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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.

Item Type:	Refereed Article
Keywords:	fracture pattern, horizontal wall, hydraulic fracturing, in-situ stress, perforation angle
Research Division:	Engineering
Research Group:	Civil Engineering
Research Field:	Civil Geotechnical Engineering
Objective Division:	Construction
Objective Group:	Construction Processes
Objective Field:	Civil Construction Processes
Author:	Liu, HY (Dr Hong Liu)
ID Code:	111790
Year Published:	2016
Deposited By:	Engineering
Deposited On:	2016-10-07
Last Modified:	2017-06-27
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