An Evaluation of the Stimulation Effect of Horizontal Well Volumetric Fracturing in Tight Reservoirs with Complex Fracture Networks
(2.School of Petroleum Engineering, China University of Petroleum (East China), Qingdao, Shandong Province, China 266580)
(3.School of Petroleum Engineering, Yangtze University, Wuhan, Hubei Province, China 430100)
【Abstract】The improvements on the effect of fracturing stimulation is essential for the economic and effective development of tight reservoirs, and it is necessary to consider the distribution characteristics of complex fracture networks while the effect of fracturing stimulation is evaluated. Based on microseismic data, the distribution characteristics of secondary fractures were obtained by a generation algorithm of fractal random fracture networks. Considering the physical property variation of the near borehole region of fractured horizontal wells, a mathematical model of fluid flow in multi-zone porous media of fractured horizontal wells is established and then resolved. Based on the model, the influences of the complexity of secondary fractures on the flow are studied. The results demonstrate that the complexity of secondary fractures has a significant impact on the entire flow stage. The findings show that the larger fractal dimension indicates the higher yield; the wider stimulated zone can lead to the longer early linear flow and the bilinear flow of quasi-steady channeling. The fracturing stimulated area with the distributed secondary fractures is the main area in the early–middle stage of production, and it makes the largest contribution to the production. Thus, during actual production, the best approach is to increase the stimulated volume so as to improve the early production and maximize the EOR of reservoirs. The research results can provide a theoretical basis for the evaluation of volumetric fracturing effect of tight reservoirs and the optimization of fracturing design.
【Keywords】 tight reservoirs; volume fracturing; fracture network; fractal characterization; multi-zone flow model; effect evaluation;
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