The key to shale gas exploration and exploitation is to form a large-scale fracture network through fracturing technology. The technology is based on the friability evaluation of shale reservoirs, which is closely related to the rock mechanics and deformation characteristics. Based on the observation of the macro and micro characteristics of the marine shales from Wufeng-Longmaxi Formations in the southern margin of Sichuan Basin, we obtained its rock mechanical parameters through uniaxial compression deformation tests. By combining the stress-strain curves and analysis of rupture morphology, we obtain the results as follows. The shale shows relatively low compressive strength and Young's modulus, and has significant brittle characteristics. The shale has two rupture modes, single cant shear rupture and splitting rupture, which are decided by the bedding and loading directions. The mechanical properties and rupture modes of shale are influenced by many factors, among which the heterogeneity is the most important.
[1] Chalmers G R,Bustin R M,Power I M.Characterization of gas shale pore systems by porosimetry,pycnometry,surface area,and field emission scanning electron microscopy/transmission electron microscopy image analyses:examples from the Barnett,Woodford,Haynesville,Marcellus,and Doig units[J]. AAPG Bulletin,2012,96(6):1099-1119.
[2] 刘大永,郭慧娟,彭平安,等. 下扬子地区下古生界页岩纳米孔隙特征及其控制因素[J].煤炭学报,2013,38(5):778-782.
[3] Wang G C,Ju Y W,Han K. Early Paleozoic shale properties and gas potential evaluation in Xiuwu Basin, western Lower Yangtze Platform[J]. Journal of Natural Gas Science & Engineering, 2015, 22(1):489-497.
[4] 朱炎铭,王阳,陈尚斌,等. 页岩储层孔隙结构多尺度定性-定量综合表征:以上扬子海相龙马溪组为例[J].地学前缘,2016,23(1):154-163.
[5] 金之钧,胡宗全,高波,等. 川东南地区五峰组-龙马溪组页岩气富集与高产控制因素[J]. 地学前缘, 2016,23(1):1-10.
[6] 姚军,孙海,黄朝琴,等. 页岩气藏开发中的关键力学问题[J].中国科学:物理学力学天文学, 2013, 43(12):1527-1547.
[7] 苗文培,姜汉桥,葛洪魁,等. 页岩气储层蠕变特性及其对页岩气开发的影响[J]. 油气地质与采收率, 2014, 21(4):97-100.
[8] Enderlin M B, Alsleben H, Beyer J A. Predicting fracability in shale reservoirs[C]//AAPG Annual Convention and Exhibition. Houston,2011:10-13.
[9] Josh M, Esteban L, Delle Piane C, et al. Laboratory characterisation of shale properties[J]. Journal of Petroleum Science and Engineering,2012,s 88-89(2):107-124.
[10] 刁海燕. 泥页岩储层岩石力学特性及脆性评价[J]. 岩石学报,2013,29(9):3300-3306.
[11] 袁俊亮,邓金根,张定宇,等. 页岩气储层可压裂性评价技术[J]. 石油学报,2013,34(3):523-528.
[12] 隋丽丽,杨永明,杨文光,等. 胜利油田东营凹陷区页岩可压裂性评价[J]. 煤炭学报,2015,40(7):1588-1594.
[13] Kuila U,Dewhurst D N,Siggins A F,et al. Stress anisotropy and velocity anisotropy in low porosity shale[J]. Tectonophysics,2011,503(1):34-44.
[14] Eseme E,Krooss B M,Littke R. Evolution of petrophysical properties of oil shales during high-temperature compaction tests:implications for petroleum expulsion[J].Marine and Petroleum Geology, 2012, 31(1):110-124.
[15] 刘俊新,刘伟,杨春和,等. 不同应变速率下泥页岩力学特性试验研究[J]. 岩土力学, 2014, 35(11):3093-3100.
[16] 李庆辉,陈勉,金衍,等. 含气页岩破坏模式及力学特性的试验研究[J]. 岩石力学与工程学报, 2012, 31(S2):3763-3771.
[17] 陈天宇,冯夏庭,张希巍,等. 黑色页岩力学特性及各向异性特性试验研究[J]. 岩石力学与工程学报, 2014,33(9):1772-1779.
[18] 贾长贵,陈军海,郭印同,等. 层状页岩力学特性及其破坏模式研究[J]. 岩土力学, 2013, 34(S2):57-61.
[19] 张永泽,刘俊新,冒海军,等. 单轴压缩下页岩力学特性的各向异性试验研究[J]. 金属矿山, 2015, 44(12):33-37.
[20] 陈尚斌,朱炎铭,王红岩,等. 四川盆地南缘下志留统龙马溪组页岩气储层矿物成分特征及意义[J]. 石油学报, 2011, 32(5):775-782.
[21] Jarvie D M,Hill R J,Rube T E,et al. Unconventional shale-gas systems:the Mississippian Barnett shale of north-central Texas as one model for thermogenic shale-gas assessment[J]. AAPG Bulletin,2007,91(4):475-499.
[22] Rickman R, Mullen M J, Petre J E, et al. A practical use of shale petrophysics for stimulation design optimization:all shale plays are not clones of the Barnett shale[C]//Spe Technical Conference and Exhibition. Society of Petroleum Engineers, 2008:1-11.
[23] 于炳松.页岩气储层的特殊性及其评价思路和内容[J]. 地学前缘,2012,19(3):252-258.
[24] 琚宜文, 卜红玲, 王国昌. 页岩气储层主要特征及其对储层改造的影响[J].地球科学进展,2014,29(4):492-506.
