Original scientific paper

https://doi.org/10.17559/TV-20151216024823

Hydraulic fracturing propagation mechanism during shale gas reservoir stimulation through horizontal well

Tian-hui Ma ; State Key Laboratory of Coastal and Offshore Engineering, Dalian, University of Technology - School of Civil Engineering, Dalian University of Technology No. 2 Linggong Road, 116024 Dalian, P. R. China
Quan-ao Wu ; School of Civil Engineering, Dalian University of Technology, No. 2 Linggong Road, 116024 Dalian, P. R. China
Chun-an Tang ; School of Civil Engineering, Dalian University of Technology, No. 2 Linggong Road, 116024 Dalian, P. R. China
Hong-yuan Liu orcid.org/0000-0002-5437-4695 ; School of Engineering and ICT, University of Tasmania, Hobart, TAS7001, Australia

Abstract

The fracture pattern of rock mass in shale gas reservoirs is one of the main factors affecting the efficiency of hydraulic fracturing. In this paper, physical experiments and numerical modelling were conducted to systematically investigate the effect of the in-situ stress and perforation angle on the hydraulic fracture initiation pressure and location, fracture propagation, and fracture pattern in a horizontal well drilled by Sinopec Corp. in Luojia area of Shengli Oilfield. A total of six different in-situ stress combinations and eight different perforation angles were considered for the stratified rock mass during the hydraulic fracturing. A summary of the fracture initiations and propagation, and the final fracture patterns induced by the hydraulic fracturing in the stratified rock masses reveals that, for the stratified rock masses with the same perforation angle, the larger the in-situ stress ratio (i.e. lower maximum horizontal principal stress when the vertical stress remains constant) is, the lower hydraulic pressure is required for hydraulic fracturing initiation and propagation. Moreover, it is found that, for the stratified rock mass under the same stress ratio, the hydraulic fracturing pressure in the case with a perforation angle of 30° is higher than that in all other cases. Furthermore, it is noted that the effect of the stratification on the hydraulic fracturing becomes weaker with the in-situ stress ratio increasing. It is finally concluded that the results from this study can provide important theoretical guidance for improving the hydraulic fracturing design in order to ensure the effective shale gas reservoir stimulations.

Keywords

fracture pattern; horizontal well; hydraulic fracturing; in-situ stress; perforation angle

Hrčak ID:

156838

URI

https://hrcak.srce.hr/156838

Publication date:

27.4.2016.

Article data in other languages: croatian

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