沁水盆地南部高煤阶煤层气水平井地质适应性探讨
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摘要
沁水盆地南部煤层气水平井开发10 a实践表明,相同地质条件下不同类型水平井开发效果存在较大差异,亟需就水平井开发地质适应性进行深入研究。基于樊庄一郑庄区块水平井开发现状,通过生产数据统计分析,结合煤矿井下观察和室内实验,研究了水平井完井方式、储层改造方式的地质适应性。结果表明,地应力大小、方向和煤体结构决定水平井完井方式。水平井完井方式主要包括裸眼完井、套管或筛管完井等,在保证水平井井眼稳定的前提下采用裸眼完井经济效益最好。但埋深超过600 m时,煤岩承受的垂向应力大于抗压强度,裸眼水平井易垮塌,应使用筛管、套管完井;当埋深为600～700 m时,筛管水平井产量可达3 000 m~3/d以上,可用筛管完井;当埋深大于700 m,需要进行压裂,用套管完井。水平井井眼走向与煤层最大水平主应力方向之间夹角越小,井眼受到的有效应力越大,裸眼井眼越容易变形垮塌,应采用筛管、套管完井,当水平井井眼走向垂直于煤层最大水平主应力方向时,裸眼水平井产量最高,可以采用裸眼水平井完井。水平井井眼穿过碎粒、糜棱煤发育区,裸眼井眼易垮塌,裸眼水平井平均单井产气量仅1 000 m~3/d左右,而筛管水平井可以达到4 500 m~3/d左右,应采用筛管完井。煤层微观裂缝发育程度和垂向非均质性决定水平井是否需要压裂,微观裂缝发育程度可以用裂缝指数定量表征。当裂缝指数高于100时,筛管水平井产量一般高于3 000 m~3/d,开发效果较好;当裂缝指数低于100时,储层渗透性差,单井控制面积小,筛管水平井产量低于1 000 m~3/d,分段压裂后储层渗透率提高,产量达到7 000 m~3/d以上。煤层垂向上存在局部裂缝指数小于100的低渗层时,气体垂向渗流阻力大,筛管井产气效果差,需进行分段压裂,分段压裂水平井产量可达到8 000 m~3/d以上。
The practical development experiences of CBM horizontal well for 10 years in southern Qinshui Basin shows that there is a big development difference among the different types of horizontal wells under the same geological conditions and among the same type of horizontal well under different geological conditions. Therefore, the geological adaptability of horizontal wells needs to further be investigated. This paper studies the effects of key geological parameters of horizontal well on the completion method and the stimulation method, based on present development situation of horizontal wells, coal mine observation and indoor experiments by statistics data in Fanzhuang and Zhengzhuang block. The results show that the size and direction of ground stress and the coal structure decide the completion method of horizontal wells. The completion method consists of open-hole completion,casing completion,screen completion and so on. The open-hole completion is the most economic method if the well bore is stable. When the buried depth is more than 600 m,the vertical stress of the coal and rock is greater than the compressive strength,which results in that the open hole of horizontal well is prone to collapse and the casing completion method and the screen completion method should be adopted. When the buried depth is between 600 m to 700 m,the daily production of screen completion horizontal well can be over 3 000 m~3/d. However,when the buried depth is deeper than 700 m,the hydraulic stimulation is needed,so the casing completion method is suitable. The production of horizontal well decreases with the increase of the angle between the horizontal well borehole trends and the greater the maximum horizontal principal stress direction because the smaller the angle, the greater the effective stress on open hole, and the easier the deformation and collapse of open hole,where the casing and screen completion way should be adopted. When the borehole trend is perpendicular to the direction of the maximum horizontal principal stress, the production of the open-hole horizontal well is the highest,so the open-hole completion method should be adopted. When the horizontal well hole passes through the granule or mylonite coal development zone,the open-hole horizontal well is much easier to collapse,leading to daily production only about 1 000 m~3/d. While the daily production is up to 4 500 m~3/d,when the screen completion way should be adopted. The micro-fractures development degree and the vertical heterogeneity of coal seam determine whether horizontal wells need to be fractured. The micro-fractures development degree can be quantitatively characterized by the fracture index. When the fracture index is higher than 100, the daily production of screen horizontal wells is higher than 3 000 m~3/d. When the fracture index is less than 100, the low permeability results in a small single-well controlling area and hydraulic fracturing is required,where the production of the screen horizontal well is lower than1 000 m~3/d while the production can reach 7 000 m~3/d after hydraulic fracturing. If there are low-permeability layers with fracture index less than 100 in vertical direction of coal seams,the gas production is poor with screen completion and hydraulic fracturing is also required, where the gas production can be up to 8 000 m3/d.
The practical development experiences of CBM horizontal well for 10 years in southern Qinshui Basin shows that there is a big development difference among the different types of horizontal wells under the same geological conditions and among the same type of horizontal well under different geological conditions. Therefore, the geological adaptability of horizontal wells needs to further be investigated. This paper studies the effects of key geological parameters of horizontal well on the completion method and the stimulation method, based on present development situation of horizontal wells, coal mine observation and indoor experiments by statistics data in Fanzhuang and Zhengzhuang block. The results show that the size and direction of ground stress and the coal structure decide the completion method of horizontal wells. The completion method consists of open-hole completion,casing completion,screen completion and so on. The open-hole completion is the most economic method if the well bore is stable. When the buried depth is more than 600 m,the vertical stress of the coal and rock is greater than the compressive strength,which results in that the open hole of horizontal well is prone to collapse and the casing completion method and the screen completion method should be adopted. When the buried depth is between 600 m to 700 m,the daily production of screen completion horizontal well can be over 3 000 m~3/d. However,when the buried depth is deeper than 700 m,the hydraulic stimulation is needed,so the casing completion method is suitable. The production of horizontal well decreases with the increase of the angle between the horizontal well borehole trends and the greater the maximum horizontal principal stress direction because the smaller the angle, the greater the effective stress on open hole, and the easier the deformation and collapse of open hole,where the casing and screen completion way should be adopted. When the borehole trend is perpendicular to the direction of the maximum horizontal principal stress, the production of the open-hole horizontal well is the highest,so the open-hole completion method should be adopted. When the horizontal well hole passes through the granule or mylonite coal development zone,the open-hole horizontal well is much easier to collapse,leading to daily production only about 1 000 m~3/d. While the daily production is up to 4 500 m~3/d,when the screen completion way should be adopted. The micro-fractures development degree and the vertical heterogeneity of coal seam determine whether horizontal wells need to be fractured. The micro-fractures development degree can be quantitatively characterized by the fracture index. When the fracture index is higher than 100, the daily production of screen horizontal wells is higher than 3 000 m~3/d. When the fracture index is less than 100, the low permeability results in a small single-well controlling area and hydraulic fracturing is required,where the production of the screen horizontal well is lower than1 000 m~3/d while the production can reach 7 000 m~3/d after hydraulic fracturing. If there are low-permeability layers with fracture index less than 100 in vertical direction of coal seams,the gas production is poor with screen completion and hydraulic fracturing is also required, where the gas production can be up to 8 000 m3/d.
引文
[1]鲜保安,高德利,王一兵,等.多分支水平井在煤层气开发中的应用机理分析[J].煤田地质与勘探,2005,33(6):34-37.XIAN Baoan.GAO Deli, WANG Yibing, et al. Analysis on applied mechanism of multiple laterals horizontal well in developing coalbed methane[J]. Coal Geology&Exploration, 2005,33(6):34-37.
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[3]张建国,苗耀,李梦溪,等.沁水盆地煤层气水平井产能影响因素分析——以樊庄区块水平井开发示范工程为例[J].中国石油勘探,2010(2):49-55.ZHANG Jianguo,MIAO Yao,LI Mengxi,et al. Influential factors of CBM horizontal well productivity in Qinshui Basin[J]. China Petroleum Exploration,2010(2):49-55.
[4]刘志强,胡汉月,刘海翔,等.煤层气多分支水平井技术探讨[J].中国煤层气,2011,8(3):26-30.LIU Zhiqiang.HU Hanyue,LIU Haixiang.et al. Discussion on multiple lateral horizontal well technology[J]. China Coalbed Methane,2011,8(3):26-30.
[5]杨勇,崔树清,倪元勇,等.煤层气仿树形水平井的探索与实践[J].天然气工业,2014,34(8):92-96.YANG Yong,CUI Shuqing,NI Yuanyong,et al. A new attempt of a CBM tree-like horizontal well:A pilot case of well ZSIP-5H in the Qinshui Basin[J]. Natural Gas Industry,2014,34(8):92-96.
[6]李梦溪,刘庆昌,张建国,等.构造模式与煤层气井产能的关系——以晋城煤区为例[J].天然气工业,2010,30(11):10-13,114.LI Mengxi,LIU Qingchang,ZHANG Jianguo,et al. Relationship be-tween structural style and CBM well productivity:A case study of the Jincheng coalfield[J]. Natural Gas Industry, 2010,30(11):10-13,114.
[7]易新斌,丁云宏,王欣,等.煤层气完井方式和增产措施的优选分析[J].煤炭学报,2013,38(4):629-632.YI Xinbin, DING Yunhong, WANG Xin, et al. The optimization of coal-bed methane completion and stimulation technologies[J].Journal of China Coal Society,2013,38(4):629-632.
[8]杨健,倪元勇,王生维,等.影响煤层气水平井井壁稳定性的地质因素分析[J].石油钻釆工艺,2015,37(5):5-9.YANG Jian,NI Yuanyong, WANG Shengwei,et al. Analysis of geologic factors affecting wellbore stability of CBM horizontal wells[J].Oil Drilling&Production Technology,2015,37(5):5-9.
[9]胡秋嘉,李梦溪,乔茂坡,等.沁水盆地南部高阶煤煤层气井压裂效果关键地质因素分析[J].煤炭学报,2017,42(6):1506-1516.HU Qiujia,LI Mengxi,QIAO Maopo,et al. Analysis of key geologic factors of fracturing effect of CBM wells for high-rank coal in Southern Qinshui Basin[J]. Journal of China Coal Society,2017,42(6):1506-1516.
[10]秦勇,申建,沈玉林.叠置含气系统共采兼容性——煤系“三气”及深部煤层气开釆中的共性地质问题[J].煤炭学报,2016,41(1):14-23.QIN Yong,SHEN Jian,SHEN Yulin. Joint mining compatibility of superposed gas-bearing systems:A general geological problem for extraction of three natural gases and deep CBM in coal series[J].Journal of China Coal Society,2016,41(1):14-23.
[11]杨延辉,孟召平,陈彦君,等.沁南-夏店区块煤储层地应力条件及其对渗透性的影响[J].石油学报,2015,36(S1):91-96.YANG Yanhui, MENG Zhaoping, CHEN Yanjun, et al. Geostress conditions of coal reservoirs in Qinnan-Xiadian block and its influences on permeability[J]. Acta Petrolei Sinica,2015,36(S1):91-96.
[12]孟召平,田永东,李国富.沁水盆地南部地应力场特征及其研究意义[J].煤炭学报,2010,35(6):975-981.MENG Zhaoping,TIAN Yongdong,LI Guofu. Characteristics of insitu stress field in Southern Qinshui Basin and its research significance[J]. Journal of China Coal Society,2010,35(6):975-981.
[13] HOCK E, BROWN E T. Underground excavations in rock[M].London:Institution of Mining and Metallurgy, 1980.
[14]李松,汤达祯,许浩,等.不同煤体结构煤储层物性差异分析[A]. 2011年煤层气学术研讨会论文集[C]. 2011:123-130.
[15]林堃琦,黄文辉,张谦,等.基于测井信息对沁水盆地南部构造煤分布规律的研究[J].中国煤炭地质,2016,28(3):74-78.LIN Kunqi,HUANG Wenhui,ZHANG Qian,et al. Study on tectonoclastic coal distribution pattern in Southern Qinshui Basin based on well logging information[J]. Coal Geoloey of China, 2016,28(3):74-78.
[16]王好龙,董守华,黄亚平.基于测井数据判别分析法识别构造煤的应用[J].煤炭技术,2014,33(12):317-320.WANG Haolong,DONG Shouhua, HUANG Yaping. Application of identifying tectonic coal with discriminant analysis method based on logging data[J]. Coal Technology,2014,33(12):317-320.
[17]姜波,李明,屈争辉,等.构造煤研究现状及展望[J].地球科学进展,2016,31(4):335-342.JIANG Bo, LI Ming, QU Zhenghui, et al. Current research status and prospect of tectonically deformed coal[J]. Advances in Earth Science,2016,31(4):335-342.
[18]王海平,石雪峰,钢胡雅格,等.煤层裂缝填充物特征及其对渗透率的影响[J].煤炭科学技术,2016,44(9):115-121.WANG Haiping,SHI Xuefeng,GANG Huyage,et al. Characteristics of fillings in cracks of seam and influences to seam permeability[J]. Coal Science and Technology,2016,44(9):115-121.
[19]李丹琼,张士诚,张遂安,等.基于煤系渗透率各向异性测试的水平井穿层压裂效果模拟[J].石油学报,2015,36(8):988-994.LI Danqiong,ZHANG Shicheng,ZHANG Suian,et al. Effect simulation of horizontal well fracturing through strata based on coal seam permeability anisotropy test[J]. Acta Petrolei Sinica, 2015,36(8):988-994.
[20]李辛子,王运海,姜昭琛,等.深部煤层气勘探开发进展与研究[J].煤炭学报,2016,41(1):24-31.LI Xinzi, WANG Yunhai, JIANG Zhaochen, et al. Progress and study on exploration and production for deep coalbed methane[J].Journal of China Coal Society,2016,41(1):24-31.
[2]鲜保安,陈彩红,王宪花,等.多分支水平井在煤层气开发中的控制因素及增产机理分析[J].中国煤层气,2005,2(1):14-17.XIAN Baoan, CHEN Caihong, WANG Xianhua, et al. Analysis on control factors and production enhancing mechanism of multiple laterals horizontal well in deveopling CBM[J]. China Coalbed Methane,2005,2(1):14-17.
[3]张建国,苗耀,李梦溪,等.沁水盆地煤层气水平井产能影响因素分析——以樊庄区块水平井开发示范工程为例[J].中国石油勘探,2010(2):49-55.ZHANG Jianguo,MIAO Yao,LI Mengxi,et al. Influential factors of CBM horizontal well productivity in Qinshui Basin[J]. China Petroleum Exploration,2010(2):49-55.
[4]刘志强,胡汉月,刘海翔,等.煤层气多分支水平井技术探讨[J].中国煤层气,2011,8(3):26-30.LIU Zhiqiang.HU Hanyue,LIU Haixiang.et al. Discussion on multiple lateral horizontal well technology[J]. China Coalbed Methane,2011,8(3):26-30.
[5]杨勇,崔树清,倪元勇,等.煤层气仿树形水平井的探索与实践[J].天然气工业,2014,34(8):92-96.YANG Yong,CUI Shuqing,NI Yuanyong,et al. A new attempt of a CBM tree-like horizontal well:A pilot case of well ZSIP-5H in the Qinshui Basin[J]. Natural Gas Industry,2014,34(8):92-96.
[6]李梦溪,刘庆昌,张建国,等.构造模式与煤层气井产能的关系——以晋城煤区为例[J].天然气工业,2010,30(11):10-13,114.LI Mengxi,LIU Qingchang,ZHANG Jianguo,et al. Relationship be-tween structural style and CBM well productivity:A case study of the Jincheng coalfield[J]. Natural Gas Industry, 2010,30(11):10-13,114.
[7]易新斌,丁云宏,王欣,等.煤层气完井方式和增产措施的优选分析[J].煤炭学报,2013,38(4):629-632.YI Xinbin, DING Yunhong, WANG Xin, et al. The optimization of coal-bed methane completion and stimulation technologies[J].Journal of China Coal Society,2013,38(4):629-632.
[8]杨健,倪元勇,王生维,等.影响煤层气水平井井壁稳定性的地质因素分析[J].石油钻釆工艺,2015,37(5):5-9.YANG Jian,NI Yuanyong, WANG Shengwei,et al. Analysis of geologic factors affecting wellbore stability of CBM horizontal wells[J].Oil Drilling&Production Technology,2015,37(5):5-9.
[9]胡秋嘉,李梦溪,乔茂坡,等.沁水盆地南部高阶煤煤层气井压裂效果关键地质因素分析[J].煤炭学报,2017,42(6):1506-1516.HU Qiujia,LI Mengxi,QIAO Maopo,et al. Analysis of key geologic factors of fracturing effect of CBM wells for high-rank coal in Southern Qinshui Basin[J]. Journal of China Coal Society,2017,42(6):1506-1516.
[10]秦勇,申建,沈玉林.叠置含气系统共采兼容性——煤系“三气”及深部煤层气开釆中的共性地质问题[J].煤炭学报,2016,41(1):14-23.QIN Yong,SHEN Jian,SHEN Yulin. Joint mining compatibility of superposed gas-bearing systems:A general geological problem for extraction of three natural gases and deep CBM in coal series[J].Journal of China Coal Society,2016,41(1):14-23.
[11]杨延辉,孟召平,陈彦君,等.沁南-夏店区块煤储层地应力条件及其对渗透性的影响[J].石油学报,2015,36(S1):91-96.YANG Yanhui, MENG Zhaoping, CHEN Yanjun, et al. Geostress conditions of coal reservoirs in Qinnan-Xiadian block and its influences on permeability[J]. Acta Petrolei Sinica,2015,36(S1):91-96.
[12]孟召平,田永东,李国富.沁水盆地南部地应力场特征及其研究意义[J].煤炭学报,2010,35(6):975-981.MENG Zhaoping,TIAN Yongdong,LI Guofu. Characteristics of insitu stress field in Southern Qinshui Basin and its research significance[J]. Journal of China Coal Society,2010,35(6):975-981.
[13] HOCK E, BROWN E T. Underground excavations in rock[M].London:Institution of Mining and Metallurgy, 1980.
[14]李松,汤达祯,许浩,等.不同煤体结构煤储层物性差异分析[A]. 2011年煤层气学术研讨会论文集[C]. 2011:123-130.
[15]林堃琦,黄文辉,张谦,等.基于测井信息对沁水盆地南部构造煤分布规律的研究[J].中国煤炭地质,2016,28(3):74-78.LIN Kunqi,HUANG Wenhui,ZHANG Qian,et al. Study on tectonoclastic coal distribution pattern in Southern Qinshui Basin based on well logging information[J]. Coal Geoloey of China, 2016,28(3):74-78.
[16]王好龙,董守华,黄亚平.基于测井数据判别分析法识别构造煤的应用[J].煤炭技术,2014,33(12):317-320.WANG Haolong,DONG Shouhua, HUANG Yaping. Application of identifying tectonic coal with discriminant analysis method based on logging data[J]. Coal Technology,2014,33(12):317-320.
[17]姜波,李明,屈争辉,等.构造煤研究现状及展望[J].地球科学进展,2016,31(4):335-342.JIANG Bo, LI Ming, QU Zhenghui, et al. Current research status and prospect of tectonically deformed coal[J]. Advances in Earth Science,2016,31(4):335-342.
[18]王海平,石雪峰,钢胡雅格,等.煤层裂缝填充物特征及其对渗透率的影响[J].煤炭科学技术,2016,44(9):115-121.WANG Haiping,SHI Xuefeng,GANG Huyage,et al. Characteristics of fillings in cracks of seam and influences to seam permeability[J]. Coal Science and Technology,2016,44(9):115-121.
[19]李丹琼,张士诚,张遂安,等.基于煤系渗透率各向异性测试的水平井穿层压裂效果模拟[J].石油学报,2015,36(8):988-994.LI Danqiong,ZHANG Shicheng,ZHANG Suian,et al. Effect simulation of horizontal well fracturing through strata based on coal seam permeability anisotropy test[J]. Acta Petrolei Sinica, 2015,36(8):988-994.
[20]李辛子,王运海,姜昭琛,等.深部煤层气勘探开发进展与研究[J].煤炭学报,2016,41(1):24-31.LI Xinzi, WANG Yunhai, JIANG Zhaochen, et al. Progress and study on exploration and production for deep coalbed methane[J].Journal of China Coal Society,2016,41(1):24-31.
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