Research Article | | Peer-Reviewed

Research on the Application of Efficient Replacement Technology for Wellhead Casing Heads in Gas Storage Facilities

Received: 14 May 2024     Accepted: 19 June 2024     Published: 25 June 2024
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Abstract

When it comes to gas storage facilities, it generally refers to underground gas storage facilities. Underground gas storage is a supporting project of long-distance pipelines, which is an artificial gas field or reservoir formed by injecting natural gas back into the underground space where gas can be stored. Suqiao Gas Storage is currently the deepest buried and highest pressure storage group in China. The storage group is located in Bazhou City and Yongqing County, Hebei Province, consisting of 5 gas storage facilities including Su 1, Su 20, Su 4, Su 49, and Gu Xinzhuang. The designed storage capacity is 6.738 billion cubic meters, with a working gas of 2.332 billion cubic meters. As of the end of 2020, a total of 3.5 billion cubic meters of gas injection and 2 billion cubic meters of gas production have gradually played an important role in natural gas peak shaving and supply guarantee in the Beijing Tianjin Hebei region. The Su 49 well is an injection production well for the reuse of an old well in the Su 49 gas storage. During the gas production period in 2020, there was a phenomenon of wellhead uplift. In order to ensure the safe production of the well, construction began from May 2021 and ended in July 2021. The successful implementation of this well has important reference and guidance significance for the replacement of casing heads in other wells of the gas storage.

Published in Science Discovery (Volume 12, Issue 3)
DOI 10.11648/j.sd.20241203.17
Page(s) 73-77
Creative Commons

This is an Open Access article, distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution and reproduction in any medium or format, provided the original work is properly cited.

Copyright

Copyright © The Author(s), 2024. Published by Science Publishing Group

Keywords

Gas Storage, Casing Head, Upward, Reinforcement Technology

1.前言
储气库就是一个装天然气的“储存器”。通常谈到储气库,一般指地下储气库。地下储气库是长输管道的配套工程,是将天然气重新注入地下可以保存气体的空间而形成的人工气田或人工气藏[1]。苏桥储气库是目前国内埋藏最深、压力等级最高的储气库群。库群位于河北省霸州市和永清县境内,由苏1、苏20、苏4、苏49、顾辛庄等5座储气库组成,设计库容67.38亿立方米,工作气23.32亿立方米。截至2020年底,累计注气35亿立方米、采气20亿立方米,在京津冀地区天然气调峰保供中逐渐发挥重要作用[6, 13]。
储气库在短期快速高低压反复运行,运行上限压力往往超过气藏原始地层压力,特别是冬季4个月的高速度强采使地层压力快速下降到下限压力,并在同一年近8个月的注气过程使地层压力由下限压力回升到原始地层压力或超过地层压力,这样长期年复一年的频繁和剧烈的注采气和压差变化极大的冲击着气井的寿命和安全性,特别是套管头部分,极易发生套管头升高,导致井口偏斜、晃动,严重影响储气库井的正常生产。苏49井为苏49储气库一口老井再利用的注采井,于2020年采气期发生井口抬升现象,为保证该井安全生产,2021年5月开始施工至7月结束,该井的成功实施对储气库其余井的换套管头施工具有重要的借鉴和指导意义[12]。
2.苏49井基本情况
图1 苏49井原井原井井身结构图。
苏49井位于冀中坳陷文安斜坡苏桥-信安镇潜山构造带苏桥油气田苏49潜山,地理位置为河北省永清县三圣口乡吴家场村,作为苏49储气库一口老井再利用的注采井,于1998年3月20日开钻,1998年10月26日完钻,1998年11月20日完井,完钻井深5250m。2011年7月,俄罗斯天然气科学研究院对苏49井进行了老井检测及评价认为该井技术套管、油层套管和尾管的完整性未受损可以作为储气库生产井使用。该井四开完井,油层套管为7”套管,水泥返深3241.8m,原井井身结构见图1;该井最高日注气量37.1×104m3,最高日采气量71.7×104m3,A环空最高压力为21.32MPa,B环空不带压;2019年12月出现采气树倾斜情况,2020年采气期发生井口抬升现象,最高抬升高度8.5cm,停产后井口抬升回落至2cm;同时,该井存在天然气泄漏问题,经检测H2S含量16.5mg/m3,存在安全风险,急需开展治理工作。
3.技术原理
主要技术原理是切割去掉地面以上的油层套管,在切割后的油层套管上部重新车制生产套管螺纹,连接井口并固定井口油层套管,达到降低井口高度、恢复油水井生产及消除套管上窜造成的生产和作业施工的安全隐患的目的[10]。
设计核心分为以下三步:
第一步是切除上窜套管:在对油层套管内液流通道实施控制后,以地面为基准,利用套管冷切割机将井口已经上窜的油层套管切割去掉,降低井口油层套管的高度[4];
第二步是套管制扣:在切割后的油层套管上安装数控车床,利用数控车床在切割后的油层套管上部,按照套管螺纹 API 标准规格重新制扣,重新达到套管与接箍螺纹连接的目的,保障井口与套管之间连接的密封要求和连接强度[5];
第三步是固定井口及拉伸套管:在制扣后的油层套管与表层套管之间安装套管可调式升高器,用以密封油套环空,再在新套管顶端依次连接套管接箍、升高短节、底法兰和套管提拉短节,利用现场作业修井设备对油层套管施加一定负荷的拉升力,使油层套管拉伸一定的弹性伸长量,调整套管可调式升套器上端面与油层套管接箍下端面接触,承载油层套管的拉升负荷,靠拉伸后油层套管的反向下压力,用以固定井口。井口固定后井口降套工艺施工完毕,重新安装井口采油树,恢复油水井生产[7, 8]。
4.施工要求及风险点
4.1.施工要求
1. 起原井管柱,更换套管头;
2. 环空安装压力表;
3. 更换套管头后,若仍窜漏则封井处理。
4.2.施工风险点
4.2.1.各工序重大风险识别
1) 暂堵施工时,工作压力较高,存在压井管汇及管线刺漏,造成人员伤害或其它工程事故的风险。
2) 拆采气树及安装防喷器期间,由于井漏,存在发生溢流和井喷的风险。
3) 起下作业管柱时,由于抽汲及压井液漏失等原因,存在发生溢流、井喷的风险。
4) 下注采完井管柱时,由于压井液漏失等原因,作业中存在发生溢流、井喷的风险。
4.2.2.防范措施
1)暂堵措施
管线若出现刺漏情况,需有专人负责及时关闭与暂堵施工管线连接的闸阀。暂堵施工管线或出口管线若出现刺漏情况,需有专人负责及时关闭与出口管线连接的闸阀[9]。
2)防漏、防井喷措施
暂堵施工后采用定时定量灌液结合氮气测液面的方式,摸清该井稳定液面,确定灌液制度及灌液量。特别是起管柱时注意边起边向井内灌注清水(根据漏速确定灌入量),保持液面稳定[10]。
3)作业期间,循环压井时的防范措施
起下钻过程中,井口可采用安装自封或防落物胶皮等措施,全程做好防落物工作。循环压井时,井口、循环管汇处派专人坐岗。备自动点火装置;自动点火启动装置距离火炬10m以上。放喷管线接出井口50m以远,管线通径不小于50mm;点火前,应观察风向,火炬处于井口的下风方向;若风向不对且较大,推迟点火时间[11]。
4)防硫化氢等有毒有害气体安全措施
该井经检测H2S含量16.5mg/m3,必须配备周期检定合格的有毒有害气体监测仪,在井口处、钻台上下、循环罐、放喷管线出口等有毒有害气体易聚积的场所应随时监测,要安装防爆排风扇以驱散工作场所弥漫的硫化氢等有毒有害气体。加强巡检力度,发现情况立即通知现场负责人采取应对措施,防止事态进一步扩大。井口值守人员轮流值班,防止人员疲劳值岗,每班两人,相互照应[2, 3]。
5.具体施工过程
5.1.前期准备工作:处理井筒和井口
1、油管连续灌液767.20m3,测量套压为16MPa,油管液面深度为180m;
2、用清水33m3混合交联剂360㎏、聚合物180㎏,使用搅拌罐搅拌配制0.6%高粘度凝胶堵剂,正挤0.60%高粘度凝胶堵剂30m3,正挤清水20m3
3、用清水正送氧化铝可解堵球并配合钢丝作业下放工具至预定深度开始向下震击滑套,滑套打开;
4、用清水20m3反循环洗井脱气至油、套压0MPa,持续液面监测,环空液面至井口;
5、拆井口,装防喷器。起原井管柱准备;
6、上提管柱悬重,原井封隔器解封;
7、下通井规和刮削器进行通井刮削;
8、下可捞式桥塞,用清水对井筒试压,正试压20MPa,历时30min,压力不降,试压合格;
9、底带电磁探伤仪器和四十臂井径仪进行测井;
10、下可捞式压裂桥塞,用清水0.3m3对桥塞正试压20MPa,30min压力不降,试压合格,做好更换原井套管头准备。
5.2.安装套管头
1、以井口为中心挖方坑,长 3.7m、宽 2.4m、深1.8m方坑,如图2所示,做好防塌方安全措施,用清水井筒灌液,始终保持液面在井口,将井筒灌满,时刻监测井口可燃气体的浓度;
2、在油层套管—油管、油层套管—表层套管、表层套管—导管环空灌清水排空,防止闪爆;
3、切割原井导管、表层套管,割完后打磨,用角磨机将坡口打磨成10 × 30°,要求坡口棱角且手感光滑,然后用金刚砂纸仔细打磨露在外面的套管头表层密封部位,使用立式车床对切割后的套管进行车扣,见图3;
4、装一级套管头,对一级套管头BT密封,注脂压力10MPa,试压10MPa,稳压15min压力不降,试压合格。继续安装二级套管头,对二级套管头BT密封,注脂压力16MPa,试压16MPa,稳压15min压力不降,试压合格,对二级套管头金属密封,试压16MPa,稳压15min压力不降,试压合格。上提套管悬重至400kN,套管上行10cm,装套管卡瓦,下放套管下行0.5cm。装70MPa采气树大四通。对大四通金属密封,试压6000psi,稳压10min压力不降,试压合格,至此套管头更换完毕,更换后的套管头见图4。
5、后期收尾工作
1) 装井口大四通与防喷器、下可捞式桥塞打捞器打捞桥塞、下完井管柱、下安全阀、坐油管挂、装井口、封隔器坐封、顶替保护液;
2) 连防喷管钢丝作业,通井后环空氮气打压8MPa。观察,油压0MPa,A环空压力8MPa,B环空压力0MPa。再次环空氮气升压至15MPa,经10min压力不降,试压合格,放压至5MPa关井,安装压力表监控压力变化;
3) 苏49井完井收工。
6.结论与建议
1) 储气库井受注采周期影响,频繁的接受交变应力容易发生套管头升高,导致井口偏斜、晃动,所以对于该类井必须及时应因地制宜选择合适的治理措施,如采用套管上窜加固技术等,防止造成更严重的后果[14];
2) 由于井口挖掘深度较深且面积较大,人员下入时应系好安全带,在受限空间进行切割、电焊作业时,要劳保穿戴齐全,避免切割件受力弹开造成击伤。此外在施工过程中应采取有效手段检测油套及油、表套环空内的气体组分,防止易燃易爆及有毒有害气体造成意外事故或人身伤害[15];
3) 利用换套管头技术对储气库苏49井套管上窜问题进行加固处理尚属首次,通过优选施工方案,合理组织现场施工,更换好的套管头能够承受高压注采生产的检验,没有发生泄露现象,形成了一套适合储气库更换套管头的特色技术值得应用推广。
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Cite This Article
  • APA Style

    Dong, Y., Yongqiang, R., Wei, Z., Zhihong, W., Jianbao, W., et al. (2024). Research on the Application of Efficient Replacement Technology for Wellhead Casing Heads in Gas Storage Facilities. Science Discovery, 12(3), 73-77. https://doi.org/10.11648/j.sd.20241203.17

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    ACS Style

    Dong, Y.; Yongqiang, R.; Wei, Z.; Zhihong, W.; Jianbao, W., et al. Research on the Application of Efficient Replacement Technology for Wellhead Casing Heads in Gas Storage Facilities. Sci. Discov. 2024, 12(3), 73-77. doi: 10.11648/j.sd.20241203.17

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    AMA Style

    Dong Y, Yongqiang R, Wei Z, Zhihong W, Jianbao W, et al. Research on the Application of Efficient Replacement Technology for Wellhead Casing Heads in Gas Storage Facilities. Sci Discov. 2024;12(3):73-77. doi: 10.11648/j.sd.20241203.17

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  • @article{10.11648/j.sd.20241203.17,
      author = {Yang Dong and Ren Yongqiang and Zhang Wei and Wei Zhihong and Wang Jianbao and Zhou Jianhua},
      title = {Research on the Application of Efficient Replacement Technology for Wellhead Casing Heads in Gas Storage Facilities
    },
      journal = {Science Discovery},
      volume = {12},
      number = {3},
      pages = {73-77},
      doi = {10.11648/j.sd.20241203.17},
      url = {https://doi.org/10.11648/j.sd.20241203.17},
      eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.sd.20241203.17},
      abstract = {When it comes to gas storage facilities, it generally refers to underground gas storage facilities. Underground gas storage is a supporting project of long-distance pipelines, which is an artificial gas field or reservoir formed by injecting natural gas back into the underground space where gas can be stored. Suqiao Gas Storage is currently the deepest buried and highest pressure storage group in China. The storage group is located in Bazhou City and Yongqing County, Hebei Province, consisting of 5 gas storage facilities including Su 1, Su 20, Su 4, Su 49, and Gu Xinzhuang. The designed storage capacity is 6.738 billion cubic meters, with a working gas of 2.332 billion cubic meters. As of the end of 2020, a total of 3.5 billion cubic meters of gas injection and 2 billion cubic meters of gas production have gradually played an important role in natural gas peak shaving and supply guarantee in the Beijing Tianjin Hebei region. The Su 49 well is an injection production well for the reuse of an old well in the Su 49 gas storage. During the gas production period in 2020, there was a phenomenon of wellhead uplift. In order to ensure the safe production of the well, construction began from May 2021 and ended in July 2021. The successful implementation of this well has important reference and guidance significance for the replacement of casing heads in other wells of the gas storage.
    },
     year = {2024}
    }
    

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  • TY  - JOUR
    T1  - Research on the Application of Efficient Replacement Technology for Wellhead Casing Heads in Gas Storage Facilities
    
    AU  - Yang Dong
    AU  - Ren Yongqiang
    AU  - Zhang Wei
    AU  - Wei Zhihong
    AU  - Wang Jianbao
    AU  - Zhou Jianhua
    Y1  - 2024/06/25
    PY  - 2024
    N1  - https://doi.org/10.11648/j.sd.20241203.17
    DO  - 10.11648/j.sd.20241203.17
    T2  - Science Discovery
    JF  - Science Discovery
    JO  - Science Discovery
    SP  - 73
    EP  - 77
    PB  - Science Publishing Group
    SN  - 2331-0650
    UR  - https://doi.org/10.11648/j.sd.20241203.17
    AB  - When it comes to gas storage facilities, it generally refers to underground gas storage facilities. Underground gas storage is a supporting project of long-distance pipelines, which is an artificial gas field or reservoir formed by injecting natural gas back into the underground space where gas can be stored. Suqiao Gas Storage is currently the deepest buried and highest pressure storage group in China. The storage group is located in Bazhou City and Yongqing County, Hebei Province, consisting of 5 gas storage facilities including Su 1, Su 20, Su 4, Su 49, and Gu Xinzhuang. The designed storage capacity is 6.738 billion cubic meters, with a working gas of 2.332 billion cubic meters. As of the end of 2020, a total of 3.5 billion cubic meters of gas injection and 2 billion cubic meters of gas production have gradually played an important role in natural gas peak shaving and supply guarantee in the Beijing Tianjin Hebei region. The Su 49 well is an injection production well for the reuse of an old well in the Su 49 gas storage. During the gas production period in 2020, there was a phenomenon of wellhead uplift. In order to ensure the safe production of the well, construction began from May 2021 and ended in July 2021. The successful implementation of this well has important reference and guidance significance for the replacement of casing heads in other wells of the gas storage.
    
    VL  - 12
    IS  - 3
    ER  - 

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Author Information
  • China National Petroleum Corporation Bohai Drilling Engineering Company Limited Downhole Services Company, Renqiu, China

    Biography: 杨东,男,1982年7月出生,本科,工程师,2012年毕业于西南石油大学石油工程专业,主要从事油气田试油、试气技术管理工作。

  • China National Petroleum Corporation Bohai Drilling Engineering Company Limited Downhole Services Company, Renqiu, China

  • China National Petroleum Corporation Bohai Drilling Engineering Company Limited Downhole Services Company, Renqiu, China

  • China National Petroleum Corporation Bohai Drilling Engineering Company Limited Downhole Services Company, Renqiu, China

  • China National Petroleum Corporation Bohai Drilling Engineering Company Limited Downhole Services Company, Renqiu, China

  • China National Petroleum Corporation Bohai Drilling Engineering Company Limited Downhole Services Company, Renqiu, China