超临界CO_2岩石致裂机制分析
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摘要
超临界CO_2是一种介于气体和液体之间的特殊状态的CO_2流体,具有低黏、高扩散性和零表面张力等独特的性质。利用超临界CO_2作为压裂液,有助于裂缝的起裂和扩展,同时可避免储层伤害。通过研究超临界CO_2射流破岩和压裂特性,分析得到了超临界CO_2岩石致裂机制。研究结果表明,超临界CO_2低黏等特性使其更容易进入岩石微孔和微缝之中,在岩石内部建立大小不一的流体压力系统,使岩石发生拉伸和剪切破坏;常规流体压裂起裂压力较高,裂缝一般为单条或多条平直裂缝,大多沿着同一方向贯穿强度较高的胶结颗粒,且裂缝断面光滑、平整;超临界CO_2压裂起裂压力相比于常规流体压裂低,在岩石中形成的裂缝网络较为复杂,裂缝互相连通,一般沿着强度较低的胶结物开裂,较少贯穿胶结颗粒,裂缝断面较为粗糙。该研究结果可为超临界CO_2压裂技术的实施提供理论支撑。
Supercritical CO_2 is a kind of fluid, which is in a special state between gas and liquid, with unique properties such as low viscosity, high diffusivity, and zero surface tension. Thus, supercritical CO_2 can be used as fracturing liquid to assist crack initiation and propagation without leading to the damage of reservoir zones. In this study, the mechanisms of supercritical CO_2 fracturing were obtained by studying and analysing the characteristics of rock breaking and fracturing with supercritical CO_2. The results indicate that, owing to its lower viscosity, supercritical CO_2 can easily penetrate into micro-pores and micro-cracks and build fluid pressure systems with varied magnitudes in rocks, which results in tensile and shear failure. In conventional hydraulic fracturing, the initiation pressure is high, and the fractures are single or multiple straight cracks. Most fractures penetrate through mineral grains with high strength along the same direction, and the fracture sections are smooth and flat. However, the initiation pressure of supercritical CO_2 fracturing is lower than that of conventional fluid fracturing methods; the fracture network is complex, and fractures are connected with each other. Generally, the induced fracture majorly initiates along the lower-strength grain boundaries, but seldom penetrates the mineral grains. Moreover, the fracture planes are rough. This study provides theoretical support for implementation of supercritical CO_2 fracturing technology.
Supercritical CO_2 is a kind of fluid, which is in a special state between gas and liquid, with unique properties such as low viscosity, high diffusivity, and zero surface tension. Thus, supercritical CO_2 can be used as fracturing liquid to assist crack initiation and propagation without leading to the damage of reservoir zones. In this study, the mechanisms of supercritical CO_2 fracturing were obtained by studying and analysing the characteristics of rock breaking and fracturing with supercritical CO_2. The results indicate that, owing to its lower viscosity, supercritical CO_2 can easily penetrate into micro-pores and micro-cracks and build fluid pressure systems with varied magnitudes in rocks, which results in tensile and shear failure. In conventional hydraulic fracturing, the initiation pressure is high, and the fractures are single or multiple straight cracks. Most fractures penetrate through mineral grains with high strength along the same direction, and the fracture sections are smooth and flat. However, the initiation pressure of supercritical CO_2 fracturing is lower than that of conventional fluid fracturing methods; the fracture network is complex, and fractures are connected with each other. Generally, the induced fracture majorly initiates along the lower-strength grain boundaries, but seldom penetrates the mineral grains. Moreover, the fracture planes are rough. This study provides theoretical support for implementation of supercritical CO_2 fracturing technology.
引文
[1]任闽燕,姜汉桥,李爱山,等.常规天然气增产改造技术研究进展及其发展方向[J].油气地质与采收率,2013,20(2):103-107.REN Min-yan,JIANG Han-qiao,LI Ai-shan,et al.Review on study progress of unconventional gas stimulation technology[J].Petroleum Geology and Recovery Efficiency,2013,20(2):103-107.
[2]张大权,张家强,王玉芳,等.中国非常规油气勘探开发进展与前景[J].资源科学,2015,37(5):1068-1075.ZHANG Da-quan,ZHANG Jia-qiang,WANG Yu-fang,et al.China's unconventional oil and gas exploration and development:Progress and prospects[J].Resources Science,2015,37(5):1068-1075.
[3]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(02):129-136.JIA Cheng-zao,ZHENG Min,ZHANG Yong-feng.Unconventional hydrocarbon resources in China and the prospect of exploration and development[J].Petroleum Exploration and Development,2012,39(2):129-136.
[4]HORNER P,HALLDORSON B,SLUTZ J A,et al.Shale gas water treatment value chain-A review of technologies,including case studies[C]//SPE Annual Technical Conference and Exhibition.Denver,Colorado:Society of Petroleum Engineers,2011.
[5]DIAZ-PEREZ A,CORTES-MONROY I,ROEGIERS J C.The role of water/clay interaction in the shale characterization[J].Journal of Petroleum Science and Engineering,2007,58(1):83-98.
[6]张东晓,杨婷云.美国页岩气水力压裂开发对环境的影响[J].石油勘探与开发,2015,42(6):801-806.ZHANG Dong-xiao,YANG Ting-yun.Environmental impacts of hydraulic fracturing in shale gas development in the United States[J].Petroleum Exploration and Development,2015,42(6):801-806.
[7]FANG C,CHEN W,AMRO M,et al.Simulation study of hydraulic fracturing using super critical CO2 in shale[C]//Abu Dhabi International Petroleum Exhibition and Conference.Abu Dhabi:Society of Petroleum Engineers,2014.
[8]王海柱,沈忠厚,李根生.超临界CO2开发页岩气技术[J].石油钻探技术,2011,39(3):30-35.WANG Hai-zhu,SHEN Zhong-hou,LI Gen-sheng.Feasibility analysis on shale gas exploitation with supercritical CO2[J].Petroleum Drilling Techniques,2011,39(3):30-35.
[9]李根生,王海柱,沈忠厚,等.超临界CO2射流在石油工程中应用研究与前景展望[J].中国石油大学学报(自然科学版),2013,37(5):76-80.LI Gen-sheng,WANG Hai-zhu,SHEN Zhong-hou,et al.Application investigations and prospects of supercritical CO2 jet in petroleum engineering[J].Journal of China University of Petroleum(Natural Science Edition),2013,37(5):76-80.
[10]孙宝江,张彦龙,杜庆杰,等.CO2在页岩中的吸附解吸性能评价[J].中国石油大学学报(自然科学版),2013,37(5):95-99.SUN Bao-jiang,ZHANG Yan-long,DU Qing-jie,et al.Property evaluation of CO2 adsorption and desorption on shale[J].Journal of China University of Petroleum(Natural Science Edition),2013,37(5):95-99.
[11]杜玉昆,王瑞和,倪红坚,等.超临界二氧化碳射流破岩试验[J].中国石油大学学报(自然科学版),2012,36(4):93-96.DU Yu-kun,WANG Rui-he,NI Hong-jian,et al.Rockbreaking experiment with supercritical carbon dioxide jet[J].Journal of China University of Petroleum(Natural Science Edition),2012,36(4):93-96.
[12]MIDDLETON R S,CAREY J W,CURRIER R P,et al.Shale gas and non-aqueous fracturing fluids:Opportunities and challenges for supercritical CO2[J].Applied Energy,2015,147(3):500-509.
[13]蒋翔,钱昆,王小书,等.基于声发射与NMR的超临界CO2对砂岩力学特性影响研究[J].岩土力学,2018,39(4):1355-1361.JIANG Xiang,QIAN Kun,WANG Xiao-shu,et al.Effect of supercritical CO2 on mechanical properties of sandstone using acoustic emission and NMR[J].Rock and Soil Mechanics,2018,39(4):1355-1361.
[14]王香增,吴金桥,张军涛.陆相页岩气层的CO2压裂技术应用探讨[J].天然气工业,2014,34(1):64-67.WANG Xiang-zeng,WU Jin-qiao,ZHANG Jun-tao.Application of CO2 fracturing technology for terrestrial shale gas reservoirs[J].Natural Gas Industry,2014,34(1):64-67.
[15]宋振云,苏伟东,杨延增,等.CO2干法加砂压裂技术研究与实践[J].天然气工业,2014,34(6):55-59.SONG Zhen-yun,SU Wei-dong,YANG Yan-zeng,et al.Experimental studies of CO2/sand dry-frac process[J].Natural Gas Industry,2014,34(6):55-59.
[16]程宇雄,李根生,王海柱,等.超临界CO2喷射压裂孔内增压机制[J].石油学报,2013,34(3):550-555.CHENG Yu-xiong,LI Gen-sheng,WAND Hai-zhu,et al.Pressure boost mechanism within cavity of the supercritical CO2 jet fracturing[J].Acta Petrolei Sinica,2013,34(3):550-555.
[17]郭建春,曾冀.超临界二氧化碳压裂井筒非稳态温度-压力耦合模型[J].石油学报,2015,36(2):203-209.GUO Jian-chun,ZENG Ji.A coupling model for wellbore transient temperature and pressure of fracturing with supercritical carbon dioxide[J].Acta Petrolei Sinica,2015,36(2):203-209.
[18]ISHIDA T.AE monitoring of hydraulic fracturing laboratory experiment with supercritical and liquid state CO2[C]//ISRM International Symposium-EUROCK 2012.Stockholm,Sweden:[s.n.],2012.
[19]KIZAKI A.Hydraulic fracturing in Inada granite and Ogino tuff with super critical carbon dioxide[C]//ISRMRegional Symposium-7th Asian Rock Mechanics Symposium.Seoul,Korea:[s.n.],2012.
[20]INUI S,ISHIDA T,NAGAYA Y,et al.AE monitoring of hydraulic fracturing experiments in granite blocks using supercritical CO2,water and viscous oil[C]//US Rock Mechanics/Geomechanics Symposium.Minneapolis:[s.n.],2014.
[21]CHEN Y,NAGAYA Y,ISHIDA T.Observations of fractures induced by hydraulic fracturing in anisotropic granite[J].Rock Mechanics and Rock Engineering,2015,48(4):1455-1461.
[22]LI X,FENG Z,HAN G,et al.Hydraulic fracturing in shale with H2O,CO2 and N2[C]//US Rock Mechanics/Geomechanics Symposium.San Francisco,CA:[s.n.],2015.
[23]陈立强,田守嶒,李根生,等.超临界CO2压裂起裂压力模型与参数敏感性研究[J].岩土力学,2015,36(增刊2):125-131.CHEN Li-qiang,TIAN Shou-ceng,LI Gen-sheng,et al.Initiation pressure models for supercritical CO2 fracturing and sensitivity analysis[J].Rock and Soil Mechanics,2015,36(Supp.2):125-131.
[24]WANG H,LI G,SHEN Z,et al.Experiment on rock breaking with supercritical carbon dioxide jet[J].Journal of Petroleum Science and Engineering,2015,127:305-310.
[25]汤积仁,卢义玉,陈钰婷,等.超临界CO2作用下页岩力学特性损伤的试验研究[J].岩土力学,2018,39(3):797-802.TANG Ji-ren,LU Yi-yu,CHEN Yu-ting,et al.Experimental study of damage of shale mechanical properties under supercritical CO2[J].Rock and Soil Mechanics,2018,39(3):797-802.
[26]SONDERGELD C H,AMBROSE R J,RAI C S,et al.Micro-structural studies of gas shales[C]//SPEUnconventional Gas Conference.Pittsburgh,Pennsylvania:[s.n.],2010.
[27]CURTIS M E,SONDERGELD C H,AMBROSE R J,et al.Microstructural investigation of gas shales in two and three dimensions using nanometer-scale resolution imaging[J].AAPG Bulletin,2012,96(4):665-677.
[28]KOLLE J J.Coiled-tubing drilling with supercritical carbon dioxide[R].SPE/CIM International Conference on Horizontal Well Technology.Calgary,Alberta:[s.n.],2000.
[2]张大权,张家强,王玉芳,等.中国非常规油气勘探开发进展与前景[J].资源科学,2015,37(5):1068-1075.ZHANG Da-quan,ZHANG Jia-qiang,WANG Yu-fang,et al.China's unconventional oil and gas exploration and development:Progress and prospects[J].Resources Science,2015,37(5):1068-1075.
[3]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(02):129-136.JIA Cheng-zao,ZHENG Min,ZHANG Yong-feng.Unconventional hydrocarbon resources in China and the prospect of exploration and development[J].Petroleum Exploration and Development,2012,39(2):129-136.
[4]HORNER P,HALLDORSON B,SLUTZ J A,et al.Shale gas water treatment value chain-A review of technologies,including case studies[C]//SPE Annual Technical Conference and Exhibition.Denver,Colorado:Society of Petroleum Engineers,2011.
[5]DIAZ-PEREZ A,CORTES-MONROY I,ROEGIERS J C.The role of water/clay interaction in the shale characterization[J].Journal of Petroleum Science and Engineering,2007,58(1):83-98.
[6]张东晓,杨婷云.美国页岩气水力压裂开发对环境的影响[J].石油勘探与开发,2015,42(6):801-806.ZHANG Dong-xiao,YANG Ting-yun.Environmental impacts of hydraulic fracturing in shale gas development in the United States[J].Petroleum Exploration and Development,2015,42(6):801-806.
[7]FANG C,CHEN W,AMRO M,et al.Simulation study of hydraulic fracturing using super critical CO2 in shale[C]//Abu Dhabi International Petroleum Exhibition and Conference.Abu Dhabi:Society of Petroleum Engineers,2014.
[8]王海柱,沈忠厚,李根生.超临界CO2开发页岩气技术[J].石油钻探技术,2011,39(3):30-35.WANG Hai-zhu,SHEN Zhong-hou,LI Gen-sheng.Feasibility analysis on shale gas exploitation with supercritical CO2[J].Petroleum Drilling Techniques,2011,39(3):30-35.
[9]李根生,王海柱,沈忠厚,等.超临界CO2射流在石油工程中应用研究与前景展望[J].中国石油大学学报(自然科学版),2013,37(5):76-80.LI Gen-sheng,WANG Hai-zhu,SHEN Zhong-hou,et al.Application investigations and prospects of supercritical CO2 jet in petroleum engineering[J].Journal of China University of Petroleum(Natural Science Edition),2013,37(5):76-80.
[10]孙宝江,张彦龙,杜庆杰,等.CO2在页岩中的吸附解吸性能评价[J].中国石油大学学报(自然科学版),2013,37(5):95-99.SUN Bao-jiang,ZHANG Yan-long,DU Qing-jie,et al.Property evaluation of CO2 adsorption and desorption on shale[J].Journal of China University of Petroleum(Natural Science Edition),2013,37(5):95-99.
[11]杜玉昆,王瑞和,倪红坚,等.超临界二氧化碳射流破岩试验[J].中国石油大学学报(自然科学版),2012,36(4):93-96.DU Yu-kun,WANG Rui-he,NI Hong-jian,et al.Rockbreaking experiment with supercritical carbon dioxide jet[J].Journal of China University of Petroleum(Natural Science Edition),2012,36(4):93-96.
[12]MIDDLETON R S,CAREY J W,CURRIER R P,et al.Shale gas and non-aqueous fracturing fluids:Opportunities and challenges for supercritical CO2[J].Applied Energy,2015,147(3):500-509.
[13]蒋翔,钱昆,王小书,等.基于声发射与NMR的超临界CO2对砂岩力学特性影响研究[J].岩土力学,2018,39(4):1355-1361.JIANG Xiang,QIAN Kun,WANG Xiao-shu,et al.Effect of supercritical CO2 on mechanical properties of sandstone using acoustic emission and NMR[J].Rock and Soil Mechanics,2018,39(4):1355-1361.
[14]王香增,吴金桥,张军涛.陆相页岩气层的CO2压裂技术应用探讨[J].天然气工业,2014,34(1):64-67.WANG Xiang-zeng,WU Jin-qiao,ZHANG Jun-tao.Application of CO2 fracturing technology for terrestrial shale gas reservoirs[J].Natural Gas Industry,2014,34(1):64-67.
[15]宋振云,苏伟东,杨延增,等.CO2干法加砂压裂技术研究与实践[J].天然气工业,2014,34(6):55-59.SONG Zhen-yun,SU Wei-dong,YANG Yan-zeng,et al.Experimental studies of CO2/sand dry-frac process[J].Natural Gas Industry,2014,34(6):55-59.
[16]程宇雄,李根生,王海柱,等.超临界CO2喷射压裂孔内增压机制[J].石油学报,2013,34(3):550-555.CHENG Yu-xiong,LI Gen-sheng,WAND Hai-zhu,et al.Pressure boost mechanism within cavity of the supercritical CO2 jet fracturing[J].Acta Petrolei Sinica,2013,34(3):550-555.
[17]郭建春,曾冀.超临界二氧化碳压裂井筒非稳态温度-压力耦合模型[J].石油学报,2015,36(2):203-209.GUO Jian-chun,ZENG Ji.A coupling model for wellbore transient temperature and pressure of fracturing with supercritical carbon dioxide[J].Acta Petrolei Sinica,2015,36(2):203-209.
[18]ISHIDA T.AE monitoring of hydraulic fracturing laboratory experiment with supercritical and liquid state CO2[C]//ISRM International Symposium-EUROCK 2012.Stockholm,Sweden:[s.n.],2012.
[19]KIZAKI A.Hydraulic fracturing in Inada granite and Ogino tuff with super critical carbon dioxide[C]//ISRMRegional Symposium-7th Asian Rock Mechanics Symposium.Seoul,Korea:[s.n.],2012.
[20]INUI S,ISHIDA T,NAGAYA Y,et al.AE monitoring of hydraulic fracturing experiments in granite blocks using supercritical CO2,water and viscous oil[C]//US Rock Mechanics/Geomechanics Symposium.Minneapolis:[s.n.],2014.
[21]CHEN Y,NAGAYA Y,ISHIDA T.Observations of fractures induced by hydraulic fracturing in anisotropic granite[J].Rock Mechanics and Rock Engineering,2015,48(4):1455-1461.
[22]LI X,FENG Z,HAN G,et al.Hydraulic fracturing in shale with H2O,CO2 and N2[C]//US Rock Mechanics/Geomechanics Symposium.San Francisco,CA:[s.n.],2015.
[23]陈立强,田守嶒,李根生,等.超临界CO2压裂起裂压力模型与参数敏感性研究[J].岩土力学,2015,36(增刊2):125-131.CHEN Li-qiang,TIAN Shou-ceng,LI Gen-sheng,et al.Initiation pressure models for supercritical CO2 fracturing and sensitivity analysis[J].Rock and Soil Mechanics,2015,36(Supp.2):125-131.
[24]WANG H,LI G,SHEN Z,et al.Experiment on rock breaking with supercritical carbon dioxide jet[J].Journal of Petroleum Science and Engineering,2015,127:305-310.
[25]汤积仁,卢义玉,陈钰婷,等.超临界CO2作用下页岩力学特性损伤的试验研究[J].岩土力学,2018,39(3):797-802.TANG Ji-ren,LU Yi-yu,CHEN Yu-ting,et al.Experimental study of damage of shale mechanical properties under supercritical CO2[J].Rock and Soil Mechanics,2018,39(3):797-802.
[26]SONDERGELD C H,AMBROSE R J,RAI C S,et al.Micro-structural studies of gas shales[C]//SPEUnconventional Gas Conference.Pittsburgh,Pennsylvania:[s.n.],2010.
[27]CURTIS M E,SONDERGELD C H,AMBROSE R J,et al.Microstructural investigation of gas shales in two and three dimensions using nanometer-scale resolution imaging[J].AAPG Bulletin,2012,96(4):665-677.
[28]KOLLE J J.Coiled-tubing drilling with supercritical carbon dioxide[R].SPE/CIM International Conference on Horizontal Well Technology.Calgary,Alberta:[s.n.],2000.