The Impact of the Hydraulic Fracture Properties on the Gas Recovery from Marcellus Shale

Abstract

Abstract Marcellus Shale, a Devonian black shale, spans the majority of the Appalachian Basin from New York through Pennsylvania, West Virginia and also extends into Ohio and Maryland (Bartuska, et al. 2012). The unconventional gas reservoir is a term commonly used to refer to ultra-low permeability formations that produces mainly dry natural gas and is not able to produce an economic flow rate without stimulation treatments. The natural gas in the Marcellus Shale is produced most efficiently through horizontal wells with multiple hydraulic fracturing stimulation treatments. Even though advances in technology have unlocked considerable reserves of hydrocarbon, the long-term production behavior of the horizontal wells with multiple hydraulic fractures is not well understood. This paper provides the results of parametric studies to investigate the impact of the hydraulic fracture properties and more specifically the impact of non-uniform fracture half-length, on the gas recovery from Marcellus Shale. The purpose of this study is to evaluate the long-term production performance of horizontal wells with multiple hydraulic fractures completed in Marcellus Shale. A commercial reservoir simulator was used to develop the base model which incorporated the storage and production mechanisms inherent in shales. The core, log, completion, stimulation, and production data obtained from wells located at the Marcellus Shale Energy and Environment Laboratory (MSEEL) were utilized to generate the simulation model. MSEEL is a research collaboration between West Virginia University, Ohio State University, The Natural Energy Technology Laboratory, and Northeast Natural Energy. MSEEL aims to achieve a better understanding of the unconventional shale resources through application of advanced technology in drilling, completion, reservoir characterization, production and monitoring of horizontal wells. Furthermore, fracture properties (fracture half-length, fracture width and fracture conductivity) were obtained by using commercial software. Precision laboratory equipment was utilized to determine the shale properties from the core samples. Field production data from two original horizontal Marcellus Shale gas wells at MSEEL site were utilized for history matching to establish the missing shale parameters. History matching was initially performed using production data for two years from one the horizontal wells. The matched model was then used to predict the production for the following two years to confirm the accuracy and reliability of the model. In addition, the base model was used to predict the second horizontal well production which provided reliable results. Finally, a number of parametric studies were performed with the model to investigate the impact of the hydraulic fracture properties and non-uniform fracture half-length, on the recovery.