特种油气藏 ›› 2021, Vol. 28 ›› Issue (6): 144-150.DOI: 10.3969/j.issn.1006-6535.2021.06.019

• 钻采工程 • 上一篇    下一篇

利用预应力固井方法预防水泥环微环隙研究

席岩1, 李方园2, 王松3, 刘明杰4, 夏铭莉2, 曾夏茂5, 钟文力5   

  1. 1.北京工业大学,北京 100124;
    2.中国石油西部钻探工程有限公司,新疆 乌鲁木齐 830000;
    3.中国石油川庆钻探工程有限公司,四川 成都 610051;
    4.中国石油新疆油田分公司,新疆 克拉玛依 834000;
    5.中国石化西南石油工程有限公司,四川 德阳 618003
  • 收稿日期:2020-10-28 修回日期:2021-09-17 出版日期:2021-12-25 发布日期:2022-02-16
  • 作者简介:席岩(1985—),男,讲师,2008年毕业于中国石油大学(北京)石油工程专业,2019年毕业于该校油气井工程专业,获博士学位,现从事井筒完整性及岩石动力学方面的研究工作。
  • 基金资助:
    国家自然科学基金联合基金“页岩气水平井井筒完整性失效机理与控制方法”(U1762211);国家自然科学基金青年基金“基于压裂过程中四维地质力学的套管变形机理及控制方法研究”(52004013);北京市博士后工作经费资助项目“页岩气水平井套管剪切变形演变机理及控制方法研究”(Q6004014202003)

Study on Prevention of Micro-Annulus in Cement Sheath by Prestressed Cementing Method

Xi Yan1, Li Fangyuan2, Wang Song3, Liu Mingjie4, Xia Mingli2, Zeng Xiamao5, Zhong Wenli5   

  1. 1. Peking University, Beijing 100124, China;
    2. CNPC Xibu Drilling Engineering Company Limited, Urumqi, Xinjiang 830000, China;
    3. CNPC Chuanqing Drilling Engineering Co., Ltd., Chengdu, Sichuan 610051, China;
    4. PetroChina Xinjiang Oilfield Company, Karamay, Xinjiang 834000, China;
    5. Sinopec Southwest Petroleum Engineering Co., Ltd., Deyang, Sichuan 618003, China
  • Received:2020-10-28 Revised:2021-09-17 Online:2021-12-25 Published:2022-02-16

摘要: 深层页岩气水平井环空带压问题较为普遍,套管-水泥环界面处微环隙是导致环空带压的主要原因。针对该问题,运用力学实验手段和数值模拟方法,分析了预应力固井条件下微环隙的产生与发展,明确了不同预应力条件下水泥环耐受压裂段数。结果表明:套管内压越小,水泥环保证密封完整性时可承受的循环载荷次数越多;循环载荷作用下微环隙宽度为30.89μm是发生气窜的临界值。预应力固井显著降低了初次塑性变形量,增大了塑性变形增量;考虑预应力作用下套管产生的径向预应变,预应力固井技术显著降低了微环隙的宽度,增加了多级压裂过程中水泥环密封完整性的耐受压裂段数。预应力值越高,微环隙出现前的耐受压裂段数越多;压裂段数相同的情况下,预应力越大水泥环微环隙越小。现场应用结果表明,采用预应力固井技术及低弹性模量水泥浆,可以有效缓解深层页岩气水平井套管环空带压现象。研究结果可为页岩气水平井固井提供技术支持。

关键词: 水泥环, 密封, 微环隙, 循环载荷, 页岩气, 水平井

Abstract: The annulus pressure is more common in deep shale gas horizontal wells, which is mainly caused by the micro-annulus at the interface between casing and cement sheath. To address this problem, the generation and propagation of micro-annulus under prestressed cementing were analyzed by mechanical experimental means and numerical simulation methods, and the number of fracturing-resistant sections of cement sheath under different prestress was determined. The results showed that the lower the pressure inside the casing, the more times that the cement sheath withstood the cyclic loads on the premise of keeping the seal integrity; the micro-annulus width of 30.89 μm under cyclic load was the critical value for gas channeling. The prestressed cementing significantly reduced the initial plastic deformation and increased the plastic deformation increment; taking into account the radial prestrain generated by the casing under prestress, the prestressed cementing technology significantly reduced the micro-annulus width and increased the number of fracturing-resistant sections for cement sheath seal integrity in the multi-stage fracturing process. The higher the prestress value, the more fracturing-resistant sections before the micro-annulus appeared; with the same number of fracturing sections, the higher the prestress the smaller the micro-annulus of cement sheath. The field application results indicated that the annulus pressure of casing in deep shale gas horizontal wells was effectively reduced by prestressed cementing technology and cement slurry with low elasticity modulus. The results of the study provide technical support for the cementing of shale gas horizontal wells.

Key words: cement sheath, sealing, micro-annulus, cyclic load, shale gas, horizontal well

中图分类号: