ISSUES WITH LONG-TERM CASED-HOLE QUANTITATIVE FLUID SATURATION MONITORING

摘要

Quantitative fluid saturation monitoring in steel-cased and fiberglass-cased wells over a fifteen year time span has presented significant challenges. This paper discusses the impact of the following issues on the monitoring program: 1) changes in tool type and tool software, 2) changes in formation fluid properties, 3) issues associated with long-term storage of digital data, and 4) changes in staff handling the monitoring project. These issues are presented in the context of a monitoring project in a high porosity (25-27 pu) formation having high salinity (96,500 ppm NaCl) formation water undergoing immiscible gas displacement. Examples showing what actually happened after fifteen years compared to what was predicted ten years ago with only five years of monitoring are covered. An approach for continued monitoring for the next five to ten years is also presented.