煤层气直井产气曲线特征及其与储层条件匹配性
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摘要
煤层气产气曲线类型与地质条件的匹配与否直接影响产气效果。以沁水盆地柿庄南区块排采4 a以上的直井为研究对象,在产气曲线类型划分基础上,分析不同产气曲线特征,进一步分析产气曲线与储层参数的匹配性。结果表明:研究区产气曲线可划分为单峰快速上升、单峰稳定上升、双峰后低和双峰后高4种类型。产气曲线所表现出的特征受控于储层原始渗透率,储层动力及压裂效果。单峰快速上升型适用于含气量大于12 m~3/d、临储比大于0.4和渗透率大于0.1×10~(-3)μm~2的储层,该种曲线容易造成产气量的骤降;单峰稳定上升型适用的储层条件广泛,与储层参数匹配性较高;双峰后低型产气效果整体不佳,与储层参数的匹配性差;双峰后高型适用于压裂效果较好的井、对储层原始参数要求较低,其后峰产气量的增加速率影响整体的排采效果。基于上述分析,将储层划分为七种类型,对研究区及其相邻区块实施"一井一策"的排采制度具有重要的指导意义。
The matching of coalbed methane(CBM) production curve type and geological conditions directly affects the gas production. Based on dividing gas production curves types of vertical CBM wells in the southern block of Shizhuang in Qinshui basin over 4 years, the characteristics of gas production curve were analyzed. The matching of gas production curve with reservoir parameters was further analyzed. The paper discovered and divided the gas production curve into four types: type of fast rising of single peak, type of stable rising of single peak,bimodal type of being low later and bimodal type of being high later. The original permeability, dynamic condition,and fracturing effect control the characteristics of gas production curve. The reservoir parameters of the type of fast rising of single peak has high gas content(>12 m~3/d), high permeability(>0.1×10~(-3) μm~2), high specific value of critical desorption pressure and reservoir pressure(>0.4). This kind of curve is easy to cause sharp drop of gas production in the peak period. The type of stable rising of single peak is applicable in a wide range of reservoir conditions. Gas production of bimodal type of being low of is usually lower than other types. The gas production curve is poorly matched to the reservoir characteristics. The bimodal type of being high later is suitable for wells with better fracturing effect and have lower requirements for reservoir parameters. Gas production growth rate of the back peak determines the gas production effect. On the basis of above analysis, the reservoir is divided into seven types,which has important guiding significance for the implementation of the "one well and one scheme" drainage system in the study area and its adjacent blocks.
The matching of coalbed methane(CBM) production curve type and geological conditions directly affects the gas production. Based on dividing gas production curves types of vertical CBM wells in the southern block of Shizhuang in Qinshui basin over 4 years, the characteristics of gas production curve were analyzed. The matching of gas production curve with reservoir parameters was further analyzed. The paper discovered and divided the gas production curve into four types: type of fast rising of single peak, type of stable rising of single peak,bimodal type of being low later and bimodal type of being high later. The original permeability, dynamic condition,and fracturing effect control the characteristics of gas production curve. The reservoir parameters of the type of fast rising of single peak has high gas content(>12 m~3/d), high permeability(>0.1×10~(-3) μm~2), high specific value of critical desorption pressure and reservoir pressure(>0.4). This kind of curve is easy to cause sharp drop of gas production in the peak period. The type of stable rising of single peak is applicable in a wide range of reservoir conditions. Gas production of bimodal type of being low of is usually lower than other types. The gas production curve is poorly matched to the reservoir characteristics. The bimodal type of being high later is suitable for wells with better fracturing effect and have lower requirements for reservoir parameters. Gas production growth rate of the back peak determines the gas production effect. On the basis of above analysis, the reservoir is divided into seven types,which has important guiding significance for the implementation of the "one well and one scheme" drainage system in the study area and its adjacent blocks.
引文
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[11]胡秋嘉,李梦溪,王立龙,等.樊庄区块煤层气直井产气曲线特征分析[J].中国煤层气,2012,9(6):3-7.HU Qiujia,LI Mengxi,WANG Lilong,et al.Analysis on coalbed methane straight well gas yield curve characteristic of Fanzhuang block[J].China Coalbed Methane,2012,9(6):3-7.
[12]林柏泉,李庆钊,原德胜,等.彬长矿区低煤阶煤层气井的排采特征与井型优化[J].煤炭学报,2015,40(1):135-141.LIN Baiquan,LI Qingzhao,YUAN Desheng,et al.CBM production character and surface well selection in Binchang low rank coal field[J].Journal of China Coal Society,2015,40(1):135-141.
[13]潘建旭,王延斌,倪小明,等.资源条件与煤层气垂直井产能关系:以沁水盆地南部樊庄与潘庄区块为例[J].煤田地质与勘探,2011,39(4):24-27.PAN Jianxu,WANG Yanbin,NI Xiaoming,et al.The relationship between resource conditions and CBM productivity of vertical wells:A case of Fanzhuang and Panzhuang blocks in southern Qinshui basin[J].Coal Geology&Exploration,2011,39(4):24-27.
[14]吴国代,郭东鑫,程礼军.松藻矿区多煤层合采储层压降特征及启示[J].煤田地质与勘探,2018,46(5):123-128.WU Guodai,GUO Dongxin,CHENG Lijun,et al.Characteristics and revelation of pressure drop of reservoir during combined CBM production of multi-coal seams in Songzao mining area[J].Coal Geology&Exploration,2018,46(5):123-128.
[15]刘会虎,桑树勋,冯清凌,等.沁水盆地南部煤层气井排采储层应力敏感研究[J].煤炭学报,2014,39(9):1873-1878.LIU Huihu,SANG Shuxun,FENG Qingling,et al.Study on stress sen-sitivity of coal reservoir during drainage of coalbed methane well in southern Qinshui basin[J].Journal of China Coal Society,2014,39(9):1873-1878.
[16]郭春华,周文,孙晗森,等.考虑应力敏感性的煤层气井排采特征[J].煤田地质与勘探,2011,39(5):27-30.GUO Chunhua,ZHOU Wen,SUN Hansen,et al.The relationship between stress sensitivity and production of coalbed methane wells[J].Coal Geology&Exploration,2011,39(5):27-30.
[17]陈云涛.煤层气排采曲线特征及其影响因素分析[J].中国煤层气,2016,13(4):26-29.CHEN Yuntao.CMB emission and exploitation curve features and analysis[J].China Coalbed Methane,2016,13(4):26-29.
[18]陶树,汤达祯,许浩,等.沁南煤层气井产能影响因素分析及开发建议[J].煤炭学报,2011,36(2):194-198.TAO Shu,TANG Dazhen,XU Hao,et al.Analysis on influence factors of coalbed methane wells productivity and development proposals in southern Qinshui basin[J].Journal of China Coal Society,2011,36(2):194-198.
[19]王兴隆,赵益忠,吴桐.沁南高煤阶煤层气井排采机理与生产特征[J].煤田地质与勘探,2009,37(5):19-22.WANG Xinglong,ZHAO Yizhong,WU Tong.Study on pressure drop transmission law of coalbed methane drainage reservoir stratum[J].Coal Geology&Exploration,2009,37(5):19-22.
[20]刘世奇,桑树勋,李梦溪,等.沁水盆地南部煤层气井网排采压降漏斗的控制因素[J].中国矿业大学学报,2012,41(6):943-950.LIU Shiqi,SANG Shuxun,LI Mengxi,et al.Control factor of coalbed methane well depressurization cone under drainage well network in southern Qinshui basin[J].Journal of China University of Mining&Technology,2012,41(6):943-950.
[2]汪吉林,秦勇,傅雪海.关于煤层气排采动态变化机制的新认识[J].高校地质学报,2012,18(3):583-588.WANG Jilin,QIN Yong,FU Xuehai.New insight into the methanism for dynamic coalbed methane drainage[J].Geological Journal of China Universities,2012,18(3):583-588.
[3]刘世奇,赵贤正,桑树勋,等.煤层气井排采液面-套压协同管控:以沁水盆地樊庄区块为例[J].石油学报,2015,36(增刊1):97-108.LIU Shiqi,ZHAO Xianzheng,SANG Shuxun,et al.Cooperative control of working fluid level and casing pressure for coalbed methane production:A case study of Fanzhuang block in Qinshui basin[J].Acta Petrolei Sinica,2015,36(S1):97-108.
[4]陈金刚,秦勇,傅雪海.高煤级煤储层渗透率在煤层气排采中的动态变化数值模拟[J].中国矿业大学学报,2006,35(1):49-53.CHEN Jingang,QIN Yong,FU Xuehai.Numerical simulation on dynamic variation of the permeability of high rank coal reservoirs during gas recovery[J].Journal of China University of Mining&Technology,2006,35(1):49-53.
[5]李国富,侯泉林.沁水盆地南部煤层气井排采动态过程与差异性[J].煤炭学报,2012,37(5):798-803.LI Guofu,HOU Quanlin.Dynamic process and difference of coalbed methane wells production in southern Qinshui basin[J].Journal of China Coal Society,2012,37(5):798-803.
[6]杨秀春,李明宅.煤层气排采动态参数及其相互关系[J].煤田地质与勘探,2008,36(2):19-23.YANG Xiuchun,LI Mingzhai.Dynamic parameters of CBMwell drainage and relationship among them[J].Coal Geology&Exploration,2008,36(2):19-23.
[7]邵先杰,董新秀,汤达祯,等.煤层气开发过程中渗透率动态变化规律及对产能的影响[J].煤炭学报,2014,39(增刊1):146-151.SHAO Xianjie,DONG Xinxiu,TANG Dazhen,et al.Permeability dynamic change law and its effect on productivity during coalbed methane development[J].Journal of China Coal Society,2014,39(S1):146-151.
[8]倪小明,苏现波,魏庆喜,等.煤储层渗透率与煤层气垂直井排采曲线关系[J].煤炭学报,2009,34(9):1194-1198.NI Xiaoming,SU Xianbo,WEI Qingxi,et al.The relationship between the permeability of coalbed and production curve about coalbed methane vertical wells[J].Journal of China Coal Society,2009,34(9):1194-1198.
[9]杨国桥,唐书恒,李忠城,等.柿庄南区块煤层气高产井排采制度分析[J].煤炭科学技术,2016,44(8):176-181.YANG Guoqiao,TANG Shuheng,LI Zhongcheng,et al.Analysis on drainage system of coalbed methane high production well in south block of Shizhuang[J].Coal Science and Technology,2016,44(8):176-181.
[10]尹中山,肖建新,汪威.四川古蔺DCMT-3井排采曲线特征及开发前景分析[J].中国煤炭地质,2012,24(1):13-16.YIN Zhongshan,XIAO Jianxin,WANG Wei.Analysis of DCMT-3 well drainage curve characteristics and exploitation prospect,Gulin,Sichuan[J].Coal Geology of China,2012,24(1):13-16.
[11]胡秋嘉,李梦溪,王立龙,等.樊庄区块煤层气直井产气曲线特征分析[J].中国煤层气,2012,9(6):3-7.HU Qiujia,LI Mengxi,WANG Lilong,et al.Analysis on coalbed methane straight well gas yield curve characteristic of Fanzhuang block[J].China Coalbed Methane,2012,9(6):3-7.
[12]林柏泉,李庆钊,原德胜,等.彬长矿区低煤阶煤层气井的排采特征与井型优化[J].煤炭学报,2015,40(1):135-141.LIN Baiquan,LI Qingzhao,YUAN Desheng,et al.CBM production character and surface well selection in Binchang low rank coal field[J].Journal of China Coal Society,2015,40(1):135-141.
[13]潘建旭,王延斌,倪小明,等.资源条件与煤层气垂直井产能关系:以沁水盆地南部樊庄与潘庄区块为例[J].煤田地质与勘探,2011,39(4):24-27.PAN Jianxu,WANG Yanbin,NI Xiaoming,et al.The relationship between resource conditions and CBM productivity of vertical wells:A case of Fanzhuang and Panzhuang blocks in southern Qinshui basin[J].Coal Geology&Exploration,2011,39(4):24-27.
[14]吴国代,郭东鑫,程礼军.松藻矿区多煤层合采储层压降特征及启示[J].煤田地质与勘探,2018,46(5):123-128.WU Guodai,GUO Dongxin,CHENG Lijun,et al.Characteristics and revelation of pressure drop of reservoir during combined CBM production of multi-coal seams in Songzao mining area[J].Coal Geology&Exploration,2018,46(5):123-128.
[15]刘会虎,桑树勋,冯清凌,等.沁水盆地南部煤层气井排采储层应力敏感研究[J].煤炭学报,2014,39(9):1873-1878.LIU Huihu,SANG Shuxun,FENG Qingling,et al.Study on stress sen-sitivity of coal reservoir during drainage of coalbed methane well in southern Qinshui basin[J].Journal of China Coal Society,2014,39(9):1873-1878.
[16]郭春华,周文,孙晗森,等.考虑应力敏感性的煤层气井排采特征[J].煤田地质与勘探,2011,39(5):27-30.GUO Chunhua,ZHOU Wen,SUN Hansen,et al.The relationship between stress sensitivity and production of coalbed methane wells[J].Coal Geology&Exploration,2011,39(5):27-30.
[17]陈云涛.煤层气排采曲线特征及其影响因素分析[J].中国煤层气,2016,13(4):26-29.CHEN Yuntao.CMB emission and exploitation curve features and analysis[J].China Coalbed Methane,2016,13(4):26-29.
[18]陶树,汤达祯,许浩,等.沁南煤层气井产能影响因素分析及开发建议[J].煤炭学报,2011,36(2):194-198.TAO Shu,TANG Dazhen,XU Hao,et al.Analysis on influence factors of coalbed methane wells productivity and development proposals in southern Qinshui basin[J].Journal of China Coal Society,2011,36(2):194-198.
[19]王兴隆,赵益忠,吴桐.沁南高煤阶煤层气井排采机理与生产特征[J].煤田地质与勘探,2009,37(5):19-22.WANG Xinglong,ZHAO Yizhong,WU Tong.Study on pressure drop transmission law of coalbed methane drainage reservoir stratum[J].Coal Geology&Exploration,2009,37(5):19-22.
[20]刘世奇,桑树勋,李梦溪,等.沁水盆地南部煤层气井网排采压降漏斗的控制因素[J].中国矿业大学学报,2012,41(6):943-950.LIU Shiqi,SANG Shuxun,LI Mengxi,et al.Control factor of coalbed methane well depressurization cone under drainage well network in southern Qinshui basin[J].Journal of China University of Mining&Technology,2012,41(6):943-950.