临兴区块致密砂岩气储层损害机理及钻井液优化
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摘要
致密砂岩气储层钻井过程中,钻井液入侵将造成严重的储层伤害难题。通过岩心分析技术、岩心流动实验等系统分析了临兴区块致密砂岩气储层主要损害机理,统计并分析了现场钻井液存在的技术难题,并优化出具有良好性能的致密砂岩气储层保护钻井液。研究结果表明,临兴区块致密砂岩气储层岩石具有中-粗砂状结构,胶结致密,孔喉细小,含敏感性黏土矿物,储层潜在严重的水锁伤害与中等偏强的水敏性及应力敏感性损害(临界压力为7.0 MPa),潜在中等偏弱的速敏性(临界流速为0.75 mL/min)、盐敏性(临界矿化度为7500 mg/L)、碱敏性(临界pH值为10.0)及土酸敏感性损害;临兴区块主要存在储层损害、钻井液漏失、井眼垮塌、摩阻扭矩大与井眼清洁等钻井液技术难题。优化出的钻井液封堵性能良好,滤液表面张力低(23.3 mN·m-1),能减少固相侵入,削弱水锁效应,提高岩石渗透率恢复值至91.3%,具有良好的储层保护性能。现场应用结果表明,该储层保护钻井液完全满足复杂井段或水平井段钻进的钻井液技术要求。
Drilling fluid invasion during drilling in tight sands gas reservoirs causes serious formation damage problem. Using core analysis and core flow experiment technologies, main damage mechanisms were determined for the tight sands gas reservoir in Block Linxing. Technical difficulties in field drilling fluid operations were summarized and analyzed, and a drill-in fluid for the protection of the reservoir was formulated based on optimization. Laboratory study showed that the rocks in the tight sands gas reservoir in Linxing have medium – coarse sand structure, compact cementation, fine pore throat and sensitive clay minerals. Several kinds of formation damage are found in the reservoir rocks, such as serious water block damage, moderately strong water sensitivity and stress sensitivity damage(critical pressure is 7.0 MPa), moderately weak flow rate sensitivity(critical flow rate is 0.75 mL/min), salt sensitivity(critical salinity is 7,500 mg/L), sensitivity to alkalinity(critical pH value is 10.0) and sensitivity to mud acid. Technical difficulties found in Linxing include formation damage, mud losses, wellbore collapse, high torque and drag, and hole cleaning. The optimized drill-in fluid has good plugging capacity and low surface tension of filtrate(23.3 mN/m), and is thus able to minimize the invasion of particles and to weaken water block effect. The percent recovery of permeability of reservoir rocks was raised to 91.3% of the original value,demonstrating the reservoir protection capacity of the drill-in fluid. Field application of the drill-in fluid showed that the optimized drill-in fluid met the needs of drilling in complex formations or horizontal drilling.
Drilling fluid invasion during drilling in tight sands gas reservoirs causes serious formation damage problem. Using core analysis and core flow experiment technologies, main damage mechanisms were determined for the tight sands gas reservoir in Block Linxing. Technical difficulties in field drilling fluid operations were summarized and analyzed, and a drill-in fluid for the protection of the reservoir was formulated based on optimization. Laboratory study showed that the rocks in the tight sands gas reservoir in Linxing have medium – coarse sand structure, compact cementation, fine pore throat and sensitive clay minerals. Several kinds of formation damage are found in the reservoir rocks, such as serious water block damage, moderately strong water sensitivity and stress sensitivity damage(critical pressure is 7.0 MPa), moderately weak flow rate sensitivity(critical flow rate is 0.75 mL/min), salt sensitivity(critical salinity is 7,500 mg/L), sensitivity to alkalinity(critical pH value is 10.0) and sensitivity to mud acid. Technical difficulties found in Linxing include formation damage, mud losses, wellbore collapse, high torque and drag, and hole cleaning. The optimized drill-in fluid has good plugging capacity and low surface tension of filtrate(23.3 mN/m), and is thus able to minimize the invasion of particles and to weaken water block effect. The percent recovery of permeability of reservoir rocks was raised to 91.3% of the original value,demonstrating the reservoir protection capacity of the drill-in fluid. Field application of the drill-in fluid showed that the optimized drill-in fluid met the needs of drilling in complex formations or horizontal drilling.
引文
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[12]邱正松,董兵强,钟汉毅,等.页岩储层保护用O/W纳米乳液的制备[J].化工学报,2015,66(11):4565-4571.QIU Zhengsong,DONG Bingqiang,ZHONG Hanyi,et al.Preparation of oil-in-water nanoemulsions used for the protection of shale gas reservoirs[J].CIESC Journal,2015,66(11):4565-4571.
[13]LIU Xuefen,KANG Yili,LUO Pingya,et al.Wettability modification by fluoride and its application in aqueous phase trapping damage removal in tight sandstone reservoirs[J].Journal of Petroleum Science&Engineering,2015,133:201-207.
[14]吕开河,邱正松,王在明.自适应屏蔽暂堵钻井液技术[J].中国石油大学学报(自然科学版),2008,32(2):68-71.LYU Kaihe,QIU Zhengsong,WANG Zaiming.Techniques of auto-adapting shielding and temporary plugging drilling fluid[J].Journal of China University of Petroleum(Edition of Natural Science),2008,32(2):68-71.
[2]SHAO C,YANG Z,ZHOU G,et al.Pore network modeling of water block in low permeability reservoirs[J].Petroleum Science,2010,7(3):362-366.
[3]程宇雄,彭成勇,周建良,等.临兴致密气藏压裂水锁伤害评价与措施优化[J].特种油气藏,2017,24(3):135-139.CHENG Yuxiong,PENG Chengyong,ZHOUJianliang,et al.Assessment of water block damage during fracturing of tight gas reservoirin Linxing area and optimization of relevant countermeasures[J].Special Oil&Gas Reservoirs,2017,24(3):135-139.
[4]张浩,康毅力,李前贵,等.鄂尔多斯盆地北部致密砂岩气层黏土微结构与流体敏感性[J].钻井液与完井液,2005,22(6):22-25.ZHANG Hao,KANG Yili,LI Qiangui,et al.Clay microstructure and fluid sensitivity of fine gas sands in the north of Erdos basin[J].Drilling Fluid&Completion Fluid,2005,22(6):22-25.
[5]邵东波,陈建文.鄂尔多斯盆地致密砂岩储层敏感性特征及其控制因素-以新安边地区延长组长6储层为例[J].西安石油大学学报(自然科学版),2017,32(3):55-60.SHAO Dongbo,CHEN Jianwen.Sensitivity of tight sandstone reservoir in Erdos basin and its controlling factor:taking the Chang 6 reservoir of Yanchang formation in Xin'anbian area as example[J].Journal of Xi’an Shiyou University(Natural Science Edition),2017,32(3):55-60.
[6]游利军,康毅力,陈一健,等.致密砂岩气藏水相圈闭损害实验研究及应用[J].钻井液与完井液,2006,23(2):4-7.YOU Lijun,KANG Yili,CHEN Yijian,et al.Experiments and applications of water phase trapping in tight gas sand reservoirs[J].Drilling Fluid&Completion Fluid,2006,23(2):4-7.
[7]聂法健,田巍,李中超,等.致密砂岩气藏水锁伤害及对产能的影响[J].科学技术与工程,2016,16(18):30-35.NIE Fajian,TIAN Wei,LI Zhongchao,et al.Water blocking damage for tight sandstone gas reservoirs and its effect on productivity[J].Science Technology and Engineering,2016,16(18):30-35.
[8]徐鹏,尹达,卢虎,等.库车山前致密砂岩气藏储层伤害分析及控制对策研究[J].科学技术与工程,2016,16(6):172-177.XU Peng,YIN Da,LU Hu,et al.Damage analysis of tight sandstone gas reservoir and control measures of Kuqa piedmont structure[J].Science Technology and Engineering,2016,16(6):172-177.
[9]张红杰,陈万钢,杨琦,等.鄂尔多斯盆地东缘煤系地层致密气低产原因分析[J].内蒙古石油化工,2015(Z1):123-126.ZHANG Hongjie,CHEN Wangang,YANG Qi,et al.Reasons of low yield of tight gas in coal measure strata in eastern Erdos Basin[J].Inner Mongolia Petrochemical Industry,2015(Z1):123-126.
[10]李明瑞,张清,王明瑜.苏里格气田上古生界主要含气层系黏土矿物特征及敏感性分析[J].中国石油勘探,2012(2):32-37.LI Mingrui,ZHANG Qing,WANG Mingyu,et al.Characteristics of clay minerals and reservoir sensitivity in upper paleozoic of Sulige gas field[J].China Petroleum Exploration,2012(2):32-37.
[11]董兵强,邱正松,王伟吉,等.新型页岩气储层保护剂SDME-2的制备及特性[J].石油化工高等学校学报,2015,28(6):61-65.DONG Bingqiang,QIU Zhengsong,WANG Weiji,et al.Preparation and performance of novel reservoir protection agent SDME-2 used for shale gas reservoirs[J].Journal of Petrochemical Universities,2015,28(6):61-65.
[12]邱正松,董兵强,钟汉毅,等.页岩储层保护用O/W纳米乳液的制备[J].化工学报,2015,66(11):4565-4571.QIU Zhengsong,DONG Bingqiang,ZHONG Hanyi,et al.Preparation of oil-in-water nanoemulsions used for the protection of shale gas reservoirs[J].CIESC Journal,2015,66(11):4565-4571.
[13]LIU Xuefen,KANG Yili,LUO Pingya,et al.Wettability modification by fluoride and its application in aqueous phase trapping damage removal in tight sandstone reservoirs[J].Journal of Petroleum Science&Engineering,2015,133:201-207.
[14]吕开河,邱正松,王在明.自适应屏蔽暂堵钻井液技术[J].中国石油大学学报(自然科学版),2008,32(2):68-71.LYU Kaihe,QIU Zhengsong,WANG Zaiming.Techniques of auto-adapting shielding and temporary plugging drilling fluid[J].Journal of China University of Petroleum(Edition of Natural Science),2008,32(2):68-71.