Energy Policy Act of 2005 (Ultra-deepwater and Unconventional Resources Program)
Prediction of Fault Reactivation in Hydraulic Fracturing of Horizontal Wells in Shale Gas Reservoirs
West Virginia University Research Corporation
Range Resources Appalachian, LLC
In this project, the PI’s goal is to develop an advanced method to predict fault reactiva-tion and improve effectiveness of hydraulic fracturing stimulation of horizontal gas shale wells. The proposed project will target at the Marcellus shale in the Appalachian Basin. Four specific objectives are proposed: (1) to assess the reactivation potentials of faults by identifying the in-situ stress conditions of faults nearby fracture treatment wells; (2) develop a propagation model for multiple fractures simultaneously created; (3) to extend current 2D stress model to characterize the stress state changes of a fault and near-fault zones, and predict fault slippage due to hydraulic fracturing; (4) to optimize fracture design avoiding reactivation of faults.
Gas shale represents ultra-low permeability reservoirs and requires multi-stage hydraulic fracturing treatments to be economically viable. Hydraulic fracturing itself is featured with complex fracture propagation and geometries. In the Marcellus shale, the reservoir structure is complicated by large fault networks. Faults nearby wells may be reactivated by hydraulic fracturing. The reactivated fault can cause early aborting or failure of fracturing treatment and fluid leakage along the fault. To identify the potential of fault reactivation caused by hydraulic fracturing, a boundary element method will be used to develop a multi-fracture propagation model coupled with stress variation model to describe the interaction of stress field and fracture geometry. With these models, the stress state at any point of interest in the reservoir can be determined during the process of fracturing stimulation and hence the fault reactivation can be quantitatively evaluated based on geomechanic principle and criteria. The results of the proposed research will improve the understanding of physical phenomena related to successful stimulation and recovery of gas shales, and lead to advances in hydraulic fracturing technology applied to Marcellus shale in Appalachian Basin.
The proposed project will deliver a new technology and associated software application to provide a rapid and cost-efficient assessment of the feasibility and effectiveness of a hydraulic fracturing, and an effective fracturing design avoiding hazard situations of reactivating of faults. While it is believed the software will have commercialization potential, the objective of this project is development of the technology, not commercialization of software.
The research described in this proposal is novel and transformative because, if successful, ineffective fracturing treatment will not be initiated and risks of reactivating faults can be mitigated so that treatment cost and gas leakage impact on environment can be reduced. The outcome of this research can be used to guide hydraulic fracturing design by optimizing fracture spacing and fracture length while avoiding reactivation of faults. Ultimately, the proposed research will enhance the economic and energy security of the U.S. by improving the efficiency of energy resource exploration and the supply of domestic natural gas. Cost share for the project is being provided by the West Virginia University College of Engineering and Mineral Resources and the Department of Petroleum and Natural Gas Engineering.
Other participant: Range Resources – Appalachian LLC
Principal Investigator(s): Dr. Yueming Cheng; Co-PI: Prof. Samuel Ameri