Study Effects of Geopressured-Geothermal Subsurface Environment on Elastic Properties of Texas Gulf Coast Sandstones and Shales Using Well Logs, Core Data, and Velocity Surveys. Final Report

摘要

Relations between porosity and permeability for the Pleasant Bayou wells were determined from conventional core data. Porosities from the time average equations required compaction correction factors of 1.9 in hydropressured sandstones and 1.0 in geopressured sandstones. Best average prmeabilities in the geopressured zone were found in the primary production interval 14,687 to 14,716 ft (4477 to 4485 m). Average density gradients were 2.106 x 10 exp -3 and 2.688 x 10 exp -3 (gm/cm exp 3 )/100 ft in sandstones and shales respectively. Compressional (P-wave) and shear (S-wave) velocities from the long-spaced sonic log and bulk densities from the formation density log were used to compute in-situ elastic moduli, Poisson's ratio, V/sub p//V/sub s/, and bulk compressibility in two intervals of deep geopressured sandstone and shale in No. 2 Pleasant Bayou. Most computed values of these parameters seem reasonable. Improved accuracy of travel times from the long-spaced sonic log should permit more accurate depth-to-time correlation with seismic data. (ERA citation 06:020100)