Abstract: History of Seismic Exploration in the Sacramento Valley, California

G. Dale Gray

The Sacramento Valley has enjoyed over 60 years of seismic exploration. In the mid-1930's, seismic crews entered the Sacramento Valley using techniques developed by Amerada Hess and Gulf in the late 1920's in the Gulf Coast and successfully applied to the Los Angeles Basin and San Joaquin Valley in the early 1930's. The result was a flurry of activity along the northern portion of the Great Valley of California and the discovery of several large gas fields.

With the continued improvement of the seismic data quality by use of digital recording, computer processing, recording of the amplitude of the signal and CDP techniques, combined with the evolution of two geologic concepts, antithetic faulting and submarine fan deposits, new reserves were discovered in the 1950's and 1960's lead by Western Gulf, Texaco and Occidental Petroleum.

In the Sacramento Valley, the 1970's became the "bright spot" era because of the efforts of Shell. Shell, using these techniques, proceeded to discover 12 new fields in 1976.

In the late 1970's, through efforts by Chevron, AVO was employed for the first time any where in the world in the Sacramento Valley in 1978. AVO is now a standard tool in the geophysicist's tool box.

The next major breakthrough in the seismic exploration techniques was the use of 3D seismic data to resolve complex structural and stratigraphic relationships in the Sacramento Valley. The 3D surveys have had a dramatic success with high percentage drilling. Some counties have between 80% and 100% success ratios for over two years.

The Sacramento Valley continues to be a basin with new gas discoveries as a direct result of the application of state of the art seismic techniques integrated with new geologic concepts.

AAPG Search and Discovery Article #90958©1995 AAPG Pacific Section Meeting, San Francisco, California