基于轨迹优化扩展大位移井窄安全密度窗口
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摘要
S区块位于俄罗斯萨哈林岛东部海域,计划采用大位移井海气陆采技术进行开发。该区设计井深达12 000 m(垂深为2 800 m),水平位移约11 000 m,水平位移与垂直深度之比达3.93,初步设计四开井身结构。以往直井钻探表明,该区奥科贝凯组(Okobykaiskiy)下部及达吉组(Daginskiy)地层安全钻井液密度窗口窄(约0.3~0.4 g/cm3)、漏、塌、卡风险高,而大位移开发井相应井段窄安全密度窗口问题愈加突出。针对当前对于扩展窄安全密度窗口相关研究的不足、特别是局限于通过钻井液性能优化扩展安全密度窗口的现状,围绕窄安全密度窗口大位移井钻井难题,提出应综合力学、化学多手段全方位扩展窄安全密度窗口:首先,自井眼轨迹设计环节将优化井身剖面、改善井周围岩应力状态、扩展安全密度窗口有机结合起来,开展井眼轨迹主要参数对安全密度窗口的影响规律分析,在此基础上,兼顾井眼轨迹控制难度及施工摩阻等因素优化井眼轨迹,降低坍塌压力、提高地层破裂压力,实现安全密度窗口的先期扩展,为后续通过优化钻井液性能等手段进一步提高安全密度窗口奠定良好基础,并最终为窄安全密度窗口安全、高效钻井创造有利条件。研究形成的扩展密度窗口相关技术在S区块大位移井钻井设计中成功应用,使得目标层段安全密度窗口较轨迹优化前扩展幅度达25%~100%,对窄安全密度窗口难题的应对及防治具有指导意义。
Extended reach well technology has been used to produce the natural gas in the offshore area from onshore in developing the Block S located in the east of Sakhalin, Russia. The designed well depth(MD) was 12,000 m(TVD 2,800 m) and the horizontal displacement was about 11,000 m. The ratio of horizontal displacement to vertical depth was 3.93. The wells were designed to have four intervals. It was found from the previous experiences that the lower Okobykaiskiy formation and the Daginskiy formation had narrow safe drilling windows(0.3-0.4 g/cm3), downhole problems such as lost circulation, borehole wall collapse and pipe sticking etc. were drilling risks that needed to be considered, especially in drilling extended reach wells. Researches on how to widen narrow safe drilling window were inadequate to meet field requirement, most of which were focused on the optimization of drilling fluid properties to widen the safe drilling window. To solve the narrow safe drilling window problem in extended reach well drilling, mechanical and chemical measurements shall be adopted. First, well profile optimization, improvement of stress state around the borehole and widening of safe drilling window should all be taken into account in the well trajectory designing stage. In this stage, the effects of the main well trajectory parameters on safe drilling window should be analyzed. Based on the analyses, the well trajectory was optimized to reduce borehole collapse pressure and increase formation fracture pressure, thereby realizing the widening of safe drilling window through mechanical method, which in turn paved the way for further widening safe drilling window through chemical method, and created favorable conditions for efficient drilling in areas with narrow safe drilling windows. The technologies of widening safe drilling window obtained have been used successfully in drilling the extended reach wells in Block S, with the safe drilling window widened by 25%-100% compared with the safe drilling window prior to the well trajectory optimization. This work is of importance in dealing with narrow safe drilling window problem.
Extended reach well technology has been used to produce the natural gas in the offshore area from onshore in developing the Block S located in the east of Sakhalin, Russia. The designed well depth(MD) was 12,000 m(TVD 2,800 m) and the horizontal displacement was about 11,000 m. The ratio of horizontal displacement to vertical depth was 3.93. The wells were designed to have four intervals. It was found from the previous experiences that the lower Okobykaiskiy formation and the Daginskiy formation had narrow safe drilling windows(0.3-0.4 g/cm3), downhole problems such as lost circulation, borehole wall collapse and pipe sticking etc. were drilling risks that needed to be considered, especially in drilling extended reach wells. Researches on how to widen narrow safe drilling window were inadequate to meet field requirement, most of which were focused on the optimization of drilling fluid properties to widen the safe drilling window. To solve the narrow safe drilling window problem in extended reach well drilling, mechanical and chemical measurements shall be adopted. First, well profile optimization, improvement of stress state around the borehole and widening of safe drilling window should all be taken into account in the well trajectory designing stage. In this stage, the effects of the main well trajectory parameters on safe drilling window should be analyzed. Based on the analyses, the well trajectory was optimized to reduce borehole collapse pressure and increase formation fracture pressure, thereby realizing the widening of safe drilling window through mechanical method, which in turn paved the way for further widening safe drilling window through chemical method, and created favorable conditions for efficient drilling in areas with narrow safe drilling windows. The technologies of widening safe drilling window obtained have been used successfully in drilling the extended reach wells in Block S, with the safe drilling window widened by 25%-100% compared with the safe drilling window prior to the well trajectory optimization. This work is of importance in dealing with narrow safe drilling window problem.
引文
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[7]姜智博,周英操,王倩,等.实现窄密度窗口安全钻井的控压钻井系统工程[J].天然气工业,2011,31(8):76-79.JIANG Zhibo,ZHOU Yingcao,WANG Qian,et al.Managed pressure drilling system used in narrow density window drilling scenarios[J].Natural Gas Industry,2011,31(8):76-79.
[8]LEE JIN MING,MOHAMMED MOUSA,SETIAWAN B TRIGUNADI,et al.Overcoming a 0.35 ppg mud weight window-a case history of successful automated managed pressure drilling and managed pressure cementing offshore malaysia[R].SPE 168945.
[9]RODRIGUEZ J,A MONTERO DOMINGUEZ,S VILLALOBOS,et al.Successful exploration drilling in a very narrow mud weight window with crossflow using automated managed pressure drilling:A case history in Mexico east[R].SPE 166163.
[10]GUILLERMO R TIRADO VARGAS,CORRADO PIER MARIA LUPO,JUAN CARLOS BELTRAN,et al.MPD makes possible to drill and trip out of the hole in a gas well with a combination of a narrow mud weight window and a serious ballooning effect[R].SPE 143104.
[11]王善举,孙举,马文英.随钻提高窄安全密度窗口的泥浆技术[J].精细石油化工进展,2008,9(5):20-24.WANG Shanju,SUN Ju,MA Wenying.Drilling fluid techniques improving narrow safe density window in drilling[J].Advances in Fine Petrochemicals,2008,9(5):20-24.
[12]张增福,李益寿,汪军英,等.扩展安全密度窗口钻井液技术在吐哈油田的应用[J].钻井液与完井液,2008,25(3):55-57.ZHANG Zengfu,LI Yishou,WANG Junying.The application of drilling fluid technology of extending the safe density windows in TUHA oilfield[J].Drilling Fluid&Completion Fluid,2008,25(3):55-57.
[13]卢小川,范白涛,赵忠举,等.国外井壁强化技术的新进展[J].钻井液与完井液,2012,29(6):74-78.LU Xiaochuan,FAN Baitao,ZHAO Zhongju.New research progress on wellbore strengthening technology[J].Drilling Fluid&Completion Fluid,2012,29(6):74-78.
[14]谷穗,蔡记华,乌效鸣.窄密度窗口条件下降低循环压降的钻井液技术[J].石油钻探技术,2010,38(6):65-70.GU Sui,CAI Jihua,WU Xiaoming.Drilling fluid technologies to decrease circulating pressure loss[J].Petroleum Drilling Techniques,2010,38(6):65-70.
[15]EWERTON M P ARAUJO,SERGIO A B FONTOURA,JORGE AURELIO SANTA CRUZ PASTOR.A methodology for drilling through shales in environments with narrow mud weight window(NMWW)[R].SPE 94769.
[2]蔚宝华,邓金根,高德利,等.南海流花超大位移井井壁稳定性分析[J].石油钻采工艺,2006,28(1):1-3.YU Baohua,DENG Jin'gen,GAO Deli,et al.Borehole stability analysis for mega-extended-reach wells at Liuhua oil field in south China sea[J].Oil Drilling&Production Technology,2006,28(1):1-3.
[3]陈森,梁大川,李磊.深井超深井安全钻井液密度窗口研究进展[J].天然气工业,2008,28(1):85-87.CHEN Sen,LIANG Dachuan,LI Lei.The advancement of density window of safe drilling fluid for deep and ultradeep wells[J].Natural Gas Industry,2008,28(1):85-87.
[4]刘加杰,康毅力,王业众,等.扩展钻井液安全密度窗口理论与技术进展[J].钻井液与完井液,2007,24(4):69-73.LIU Jiajie,KANG Yili,WANG Yezhong,et al.Progresses in theory and technology of drilling fluids,safe density windows extension[J].Drilling Fluid&Completion Fluid,2007,24(4):69-473.
[5]苏勤,侯绪田.窄安全密度窗口条件下钻井设计技术探讨[J].石油钻探技术,2011,39(3)162-65.SU Qin,HOU Xutian.Research on drilling design techniques for narrow mud weight window[J].Petroleum Drilling Techniques,2011,39(3):62-65.
[6]张良万.建南地区克服窄安全密度窗口的钻井技术[J].天然气技术,2010,5(4):57-61.ZHANG Liangwan.Technological measures to overcome narrow safety density window in Jian-nan area[J].Natural Gas Industry,2010,5(4):57-61.
[7]姜智博,周英操,王倩,等.实现窄密度窗口安全钻井的控压钻井系统工程[J].天然气工业,2011,31(8):76-79.JIANG Zhibo,ZHOU Yingcao,WANG Qian,et al.Managed pressure drilling system used in narrow density window drilling scenarios[J].Natural Gas Industry,2011,31(8):76-79.
[8]LEE JIN MING,MOHAMMED MOUSA,SETIAWAN B TRIGUNADI,et al.Overcoming a 0.35 ppg mud weight window-a case history of successful automated managed pressure drilling and managed pressure cementing offshore malaysia[R].SPE 168945.
[9]RODRIGUEZ J,A MONTERO DOMINGUEZ,S VILLALOBOS,et al.Successful exploration drilling in a very narrow mud weight window with crossflow using automated managed pressure drilling:A case history in Mexico east[R].SPE 166163.
[10]GUILLERMO R TIRADO VARGAS,CORRADO PIER MARIA LUPO,JUAN CARLOS BELTRAN,et al.MPD makes possible to drill and trip out of the hole in a gas well with a combination of a narrow mud weight window and a serious ballooning effect[R].SPE 143104.
[11]王善举,孙举,马文英.随钻提高窄安全密度窗口的泥浆技术[J].精细石油化工进展,2008,9(5):20-24.WANG Shanju,SUN Ju,MA Wenying.Drilling fluid techniques improving narrow safe density window in drilling[J].Advances in Fine Petrochemicals,2008,9(5):20-24.
[12]张增福,李益寿,汪军英,等.扩展安全密度窗口钻井液技术在吐哈油田的应用[J].钻井液与完井液,2008,25(3):55-57.ZHANG Zengfu,LI Yishou,WANG Junying.The application of drilling fluid technology of extending the safe density windows in TUHA oilfield[J].Drilling Fluid&Completion Fluid,2008,25(3):55-57.
[13]卢小川,范白涛,赵忠举,等.国外井壁强化技术的新进展[J].钻井液与完井液,2012,29(6):74-78.LU Xiaochuan,FAN Baitao,ZHAO Zhongju.New research progress on wellbore strengthening technology[J].Drilling Fluid&Completion Fluid,2012,29(6):74-78.
[14]谷穗,蔡记华,乌效鸣.窄密度窗口条件下降低循环压降的钻井液技术[J].石油钻探技术,2010,38(6):65-70.GU Sui,CAI Jihua,WU Xiaoming.Drilling fluid technologies to decrease circulating pressure loss[J].Petroleum Drilling Techniques,2010,38(6):65-70.
[15]EWERTON M P ARAUJO,SERGIO A B FONTOURA,JORGE AURELIO SANTA CRUZ PASTOR.A methodology for drilling through shales in environments with narrow mud weight window(NMWW)[R].SPE 94769.