Abstract: Effects of Depth on Reservoir Characteristics and Production in Morrow and Springer Well Completions in the Anadarko Basin

SMITH, PAUL W., WALTER J. HENDRICKSON, CRAIG M. WILLIAMS, and RONALD J. WOODS

A recently published report by the Gas Research Institute entitled "Gas Well Recovery -vs- Depth in the Anadarko Basin of Western Oklahoma" (GRI Report ^sharp 96/0196) suggests that the observed increase in gas well recovery with increased depth is more influenced by increased reservoir volume than by increased pressure. The GRI conclusions are based upon the physical volumes at depth required to contain the produced gas. The study did not include an investigation into the physical reservoir parameters (ie thickness or porosity). Trends in well recovery (and required reservoir volumes) versus depth resulting from the GRI study will be presented.

Independent of the GRI study, detailed reservoir characteristic studies for numerous fields producing from Morrowan and Springeran have been conducted. Approximately 300 wells producing from Springeran Sandstones and 375 wells producing from Morrowan Sandstones were evaluated. The distribution of wells represents a wide spectrum of depth ranges. The results of the reservoir characterization studies will be presented to include trends in reservoir thickness, reservoir porosity, water saturation, and well spacing. These factors can be used to determine the reservoir volume and demonstrate trends in physical reservoir volume with depth. Using original bottom hole pressure and temperatures, one can then derive an expansion coefficient for each completion. This method can be used to make estimates of original gas in place for each completion. The original gas in place for each well was calculated using the perforated porosity and perforated thickness; the same was done using saturated thickness and saturated porosity. An interesting set of plots and data resulted. These can be used to expedite exploration strategies, exploitation strategies, and/or acquisition strategies. Guidelines for estimating the productivity of the specific reservoirs resulting from the reservoir characterization studies were generated and will be presented.

AAPG Search and Discovery Article #90944©1997 AAPG Mid-Continent Section Meeting, Oklahoma City, Oklahoma