QIAN Bin, ZHU Juhui, YANG Hai, LIANG Xing, YIN Congbin, SHI Xiaozhi, LI Deqi, LI Junlong, FANG Hui
1. Down-hole Service Company of CNPC Chuanqing Drilling Engineering Company Limited, Chengdu 610051, China; 2. PetroChina Zhejiang Oilfield Company, Hangzhou 310013, China; 3. China University of Petroleum-Beijing, Beijing 102249, China
Abstract：By using nuclear magnetic resonance (NMR) and CT scanning technologies, hydration experiments have been conducted on shale samples from the Lower Silurian Longmaxi Formation in Zhaotong area in North Yunnan and Guizhou Provinces under the confining pressure of 10 MPa to study the effect of hydration on the propagation of pores and natural fractures in shale formation. The results show that the hydration not only offsets the permeability drop caused by stress sensitivity, but makes the fracture network more complicated, the connection between fractures and pores better with larger volume, and permeability higher by facilitating the dilation, propagation and cross-connection of primary pores, natural fractures, and newly created micro-fissures; hydration damage mainly occurs along the bedding plane or the direction of primary fractures; samples with relatively-developed primary pores and fractures are most affected by hydration, samples with well-developed primary pores and natural fractures are less affected by hydration, samples with only pores are least affected by hydration; and the hydration intensity of shale plugs is affected by the development of primary pores and fractures, clay content and brittleness index jointly. Therefore, in shale reservoir stimulation, it is suggested that the pumping schedule, shut-in operation or clean-up with small choke during early flow-back process be considered according to the features of shale reservoir to enhance the complexity and connection of facture network and improve the stimulation effect.
[1] 许丹, 胡瑞林, 高玮, 等. 页岩纹层结构对水力裂缝扩展规律的影响[J]. 石油勘探与开发, 2015, 42(4): 523-528. XU Dan, HU Ruilin, GAO Wei, et al. Effects of laminated structure on hydraulic fracture propagation in shale[J]. Petroleum Exploration and Development, 2015, 42(4): 523-528. [2] ZHAO Jinzhou, YANG Hai, LI Yongming. China developing strategy for horizontal fracturing technology[J]. Oil & Gas Journal, 2013, 111(7): 70-79. [3] 马天寿, 陈平. 基于CT扫描技术研究页岩水化细观损伤特性[J]. 石油勘探与开发, 2014, 41(2): 227-233. MA Tianshou, CHEN Ping. Study of meso-damage characteristics of shale hydration based on CT scanning technology[J]. Petroleum Exploration & Development, 2014, 41(2): 227-233. [4] 石秉忠, 夏柏如, 林永学, 等. 硬脆性泥页岩水化裂缝发展的CT成像与机理[J]. 石油学报, 2012, 33(1): 137-142. SHI Bingzhong, XIA Bairu, LIN Yongxue, et al. CT imaging and mechanism analysis of crack development by hydration in hard-brittle shale formations[J]. Acta Petrolei Sinica, 2012, 33(1): 137-142. [5] 王萍, 屈展. 基于核磁共振的脆硬性泥页岩水化损伤演化研究[J]. 岩土力学, 2015, 36(3): 687-693. WANG Ping, QU Zhan. NMR technology based hydration damage evolution of hard brittle shale[J]. Rock and Soil Mechanics, 2015, 36(3): 687-693. [6] MAKHANOV K, DEHGHANPOUR H, KURU E. An experimental study of spontaneous imbibition in Horn River shales[R]. SPE 162650, 2012. [7] DUTTA R, LEE C, ODUMABO S, et al. Experimental investigation of fracturing fluid migration caused by spontaneous imbibition in fractured low-permeability sands[J]. SPE Reservoir Evaluation & Engineering, 2014, 17(1): 74-81. [8] 王家禄, 刘玉章, 陈茂谦, 等. 低渗透油藏裂缝动态渗吸机理实验研究[J]. 石油勘探与开发, 2009, 36(1): 86-90. WANG Jialu, LIU Yuzhang, CHEN Maoqian, et al. Experimental study on dynamic imbibition mechanism of low permeability reservoirs[J]. Petroleum Exploration and Development, 2009, 36(1): 86-90. [9] 汪吉林, 刘桂建, 王维忠, 等. 川东南龙马溪组页岩孔裂隙及渗透性特征[J]. 煤炭学报, 2013, 38(5): 772-776. WANG Jilin, LIU Guijian, WANG Weizhong, et al. Characteristics of pore-fissure and permeability of shales in the Longmaxi Formation in southeastern Sichuan Basin[J]. Journal of China Coal Society, 2013, 38(5): 772-776. [10] 钟建华, 刘圣鑫, 马寅生, 等. 页岩宏观破裂模式与微观破裂机理[J]. 石油勘探与开发, 2015, 42(2): 242-250. ZHONG Jianhua, LIU Shengxin, MA Yinsheng, et al. Macro-fracture mode and micro-fracture mechanism of shale[J]. Petroleum Exploration and Development, 2015, 42(2): 242-250. [11] 孙军昌, 陈静平, 杨正明, 等. 页岩储层岩芯核磁共振响应特征实验研究[J]. 科技导报, 2012, 30(14): 25-30. SUN Junchang, CHEN Jingping, YANG Zhengming, et al. Experimental study of the NMR characteristics of shale reservoir rock[J]. Science & Technology Review, 2012, 30(14): 25-30. [12] 牛磊. 核磁共振在页岩储层评价中的应用[D]. 北京: 中国地质大学(北京), 2011. NIU Lei. Application of nuclear magnetic resonance in shale reservoir evaluation[D]. Beijing: China University of Geosciences, 2011. [13] 梁利喜, 熊健, 刘向君. 水化作用和润湿性对页岩地层裂纹扩展的影响[J]. 石油实验地质, 2014, 36(6): 780-786. LIANG Lixi, XIONG Jian, LIU Xiangjun. Effects of hydration swelling and wettability on propagation mechanism of shale formation rock[J]. Petroleum Geology & Experiment, 2014, 36(6): 780-786. [14] DONG J J, HSU J Y, WU W J, et al. Stress-dependence of the permeability and porosity of sandstone and shale from TCDP Hole-A[J]. International Journal of Rock Mechanics and Mining Sciences, 2010, 47(7): 1141-1157. [15] 张睿, 宁正福, 张海山, 等. 裂缝性致密储层应力敏感机理新认识[J]. 天然气地球科学, 2016, 27(5): 918-923. ZHANG Rui, NING Zhengfu, ZHANG Haishan, et al. New insights and discussions on stress sensitivity of fractured tight reservoir[J]. Natural Gas Geoscience, 2016, 27(5): 918-923. [16] 周彤, 张士诚, 邹雨时, 等. 页岩气储层充填天然裂缝渗透率特征实验研究[J]. 西安石油大学学报(自然科学版), 2016, 31(1): 73-78. ZHOU Tong, ZHANG Shicheng, ZOU Yushi, et al. Experimental study on permeability characteristics of filled natural fractures in shale gas reservoir[J]. Journal of Xi’an Shiyou University (Natural Science Edition), 2016, 31(1): 73-78. [17] 闫传梁, 邓金根, 蔚宝华, 等. 页岩气储层井壁坍塌压力研究[J]. 岩石力学与工程学报, 2013, 32(8): 1595-1602. YAN Chuanliang, DENG Jingen, WEI Baohua, et al. Research on collapsing pressure of gas shale[J]. Chinese Journal of Rock Mechanics and Engineering, 2013, 32(8): 1595-1602.
2017, Vol. 44 
