沁水盆地寿阳区块煤层气排采动态成因机理及排采对策
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摘要
以寿阳区块的静态地质资料和动态排采资料为基础,分析了寿阳区块的排采动态特征并从系统分析观和地质因素2个方面解释了排采动态的成因机理,提出了寿阳区块的排采对策。研究表明:寿阳区块排采动态呈现出单井产水量高,产气量低或不见气的特点,合层排采井的典型日产水量大于单采井产水量之和,表现出"1+1>2"的现象;典型日产气量与典型日产水量呈现负向包络关系,高产水对产气有抑制作用;造成寿阳区块煤层气井高产水的原因有2个,一是寿阳井筒—排采煤层系统为开放系统,断裂或压裂缝沟通煤层上下的含水层,造成煤层气井低效降压;二是寿阳区块煤系地层中分支河道砂体发育,且因该区发育的断裂多为高倾角断裂,当多层合层排采时,断裂沟通含水层的概率大大上升。因此,在培育高产气井时,首先要避开断层开放型系统,远离断层,其次是避开垂直压裂缝压穿型系统,因寿阳区块煤层更易压裂,故压裂时要适当降低前期采用的压裂规模,针对具体井层,需根据顶底板隔水层的厚度,保证在不压穿顶底板隔水层的前提下,优化压裂规模,以实现在规避围岩含水层不利影响的条件下最大程度地改善煤储层的渗透率。
Based on the geological data and drainage dynamic data,the characteristics of drainage dynamic was analyzed,formation mechanism of well performance was explained from system theory and geological factors and CBM development strategy was proposed in Shouyang block.The study shows that the single well in Shouyang block is characteristized by"high water yield but low gas production"in the process of drainage.Multi-layer drainage produces more water than that of one layer,which leads to a phenomenon of"1+1>2".The typical daily gas production shows a negative enveloping relationship with typical daily water production meaning that high water production is detrimental to gas production.There are two factors for high water production.First,the wellbore-drainage system is an open system since faults or vertical hydraulic fractures connect sandstone aquifers,which leads to low efficient depressurization.Second,with branch channel sand body extensively developed and high dip angle existed,faults easily connect sand aquifers for multi-layer drainage.Building a high productive well is essential to create a closed system boreholedrainage system by staying away faults firstly,and then avoiding vertical hydraulic fractures connecting sand aquifers.Since the coal seam is easier to fracturing,it is proposed to reduce the fracturing volume adopted before for future CBM exploration and development practice in Shouyang block.For a coal interval to be hydraulically fractured in a well,the fracturing volume should be optimized on considering the thickness of proof and floor aquifluids to avoid hydraulic link between the fracturing interval and nearby sandstone aquifers.
Based on the geological data and drainage dynamic data,the characteristics of drainage dynamic was analyzed,formation mechanism of well performance was explained from system theory and geological factors and CBM development strategy was proposed in Shouyang block.The study shows that the single well in Shouyang block is characteristized by"high water yield but low gas production"in the process of drainage.Multi-layer drainage produces more water than that of one layer,which leads to a phenomenon of"1+1>2".The typical daily gas production shows a negative enveloping relationship with typical daily water production meaning that high water production is detrimental to gas production.There are two factors for high water production.First,the wellbore-drainage system is an open system since faults or vertical hydraulic fractures connect sandstone aquifers,which leads to low efficient depressurization.Second,with branch channel sand body extensively developed and high dip angle existed,faults easily connect sand aquifers for multi-layer drainage.Building a high productive well is essential to create a closed system boreholedrainage system by staying away faults firstly,and then avoiding vertical hydraulic fractures connecting sand aquifers.Since the coal seam is easier to fracturing,it is proposed to reduce the fracturing volume adopted before for future CBM exploration and development practice in Shouyang block.For a coal interval to be hydraulically fractured in a well,the fracturing volume should be optimized on considering the thickness of proof and floor aquifluids to avoid hydraulic link between the fracturing interval and nearby sandstone aquifers.
引文
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[17]Shao Longyi,Yang Zhiyu,Shang Xiaoxu,et al.Lithofacies palaeogeography of the Carboniferous and Permian in the Qinshui Basin,Shanxi Province,China[J].Journal of Paleogeography,2015,4(4):387-413.
[18]Wang Ping.A geomechanical technique-types and distribution of geostress under various tectonic forces[J].Acta Petrolei Sinica,1992,13(1):1-12.[王平.地质力学方法研究—不同构造力作用下地应力的类型和分布[J].石油学报,1992,13(1):1-12.]
[19]Wu Guodai,Sang Shuxun,Yang Zhigang,et al.Current research status and prospect of geo-stress impact on CBM exploration and exploitation[J].Coal Geology of China,2009,21(4):31-34.[吴国代,桑树勋,杨志刚,等.地应力影响煤层气勘探开发的研究现状与展望[J].中国煤炭地质,2009,21(4):31-34.]
[20]Meng Zhaoping,Tian Yongdong,Li Guofu.Theory and Method of Coalbed Methane Development Geology[M].Beijing:Science Press,2010:253-260.[孟召平,田永东,李国富.煤层气开发地质理论与方法[M].北京:科学出版社,2010:253-260.]
[21]Gu H,Siebrits E,Sabourov A.Hydraulic-fracture modeling with bedding plane interfacial slip[C].SPE 117445.Presented at the 2008 SPE Eastern Regional/AAPG Eastern Section Joint Meeting held in Pittsburgh,Pennsylvanian,USA,11-15-October 2008:1-8.
[22]Yang Huanqiang,Wang Ruihe,Zhou Weidong,et al.The study on affecting factors and characteristics about extention of vertical fractures on coal seam interface[C].The Annual Workshop of Coalbed Methane in 2014.Beijing:Petroleum Industry Press,2014.[杨焕强,王瑞和,周卫东,等.垂直裂缝在煤层界面的扩展及影响因素研究[C].2014全国煤层气学术研讨会论文集.北京:石油工业出版社,2014.]
[23]Zhang Xiaodong,Zhang Peng,Liu Hao,et al.Fracture extended model under hydraulic fracturing engineering for high rank coal reserviors[J].Journal of China University of Mining&Technology,2013,42(4):573-579.[张小东,张鹏,刘浩,等.高煤级煤储层水力压裂裂缝扩展模型研究[J].中国矿业大学学报,2013,42(4):573-579.]
[24]Feng Qing,Wu Caifang,Leibo.Coal/rock mechanics features of Qinshui Basin and fracturing crack control[J].Coal Science and Technology,2011,39(3):100-103.[冯晴,吴财芳,雷波.沁水盆地煤岩力学特征及其压裂裂缝的控制[J].煤炭科学技术,2011,39(3):100-103.]
[2]Wang Hongyan,Li Jingming,Ning Ning,et al.Practice&theory of CBM economic development in Qinshui Basin[J].Natural Gas Geosicence,2007,18(4):554-556.[王红岩,李景明,宁宁,等.沁水盆地煤层气商业性勘探开发实践及认识[J].天然气地球科学,2007,18(4):554-556.]
[3]Shao Longyi,Xiao Zhenghui,He Zhiping,et al.Palaeogeography and coal accumulation for coal measures of the Carboniferous-Permian in Qinshui Basin,southeastern Shanxi Province[J].Journal of Paleogeography,2006.8(1):43-52.[邵龙义,肖正辉,何志平,等.晋东南沁水盆地石炭二叠纪含煤岩系古地理及聚煤作用研究[J].古地理学报,2006.8(1):43-52.]
[4]Wang Zhenyun,Tang Shuheng,Sun Pengjie,et al.Feasibility study of multi-layer drainage for No.3and 9coal seams in Shouyang Block,Qinshui Basin[J].Coal Geology of China,2013,25(11):21-26.[王振云,唐书恒,孙鹏杰,等.沁水盆地寿阳区块3号和9号煤层合层排采的可行性研究[J].中国煤炭地质,2013,25(11):21-26.]
[5]Liu Shenggui,Tu Kun,Fu Yu,et al.CBM recovery rate prediction method and well spacing optimization in Shouyang block[J].Journal of Liaoning Technical University:Natural Science,2015,34(8):892-897.[刘升贵,涂坤,付裕,等.寿阳区块煤层气采收率预测方法及井间距优化[J].辽宁工程技术大学学报:自然科学版,2015,34(8):892-897.]
[6]Lv Yumin,Liang Jianshe,Liu Yinghong,et al.Multi-level fuzzy comprehensive evaluation model for favorable coalbed methane development area based on logging information:A case of Shouyang block[J].Coal Geology&Exploration,2016,44(1):56-61.[吕玉民,梁建设,柳迎红,等.基于测井信息的煤层气有利区多层次模糊综合评价模型—以寿阳区块为例[J].煤田地质与勘探,2016,44(1):56-61.]
[7]Wang Jin,Kang Yongshang,Jiang Shanyu,et al.Reasons for water production difference of CBM wells in Shouyang block,Qinshui Basin,and prediction on favorable areas[J].Natural Gas Industry,2016,36(8):52-59.[王金,康永尚,姜杉钰,等.寿阳区块煤层气井产水差异原因分析和有利区预测[J].天然气工业,2016,36(8):52-59.]
[8]Kang Yongshang,Chen Jing,Zhang Bing,et al.Identification of aquifers influencing the drainage of coalbed methane wells in Shouyang exploration area,Qinshui Basin[J].Journal of China Coal Society,2016,41(9):2263-2272.[康永尚,陈晶,张兵,等.沁水盆地寿阳勘探区煤层气井排采水源层判识[J].煤炭学报,2016,41(9):2263-2272.]
[9]Kang Yongshang,Qin Shaofeng,Han Jun,et al.Typical dynamic index analysis method system for drainage and production dynamic curves of CBM wells[J].Journal of China Coal Society,2013,38(10):1825-1830.[康永尚,秦绍锋,韩军,等.煤层气井排采动态典型指标分析方法体系[J].煤炭学报,2013,38(10):1825-1830.]
[10]Wang Weixu,Wang Xiyou,Jiang Pei,et al.Causes of high water yield from CBM wells in Shunan area and measures research[C]//The Annual Workshop of Coalbed Methane in 2014.Beijing:Petroleum Industry Press,2014.[王维旭,王希友,蒋佩,等.蜀南地区煤层气高产水井分析及对策研究[C]//2014全国煤层气学术研讨会论文集.北京:石油工业出版社,2014.]
[11]Jiang Shanyu,Kang Yongshang,Zhang Shouren,et al.Analysis on influencing factors of drainage dynamic of wells and CBM development strategy in Shizhuang block[J].Natural Gas Geoscience,2016,27(6):1134-1142.[姜杉钰,康永尚,张守仁,等.沁水盆地柿庄区块煤层气井排采动态影响因素分析及开发对策研究[J].天然气地球科学,2016,27(6):1134-1142.]
[12]Zhang Peihe,Liu Yuhui,Wang Zhengxi,et al.Geological factors of production control of CBM well in south Qinshui Basin[J].Natural Gas Geoscience,2011,22(5):909-914.[张培河,刘钰辉,王正喜,等,基于生产数据分析的沁水盆地南部煤层气井产能控制地质因素研究[J].天然气地球科学,2011,22(5):909-914.]
[13]Shao Xianjie,Dong Xiucheng,Tang Dazhen,et al.Treatment technology and method of low-of-moderate production coalbed methane wells in Hancheng mining area[J].Natural Gas Geosicence,2014,25(3):435-443.[邵先杰,董秀成,汤达祯,等.韩城矿区煤层气中低产井治理技术与方法[J].天然气地球科学,2014,25(3):435-443.]
[14]Wang Bo,Sun Fenjin,Zhao Yang,et al.Study of hydrogelogical control on CBM enrichment and high producibility-Example from FZ CBM block in the Qinshui Basin[C]//The Annual Workshop of Coalbed Methane in 2014.Beijing:Petroleum Industry Press,2014.[王勃,孙粉锦,赵阳,等.煤层气富集高产的水文地质控气规律研究—以沁水盆地FZ区块为例[C]//2014全国煤层气学术研讨会论文集.北京:石油工业出版社,2014.]
[15]Lu Xiaoxia,Huang Wenhui,Tang Xiuyi,et al.Impact of limestone of NO.15coal seam roof on the coal bed methane exploitation,south Qinshui Basin[J].Geoscience,2012,26(3):518-526.[陆小霞,黄文辉,唐修义,等.沁水盆地南部15号煤层顶板灰岩特征对煤层气开采的影响[J现代地质,2012,26(3):518-526.]
[16]Chen Jing,Kang Yongshang,Guo Mingqiang,et al.Analysis on aquosity of Taiyuan formation limestones in Shouyang area,Qinshui Basin,central China[C]//The Annual Workshop of Coalbed Methane in 2014.Beijing:Petroleum Industry Press,2014.[陈晶,康永尚,郭明强,等.沁水盆地寿阳地区太原组灰岩含水性分析[C]//2014全国煤层气学术研讨会论文集.北京:石油工业出版社,2014.]
[17]Shao Longyi,Yang Zhiyu,Shang Xiaoxu,et al.Lithofacies palaeogeography of the Carboniferous and Permian in the Qinshui Basin,Shanxi Province,China[J].Journal of Paleogeography,2015,4(4):387-413.
[18]Wang Ping.A geomechanical technique-types and distribution of geostress under various tectonic forces[J].Acta Petrolei Sinica,1992,13(1):1-12.[王平.地质力学方法研究—不同构造力作用下地应力的类型和分布[J].石油学报,1992,13(1):1-12.]
[19]Wu Guodai,Sang Shuxun,Yang Zhigang,et al.Current research status and prospect of geo-stress impact on CBM exploration and exploitation[J].Coal Geology of China,2009,21(4):31-34.[吴国代,桑树勋,杨志刚,等.地应力影响煤层气勘探开发的研究现状与展望[J].中国煤炭地质,2009,21(4):31-34.]
[20]Meng Zhaoping,Tian Yongdong,Li Guofu.Theory and Method of Coalbed Methane Development Geology[M].Beijing:Science Press,2010:253-260.[孟召平,田永东,李国富.煤层气开发地质理论与方法[M].北京:科学出版社,2010:253-260.]
[21]Gu H,Siebrits E,Sabourov A.Hydraulic-fracture modeling with bedding plane interfacial slip[C].SPE 117445.Presented at the 2008 SPE Eastern Regional/AAPG Eastern Section Joint Meeting held in Pittsburgh,Pennsylvanian,USA,11-15-October 2008:1-8.
[22]Yang Huanqiang,Wang Ruihe,Zhou Weidong,et al.The study on affecting factors and characteristics about extention of vertical fractures on coal seam interface[C].The Annual Workshop of Coalbed Methane in 2014.Beijing:Petroleum Industry Press,2014.[杨焕强,王瑞和,周卫东,等.垂直裂缝在煤层界面的扩展及影响因素研究[C].2014全国煤层气学术研讨会论文集.北京:石油工业出版社,2014.]
[23]Zhang Xiaodong,Zhang Peng,Liu Hao,et al.Fracture extended model under hydraulic fracturing engineering for high rank coal reserviors[J].Journal of China University of Mining&Technology,2013,42(4):573-579.[张小东,张鹏,刘浩,等.高煤级煤储层水力压裂裂缝扩展模型研究[J].中国矿业大学学报,2013,42(4):573-579.]
[24]Feng Qing,Wu Caifang,Leibo.Coal/rock mechanics features of Qinshui Basin and fracturing crack control[J].Coal Science and Technology,2011,39(3):100-103.[冯晴,吴财芳,雷波.沁水盆地煤岩力学特征及其压裂裂缝的控制[J].煤炭科学技术,2011,39(3):100-103.]