A crossing criterion of hydraulic fracture in shale gas reservoir with consideration of stress interference
TIAN Leng1, XIAO Cong1, LIU Mingjin2, GU Daihong1, LI Xianglong1, SONG Guangyu1, DING Daoquan1
1. Petroleum Engineering College, China University of Petroleum, Beijing 102249, China;
2. School of Geoscience and Technology, Southwest University of Petroleum, Chengdu 610500, China
Abstract:Based on the formation mechanisms of stress interference of multi-fractures induced by network fracturing in shale gas reservoirs, this paper establishes a crossing criterion with consideration of remote stress, stress intensity near the tip of fracture and stress interference of multi-fractures. The results of model analysis illustrate that the ability of hydraulic fractures to cross natural fractures decreases under impact of stress interference of multi-fractures; Meanwhile, the net fracture pressure was higher when the fracture was longer, the distance between fractures was shorter, and the natural fracture was closer to the intermediate fracture, leading to larger interference stress between fractures. With decrease of the intersection angle between the hydraulic fractures and natural fractures, the ability of the former to cross the latter decreased within a certain range of stress ratio and friction coefficient, and increased when the stress ratio and friction coefficient were beyond this range. The crossing ability is not affected by the intersection angle under high stress ratios. These results may provide references for practical fracturing stimulation of shale gas reservoirs.
[1] 贾承造, 郑民, 张永峰. 中国非常规油气资源与勘探开发前景[J]. 石油勘探与开发, 2012, 39(2): 129-136. Jia Chengzao, Zheng Min, Zhang Yongfeng. Unconventional hydrocarbon resources in China and the prospect of exploration and development[J]. Petroleum Exploration and Development, 2012, 39(2): 129-136.
[2] 吴奇, 胥云, 王晓泉, 等. 非常规油气藏体积改造技术: 内涵、优化设计与实现[J]. 石油勘探与开发, 2012, 39(3): 352-358. Wu Qi, Xu Yun, Wang Xiaoquan, et al. Volume fracturing technology of unconventional reservoirs: Connotation, optimization design and implementation[J]. Petroleum Exploration and Development, 2012, 39 (3): 352-358.
[3] 赵金洲, 李勇明, 王松, 等. 天然裂缝影响下的复杂压裂裂缝网络模拟 [J]. 天然气工业, 2014, 34(1): 68-73. Zhao Jinzhou, Li Yongming, Wang Song, et al. Simulation of a complex fracture network influenced by natural fractures[J]. Natural Gas Industry, 2014, 34(1): 68-73.
[4] Daneshy A A. Hydraulic fracture propagation in the presence of planes of weakness[C]. SPE European Spring Meeting, Amsterdam, Nether-lands, May29-30, 1974.
[5] Blanton T L. An experimental study of interaction between hydraulically induced and pre-existing fractures[R]. SPE 10847, Presented at the SPE Unconventional Gas Recovery Symposium, Pittsburgh, Pennsylvania, 1982.
[6] Warpinski N R, Teufel L W. Influence of geologic discontinuities on hydraulic fracture propagation (includes associated papers 17011 and 17074)[J]. Journal of Petroleum Technology, 1987, 39(2): 209-220.
[7] Renshaw C E, Pollard D D. An experimentally verified criterion for propagation across unbounded frictional interfaces in brittle, linear elastic materials[J]. International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, 1995, 32(3): 237-249.
[8] Gu H, Weng X. Criterion for fractures crossing frictional interfaces at nonorthogonal angles[R]. Salt Lake City: ARMA, 2010.
[9] 程万, 金衍, 陈勉, 等. 三维空间中水力裂缝穿透天然裂缝的判别准则 [J]. 石油勘探与开发, 2014, 41(3): 336-340. Cheng Wan, Jin Yan, Chen Mian, et al. A criterion for identifying hydraulic fractures crossing natural fracture in 3D space[J]. Petroleum Exploratioan and Development. 2014, 41(3): 336-340.
[10] 曾凡辉, 郭建春, 刘恒, 等. 致密砂岩气藏水平井分段压裂优化设计与应用[J]. 石油学报, 2013, 34(5): 959-968. Zeng Fanhui, Guo Jianchun, Liu Heng, et al. Optimization design and application of horizontal well staged fracturing in tight gas reservoirs [J]. Acta Petrolei Sinica, 2013, 34(5): 959-968.
[11] 陈作, 薛承瑾, 蒋廷学, 等. 页岩气井体积压裂技术在我国的应用建议[J]. 天然气工业, 2010, 30(10): 30-32. Chen Zuo, Xue Chengjin, Jiang Tingxue, et al. Proposals for the application of fracturing by stimulated reservoir volume (SRV) in shale gas wells in China[J]. Natural Gas Industry, 2010, 30(10): 30-32.
[12] Sneddon I N. The distribution of stress in the neighborhood of a crack in an elastic solid[C]//Proceedins of Royal Society, Series A, London: 1946, 187: 229-260.
[13] Crouch S L, Starfield A M. Boundary element methods in solid mechanics [M]. London: George Allen & Unwin Ltd, 1983.
[14] Olson J E, Arash D T. Modeling simultaneous growth of multiple hydraulic fractures and their interaction with natural fractures[C]. SPE-119739-MS, SPE Hydraulic Fracturing Technology Conference, Woodlands, Texas, January 19-21, 2009.