Title: Impact of proppant diagenesis on shale gas productivity

Authors: Samarth D. Patwardhan; Radhika G. Gunaji; G. Suresh Kumar

Addresses: Petroleum Engineering Program, Department of Ocean Engineering, Indian Institute of Technology, Madras, Chennai – 600036, Tamil Nadu, India ' Department of Petroleum Engineering, Maharashtra Institute of Technology, S. No, 124, Paud Road, Kothrud, Pune – 411038, Maharashtra, India ' Petroleum Engineering Program, Department of Ocean Engineering, Indian Institute of Technology, Madras, Chennai – 600036, Tamil Nadu, India

Abstract: For wells drilled in shale gas reservoirs to be economic, hydraulic fracturing has become a common completion practice. Production from these completed wells is highly dependent on the characteristics of proppants placed in the created fractures. Fracturing leads to an interaction between the minerals of the proppants, formation and the fluids; this results in the phenomenon of proppants diagenesis. It involves mechanisms such as diffusion, dissolution, precipitation along with chemical reactions that take place at the fracture surface. Over time, this combined process results in a loss of proppant pack permeability thereby leading to a decline in well productivity. This occurs due to changes in compositional differences between proppants, fracturing fluid and the formation. A mathematical model, representing this phenomenon is developed in this paper. It inculcates the phenomenon of mass transfer along the length of the fracture coupled with associated surface chemical reactions, and mass conservation equations are solved for individual components. Further, the impact of finite difference techniques on the results is studied. This is supplemented with studies involving changes in fracture aperture as well as velocity profile of the flowing fluid. Impact of results from the developed mathematical model on typical shale gas well productivity is evaluated. [Received: April 1, 2015; Accepted: September 8, 2015]

Keywords: shale gas productivity; hydraulic fracturing; fracking; mathematical modelling; proppant diagenesis; numerical techniques; proppant pack permeability; gas well productivity; mass transfer; surface chemical reactions; mass conservation equations; finite difference method; FDM; fracture aperture; flow velocity profile; fluid flow.

DOI: 10.1504/IJOGCT.2017.081096

International Journal of Oil, Gas and Coal Technology, 2017 Vol.14 No.1/2, pp.147 - 171

Received: 24 Apr 2015
Accepted: 08 Sep 2015
Published online: 21 Dec 2016 *

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