Design and implementation of a CO{sub 2} flood utilizing advanced reservoir characterization and horizontal injection wells in a shallow shelf carbonate approaching waterflood depletion. Annual Report, July 1, 1995--June 30, 1996

The work reported herein covers select tasks remaining in Budget Phase I and many of the tasks of Budget Phase II. The principal Tasks in Budget Phase I included in this report are Reservoir Analysis and Characterization; Advanced Technical Studies; and Technology Transfer, Reporting and Project Management Activities for Budget Phase I. The principle Task in Budget Phase II included in this report is Field Demonstration. Completion of these tasks has enabled an optimum carbon dioxide (CO{sub 2}) flood project to be designed, economically evaluated, and implemented in the field. Field implementation of the project commenced during late 1995, with actual CO{sub 2} injection scheduled for start-up in mid-July, 1996. The current project has focused on reducing initial investment cost by utilizing horizontal injection wells and concentrating the project in the best productivity area of the field. An innovative CO{sub 2} purchase agreement (no take-or-pay provisions, CO{sub 2} purchase price tied to West Texas Intermediate (WTI) crude oil price) and gas recycle agreements (expensing costs as opposed to a large upfront capital investment for compression) were negotiated to further improve the project economics. The Grayburg-San Andres section had previously been divided into multiple zones based on the core study and gamma ray markers that correlate wells within the Unit. Each zone was mapped as continuous across the field. Previous core studies concluded that the reservoir quality in the South Cowden Unit (SCU) is controlled primarily by the distribution of a bioturbated and diagenetically-altered rock type with a distinctive {open_quotes}chaotic{close_quotes} texture. The {open_quotes}chaotic{close_quotes} modifier is derived from the visual effect of pervasive, small-scale intermixing of tan oil-stained reservoir rock with tight gray non-reservoir rock