San Joaquin basin

Two major rivers in California influenced by a Mediterranean climate are the Sacramento River and the San Joaquin River. The Sacramento River drains 72,132 km with a relief of 4,317 m. Mean discharge is 650 m /s with peak flows in the winter and early spring and with minimum flows in the late summer and early fall. The San Joaquin River drains 83,409 km with a relief of 4,418 m. Mean discharge is 130 m /s with peak flows in spring and low flows in late summer and fall. Population density is 24 people/km in the Sacramento River basin and 29 people/km in the San Joaquin basin. Agriculture in the Central Valley of California that encompasses parts of both basins is the primary user of water in both basins [1]. 

Total storage in the major reservoirs of the Sacramento and San Joaquin basins is about 35 km. This is comparable to average annual freshwater flows [3]. Freshwater withdrawals in recent decades have averaged about 6 km annually. Reservoir operations within the catchments have altered the timing of freshwater flows into the Delta. Hows are attenuated from historical conditions from January through June, and flows are enhanced from July through October. 

Fisher J. B. and Boles J. R. (1990) Water-rock interaction in Tertiary sandstones, San Joaquin Basin, California, USA diagenetic controls on water composition. Chem. Geol. 82, 83-101. 

Franks S. G., Dias R. F., Freeman K. H., Boles J. R., Holba A. G., Fincannon A. L., and Jordan E. D. (2001) Carbon isotopic composition of organic acids in oilfield waters, San Joaquin Basin, California. Geochim. Cosmochim. Acta 65, 1301-1310. 

Hanor J. S., Land L. S., and Macpherson L. G. (1993) Carboxyhc acid anions in formation waters, San Joaquin Basin and Louisiana Gulf Coast, USA—Implications for clastic diagenesis. Critical comment. Appl. Geochem. 8, 305-307. 

Boles J. R. (1998) Carbonate cementation in Tertiary sandstones, San Joaquin Basin, Cahfomia. In Carbonate Cementation in Sandstones, Distribution Patterns and Geochemical Evolution (ed. S. Morad). International Association of Sedimentologists, Oxford, vol. 26, pp. 261-284. 

Hayes M. J. and Boles J. R. (1992) Volumetric relations between dissolved plagioclase and kaohnite in sandstones imphcations for aluminum mass transfer in the San Joaquin Basin, Cahfomia. In Origin, Diagenesis, and Petrophysics of Clay Minerals in Sandstones (eds. D. W. Houseknecht and... 

Fig. 5-13. Relation of near-surface gases to proposed deep fault adjacent to Lost Hills oil field, San Joaquin Basin, California (reproduced with permission of the American Association of Petroleum Geologists, whose permission is required for future use, from Jones and Drozd, 1983, AAPG Bull., vol. 67, no. 6, Fig. 13, p. 943, AAPG01983).

The percent-methane compositions from the auger hole surveys conducted over the Sacramento and San Joaquin Basins are plotted in Fig. 5-21. There is a decrease from 98% methane in the north of the Sacramento basin to 90% in the south part, whilst the soil gas over the San Joaquin Basin has 82% methane. These data imply that a soil-gas grid would have defined local differences regionally. Furthermore these geochemical data are repeatable (Table 5-Xl) the percent-methane values on Fig. 5-21 were all determined at least two or three times over a three-year period and found to be repeatable. Compositional data have remained repeatable throughout our experience with soil-gas surveys. 

Fig. 5-21. Percent-methane in soil gas over the Sacramento and San Joaquin Basins, California.

Schultz, J.L., Boles, J.R. Tilton, G.R. (1989) Tracking calcium in the San Joaquin basin, California a strontium isotopic study of carbonate cements at North Coles Levee. Geochim. Cosmochim. Acta, 53, 1991-1999. 

Boles, J.R. Ramseyer, K. (1987) Diagenetic carbonate in Miocene sandstone reservoir, San Joaquin Basin, California. Bull. Am. Petrol. Geol., 71, 1475-1487. 

Carbonate cementation in Tertiary sandstones, San Joaquin basin, California... 

Carbonate-cemented sandstones occur throughout the San Joaquin basin. New isotopic data from nine additional areas combined with published papers allow comparison of cement compositions throughout the basin and a quantitative model of cement timing. 

Although the San Joaquin basin has evidence for cross-formational fluid flow, in many cases each reservoir has carbonate cements with distinctive compositions. This indicates that the flow that has occurred has not been at a rate or magnitude sufficient to homogenize the pore fluids within closely spaced reservoirs. 

Carbonate cements occur in small amounts in many sandstone hydrocarbon reservoirs of the San Joaquin basin. The cements formed throughout much of the burial history of the basin, and thus provide an extensive record of organic-inorganic diagenesis. Moreover, the cements record the nature and mag-... 

Fig. 1. Location of oilfields in the San Joaquin basin with carbonate cement studies. Codes are North Coles Levee (NCL), South Coles Levee (SCL), Canal (C), Paloma (P), Landslide (L), Yowlumne (Y), Rio Viejo (RV), San Emidio Nose (SN), Rosedale Ranch (RR), Fruitvale (F), Mountain View (MV), Edison (E), Mount Poso (MP), Round Mountain (RM), Kem River (KR), Poso Creek (PC), North Belridge (NB) and Kettleman North Dome (KND). Dashed lines are thickness of sedimentary rocks (metres), after Callaway (1971). Cross-section line X-X is shown in Fig. 2.

The carbonate cements of the San Joaquin basin have been useful for reconstructing the diagenetic history of non-carbonate reactions in the basin. Where rock is completely cemented, carbonate cementation can be used to deduce the reaction progress before and after cement sealing by comparing diagenesis both within and outside the cement zone. The low permeability of extensively cemented sandstone has effectively prevented further diagenesis within that rock. This has been demonstrated for... 

Finally, carbonate cements reveal the sources of dissolved carbon in the evolving pore waters of the San Joaquin basin. The clastic-rich basin is free of carbonate rocks but contains a considerable amount of organic matter, both in fine-grained sediment and as relatively recent hydrocarbon accumulations. Potential carbon sources for the carbonate cements are marine shell tests, thermogenesis and, possibly, organic reactions related to the presence of the oil. 

Callaway (1971) provides an excellent review of the geological framework of the San Joaquin basin... 

Fig. 2. West to east cross-section across San Joaquin basin. See Fig. 1 for location of the cross-section line. Most of basin-fill is marine, including the Stevens sandstone, and is at maximum burial depth. Non-marine strata are Chanac and Kem River Formations. Low lateral continuity of beds and abundant shales have prevented meteoric water from entering the deep central basin. Cross-section from California Division of Oil and Gas.

The eastern margin of the San Joaquin basin is in depositional contact with Sierra Nevada crystalline rocks, and includes shallow marine and non-marine... 

One of the most challenging aspects of diagenesis is to quantify the time and duration of cementation. In the San Joaquin basin we used several methods to estimate when carbonate cements formed. One method, which has also been applied by many previous workers in other basins (e.g. Galloway, 1979), is to infer the porosity at the time of cementation from the volume of pore-filling cement. If the compaction history for uncemented sands is known, the cement volume in fully cemented sandstones implies the burial depth at which cementation occurred. In the case of the San Joaquin basin, most areas underwent simple subsidence to their present depth, and the relation between depth of burial and porosity for uncemented sandstones is known from abundant porosity-depth data (e.g. Ziegler Spotts, 1976). Thus the depth of cementation can be inferred and, combined with a time-depth burial curve, so can the timing of cementation. 

Fig. 4. Photomicrographs of carbonate cements in sandstones of the San Joaquin basin. (A) Siderite rhombs (arrows) in pore space (dark areas). Well NCL 88-29, 2746.5 m (9010.8 ft). White bar is 0.25 mm. (B) Dolomite pore-filling sandstone from the central basin. Note high cement volume and undeformed detrital biotite (dark grains). Detrital grains are chiefly quartz and feldspar. Well NCL 88-29, 2717 m (8913 ft). White bar is 0.5 mm. (C) Calcite pore-filling cement from central basin. Note relatively high cement volume and partially crushed biotite. Well NCL 487-29,...

Fig. 5. Oxygen and carbon isotopic composition of early-formed dolomite cements in sandstones of the central San Joaquin basin.

Fig. 8. Frequency histogram (n = 83) of the distribution of carbon isotopes (pdb) in calcite cements from the central basin. Data from Boles Ramseyer (1987), Wood Boles (1991), Table 2 (this chapter) and additional unpublished data of the author. Data indicate that carbon sources near zero are the most important in moderate to deep burial calcites of the San Joaquin basin. This carbon may in part be of non-biogenic origin (see text for discussion).

Fig. 10. (A) Oxygen and carbon stable isotopic composition of calcite cements from the San Joaquin basin margins. Data sources from Table 1. (B) Oxygen and carbon stable isotopic composition of calcite cements from the San Joaquin basin centre. Data sources from Table 1. Note the restricted range of carbon isotopes compared with basin margin cements (cf. with (A)).

Dolomitization in the San Joaquin basin, as indicated by precipitation at or near the sediment-water interface, apparently did not require long transport distances for components, which is consistent with a very shallow burial process. However, repeated calcite precipitation events during burial... 

The question of how long subsurface cementation continues can be constrained in the San Joaquin basin as well as anywhere, owing to the young age of the strata. However, in spite of the brief and simple burial history of the San Joaquin basin, the relatively well constrained fluid composition history and the relatively well documented geochemistry of its carbonate cements, we still cannot determine the growth time of a given cement zone to any better than perhaps 100 000 years or less. 

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