR T H

25S/17E 25S/28E

TNW S S 35˚30'N SNW Bu GC SSE 35˚30'N 28S/19E

Bo B St RB C St CLN A’ 31S/21E CLS P TS

35˚00'N 11N/24W 35˚00'N

10N/20W

LL

120˚30'W 120˚00'W 119˚30'W 119˚00'W 118˚30'W Figure 22.2. Detailed map of Neogene Nonassociated Gas Assessment Unit (AU). The blue line indicates the geographic limit of the AU. The 18 gas fields and pools in this AU are colored red. Fields outside the AU, or within the map boundaries of the AU but assigned to a different assessment unit, are outlined in black. Black dots represent 1,694 exploratory wells drilled for petroleum within the AU between 1916 and 2001. Well locations are from the California Department of Conservation, Division of Oil, Gas, and Geothermal Resources and are available at ftp:// ftp.conserv.ca.gov/pub/oil/maps/dist4 and at ftp://ftp.conserv.ca.gov/pub/oil/maps/dist5. Cross-section A-A’ is shown in figure 22.5. Township and range grid is indicated for scale and location; scattered labels are relative to the Mount Diablo baseline and meridian. City of Bakersfield (B) denoted with yellow square. Gas field labels are (* fields used in the assessment, ** secondary fields smaller than 3 BCF): Bo=Bowerbank; Bu=Buttonwillow; C=Canal**; CLN=Coles Levee North; CLS=Coles Levee South; DR=Dudley Ridge*; GC=Garrison City**; H=Harvester*; LL=Los Lobos**; P=Paloma; RB=Rio Bravo*; S=Semitropic; SNW=Semitropic Northwest**; SSE=Shafter Southeast**; St=Strand**; T=Trico*; TNW=Trico Northwest*; TS=Ten Section. 8 Petroleum Systems and Geologic Assessment of Oil and Gas in the San Joaquin Basin Province, California

Figure 22.3. Three-dimensional stratigraphy model of the Neogene Nonassociated Gas AU extracted from the EarthVision® model of the basin by Hosford Scheirer (this volume, chapter 7). The major stratigraphic units within the AU are shown by colors; see figure 22.4 for stratigraphic relations among the units. Gas fields and pools (red) in the AU are draped on the topographic surface. The San Joaquin Basin Province boundary (bold line), AU boundary (dashed line), and city names and locations float above the surface of the model. View is from due south at a 30° inclina- tion angle. Vertical exaggeration is x4. EarthVision is a registered trademark (Marca Registrada) of Dynamic Graphics, Inc., Alameda, Calif. Neogene Gas Total Petroleum System—Neogene Nonassociated Gas Assessment Unit of the San Joaquin Basin Province 9

SYSTEM Mega- CENTRAL SOUTH SERIES sequences Ma nd West East West East STAGE (2 order) basin axis Alluvium basin axis Alluvium 0 PLEIS. unnamed Tulare Fm San Joaquin Fm PLIO. San Joaquin Fm unnamed

5 Etchegoin Fm unnamed Etchegoin Fm Trans-

pression Reef Ridge Sh Mbr Reef Ridge Sh Mbr Monterey Fm Chanac

DEL. Antelope sh KR Santa Margarita Stevens sd Fm McLure Shale Mbr Ss Santa Figure 22.4. Generalized Monterey Fm Margarita 10 Fruitvale shale Ss stratigraphic column for McDonald Sh Mbr MOHNIAN unnamed the southern and central

NEOGENE Devilwater Sh Round Mtn Silt

LUI. San Joaquin Basin Prov- Mbr/Gould Sh unnamed 15 Temblor Fm migration Mbr, undiff Nozu sd MIOCENE ince, showing hydrocarbon

REL. B Triple junction Triple Media Sh Mbr Olcese reservoir rocks and potential Sand Zilch fm Carneros

Ss Mbr Temblor Fm hydrocarbon source rocks. 20 Santos See Hosford Scheirer and Jewett SAUCESIAN Freeman Sand Magoon (this volume, chapter Silt

Agua SsMbr Sh PH 5) for complete explanation of 25 . Bed Rio Bravo sd the figure. Formation names in italics are informal and are Vaqueros Fm Walker Fm defined as follows: Antelope

30 Subduction and magmatism unnamed Wygal Ss Mbr Vedder Sand ZEMORRIAN

OLIGOCENE shale of Graham and Williams Cymric Shale Mbr (1985), Stevens sand of Eckis REF. Leda sd 35 Tumey formation (1940), Fruitvale shale of Tumey formation Oceanic sand Miller and Bloom (1939), Nozu sand of Kasline (1942), Zilch 40 formation of Loken (1959), Rio Kreyenhagen Formation Kreyenhagen Formation Point Bravo sand of Noble (1940),

unnamed of Rocks Ss unnamed Mbr sand Famoso Oceanic sand of McMasters EOCENE 45 (1948), Tumey formation of Famoso sand Famoso subsidence Diablo Range Diablo Canoas Slts Mbr unnamed Atwill (1935), Leda sand of uplift and basin basin and uplift Domengine Fm Yokut B=Buttonbed Ss Mbr Ss PH=Pyramid Hill Sd Mbr Sullivan (1963), Famoso sand KR=Kern River Fm 50 Arroyo Hondo Sh Mbr of Edwards (1943), Gatchell Gatchell sd PALEOGENE sand of Goudkoff (1943), San Cantua Ss Mbr Oil reservoir rock Gas reservoir rock unnamed PENUTIAN ULATSIAN NARIZIAN Potential marine Potential nonmarine Carlos sand of Wilkinson Lodo Fm reservoir rock reservoir rock 55 Nonmarine Marine coarse (1960), Wheatville sand of Cal- TIAN BULI- coarse grained grained rock rock orogeny San Carlos sd laway (1964), Brown Mountain Clay/shale/ ~ ~ Coast Range mudstone/ ~ ~ ophiolite/ and Laramide ZIAN YNE- biosiliceous Granitic basement sandstone of Bishop (1970), 60 Oil-prone source Hiatus or loss by rock/ erosion and Ragged Valley silt of Hoff- Gas-prone source rock man (1964).

Flat slab subduction Wheatville sd PALEOCENE undifferentiated

Moreno Fm Cretaceous 65 CHENEYIAN 121˚W 120˚W 119˚W 38˚N miles unnamed Stockton Arch basin axis San Joaquin0 Basin 25Province

70 MAASTRICH. COAST RANGES Brown Mtn ss North RaggedValley silt SIERRA NEVADA 75 Joaquin Ridge Ss Mbr 37˚N Panoche Fm

80 LATE CAMPANIAN SAN ANDREAS FAULT Central SANT. 85 ? DCN CON. 36˚N DR DC T PH South 90 DD J TUR. undifferentiated Cretaceous Bakersfield Arch

CRETACEOUS marine and nonmarine strata 95 Pacific Ocean WWF CENO. 35˚N 100 SAN EMIGDIO,TECHAPI MOUNTAINS Sierran magmatism Sierran 160 Ma 120 Ma 160 Ma 120 Ma 105 and margin Convergent EARLY

ALBIAN Basement rocks Basement rocks 110 10 Petroleum Systems and Geologic Assessment of Oil and Gas in the San Joaquin Basin Province, California

A A’ North South Neogene Nonassociated Gas AU

Trico Semitropic Buttonwillow Field Field Field 0 Tulare Fm ? ? ? ? 5 ? ? ? ? ? ? ? San Joaquin Fm Etchegoin Fm 10 pre-Temblor Fm Antelope shale* Temblor Fm

Explanation

Depth (x1000 ft) 15

Antelope shale* Gas field N Questionable ? ? source rock basement rock 20 Petroleum Window 0.6 %Ro (oil + gas) 0.9 %R o Scale 0 25 5 10 15 20 km * of Graham and Williams (1985)

Figure 22.5. Cross section A-A’ through biogenic gas fields of the southern San Joaquin Basin. Location of cross-section is shown on figure

22.2. Stratigraphically, the AU extends from the ground surface down to the base of the Etchegoin Formation. Fm, Formation; % Ro, percent vitrinite reflectance. Modified from Magoon and others (this volume, chapter 8). Neogene Gas Total Petroleum System—Neogene Nonassociated Gas Assessment Unit of the San Joaquin Basin Province 11

Buttonwillow Gas Field FORMATION TYPICAL MEMBER ELECTRIC

SERIES & ZONE LOG

PLEISTOCENE 1 mile T27 S R 22 E T27 S R 23 E

20 foot sand* 200 foot shale* 31

36 1st Mya sd*

upper 1 6 5 Arlington sd* -2300 B Kern 5*

-2400 lower T28 S R 22 E -2600 Arlington sd* -2500 1 mile

PLIOCENE 7 8 9 San Joaquin Formation A B zone*

2nd Mya sand* T28 S R 23 E

17 16 C zone*

Contours on top of B zone*

Etchegoin Formation A B

alluvium

Reef Ridge Tulare Formation Shale Member

200 foot shale*

contoured horizon B zone* San Joaquin MIOCENE Formation C zone* Monterey Formation Monterey Antelope shale of Etchegoin Formation Graham and Williams (1985) * of Kaplow (1940)

Figure 22.6. Map, cross-section, and stratigraphic column of Buttonwillow gas field, illustrating typical stratigraphic sand lenses in the Neogene Nonassociated Gas AU. Green shading (underlying township- range grid) denotes reported 1998 limits of productive sand units within the fields. All depths are in feet. Formations in italics denote informal geologic names. Informal names not previously defined are the 20 foot sand, Arlington sand, Kern 5, first Mya sand, second Mya sand, B zone, C zone, and 200 foot shale, all of Kaplow (1940). See figure 22.2 for location of field. Figure redrafted from CDOGGR (1998). sd, sand. 12 Petroleum Systems and Geologic Assessment of Oil and Gas in the San Joaquin Basin Province, California

Trico Gas Field 1 mile FORMATION TYPICAL MEMBER ELECTRIC 1 mile -2350

SERIES & ZONE LOG 35 36 31 32 33 34 T 23S R 22E -2300 T 23S R 23E Tulare Fm -2400 -2350

PLEIST. first Mya sd* -2300 Contours on 2 1 6 -2250 5 4 3 first Mya sand* -2200 Electric log marker

San Joaquin Fm

11 Atwell Island -2200 7 8 9 10 11 sd* -2350 -2300 -2250 12 PLIOCENE -2270

A 14 13 18 Etchegoin Fm 17 B 15 14 13

T 24S R 22E T 24S R 23E

23 24 19 20 -2250 23 24 -2200

-2300

-2200

26 -2250

Monterey Fm Monterey 25 30 29 28 26 25 -2350 MIOCENE Kings County Tulare County Tulare Round Mountain 35 36 31 Silt 32 33 34 35 36 -2250

Kern -2200 Olcese Sand County

-2200 1 6 5 4 Freeman Silt- 2 1 6 5 Jewett Sand -2250

T 25S R 22E T 25S R 23E Pyramid Hill Sd T 25S R 24E Mbr of Jewett Sd 12 7 8 9 10 11 12 7 Vedder Sand OLIGOCENE

Tumey fm of Atwill (1935) Kreyenhagen Fm A B Walker Fm E-log marker Tulare Fm contoured EOCENE first Mya sand* horizon

undiffer- San Joaquin Fm entiated marine C zone* strata Atwell Island sand* LATE CRETACEOUS (?) LATE CRETACEOUS * of Kaplow (1940)

Figure 22.7. Map, cross-section, and stratigraphic column of Trico gas field, illustrating typical asymmetrical, anticlinal trap in the Neogene Nonassociated Gas AU. Green shading (underlying township-range grid) denotes reported 1998 limits of productive sand units within the fields. All depths are in feet. Formations in italics denote informal geologic names. Informal names not previously defined are Tumey formation of Atwill (1935) and Atwill Island sand of Kaplow (1940). See figure 22.2 for location of field. Figure redrafted from CDOGGR (1998). Fm, Formation; fm, formation; Mbr, Member; Pleist., Pleistocene; Sd, Sand; sd, sand. Neogene Gas Total Petroleum System—Neogene Nonassociated Gas Assessment Unit of the San Joaquin Basin Province 13

Neogene Nonassociated Gas, Assessment Unit 50100501 1,000

100

10 KNOWN GAS-ACCUMULATION SIZE (BCFG)

1 1920 1930 1940 1950 1960 1970 1980 1990 2000 ACCUMULATION-DISCOVERY YEAR

Figure 22.8. Gas-accumulation size versus year of accumulation discovery in the Neogene Nonassociated Gas AU. Figure is excerpted from data file k100501.pdf (see Klett and Le, this volume, chapter 28, for explanation of data file). 14 Petroleum Systems and Geologic Assessment of Oil and Gas in the San Joaquin Basin Province, California

Table 22.1. Production statistics for primary fields in the Neogene Nonassociated Gas Assessment Unit.

[Recoverable gas is the sum of cumulative production and estimated proved reserves. Data source is CDOGGR (2003). BCF, billion cubic feet. Primary fields are defined as those with recoverable gas equal to or greater than 3 BCF. Six additional fields have recoverable gas of less than 3 BCF. Five fields (*) were analyzed for assessment purposes. Fields with zero producing wells are abandoned]

Estimated Ultimate Number of Field Recoverable Percent of Total Producing Wells Gas through in 2002 2002 (BCF) Trico* 201.4 48.6 5

Coles Levee South 43.9 10.6 2 Buttonwillow 38.4 9.3 0 Paloma 26.0 6.3 2 Bowerbank 24.9 6.0 7 Semitropic 23.9 5.8 3 Coles Levee North 13.0 3.1 2 Rio Bravo* 11.1 2.7 0 Ten Section 9.1 2.2 0 Trico Northwest* 9.1 2.2 0 Harvester* 8.9 2.2 0 Dudley Ridge* 4.9 1.2 0 Total 414.6 100.0 21