Computer-based engineering evaluation on underground waterflooding fields in the Appalachian region

The Appalachian region contains hundreds of oil fields that were developed during the late 1800's and early 1900's. These fields contain oil reserves that may be recovered using secondary recovery methods such as waterflooding. Technical and economic evaluation of these fields for these capital-intensive operations requires in-depth engineering studies that usually include a field-scale computer model. The objective of this study is the computer based engineering assessment of the mechanisms attendant to waterflooding of Gordon sandstone fields located in the Appalachian basin. To accomplish this objective, two case studies are presented. One is the Washington-Taylorstown field in Pennsylvania and the other is the Wileyville field in West Virginia. The computer models developed include the history matching of the production data and the analysis of dynamic skin factor. The history matching protocol utilizes a systematic approach to complete the simulation of the historical data, which proved to be effective in understanding the behavior of the reservoir under study. It was concluded that the change in skin with time in waterflooding operations is not only due to matrix permeability variations; but also external factors such as mixed fluids injection, suspended particles and particle deposition. The results obtained provide the operators of the Appalachian basin with a tool to characterize, initialize and perform computer simulation studies of any of the hundreds of reservoirs in the basin.