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| RESEARCH ON THE DETERMINATION OF TYPE I AND II OF SHALE FORMATION FRACTURE TOUGHNESS |
| CHEN Jianguo1，DENG Jingen1，YUAN Junliang2，YAN Wei1，YU Baohua1，TAN Qiang1 |
(1. State Key Laboratory of Petroleum Resources and Prospecting，China University of Petroleum，Beijing 102249，China；
2. CNOOC Research Institute，Beijing 100027，China) |
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Abstract Fracture toughness of rock is one of the most important factors for evaluating the fracability of shale reservoir quantitatively. Based on straight seam grooving Brazilian disc test(SNBD)，fourteen shale pieces taken from Longmaxi Formation have been tested to measure fracture toughness of both type I and II. And by using the above results，combining with the logging data where the cores locate，the paper makes a regression of the shale fracture toughness with the data of density，acoustic time and GR logging. Comparing previous prediction model based on tensile strength，a direct relationship between fracture toughness and geophysical logging data was established in this paper. According to the prediction model，fracture toughness of organic-rich shale is proportional to the density and interval transit time of rock，while inversely proportional to its shale content. The more total organic carbon(TOC) or clay mineral is， the smaller fracture toughness is，it is more easily to extend forward after crack initiation. The results indicate that the fracture toughness of predication model has a pretty good correlation with that measured by SNBD. This paper can provide important theoretical basis for engineering design process to identify“Sweet Spots”.
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| [1] 龙鹏宇，张金川，李玉喜，等. 重庆及其周缘地区下古生界页岩气资源勘探潜力[J]. 天然气工业，2009，29(12).(LONG Pengyu，ZHANG Jinchuan，LI Yuxi，et al. Potentials of the Lower Palaeozoic shale gas resources in Chongqing and its adjacent areas[J]. Natural Gas Industry，2009，29(12).(in Chinese))
[2] 李庆辉，陈 勉，金 衍，等. 页岩脆性的室内评价方法及改进[J]. 岩石力学与工程学报，2012，31(8)：1 680–1 685.(LI Qinghui，CHEN Mian，JIN Yan，et al. Indoor evaluation method for shale brittleness and improvement[J]. Chinese Journal of Rock Mechanics and Engineering，2012，31(8)：1 680–1 685.(in Chinese))
[3] 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)：1 595–1 602.(YAN Chuanliang， DENG Jingen，YU Baohua，et al. Research on collapsing pressure of gas shale[J]. Chinese Journal of Rock Mechanics and Engineering，2013，32(8)：1 595–1 602.(in Chinese))
[4] 楼一珊，陈 勉，史明义，等. 岩石I、II型断裂韧性的测试及其影响因素分析[J]. 中国石油大学学报：自然科学版，2007，31(4)：85–89.(LOU Yishan，CHEN Mian，SHI Mingyi，et al. Measurement of type-I and type-IIfracture toughness for rocks and influence factors analysis[J]. Journal of China University of Petroleum：Natural Science，2007，31(4)：85–89.(in Chinese))
[5] KAHRAMAN S，ALTINDAG R. A brittleness index to estimate fracture toughness[J]. International Journal of Rock Mechanics and Mining Sciences，2004，41(2)：343–348.
[6] 张广清，陈 勉. 裂纹宽度对岩石断裂韧性测试结果的影响[J]. 石油大学学报：自然科学版，2002，26(6)：42–45.(ZHANG Guangqing，CHEN Mian. Influence of fracture width on rock toughness measurement[J]. Journal of China University of Petroleum： Natural Science，2002，26(6)：42–45.(in Chinese))
[7] ZHANG Z X. An empirical relation between mode I fracture toughness and the tensile strength of rock[J]. International Journal of Rock Mechanics and Mining Sciences，2002，39(3)：401–406.
[8] GOLSHANI A，ODA M，OKUI Y，et al. Numerical simulation of the excavation damaged zone around an opening in brittle rock[J]. International Journal of Rock Mechanics and Mining Sciences，2007，44(6)：835–845.
[9] GOLSHANI A，OKUI Y，ODA M，et al. A micromechanical model for brittle failure of rock and its relation to crack growth observed in triaxial compression tests of granite[J]. Mechanics of Materials，2006，38(4)：287–303.
[10] LI H B，ZHAO J，LI T J. Triaxial compression tests on a granite at different strain rates and confining pressures[J]. International Journal of Rock Mechanics and Mining Sciences，1999，36(8)：1 057–1 063.
[11] COWIE P A，SCHOLZ C H. Physical explanation for the displacement- length relationship of faults using a post-yield fracture mechanics model[J]. Journal of Structural Geology，1992，14(10)：1 133–1 148.
[12] 穆海林，刘兴浩，刘江浩，等. 非常规储层体积压裂技术在致密砂岩储层改造中的应用[J]. 天然气勘探与开发，2014，37(2).(MU Hailin，LIU Xinghao，LIU Jianghao，et al. Unconventional reservoir volume fracturing technology in the transformation of tight sandstone reservoirs[J]. Natural Gas Exploration and Development，2014，37(2). (in Chinese))
[13] 陈 勉，金 衍. 围压条件下岩石断裂韧性的实验研究[J]. 力学与实践，2001，23(4)：32–35.(CHEN Mian，JIN Yan. Study on the experiment for fracture toughness under confining pressure[J] Mechanics in Engineering，2001，23(4)：32–35.(in Chinese))
[14] 金 衍，张旭东. 利用测井资料预测深部地层岩石断裂韧性[J]. 岩石力学与工程学报，2001，20(4)：454–456.(JIN Yan，ZHANG Xudong. Determination of fracture toughness for deep well rock with geophysical logging data[J]. Chinese Journal of Rock Mechanics and Engineering，2001，20(4)：454–456.(in Chinese))
[15] 金 衍，陈 勉，王怀英，等. 利用测井资料预测岩石II型断裂韧性的方法研究[J]. 岩石力学与工程学报，2008，27(2)：3 630–3 635. (JIN Yan，CHEN Mian，WANG Huaiying，et al. Study on prediction method of fracture toughness of rock mode II by logging data. Chinese Journal of Rock Mechanics and Engineering，2008，27(2)：3 630–3 635. (in Chinese))
[16] 陈治喜，陈 勉. 岩石断裂韧性与声波速度相关性的试验研究[J]. 石油钻采工艺，1997，19(5)：56–60.(CHEN Zhixi，CHEN Mian. Experimental study on the relationship between rock fracture toughness and acoustic velocity[J]. Oil Drilling and Production Technology，1997，19(5)：56–60.(in Chinese))
[17] 赵 飞. 页岩气储层物理力学参数测试与地球物理解释方法研究.北京：中国石油大学(北京)，硕士学位论文：2013.(ZHAO Fei. Research of Mechanical Parameters with Geophysical Method in Shale Gas Reservoir. Beijing：China University of Petroleum(Beijing)，Master thesis：2013.(in Chinese))
[18] ATKINSON C，SMELSER R E，SANCHEZ J. Combined mode fracture via the cracked Brazilian disk test[J]. International Journal of Fracture，1982，18(4)：279–291.
[19] AWAJI H，SATO S. Combined mode fracture toughness measurement by the disk test[J]. Journal of Engineering Materials and Technology，1978，100(2)：175–182. |
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2015, Vol. 34 
