The domestic United States has more than 30,000 coalbed-methane (CBM) wells drilled and producing. The majority of these are vertical, producing wells that have been completed with hydraulic fracturing to access coal-seam gas. Mature CBM fields can still provide an opportunity to deliver more gas production. While incomplete primary-stimulation and additional-pay intervals can be easily identified as candidates, wells with scaling issues, fines invasion, or proppant production can be more difficult to ascertain. Determining the best recompletion solution requires an integrated review of the well history from its construction through completion as well as each well’s production profile.

This paper describes the methodology used for determining which wells to recomplete in a 30-well program in 2007. Four types of recompletions were established with at least three wells in each category, allowing comparison of different recompletions methods. A diagnostic approach is described that determined the proper course of action as field work confirmed the well problem. After at least 12 months of post-treatment production, this project was deemed a success with an uplift greater than 10 Mcf/day on 63% of the wells and 403 MMcf in additional gas sold to market.

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