深层海相页岩脆性特征分析与表征
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摘要
针对中国南方深层海相页岩气开发尚未突破的现实,以四川盆地五峰组—龙马溪组页岩为研究对象,聚焦深层海相页岩的脆性表征,建立了基于全应力—应变曲线的脆性定量评价指标,以峰值应变和峰后坡降陡度分别表示页岩发生脆性破坏的难易程度和充分程度。在此基础上,通过对硅质页岩、钙质硅质页岩、钙质页岩和黏土质硅质页岩开展高围压三轴压缩岩石力学实验,明确了围压对页岩脆性的影响,建立了适用于研究区深层海相页岩的脆性评价方法,开展了深浅层页岩脆性对比。结果表明,低围压时,围压主要表现为对页岩抗压强度的强化,脆性随围压增加而增强,高围压时,围压则主要表现为对裂缝产生与扩展的抑制,脆性随围压增加而减弱;以弹性参数为岩性指示因子,以断裂韧性为围压指示因子,建立了力学脆性指数,可作为矿物法和弹性参数法的补充,有效应用于3 500 m以深页岩储集层的脆性评价;硅质页岩和钙质硅质页岩在4 500～5 000 m仍具有优质储集层的潜力,但是深层海相页岩脆性的弱化使得优质储集层厚度减小。
Aiming at the challenges of deep-marine shale gas development in the southern China, and taking the Wufeng-Longmaxi shale in the Sichuan basin as the research object, the paper focuses on the brittleness analysis and characterization of deep marine shale, estab-lishes a quantitative assessment index of shale brittleness based on the complete stress-strain curve, and uses the peak strain and steepness of post-peak slope as indicators to express the degrees of brittle failure complexity and adequacy, respectively. Then according to the results of high-confining-pressure triaxial compression tests for main shale lithofacies including siliceous shale, calcareous-siliceous shale, calcareous shale and clay-siliceous shale, the paper analyzes the influence of confining pressure on shale brittleness, establishes a brittleness eval-uation method for deep marine shales and compares the brittleness of deep and shallow shale reservoirs. The results show that under low confining pressure, the pressure mainly enhances the compressive strength of the shale and the shale brittleness increases with the enhance-ment of the confining pressure; while under high confining pressure, the pressure mainly restrains the initiation and propagation of fractures and the shale brittleness decreases with the weakening of the confining pressure; using elastic parameters as the indicators of lithology and fracture toughness as an indicator of confining pressure, a mechanical brittleness index is established, which can be effectively used in the brittleness evaluation of the deep shale reservoirs below 3 500 m as the supplementary of the mineral method and elastic parameter method;the siliceous shale and calcareous-siliceous shale still have the potential to be favorable reservoirs at the depth of 4 500-5 000m. However,the deep marine shales have thinner "sweet spot" layers and lower development potential due to the brittleness weakening.
Aiming at the challenges of deep-marine shale gas development in the southern China, and taking the Wufeng-Longmaxi shale in the Sichuan basin as the research object, the paper focuses on the brittleness analysis and characterization of deep marine shale, estab-lishes a quantitative assessment index of shale brittleness based on the complete stress-strain curve, and uses the peak strain and steepness of post-peak slope as indicators to express the degrees of brittle failure complexity and adequacy, respectively. Then according to the results of high-confining-pressure triaxial compression tests for main shale lithofacies including siliceous shale, calcareous-siliceous shale, calcareous shale and clay-siliceous shale, the paper analyzes the influence of confining pressure on shale brittleness, establishes a brittleness eval-uation method for deep marine shales and compares the brittleness of deep and shallow shale reservoirs. The results show that under low confining pressure, the pressure mainly enhances the compressive strength of the shale and the shale brittleness increases with the enhance-ment of the confining pressure; while under high confining pressure, the pressure mainly restrains the initiation and propagation of fractures and the shale brittleness decreases with the weakening of the confining pressure; using elastic parameters as the indicators of lithology and fracture toughness as an indicator of confining pressure, a mechanical brittleness index is established, which can be effectively used in the brittleness evaluation of the deep shale reservoirs below 3 500 m as the supplementary of the mineral method and elastic parameter method;the siliceous shale and calcareous-siliceous shale still have the potential to be favorable reservoirs at the depth of 4 500-5 000m. However,the deep marine shales have thinner "sweet spot" layers and lower development potential due to the brittleness weakening.
引文
[1]徐政语，梁兴，王维旭，等.上扬子区页岩气甜点分布控制因素探讨--以上奥陶统五峰组-下志留统龙马溪组为例[J].天然气工业，2016,36(9):35-43.XU Zhengyu,LIANG Xing,WANG Weixu,et al.Controlling factors for shale gas sweet spots distribution in the Upper Yangtze region:a case study of the Upper Ordovician Wufeng Fm-Lower Silurian Longmaxi Fm,Sichuan basin[J].Natural Gas Industry,2016,36(9):35-43.
[2]董大忠，高世葵，黄金亮，等.论四川盆地页岩气资源勘探开发前景[J].天然气工业，2014,34(12):1-15.DONG Dazhong,GAO Shikui,HUANG Jinliang,et al.A discussion on the shale gas exploration&development prospect in the Sichuan basin[J].Natural Gas Industry,2014,34(12):1-15.
[3]蒋裕强，董大忠，漆麟，等.页岩气储层的基本特征及其评价[J].天然气工业，2010,30(10):7-12.JIANG Yuqiang,DONG Dazhong,QI Lin,et al.Basic features and evaluation of shale gas reservoirs[J].Natural Gas Industry,2010,30(10):7-12.
[4]朱德宇，罗群，姜振学，等.吉木萨尔凹陷芦草沟组致密储集层裂缝特征及主控因素[J].新疆石油地质，2019,40(3):276-283.ZHU Deyu,LUO Qun,JIANG Zhenxue,et al.Fracture characteristics and main controlling factors of tight reservoirs in Lucaogou formation of Jimsar sag,Junggar basin[J].Xinjiang Petroleum Geology,2019,40(3):276-283.
[5]李庆辉，陈勉，WANG F P，等.工程因素对页岩气产量的影响--以北美Haynesville页岩气藏为例[J].天然气工业，2012,32(4):54-59.LI Qinghui,CHEN Mian,WANG F P,et al.Influence of engineering factors on shale gas productivity:a case study from the Haynesville shale gas reservoir in north America[J].Natural Gas Industry,2012,32(4):54-59.
[6]吴奇，梁兴，鲜成钢，等.地质-工程一体化高效开发中国南方海相页岩气[J].中国石油勘探，2015,20(4):1-23.WU Qi,LIANG Xing,XIAN Chenggang,et al.Geoscience-to-production integration ensures effective and efficient south China marine shale gas development[J].China Petroleum Exploration,2015,20(4):1-23.
[7]唐颖，邢云，李乐忠，等.页岩储层可压裂性影响因素及评价方法[J].地学前缘，2012,19(5):356-363.TANG Ying,XING Yun,LI Lezhong,et al.Influence factors and evaluation methods of the gas shale fracability[J].Earth Science Frontiers,2012,19(5):356-363.
[8]JARVIE D M,HILL R J,RUBLE T E,et al.Unconventional shalegas 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.
[9]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[R].SPE 115258,2008.
[10]张晨晨，董大忠，王玉满，等.页岩储集层脆性研究进展[J].新疆石油地质，2017,38(1):111-118.ZHANG Chenchen,DONG Dazhong,WANG Yuman,et al.Research progress on brittleness of shale reservoirs[J].Xinjiang Petroleum Geology,2017,38(1):111-118.
[11]刘致水，孙赞东.新型脆性因子及其在泥页岩储集层预测中的应用[J].石油勘探与开发，2015,42(1):117-124.LIU Zhishui,SUN Zandong.New brittleness indexes and their application in shale/clay gas reservoir prediction[J].Petroleum Exploration and Development,2015,42(1):117-124.
[12]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.Brittle fractures characteristics and micro-fracture mechanism of shale[J].Petroleum Exploration and Development,2015,42(2):242-250.
[13]陈勉，金衍，卢运虎.页岩气开发：岩石力学的机遇与挑战[J].中国科学(物理学力学天文学)，2017,47(11):114 601.CHEN Mian,JIN Yan,LU Yunhu.Shale gas development:opportunities and challenges for rock mechanics[J].Scientia Sinica(Physica,Mechanica&Astronomica),2017,47(11):114 601.
[14]陈勉，葛洪魁，赵金洲，等.页岩油气高效开发的关键基础理论与挑战[J].石油钻探技术，2015,43(5):7-14.CHEN Mian,GE Hongkui,ZHAO Jinzhou,et al.The key fundamentals for the efficient exploration of shale oil and gas and its related challenges[J].Petroleum Drilling Techniques,2015,43(5):7-14.
[15]蒋廷学，卞晓冰，王海涛，等.深层页岩气水平井体积压裂技术[J].天然气工业，2017,37(1):90-96.JIANG Tingxue,BIAN Xiaobing,WANG Haitao,et al.Volume fracturing of deep shale gas horizontal wells[J].Natural Gas Industry,2017,37(1):90-96.
[16]曾义金，陈作，卞晓冰.川东南深层页岩气分段压裂技术的突破与认识[J].天然气工业，2016,36(1):61-67.ZENG Yijin,CHEN Zuo,BIAN Xiaobing.Breakthrough in staged fracturing technology for deep shale gas reservoirs in SE Sichuan basin and its implications[J].Natural Gas Industry,2016,36(1):61-67.
[17]张晨晨，王玉满，董大忠，等.四川盆地五峰组-龙马溪组页岩脆性评价与“甜点层”预测[J].天然气工业，2016,36(9):51-60.ZHANG Chenchen,WANG Yuman,DONG Dazhong,et al.Evaluation of the Wufeng-Longmaxi shale brittleness and prediction of“sweet spot layers”in the Sichuan basin[J].Natural Gas Industry,2016,36(9):51-60.
[18]王玉满，王宏坤，张晨晨，等.四川盆地南部深层五峰组-龙马溪组裂缝孔隙评价[J].石油勘探与开发，2017,44(4):531-539.WANG Yuman,WANG Hongkun,ZHANG Chenchen,et al.Fracture pore evaluation of the Upper Ordovician Wufeng to Lower Silurian Longmaxi formations in southern Sichuan basin,SW China[J].Petroleum Exploration and Development,2017,44(4):531-539.
[19]陈勉，金衍，张广清.石油工程岩石力学[M].北京：科学出版社，2008.CHEN Mian,JIN Yan,ZHANG Guangqing.Rock mechanics in petroleum engineering[M].Beijing:Science Press,2008.
[20]BISHOP A W.Progressive failure with special reference to the mechanism causing it[C]//Proceedings of the Geotechnical Conference on the Shear Strength of Natural Soils and Rocks.Oslo:Norwegian Geotechnical Institute,1967:142-150.
[21]HUCKA V,DAS B.Brittleness determination of rocks by different methods[J].International Journal of Rock Mechanics and Mining Sciences&Geomechanics Abstracts,1974,11(10):389-392.
[22]HAJIABDOLMAJID V,KAISER P.Brittleness of rock and stability assessment in hard rock tunneling[J].Tunnelling and Underground Space Technology,2003,18(1):35-48.
[23]JIN X C,SHAH S N,ROEGIERS J C,et al.Fracability evaluation in shale reservoirs-an integrated petrophysics and geomechanics approach[R].SPE 168589,2014.
[24]HONDA H,SANADA Y.Hardness of coal[J].Fuel,1956,35(4):451-461.
[25]PROTODYAKONOV M M.Mechanical properties and drillability of rocks[C]//Proceedings of the 5th Symposium on Rock Mechanics.University of Minnesota,Minneapolis,Minnesota,USA,1962:103-118.
[26]LAWN B R,MARSHALL D B.Hardness,toughness,and brittleness-an in RHOB tation analysis[J].Journal of the American Ceramic Society,1979,62(7):347.
[27]JOHNSTON I W.Strength of intact geomechanical materials[J].Journal of Geotechnical Engineering,1985,111(6):730-749.
[28]BAZANT Z P,KAZEMI M T.Determination of fracture energy,process zone longth and brittleness number from size effect,with application to rock and conerete[J].International Journal of Fracture,1990,44(2):111-131.
[29]AUBERTIN M,GILL D E,SIMON R.On the use of the brittleness index modified(BIM)to estimate the post-peak behavior of rocks[R]//1st North American Rock Mechanics Symposium,Austin,Texas.American Rock Mechanics Association,1994.
[30]GEORGE E A.Brittle failure of rock material:test results and constitutive models[J].AA Balkema/Rotterdam/Brolkfield,1995:123-128.
[31]ALTINDAG R.Correlation of specific energy with rock brittleness concepts on rock cutting[J].Journal of the South African Institute of Mining and Metallurgy,2003,103(3):163-171.
[32]YAGIZ S.An investigation on the relationship between rock strength and brittleness[C]//Proceedings of the 59th Geological Congress of Turkey.Ankara,Turkey:MTA General Directory Press,2006:352.
[33]TARASOV B,POTVIN Y.Universal criteria for rock brittleness estimation under triaxial compression[J].International Journal of Rock Mechanics&Mining Sciences,2013,59:57-69.
[2]董大忠，高世葵，黄金亮，等.论四川盆地页岩气资源勘探开发前景[J].天然气工业，2014,34(12):1-15.DONG Dazhong,GAO Shikui,HUANG Jinliang,et al.A discussion on the shale gas exploration&development prospect in the Sichuan basin[J].Natural Gas Industry,2014,34(12):1-15.
[3]蒋裕强，董大忠，漆麟，等.页岩气储层的基本特征及其评价[J].天然气工业，2010,30(10):7-12.JIANG Yuqiang,DONG Dazhong,QI Lin,et al.Basic features and evaluation of shale gas reservoirs[J].Natural Gas Industry,2010,30(10):7-12.
[4]朱德宇，罗群，姜振学，等.吉木萨尔凹陷芦草沟组致密储集层裂缝特征及主控因素[J].新疆石油地质，2019,40(3):276-283.ZHU Deyu,LUO Qun,JIANG Zhenxue,et al.Fracture characteristics and main controlling factors of tight reservoirs in Lucaogou formation of Jimsar sag,Junggar basin[J].Xinjiang Petroleum Geology,2019,40(3):276-283.
[5]李庆辉，陈勉，WANG F P，等.工程因素对页岩气产量的影响--以北美Haynesville页岩气藏为例[J].天然气工业，2012,32(4):54-59.LI Qinghui,CHEN Mian,WANG F P,et al.Influence of engineering factors on shale gas productivity:a case study from the Haynesville shale gas reservoir in north America[J].Natural Gas Industry,2012,32(4):54-59.
[6]吴奇，梁兴，鲜成钢，等.地质-工程一体化高效开发中国南方海相页岩气[J].中国石油勘探，2015,20(4):1-23.WU Qi,LIANG Xing,XIAN Chenggang,et al.Geoscience-to-production integration ensures effective and efficient south China marine shale gas development[J].China Petroleum Exploration,2015,20(4):1-23.
[7]唐颖，邢云，李乐忠，等.页岩储层可压裂性影响因素及评价方法[J].地学前缘，2012,19(5):356-363.TANG Ying,XING Yun,LI Lezhong,et al.Influence factors and evaluation methods of the gas shale fracability[J].Earth Science Frontiers,2012,19(5):356-363.
[8]JARVIE D M,HILL R J,RUBLE T E,et al.Unconventional shalegas 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.
[9]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[R].SPE 115258,2008.
[10]张晨晨，董大忠，王玉满，等.页岩储集层脆性研究进展[J].新疆石油地质，2017,38(1):111-118.ZHANG Chenchen,DONG Dazhong,WANG Yuman,et al.Research progress on brittleness of shale reservoirs[J].Xinjiang Petroleum Geology,2017,38(1):111-118.
[11]刘致水，孙赞东.新型脆性因子及其在泥页岩储集层预测中的应用[J].石油勘探与开发，2015,42(1):117-124.LIU Zhishui,SUN Zandong.New brittleness indexes and their application in shale/clay gas reservoir prediction[J].Petroleum Exploration and Development,2015,42(1):117-124.
[12]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.Brittle fractures characteristics and micro-fracture mechanism of shale[J].Petroleum Exploration and Development,2015,42(2):242-250.
[13]陈勉，金衍，卢运虎.页岩气开发：岩石力学的机遇与挑战[J].中国科学(物理学力学天文学)，2017,47(11):114 601.CHEN Mian,JIN Yan,LU Yunhu.Shale gas development:opportunities and challenges for rock mechanics[J].Scientia Sinica(Physica,Mechanica&Astronomica),2017,47(11):114 601.
[14]陈勉，葛洪魁，赵金洲，等.页岩油气高效开发的关键基础理论与挑战[J].石油钻探技术，2015,43(5):7-14.CHEN Mian,GE Hongkui,ZHAO Jinzhou,et al.The key fundamentals for the efficient exploration of shale oil and gas and its related challenges[J].Petroleum Drilling Techniques,2015,43(5):7-14.
[15]蒋廷学，卞晓冰，王海涛，等.深层页岩气水平井体积压裂技术[J].天然气工业，2017,37(1):90-96.JIANG Tingxue,BIAN Xiaobing,WANG Haitao,et al.Volume fracturing of deep shale gas horizontal wells[J].Natural Gas Industry,2017,37(1):90-96.
[16]曾义金，陈作，卞晓冰.川东南深层页岩气分段压裂技术的突破与认识[J].天然气工业，2016,36(1):61-67.ZENG Yijin,CHEN Zuo,BIAN Xiaobing.Breakthrough in staged fracturing technology for deep shale gas reservoirs in SE Sichuan basin and its implications[J].Natural Gas Industry,2016,36(1):61-67.
[17]张晨晨，王玉满，董大忠，等.四川盆地五峰组-龙马溪组页岩脆性评价与“甜点层”预测[J].天然气工业，2016,36(9):51-60.ZHANG Chenchen,WANG Yuman,DONG Dazhong,et al.Evaluation of the Wufeng-Longmaxi shale brittleness and prediction of“sweet spot layers”in the Sichuan basin[J].Natural Gas Industry,2016,36(9):51-60.
[18]王玉满，王宏坤，张晨晨，等.四川盆地南部深层五峰组-龙马溪组裂缝孔隙评价[J].石油勘探与开发，2017,44(4):531-539.WANG Yuman,WANG Hongkun,ZHANG Chenchen,et al.Fracture pore evaluation of the Upper Ordovician Wufeng to Lower Silurian Longmaxi formations in southern Sichuan basin,SW China[J].Petroleum Exploration and Development,2017,44(4):531-539.
[19]陈勉，金衍，张广清.石油工程岩石力学[M].北京：科学出版社，2008.CHEN Mian,JIN Yan,ZHANG Guangqing.Rock mechanics in petroleum engineering[M].Beijing:Science Press,2008.
[20]BISHOP A W.Progressive failure with special reference to the mechanism causing it[C]//Proceedings of the Geotechnical Conference on the Shear Strength of Natural Soils and Rocks.Oslo:Norwegian Geotechnical Institute,1967:142-150.
[21]HUCKA V,DAS B.Brittleness determination of rocks by different methods[J].International Journal of Rock Mechanics and Mining Sciences&Geomechanics Abstracts,1974,11(10):389-392.
[22]HAJIABDOLMAJID V,KAISER P.Brittleness of rock and stability assessment in hard rock tunneling[J].Tunnelling and Underground Space Technology,2003,18(1):35-48.
[23]JIN X C,SHAH S N,ROEGIERS J C,et al.Fracability evaluation in shale reservoirs-an integrated petrophysics and geomechanics approach[R].SPE 168589,2014.
[24]HONDA H,SANADA Y.Hardness of coal[J].Fuel,1956,35(4):451-461.
[25]PROTODYAKONOV M M.Mechanical properties and drillability of rocks[C]//Proceedings of the 5th Symposium on Rock Mechanics.University of Minnesota,Minneapolis,Minnesota,USA,1962:103-118.
[26]LAWN B R,MARSHALL D B.Hardness,toughness,and brittleness-an in RHOB tation analysis[J].Journal of the American Ceramic Society,1979,62(7):347.
[27]JOHNSTON I W.Strength of intact geomechanical materials[J].Journal of Geotechnical Engineering,1985,111(6):730-749.
[28]BAZANT Z P,KAZEMI M T.Determination of fracture energy,process zone longth and brittleness number from size effect,with application to rock and conerete[J].International Journal of Fracture,1990,44(2):111-131.
[29]AUBERTIN M,GILL D E,SIMON R.On the use of the brittleness index modified(BIM)to estimate the post-peak behavior of rocks[R]//1st North American Rock Mechanics Symposium,Austin,Texas.American Rock Mechanics Association,1994.
[30]GEORGE E A.Brittle failure of rock material:test results and constitutive models[J].AA Balkema/Rotterdam/Brolkfield,1995:123-128.
[31]ALTINDAG R.Correlation of specific energy with rock brittleness concepts on rock cutting[J].Journal of the South African Institute of Mining and Metallurgy,2003,103(3):163-171.
[32]YAGIZ S.An investigation on the relationship between rock strength and brittleness[C]//Proceedings of the 59th Geological Congress of Turkey.Ankara,Turkey:MTA General Directory Press,2006:352.
[33]TARASOV B,POTVIN Y.Universal criteria for rock brittleness estimation under triaxial compression[J].International Journal of Rock Mechanics&Mining Sciences,2013,59:57-69.
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