This paper presents the initial results of a survey of the occurrence and characteristics of geopressured fluid resources in California using the publicly-available database involving more than 150,000 oil and gas wells drilled in the State. Of the 975 documented on-shore oil and gas pools studied, about 42% were identified as potentially geopressured. Geothermal gradients in California oil and gas fields lie within the normal range of 1°F to 2°F per 100 feet. Except for the Los Angeles Basin, there was no evidence of higher temperatures or temperature gradients in geopressured pools. The porosity of geopressured pools shows the same normal distribution as for normal pressured pools, with a mode in the range of 20 to 25%. The salinity distribution of both the geopressured and normal pressured pools appear to be bimodal, each with two peak ranges of 0 to 10,000 and 25,000 to 30,000 ppm.

The publicly available database on oil and gas fields in California provides a significant and consistent source of information which can be used to evaluate geopressure. A total of 410 pools have pressure gradients exceeding 0.45 psi/foot; these are considered to be potentially geopressured. At least 70 of these have pressures distinctly higher than predicted by the regional hydrostatic gradient, and 8 pools are super pressured.

This paper presents the results of a continuing study of geopressured resources in California. Three aspects of geopressured resources were examined in this study: the identification of geopressured zones in wells; quantification of the excess pressure from well logs; and the quantity of dissolved methane in California geopressured fluids.

This paper presents the initial results of a survey of the occurrence and characteristics of geopressured fluid resources in California using the publicly-available database involving more than 150,000 oil and gas wells drilled in the State. Of the 975 documented on-shore oil and gas pools studied, about 42 % were identified as potentially geopressured. Geothermal gradients in California oil and gas fields lie within the normal range of 1°F to 2 OF per 100 feet. Except for the Los Angeles Basin, there was no evidence of higher temperatures or temperature gradients in geopressured pools. The porosity of geopressured pools shows the same normal distribution as for normal pressured pools, with a mode in the range of 20 to 25 %. The salinity distribution of both the geopressured and normal pressured pools appear to be bimodal, each with two peak ranges of o to 10,000 and 25,000 to 30,000 ppm. Compared to the U. S. Gulf Coast region, geopressured pools in California display much lower water salinity, and therefore, should have a higher solubility for methane.