沁水盆地柿庄北区块3号煤层裂缝预测
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摘要
柿庄北地区位于沁水盆地东南部,是我国重要的煤层气产区。煤层裂缝作为主要的渗流通道,对煤层气高产富集起到重要控制作用。该区山西组3号煤层中褶皱轴部走向为近南北向,野外露头区发育一组共轭剪裂缝,优势方位为NW与近EW向,其次是近SN向。根据构造形迹确定燕山期应力场以SEE105°挤压为主。利用水力加砂压裂法对现今井点目的层地应力进行计算,通过古地磁定向与声速各向异性确定现今最大水平主应力方向为NE55°。将煤层构造与地表起伏形态作为主要影响因素,采用有限元法对燕山期及现今地应力场进行数值模拟,利用弹性力学理论对裂缝参数进行计算,计算结果认为柿庄北3号裂缝孔隙度、渗透率普遍较小,整体上中部背斜区>中部平缓区>东部单斜区>中部向斜区>西部地区。模拟的裂隙特征与实测数据所反映的裂缝特征相近,单井产气量高的地区,裂隙较发育。
Northern Shizhuang, an important area for CBM production, is located in the southeast of Qinshui basin. As the primary seepage channel, fractures in coal seams make a great significance for the enrichment and production of CBM. The direction of the fold axes in sem No.3 is nearly NS, while a group of conjugate shear fractures was developed in outcrops, of which the dominant direction is NW and nearly EW, followed by nearly NS. According to the structural features, the stress field of Yanshanian was mainly compression from SEE105°. The stress in well points was calculated by using the hydraulic fracturing method, the direction of the maximum horizontal principal stress which is NE55°, was determined by restoring the original position through paleomagnetic and according to the velocity anisotropy. Considering the coal structure and surface topography as the main influencing factors, using the finite element method to simulate Yanshanian and the present stress field, and the precision is high. By using elastic mechanics theory to calculate fracture parameters, the porosity and permeability of SEAM No.3 in northern Shizhuang is generally small. In general, the porosity and permeability in central anticlinal area > central flat area > eastern monoclinic area > central synclinal area > western district, the simulation results were consistant with the measured data and single well gas production line, the credibility was high.
Northern Shizhuang, an important area for CBM production, is located in the southeast of Qinshui basin. As the primary seepage channel, fractures in coal seams make a great significance for the enrichment and production of CBM. The direction of the fold axes in sem No.3 is nearly NS, while a group of conjugate shear fractures was developed in outcrops, of which the dominant direction is NW and nearly EW, followed by nearly NS. According to the structural features, the stress field of Yanshanian was mainly compression from SEE105°. The stress in well points was calculated by using the hydraulic fracturing method, the direction of the maximum horizontal principal stress which is NE55°, was determined by restoring the original position through paleomagnetic and according to the velocity anisotropy. Considering the coal structure and surface topography as the main influencing factors, using the finite element method to simulate Yanshanian and the present stress field, and the precision is high. By using elastic mechanics theory to calculate fracture parameters, the porosity and permeability of SEAM No.3 in northern Shizhuang is generally small. In general, the porosity and permeability in central anticlinal area > central flat area > eastern monoclinic area > central synclinal area > western district, the simulation results were consistant with the measured data and single well gas production line, the credibility was high.
引文
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[16]孙梦迪,于炳松,朱华,等.山西沁水盆地南部3号煤层储集空间特征与变质程度的关系[J].中国煤炭地质,2011,23(11):31–35.SUN Mengdi,YU Bingsong,ZHU Hua,et al.Relationship between No.3 coal seam reservoir space characteristics and degree of coal metamorphism in southern Qinshui basin,Shanxi[J].Coal Geology of China,2011,23(11):31–35.
[17]邢力仁.沁水盆地柿庄南区块煤层气有利储层预测[D].北京:中国地质大学,2014:19.
[18]傅雪海,姜波,秦勇,等.用测井曲线划分煤体结构和预测煤层渗透率[J].测井技术,2003,27(2):140–143.FU Xuehai,JIANG Bo,QIN Yong,et al.Classification of coalbody strucure and prediction of coal reservoir permeability with log curves[J].Well Logging Technology,2003,27(2):140–143.
[19]刘升贵,彭智高,王振彪,等.沁水盆地煤储层参数影响产气量数值模拟[J].辽宁工程技术大学学报(自然科学版),2014,33(10):1302–1305.LIU Shenggui,PENG Zhigao,WANG Zhenbiao,et al.Numerical simulation of reservoir parameters influence on gas production in Qinshui basin[J].Journal of Liaoning Technical University(Natural Science),2014,33(10):1302–1305.
[2]刘洪林,李贵中,王广俊,等.沁水盆地煤层气地质特征与开发前景[M].北京:石油工业出版社,2009:33–37.
[3]叶建平,史保生,张春才.中国煤储层渗透性及其主要影响因素[J].煤炭学报,1999,24(2):118–122.YE Jianping,SHI Baosheng,ZHANG Chuncai.Coal reservoir permeability and its controlled factors in China[J].Journal of China Coal Society,1999,24(2):118–122.
[4]李火银,岛田莊平.构造应力对日本钏路煤田煤层气体渗透率的影响[J].中国煤层气,2005,2(1):18–21.LI Huoyin,SOHEI Shimada.Impact of tectonic stress on gas permeability of a coal seam at Kushiro coalfield,Japan[J].China Coalbed Methane,2005,2(1):18–21.
[5]孙立东,赵永军.沁水盆地煤储层渗透性影响因素研究[J].煤炭科学技术,2006,34(10):74–78.SUN Lidong,ZHAO Yongjun.Research on permeability influence factors of coal deposit layer in Qinshui basin[J].Coal Science and Technology,2006,34(10):74–78.
[6]刘晔,王云.山西沁水盆地煤层气产业发展规划研究[J].中国煤层气,2008,5(2):6–10.LIU Ye,WANG Yun.Study on the development program of CBM/CMM industry in Shanxi Qinshui basin[J].China Coalbed Methane,2008,5(2):6–10.
[7]叶建平,张兵,WONG S.山西沁水盆地柿庄北区块3#煤层注入埋藏CO2提高煤层气采收率试验和评价[J].中国工程科学,2012,14(2):38–44.YE Jianping,ZHANG Bing,WONG S.Test of and evaluation on elevation of coalbed methane recovery ratio by injecting and burying CO2 for 3#coal seam of north section of Shizhuang,Qinshui basin,Shanxi[J].Engineering Sciences,2012,14(2):38–44.
[8]戴俊生,汪必峰,马占荣.脆性低渗透砂岩破裂准则研究[J].新疆石油地质,2007,28(4):393–395.DAI Junsheng,WANG Bifeng,MA Zhanrong.Research on cracking principles of brittle low permeability sands[J].Xinjiang Petroleum Geology,2007,28(4):393–395.
[9]申卫兵,张保平.不同煤阶煤岩力学参数测试[J].岩石力学与工程学报,2000,19(增刊1):860–862.SHEN Weibing,ZHANG Baoping.Testing study on mechanical parameters of coal[J].Chinese Journal of Rock Mechanics and Engineering,2000,19(Sl):860–862.
[10]WILLIS R J,WATANABE K,TAKAHASHI H.Progress toward a stochastic rock mechanics model of engineered geothermal systems[J].Journal of Geophysical Research,1996,101:17481–17496.
[11]秦勇,姜波,王继尧,等.沁水盆地煤层气构造动力条件耦合控藏效应[J].地质学报,2008,82(10):1355–1362.QIN Yong,JIANG Bo,WANG Jiyao,et al.Coupling control of tectonic dynamical conditions to coalbed methane reservoir formation in the Qinshui basin,Shanxi,China[J].Acta Geologica Sinica,2008,82(10):1355–1362.
[12]侯明勋,葛修润,王水林.水力压裂法地应力测量中的几个问题[J].岩土力学,2003,24(5):841–844.HOU Mingxun,GE Xiurun,WANG Shuilin.Discussion on application of hydraulic fracturing method to geostress measurement[J].Rock and Soil Mechanics,2003,24(5):841–844.
[13]侯守信,田国荣.古地磁岩心定向及其在地应力测量上的应用[J].地质力学学报,1999,5(1):90–96.HOU Shouxin,TIAN Guorong.Palaeomagnetic orientation of cores and its applications for insitu stress measurements[J].Journal of Geomechanics,1999,5(1):90–96.
[14]戴俊生,李理.油区构造分析[M].东营:中国石油大学出版社,2011:171–173.
[15]管俊芳,侯瑞云.煤储层基质孔隙和割理孔隙的特征及孔隙度的测定方法[J].华北水利水电学院学报,1999,20(1):23–27.GUAN Junfang,HOU Ruiyun.Coal pore properties of matrix&cleat and their porosity measurement methods[J].Journal of North China Institute of Water Conservancy and Hydroelectric Power,1999,20(1):23–27.
[16]孙梦迪,于炳松,朱华,等.山西沁水盆地南部3号煤层储集空间特征与变质程度的关系[J].中国煤炭地质,2011,23(11):31–35.SUN Mengdi,YU Bingsong,ZHU Hua,et al.Relationship between No.3 coal seam reservoir space characteristics and degree of coal metamorphism in southern Qinshui basin,Shanxi[J].Coal Geology of China,2011,23(11):31–35.
[17]邢力仁.沁水盆地柿庄南区块煤层气有利储层预测[D].北京:中国地质大学,2014:19.
[18]傅雪海,姜波,秦勇,等.用测井曲线划分煤体结构和预测煤层渗透率[J].测井技术,2003,27(2):140–143.FU Xuehai,JIANG Bo,QIN Yong,et al.Classification of coalbody strucure and prediction of coal reservoir permeability with log curves[J].Well Logging Technology,2003,27(2):140–143.
[19]刘升贵,彭智高,王振彪,等.沁水盆地煤储层参数影响产气量数值模拟[J].辽宁工程技术大学学报(自然科学版),2014,33(10):1302–1305.LIU Shenggui,PENG Zhigao,WANG Zhenbiao,et al.Numerical simulation of reservoir parameters influence on gas production in Qinshui basin[J].Journal of Liaoning Technical University(Natural Science),2014,33(10):1302–1305.