提高四川盆地页岩气开发效益的工程方案
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摘要
四川盆地川南地区上奥陶统五峰组—下志留统龙马溪组海相页岩是该区页岩气开发的目的层,甜点主力气层为龙马溪组龙_1~1小层,其上的龙一_1~3—龙一_2非主力气层因水平井压裂裂缝缝高延伸受限未能得到充分的改造,采用新井开发又不经济,导致大量页岩气资源(约占总储量的2/3)无法动用。为此,提出了"生产套管合理封固+套管切割+高效段铣+常规侧钻钻完井与压裂"的方案,并分析了关键技术的可行性和方案的经济性。研究结果表明:①确定合理封固段长度,配套井口安全阀、井下环空封隔装置等,确保满足后续压裂和生产要求,新井生产套管水泥返至技术套管内合适位置即可;②机械式套管切割技术成熟,较之于常规技术,高效段铣的段铣效率、工具寿命均提高2倍以上;③高效低成本井筒处理和常规侧钻钻完井与压裂技术,可支撑方案目标的实现;④较之于钻新井,该方案可节省建井成本30%左右,非主力气层预计单井测试日产气5.2×10~4m~3,10年累计产气0.49×10~8m~3,经济性良好。结论认为,该方案为页岩气非主力气层经济有效开发提供了一条新思路,有助于实现我国页岩气快速上产和长期稳产。
The marine shale of Upper Ordovician Wufeng Fm to Lower Silurian Longmaxi Fm is the target layer of shale gas development in the south of the Sichuan Basin. The L1_1~1 sublayer of Longmaxi Fm is the "sweet spot" principal shale gas reservoir. The "non-essential"shale gas reservoir of L1_1~3–L1_2 above L1_1~1 sublayer cannot be stimulated sufficiently due to the restriction of the fracture propagation upward in horizontal wells, and its development is not cost effective by drilling new wells, so a great deal of resources(about two thirds of the total shale gas reserves) cannot be produced. In regard of this, an engineering scheme of "reasonable production casing cementing +casing cutting + efficient milling + conventional sidetrack drilling, completion and fracturing" was put forward. In addition, the feasibility of the key technologies and economy of the scheme were analyzed. And the following research results were obtained. First, determine the reasonable cementing length, together with the wellhead safety valve and downhole annular packoff to ensure that subsequent fracturing and production requirements are satisfied, and the to the cement of the production casing of a new well can be returned to an appropriate depth in the intermediate casing. Second, the mechanical casing cutting technology is mature, and compared with conventional milling technologies, its milling efficiency and service time of efficient milling are twice higher. Third, these low-cost efficient wellbore treatment and conventional sidetrack drilling & completion and fracturing technologies enable the scheme goal to be realized. Fourth,compared with the scheme of drilling new wells, this scheme can save the well construction cost by about 30%. The estimated daily testing production rate of "non-essential" shale gas reservoirs is 52 thousand m~3 per well, and the accumulative production of 10 years is 49 million m~3, which means a good economic return. In conclusion, this scheme provides a new idea for the economic and efficient development of "non-essential" shale gas reservoirs, and it is conducive to the fast production increase and long-term stable production of shale gas in China.
The marine shale of Upper Ordovician Wufeng Fm to Lower Silurian Longmaxi Fm is the target layer of shale gas development in the south of the Sichuan Basin. The L1_1~1 sublayer of Longmaxi Fm is the "sweet spot" principal shale gas reservoir. The "non-essential"shale gas reservoir of L1_1~3–L1_2 above L1_1~1 sublayer cannot be stimulated sufficiently due to the restriction of the fracture propagation upward in horizontal wells, and its development is not cost effective by drilling new wells, so a great deal of resources(about two thirds of the total shale gas reserves) cannot be produced. In regard of this, an engineering scheme of "reasonable production casing cementing +casing cutting + efficient milling + conventional sidetrack drilling, completion and fracturing" was put forward. In addition, the feasibility of the key technologies and economy of the scheme were analyzed. And the following research results were obtained. First, determine the reasonable cementing length, together with the wellhead safety valve and downhole annular packoff to ensure that subsequent fracturing and production requirements are satisfied, and the to the cement of the production casing of a new well can be returned to an appropriate depth in the intermediate casing. Second, the mechanical casing cutting technology is mature, and compared with conventional milling technologies, its milling efficiency and service time of efficient milling are twice higher. Third, these low-cost efficient wellbore treatment and conventional sidetrack drilling & completion and fracturing technologies enable the scheme goal to be realized. Fourth,compared with the scheme of drilling new wells, this scheme can save the well construction cost by about 30%. The estimated daily testing production rate of "non-essential" shale gas reservoirs is 52 thousand m~3 per well, and the accumulative production of 10 years is 49 million m~3, which means a good economic return. In conclusion, this scheme provides a new idea for the economic and efficient development of "non-essential" shale gas reservoirs, and it is conducive to the fast production increase and long-term stable production of shale gas in China.
引文
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[10]李瑞明,陶瑞东,何卫滨,夏鹤铭,王鹏,李军生.深层小井眼侧钻水平井钻井技术实践[J].钻采工艺,2015,38(4):113-114.Li Ruiming,Tao Ruidong,He Weibin,Xia Heming,Wang Peng&Li Junsheng.Practice of deep slim hole sidetrack horizontal well[J].Drilling&Production Technology,2015,38(4):113-114.
[11]王建龙,张雯琼,于志强,李瑞明,柳鹤,张苏.侧钻水平井水平段延伸长度预测及应用研究[J].石油机械,2016,44(3):26-29.Wang Jianlong,Zhang Wenqiong,Yu Zhiqiang,Li Ruiming,Liu He&Zhang Su.Prediction of sidetrack horizontal well extension length[J].China Petroleum Machinery,2016,44(3):26-29.
[12]汪洋,骆新颖,张斌.中石油国家页岩气示范区水平井钻井关键技术研究[J].钻采工艺,2017,40(5):26-28.Wang Yang,Luo Xinying&Zhang Bin.Concerns key to horizontal drilling in Demonstration Zone of National PetroChina Shale Gas Development[J].Drilling&Production Technology,2017,40(5):26-28.
[13]余雷,高清春,吴兴国,丁文正.四川盆地页岩气开发钻井技术难点与对策分析[J].钻采工艺,2014,37(2):1-4.Yu Lei,Gao Qingchun,Wu Xingguo&Ding Wenzheng.Drilling technical difficulties and countermeasures in shale gas development in Sichuan Basin[J].Drilling&Production Technology,2014,37(2):1-4.
[14]杨行,孙巧雷,冯定,周廪,王哲,陈正.用于深水套管切割的水力式内切割装置设计[J].科学技术与工程,2018,18(25):45-50.Yang Hang,Sun Qiaolei,Feng Ding,Zhou Lin,Wang Zhe&Chen Zheng.Design of hydraulic internal cutting device for deep water casing cutting[J].Science Technology and Engineering,2018,18(25):45-50.
[15]颜生鹏.青海油田套管切割工艺改进与应用[J].石油钻采工艺,2014,36(5):134-137.Yan Shengpeng.Improvement and application for casing cutting technology in Qinghai Oilfield[J].Oil Drilling&Production Technology,2014,36(5):134-137.
[16]田晓洁,刘永红,林荣桔,王飞.深海套管切割工具的研究和发展现状[J].石油机械,2011,39(11):67-71.Tian Xiaojie,Liu Yonghong,Lin Rongju&Wang Fei.Research and development status of deepsea casing cutting tools[J].China Petroleum Machinery,2011,39(11):67-71.
[17]孙振旭.双套压力体系侧钻井尾管及悬挂器段铣技术[J].石油钻采工艺,2018,40(3):297-300.Sun Zhenxu.Section milling technology of liners and hangers of sidetracking wells under double-sets pressure system[J].Oil Drilling&Production Technology,2018,40(3):297-300.
[18]刘祖林,杨保军,曾雨辰.页岩气水平井泵送桥塞射孔联作常见问题及对策[J].石油钻采工艺,2014,36(3):75-78.Liu Zulin,Yang Baojun&Zeng Yuchen.Common problems of pumping bridge plug and clustering perforation for horizontal shale gas well and countermeasures[J].Oil Drilling&Production Technology,2014,36(3):75-78.
[2]张全林,邓虎成,熊亮,刘岩.四川盆地龙马溪组页岩储层特征差异性探讨--以威远与涪陵地区为例[J].长江大学学报(自科版),2016,13(17):1-7.Zhang Quanlin,Deng Hucheng,Xiong Liang&Liu Yan.Analysis of shale reservoir difference of Longmaxi Formation in Sichuan Basin-By taking Weiyuan and Fuling areas for example[J].Journal of Yangtze University(Natural Science Edition),2016,13(17):1-7.
[3]刘乃震,王国勇,熊小林.地质工程一体化技术在威远页岩气高效开发中的实践与展望[J].中国石油勘探,2018,23(2):59-68.Liu Naizhen,Wang Guoyong&Xiong Xiaolin.Practice and prospect of geology-engineering integration technology in the efficient development of shale gas in Weiyuan Block[J].China Petroleum Exploration,2018,23(2):59-68.
[4]中国石油天然气股份有限公司勘探与生产公司.中国石油页岩气测井采集与评价技术管理规定(试行)[R].北京:中国石油天然气股份有限公司勘探与生产公司,2014.PetroChina Exploration&Production Company.CNPC shale gas logging acquisition and evaluation techniques regulations(Trial)[R].Beijing:PetroChina Exploration&Production Company,2014.
[5]谢军,张浩淼,佘朝毅,李其荣,范宇,杨扬.地质工程一体化在长宁国家级页岩气示范区中的实践[J].中国石油勘探,2017,22(1):21-28.Xie Jun,Zhang Haomiao,She Chaoyi,Li Qirong,Fan Yu&Yang Yang.Practice of geology-engineering integration in Changning state shale gas demonstration area[J].China Petroleum Exploration,2017,22(1):21-28.
[6]刘乃震,王国勇.四川盆地威远区块页岩气甜点厘定与精准导向钻井[J].石油勘探与开发,2016,43(6):978-985.Liu Naizhen&Wang Guoyong.Shale gas sweet spot identification and precise geo-steering drilling in Weiyuan Block of Sichuan Basin,SW China[J].Petroleum Exploration and Development,2016,43(6):978-985.
[7]贾成业,贾爱林,何东博,位云生,齐亚东,王军磊.页岩气水平井产量影响因素分析[J].天然气工业,2017,37(4):80-88.Jia Chengye,Jia Ailin,He Dongbo,Wei Yunsheng,Qi Yadong&Wang Junlei.Key factors influencing shale gas horizontal well production[J].Natural Gas Industry,2017,37(4):80-88.
[8]刘乃震,王廷瑞,丁文正,张世军,曹生.油气井侧钻技术研究与应用[J].特种油气藏,2008,15(5):97-100.Liu Naizhen,Wang Tingrui,Ding Wenzheng,Zhang Shijun&Cao Sheng.Study and application of sidetrack drilling technology[J].Special Oil&Gas Reservoirs,2008,15(5):97-100.
[9]刘乃震,何凯,叶成林.地质工程一体化在苏里格致密气藏开发中的应用[J].中国石油勘探,2017,22(1):53-60.Liu Naizhen,He Kai&Ye Chenglin.Application of geology-engineering integration in the development of tight gas reservoir in Sulige Gasfield[J].China Petroleum Exploration,2017,22(1):53-60.
[10]李瑞明,陶瑞东,何卫滨,夏鹤铭,王鹏,李军生.深层小井眼侧钻水平井钻井技术实践[J].钻采工艺,2015,38(4):113-114.Li Ruiming,Tao Ruidong,He Weibin,Xia Heming,Wang Peng&Li Junsheng.Practice of deep slim hole sidetrack horizontal well[J].Drilling&Production Technology,2015,38(4):113-114.
[11]王建龙,张雯琼,于志强,李瑞明,柳鹤,张苏.侧钻水平井水平段延伸长度预测及应用研究[J].石油机械,2016,44(3):26-29.Wang Jianlong,Zhang Wenqiong,Yu Zhiqiang,Li Ruiming,Liu He&Zhang Su.Prediction of sidetrack horizontal well extension length[J].China Petroleum Machinery,2016,44(3):26-29.
[12]汪洋,骆新颖,张斌.中石油国家页岩气示范区水平井钻井关键技术研究[J].钻采工艺,2017,40(5):26-28.Wang Yang,Luo Xinying&Zhang Bin.Concerns key to horizontal drilling in Demonstration Zone of National PetroChina Shale Gas Development[J].Drilling&Production Technology,2017,40(5):26-28.
[13]余雷,高清春,吴兴国,丁文正.四川盆地页岩气开发钻井技术难点与对策分析[J].钻采工艺,2014,37(2):1-4.Yu Lei,Gao Qingchun,Wu Xingguo&Ding Wenzheng.Drilling technical difficulties and countermeasures in shale gas development in Sichuan Basin[J].Drilling&Production Technology,2014,37(2):1-4.
[14]杨行,孙巧雷,冯定,周廪,王哲,陈正.用于深水套管切割的水力式内切割装置设计[J].科学技术与工程,2018,18(25):45-50.Yang Hang,Sun Qiaolei,Feng Ding,Zhou Lin,Wang Zhe&Chen Zheng.Design of hydraulic internal cutting device for deep water casing cutting[J].Science Technology and Engineering,2018,18(25):45-50.
[15]颜生鹏.青海油田套管切割工艺改进与应用[J].石油钻采工艺,2014,36(5):134-137.Yan Shengpeng.Improvement and application for casing cutting technology in Qinghai Oilfield[J].Oil Drilling&Production Technology,2014,36(5):134-137.
[16]田晓洁,刘永红,林荣桔,王飞.深海套管切割工具的研究和发展现状[J].石油机械,2011,39(11):67-71.Tian Xiaojie,Liu Yonghong,Lin Rongju&Wang Fei.Research and development status of deepsea casing cutting tools[J].China Petroleum Machinery,2011,39(11):67-71.
[17]孙振旭.双套压力体系侧钻井尾管及悬挂器段铣技术[J].石油钻采工艺,2018,40(3):297-300.Sun Zhenxu.Section milling technology of liners and hangers of sidetracking wells under double-sets pressure system[J].Oil Drilling&Production Technology,2018,40(3):297-300.
[18]刘祖林,杨保军,曾雨辰.页岩气水平井泵送桥塞射孔联作常见问题及对策[J].石油钻采工艺,2014,36(3):75-78.Liu Zulin,Yang Baojun&Zeng Yuchen.Common problems of pumping bridge plug and clustering perforation for horizontal shale gas well and countermeasures[J].Oil Drilling&Production Technology,2014,36(3):75-78.