Analysis of Borehole Stability and Drilling Fluids for SFE (Staged Field Experiment) No. 2

摘要

The Gas Research Institute's (GRI) Tight Gas Sands program is actively engaged in collecting geophysical data from the Travis Peak formation in the East Texas Basin. Poor quality electrical wireline measurements and disintegrating core were observed in eight GRI cooperative wells and in the first Staged Field Experiment well. The adverse conditions contributing to the poor quality data were attributed to unstable borehole conditions resulting from geochemical reactions between formation clays and the drilling fluid water, causing them to swell. Tests performed on a section of core from a well within one mile of the second Staged Field Experiment well using eight different drilling fluids indicated a water-base drilling fluid with potassium chloride and a shale inhibiting polymer would enhance borehole stability. This drilling fluid system's ability to prevent clay swelling and promote geophysical data quality was determined by analyzing caliper logs, wireline log data quality and whole core.