Optimization and Evaluation of Multiple Hydraulically Fractured Parameters in Random Naturally Fractured Model Blocks: An Experimental Investigation
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Researchers have recently realized that the non-tectonic natural fractures are developed in shale formations and significant for the exploitation of shale gas. Studies have shown that the tectonic fractures in naturally fractured reservoirs have influences on the maximization of stimulated reservoir volume (SRV) during hydraulic fracturing. However, the effect of the non-tectonic randomly natural fractures on the fracturing network propagation is not well understood. Laboratory experiments are proposed to study the evolution of fracturing network in naturally fractured formations with specimens that contain non-tectonic random fractures. The influences of the dominating factors were studied and analyzed, with an emphasis on natural fracture density, stress ratio, and injection rate. The response surface methodology was employed to perform the multiple-factor analysis and optimization in the maximization of the SRV. A sensitivity study reveals a number of interesting observations resulting from these parameters on the fracturing network evaluation. It is suggested from the geometry morphology of fracturing network that high natural fracture density and injection rate tend to maximize the fracturing network. The influence of stress contrast on fracturing network is nonlinear; an optimal value exists resulting in the best hydraulic fracturing effectiveness.
KeywordsHydraulic fracturing network Non-tectonic micro-fracture Simulation experiment Response surface methodology
The authors would like to thank the editors and the anonymous reviewers for their helpful and constructive comments. This work was supported by the National Natural Science Foundation of China (Grants nos. 41502294, 51574014), Fundamental Research Funds for the Central Universities (2302017FRF-TP-17-027A1), National key technologies Research & Development program (2017YFC0804609).
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Conflict of interest
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
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