THE ALISO CANYON GAS STORAGE FIELD 3-D GEOLOGIC MODEL, LOS ANGELES, COUNTY, CALIFORNIA

The Aliso Canyon gas storage field is among the 10 largest fields in the United States and is one of five operated by Southern California Gas Co. Currently operating are 89 injection/withdrawal wells, 16 storage zone oil-producing wells and 8 observation wells. The field has cushion gas and working gas capacity of 91.5 and 70 billion cubic feet respectively. Natural gas from fields in Texas, Oklahoma and New Mexico is injected from April 1 to November 1 for winter demand.

The subsurface geology of Aliso Canyon field is typical of many large California oil fields in that it is structurally complex. The field has numerous fault-bounded blocks, three unconformities, reservoir sand discontinuities and varying fluid contacts. The subsurface data available ranged in age from 62 years to 5 years old and there were no digital records of any kind. The geologic model was created to replicate the 2D maps and sections from earlier studies.

A number of previous geologic and petrophysical studies were integrated to obtain a geologic model of the field. 3-D computer generated modeling enable us to achieve a field-wide view of both the shallow oil and deep storage zones. Advantages of this approach included the systematic organization of vast quantities of data, visualization of the role of faulting in reservoir pressure and well performance and testing the validity of reservoir sand continuity. The information generated as a result of the study was incorporated into an integrated computerized geologic and engineering model, which served as a tool for better understanding the field and was input into a reservoir simulation model. Results of this project resulted in identification of future drilling locations, optimum base-load determination, storage inventory verification and oil production and gas injection/withdrawal optimization.