Application of Borehole-Imaging Logs to Geologic Analysis, Cotton Valley Group and Travis Peak Formation, GRI Staged Field Experiment Wells, East Texas. Topical Report January 1987-February 1990

摘要

The report summarizes studies of two geophysical logging tools, the borehole televiewer and the Formation Microscanner, that were used in GRI's three Staged Field Experiment wells and in a cooperative well in East Texas. These tools can detect natural fractures and induced fractures that reflect in situ stress conditions, as well as lithologic features that can be important for geologic interpretation. Improvement in borehole televiewer and Formation Microscanner technology has been rapid in the past several years, but calibration of the logs with core is needed to ensure accurate interpretations of the logs. The authors study compares borehole televiewer and Formation Microscanner logs with core from wells in low-permeability gas reservoir sandstone. Vertical fractures in Travis Peak and Cotton Valley sandstone usually are visible on borehole televiewer and Flormation Microscanner logs, but some fractures were missed or are indistinct. Formation Microscanner images can be used to help document and interpret depositional environment, and they provide images of sedimentary structures and thin beds.