About This Item

Share This Item

The AAPG/Datapages Combined Publications Database

AAPG Bulletin

Abstract


Volume: 46 (1962)

Issue: 2. (February)

First Page: 281

Last Page: 282

Title: Sacramento and Northern San Joaquin Valley Gas Areas: ABSTRACT

Author(s): D. H. Thamer, A. S. Hawley

Article Type: Meeting abstract

Abstract:

The Sacramento and Northern San Joaquin Valleys are now a major dry gas province, there being about 65 dry gas fields from Fresno on the south to Redding in the north, a distance of approximately 300 miles. The Sacramento and Northern San Joaquin Valleys are a southeasterly plunging synclinorium bounded on the east by the Sierra Nevada and on the west by the Coast Ranges. This sedimentary trough is asymmetrical, the west flank steeper than the east. The stratigraphic section from Cretaceous through Recent represents a composite thickness of approximately 50,000 feet. Because of tilting and subsequent truncation, the stratigraphic section of the Sacramento Valley becomes successively younger in a southerly direction. Stratigraphic traps formed by the truncation of the sout erly plunging section are economically significant. The configuration of the resultant edge lines takes parabolic form with its apex at the north. Three unique detritus-filled erosional gorges transect the Sacramento Valley within the subsurface.

The synclinorium is broken by several northeasterly trending subsurface anomalies: the Red Bluff arch, the Marysville-Colusa arch, the Sacramento hinge-line, and the Stockton fault which structurally separates the Sacramento Valley from the San Joaquin Valley. The Marysville Buttes, Dunningan Hills, Kirby, and Potrero Hills are several prominent topographic features closely associated with gas accumulation.

In general, the Sacramento Valley gas production is separated on the basis of stratigraphy into two parts by the Sacramento hinge-line. The Rio Vista basin,

End_Page 281------------------------------

south of the hinge-line, contains a thick Miocene-Eocene section deposited in a saucer-shape basin unconformably overlying Upper Cretaceous sediments. Production in the Rio Vista basin is predominantly from "blanket" type Eocene sands on structural anomalies. North of the Sacramento hinge-line, the majority of the gas production, which is firmly established over this broad area, is stratigraphically entrapped in erratic lenticular Upper Cretaceous sands.

It is anticipated that extensive Upper Cretaceous production present north of the Sacramento hinge-line will be found in the Rio Vista basin and the Northern San Joaquin Valley. The economic depth limit for testing the Cretaceous will be effectively lowered as the intrinsic value of gas increase.

End_of_Article - Last_Page 282------------

Copyright 1997 American Association of Petroleum Geologists