Numerical modeling of carbon dioxide injection at a pilot sequestration site

Over the past several years, lessons learned from various sequestration sites have identified deep, unmineable coal seams as favorable and profitable reservoirs for commercial carbon dioxide (CO2) sequestration and long-term CO2 storage. Long-term consequences, however, have not been completely identified and understood. In order to assess the aptitude of such deep unmineable coal seams for a possible commercial sequestration site, a reservoir modeling study was performed at an ongoing Pump Canyon, NM sequestration site located in the coalbed methane (CBM) fairway region of the well-established San Juan basin. The demonstration at the Pump Canyon pilot area is a part of the Southwest Regional Partnership on CO2 sequestration sponsored by the U.S. Department of Energy to evaluate available---technologies and practices to capture and store greenhouse gases such as CO2.;The present paper includes three objectives---(1) to study the history of CBM production in the region and construct an appropriate reservoir model based on the cleat geometry and available geological information, (2) to identify any unknown reservoir and geologic properties at the site through a history matching process, and (3) to model CO2 and tracer injections to aid in understanding fluid flow through the system. CBM production data over past two decades demonstrates an adequate facility for deploying the first commercial sequestration in the San Juan basin. A reservoir model was constructed using a modified existing simulator and based on available reservoir and geologic data. Several simulations were performed to obtain a history-match and analyze the CBM production history before and after CO2 injection. During CO2 injection a tracer was injected into the reservoir for tracking purposes. The tracer\u27s movement through the reservoir system was tracked using data from nearby producing wells. Tracer breakthrough occurred when nearby wells began to produce significant quantities of the injected tracer. Several simulations were performed to obtain matches with breakthrough data and tracer properties and further refine the model. The successful performance of this reservoir identifies the San Juan basin as a promising site for commercial sequestration of carbon dioxide