Evaluation of rock brittleness and analysis of related factors for tight sandstone reservoirs

Abstract

Abstract: Brittleness of tight sandstone is a key element for exploration and development of tight reservoirs. Taking the Longmenshan Foreland Basin as an example, microscopic identification of sandstone composition and mineral content analysis with X-ray diffraction were carried out with the geological data, e.g. outcrop rock samples, drilling cores, rock slices, and geochemical characteristics. It was demonstrated that the sandstone has higher debris content. Accordingly, a rock brittleness formula corresponding to the regional setting was established. The research results show that the tight sandstone reservoirs in the Longmenshan Foreland Basin are more brittle. According to the analysis of rock mechanics features, the reservoir rocks in the study area are characterized by high Young's modulus and low Poisson's ratio, with better brittle behavior and fracturing potential. Finally, the correlation between geochemical characteristic index and brittleness of sandstones was analyzed, and the relationship between index of compositional variability (ICV) and chemical index of alteration (CIA) of tight sandstones were discussed.

Key words: tight sandstone, brittleness of composition, mechanical characteristics, geochemistry, oil and gas exploration

Wang Weiming, Li Yong, Wang Zhengjiang, Nie Zhou, Chen Bin, Yan Zhaokun, Yan Liang, Shao Chongjian, Lu Shengjie. Evaluation of rock brittleness and analysis of related factors for tight sandstone reservoirs[J]. China Petroleum Exploration, 2016, 21(6): 50-57.

References

[1] 付金华，喻建，徐黎明，等. 鄂尔多斯盆地致密油勘探开发新进展及规模富集可开发主控因素[J]. 中国石油勘探，2015,20(5):9-19. Fu Jinhua, Yu Jian, Xu Liming, et al. New progress in exploration and development of tight oil in Ordos Basin and main controlling factors of large scale enrichment and exploitable capacity[J]. China Petroleum Exploration, 2015,20(5):9-19.
[2] 罗啸泉，李书兵，何秀彬. 川西龙门山油气保存条件探讨[J]. 石油实验地质，2010,32(1):10-14. Luo Xiaoquan, Li Shubing, He Xiubin. Hydrocarbon preservation condition in Longmen Mountain，west Sichuan Basin[J]. Petroleum Geology & Experiment, 2010,32(1):10-14.
[3] 谢刚平，叶素娟，田苗. 川西坳陷致密砂岩气藏勘探开发实践新认识[J]. 天然气工业，2014,34(1):44-53. Xie Gangping，Ye Sujuan, Tian Miao. New understanding of exploration and development practices in tight sandstone gas reservoirs in western Sichuan depression[J]. Natural Gas Industry, 2014,34(1):44-53.
[4] 蒲秀刚，韩文中，周立宏，等. 黄骅坳陷沧东凹陷孔二段高位体系域细粒相区岩性特征及地质意义[J]. 中国石油勘探，2015,20(5):30-40. Pu Xiugang, Han Wenzhong, Zhou Lihong, et al. Lithologic characteristics and geological implication of fine-grained sedimentation in Ek2 high stand system tract of Cangdong sag, Huanghua depression[J]. China Petroleum Exploration, 2015,20(5):30-40.
[5] 吕正祥，刘四兵. 川西须家河组超致密砂岩成岩作用与相对优质储层形成机制[J]. 岩石学报，2009,25(10):2373-2383． Lv Zhengxiang, Liu Sibing. Ultra-tight sandstone diagenesis and mechanism for the formation of relatively high quality reservoir of Xujiahe Group in western Sichuan[J]. Acta Petrologica Sinica, 2009,25(10):2373-2383．
[6] 李勇，曾允孚. 龙门山前陆盆地充填序列[J]. 成都理工学院学报，1994,21(3):46-55. Li Yong, Zeng Yunfu. Fill Sequence of Longmen Mountains foreland basin[J]. Journal of Chengdu Institute of Technology, 1994,21(3):46-55.
[7] 曾允孚，李勇. 龙门山前陆盆地形成与演化[J]. 矿物岩石，1995,15(1):40-49. Zeng Yunfu，Li Yong. The formation and evolution of Longmen Mountains foreland basin[J]. Journal of Mineralogy and Petrology, 1995,15(1):40-49.
[8] 林小兵，刘莉萍，田景春，等. 川西坳陷合兴场—丰谷地区须家河组致密砂岩气藏精细勘探[J]. 石油与天然气地质，2013,34(1):77-84. Lin Xiaobing, Liu Liping, Tian Jingchun, et al. Fine exploration of tight sandstone gas reservoirs in the Xujiahe Formation Hexingchang-Fenggu area the western Sichuan Basin[J]. Oil & Gas Geology, 2013,34(1):77-84.
[9] 李钜源. 东营凹陷泥页岩矿物组成及脆度分析[J]. 沉积学报，2013,31(4):616-620. Li Juyuan. Analysis on mineral components and frangibility of shales in Dongying depression[J]. Acta Sedimentologica Sinica, 2013,31(4):616-620.
[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. Diao Haiyan. Rock mechanical properties and brittleness evaluation of shale reservoir[J]. Acta Petrologica Sinica, 2013, 29(9):3300-3306.
[11] 贾承造. 中国中西部前陆冲断带构造特征与天然气富集规律[J]. 石油勘探与开发，2005,32(4):9-15. Jia Chengzao. Foreland thrust-fold belt features and gas accumulation in Midwest China[J]. Petroleum Exploration and Develoment, 2005,32(4):9-15.
[12] 张本琪，余宏忠，姜在兴，等. 应用阴极发光技术研究母岩性质及成岩环境[J]. 石油勘探与开发，2003,30(3):117-120. Zhang Benqi, Yu Hongzhong, Jiang Zaixing, et al. Characteristics and diagenetic environments of source rocks by cathodoluminescence[J]. Petroleum Exploration and Develoment, 2003,30(3):117-120.
[13] 李勇，王成善，曾允孚. 造山作用与沉积响应[J]. 矿物岩石，2000, 20(2):49-56. Li Yong, Wang Chengshan, Zeng Yunfu. Orogeny and sedimentary response[J]. Journal of Mineralogy and Petrology, 2000,20(2):49-56.
[14] 李勇，贺佩，颜照坤，等. 晚三叠世龙门山前陆盆地动力学分析[J].成都理工大学学报，2010,37(4);401-411. Li Yong, He Pei, Yan Zhaokun, et al. Dynamics of Late Triassic Longmenshan foreland basin[J]. Journal of Chengdu Institute of Technology, 2010,37(4);401-411.
[15] Armstrong J, Lee Y, Verma S, et al. Geochemistry of sandstones from the upper Miocene Kudankulam Formation, southern India: Implications for provenance，weathering，and tectonic setting[J]．Journal of Sedimentary Research，2004,74(2): 285-297.
[16] 柏道远，周亮，王先辉，等. 湘东南南华系—寒武系砂岩地球化学特征及对华南新元古代—早古生代构造背景的制约[J]. 地质学报，2007,81(6):755-771. Bai Daoyuan，Zhou Liang，Wang Xianhui，et al. Geochemistry of Nanhuan - Cambrian sandstones in southeastern Hunan，and its constraints on Neoproterozoic-Early Paleozoic tectonic setting of South China[J]．Acta Geologica Sinica，2007,81(6):755-771.
[17] 林良彪，陈洪德，翟常博，等. 四川盆地西部须家河组砂岩组分及其古地理探讨[J]．石油实验地质，2006,28(6):511-517. Lin Liangbiao，Chen Hongde，Zhai Changbo，et al. Sandstone compositions and paleogeographic evolution of the Upper Triassic Xujiahe Formation in the western Sichuan basin，China[J].Petroleum Geology＆ Experiment，2006,28(6):511-517.
[18] 孟昱璋，刘鹏. 济阳坳陷渤南洼陷沙四上亚段碎屑岩成岩作用及其孔隙演化[J]. 中国石油勘探，2015,20(6):14-21. Meng Yuzhang, Liu Peng. Diagenesis and porous development of clastic rock in upper part of 4th member of Shahejie Formation in Bonan sag of Jiyang depression[J]. China Petroleum Exploration, 2015,20(6):14-21.
[19] 冯连君，储雪蕾，张启锐. 化学蚀变指数（CIA）及其在新元古代碎屑岩中的应用[J]. 地学前缘，2003,10(4):539-543. Feng Lianjun, Chu Xuelei, Zhang Qirui. CIA (Chemical Index of Alteration) and its applications in the Neoproterozoic clastic rocks[J]. Earth Science Frontiers, 2003,10(4):539-543.