Title: Physics of unconventional shale gas reservoirs for a long-term production perspective

Authors: Mohammad O. Eshkalak; Umut Aybar; Kamy Sepehrnoori

Addresses: Department of Petroleum and Geosystems Engineering, The University of Texas at Austin, 200 E. Dean Keeton St., Austin, TX 78712, USA ' Department of Petroleum and Geosystems Engineering, The University of Texas at Austin, 200 E. Dean Keeton St., Austin, TX 78712, USA ' Department of Petroleum and Geosystems Engineering, The University of Texas at Austin, 200 E. Dean Keeton St., Austin, TX 78712, USA

Abstract: A simple unconventional reservoir model is developed that accounts for complex physics affecting production from hydraulically-fractured wells in shale resources. Integrating these physics and evaluating their order of importance on future production of an unconventional reservoir is very essential. The proposed model divides the formation into three zones, rock matrix (I), induced-fracture (II) and hydraulic fracture (III) that hold varying characteristics. Also, a history matching process with Marcellus shale field production data is performed in order to obtain the most uncertain parameters defined in the model. Results showed that combined effect of permeability losses of hydraulic and induced-fracture zones results in 15% gas production drop in 30 years. It is also concluded that the minimum ingredients required for long-term production forecast of unconventional shale gas reservoirs are considering two physics; shale surface methane desorption along with pressure-dependent permeability for fracture network and other physical phenomena are inconsequential. [Received: August 12, 2014; Accepted: December 13, 2014]

Keywords: shale complex physics; pressure-dependent phenomena; hydraulic fracture networks; shale gas production; unconventional resources; fracking; shale gas reservoirs; long-term production; hydraulic fracturing; rock matrix; induced fracture; uncertainty; permeability losses; surface methane desorption.

DOI: 10.1504/IJOGCT.2015.070079

International Journal of Oil, Gas and Coal Technology, 2015 Vol.10 No.1, pp.1 - 22

Received: 15 Aug 2014
Accepted: 13 Dec 2014

Published online: 26 Jun 2015 *

Full-text access for editors Full-text access for subscribers Purchase this article Comment on this article