This paper summarizes results in Antrim Shale, Michigan. Well testing was conducted in an 8-well pattern to select a single well for restimulation. This well was restimulated in two stages designed for merely 10,000 lb proppant. Incremental rate of 348 mcfd (FOI=6.6). Incremental reserves of 0.64 Bcf later estimated by GRI, with the restimulation cost only $15,000.
During the past five years, nearly 10,000 Antrim Shale, Devonian Shale and eastern coalbed methane wells have been drilled and completed in eastern basins. A portion of these new wells (and previously drilled, older wells) appear to have been inefficiently completed, stimulated and produced, due to limited understanding of the production mechanisms and lack of sound data on the interaction of drilling fluids on the shale or coal reservoir. Thus, substantial improvements may be achieved by remediating these wells. The economic incentives for remediation are particularly powerful. Successful remediation not only provides additional low cost gas production but may also provide additional Section 29 tax credits.
In the Antrim Shale, remediation involving pump refracturing and completion of additional zones have led to substantial gains in gas production. However, the identification of wells requiring restimulation has been more challenging. Pressure buildup testing and productivity index matching have been utilized to identify such candidates.
In the Warrior Basin, restimulation of poorly producing wells has had more mixed results. Based on the experiences learned from the GRI Rock Creek Field Laboratory, a remediation program is being initiated in the Warrior Basin with support of GRI and basin operators.
This paper sets forth a technical and economic rationale for a remediation research and deployment program for eastern gas shale and coalbed methane wells. A series of case studies summarize some of the results achieved to date.
Author(s): Kuuskraa, V.A., Reeves, S.R., Advanced Resources Intl. Inc.; Schraufnagel, R.A., Gas Research Inst.; Spafford, S.D., Taurus Exploration
Paper Number: SPE 26894