Prediction of production performance by comprehensive methodology for hydraulically fractured well in coalbed methane reservoirs

Abstract

Production data from hydraulically fractured well in coalbed methane (CBM) reservoirs was analysed using decline curve analysis (DCA), flow regime analysis, and flowing material balance to forecast the production performance and to determine estimated ultimate recovery (EUR) and timing for applying the DCA. To generate synthetic production data, reservoir models were built based on the CBM properties of the San Juan Basin and Appalachian Basin. Production data analysis shows that the transient flow (TF) occurs for 1~3 years in the vertical well and 6~16 years in the horizontal well and then the boundary dominated flow (BDF) was reached. In the TF period, it is impossible to forecast the production performance. In case of vertical well, if the production data are available for more than three years after the BDF has been reached, the production rate and EUR can be predicted with EUR error of approximately 5%. In the case of a horizontal well, the prediction can be conducted using the production data of more than a year after reached BDF with EUR error of approximately 5%. [Received: January 30, 2016; Accepted: February 3, 2017]