**Author details**

Arshad Islam1\* and Antonin Settari2

\*Address all correspondence to: aislam@trican.ca

1 Trican Well Service Ltd., Calgary, Canada

2 University of Calgary, Calgary, Canada

#### **References**


[5] Ji, L., Settari, A., and Sullivan, R. B. 2009. A Novel Hydraulic Fracturing Model Fully Coupled with Geomechanics and Reservoir Simulation. *SPE Journal* 14 (3): 423-430. SPE-110845-PA.

*α*= Biot's constant

*υ*= Poisson's ratio

**Author details**

**References**

ber 2012).

& Sons, Inc.

tember.

Arshad Islam1\* and Antonin Settari2

\*Address all correspondence to: aislam@trican.ca

Calgary, Alberta, Oct. 30 – Nov. 1.

1 Trican Well Service Ltd., Calgary, Canada

2 University of Calgary, Calgary, Canada

**Acknowledgements**

324 Effective and Sustainable Hydraulic Fracturing

We would like to acknowledge help from Taurus Reservoir Solutions Ltd. for providing the TRS® reservoir and GeoSim® geomechanical simulator. We also wish to acknowledge the financial aid from the JIP consortium for Tight Gas Sands and Shale Gas Modeling at University of Calgary for supporting the research fund. We wish to thank Vikram Sen for helping during

[1] Islam, A., Settari, A., and Sen, V. 2012. Productivity Modeling of Multifractured Hor‐ izontal Wells Coupled With Geomechanics - Comparison of Various Methods. Paper SPE 162793 presented at the SPE Canadian Unconventional Resources Conference,

[2] Islam, A. 2012. Geomechanical Productivity and Injectivity Modeling of Multifrac‐ tured Horizontal Wells. MSc thesis, University of Calgary, Calgary, Alberta (Septem‐

[3] Economides, M. J., and Nolte, K .G. 2000. *Reservoir Simulation*, Third Ed. John Wiley

[4] Ji, L., Settari, A., Sullivan, R. B. et al. 2004. Methods for Modeling Dynamic Fractures in Coupled Reservoir and Geomechanics Simulation. Paper SPE 90874 presented at the SPE Annual Technical Conference and Exhibition, Houston, Texas, 26 – 29 Sep‐

this project and Apache Canada for providing us data for this study.


**Chapter 16**

**The Role of Natural Fractures in Shale Gas Production**

Natural fractures seem to be ubiquitous in shale gas plays. It is often said that their presence is one of the most critical factors in defining an economic or prospective shale gas play. Many investigators have presumed that open natural fractures are critical to gas production from deeper plays such as the Barnett, as they are for shallower gas shales such as the Dev‐ onian shales of the northeastern US and for coal bed methane plays. A common view on production mechanisms in shales is "because the formations are so tight gas can be pro‐ duced only when extensive networks of natural fractures exist" [6]. However, there is now a growing body of evidence that any natural fractures that do exist may well be filled with calcite or other minerals and it has even been suggested that open natural fractures would in

Commercial exploitation of low mobility gas reservoirs has been improved with multi-stage hydraulic fracturing of long horizontal wells. Favorable results have been associated with large fracture surface area in contact with the shale matrix and it is here that the role of natu‐ ral fractures is assumed to be critical. For largely economic reasons hydraulic fracturing for increasing production from shale gas reservoirs is often carried out using large volumes of slickwater injected at pressures/rates high enough to create and propagate extensive hy‐ draulic fracture systems. The fracture systems are often complex, due essentially to intersec‐ tion of the hydraulic fractures with the natural fracture network. After hydraulic fracturing operations the injected water is flowed back. Typically, only a small percentage (on the or‐

In this paper we investigate the role played by natural fractures in the gas production proc‐ ess. By applying a new model of the production process to data from many shale gas wells across a number of shale plays in North America, we can for the first time begin to sort out assertion from inference in the role that these fractures play. Specifically, we are able to esti‐

and reproduction in any medium, provided the original work is properly cited.

© 2013 Walton and McLennan; licensee InTech. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

© 2013 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution,

Ian Walton and John McLennan

http://dx.doi.org/10.5772/56404

der of 20 to 40%) is recovered.

**Abstract**

Additional information is available at the end of the chapter

fact be detrimental to Barnett shale gas production [9].
