张俊成,李军,谢士远,王雪刚,张浩,宋琳. 考虑井筒完整性的固井方案风险评价方法[J]. 石油钻采工艺,2024,46(1):53-59. DOI: 10.13639/j.odpt.202304024
引用本文: 张俊成,李军,谢士远,王雪刚,张浩,宋琳. 考虑井筒完整性的固井方案风险评价方法[J]. 石油钻采工艺,2024,46(1):53-59. DOI: 10.13639/j.odpt.202304024
ZHANG Juncheng, LI Jun, XIE Shiyuan, WANG Xuegang, ZHANG Hao, SONG Lin. Risk assessment method for cementing program considering well integrity[J]. Oil Drilling & Production Technology, 2024, 46(1): 53-59. DOI: 10.13639/j.odpt.202304024
Citation: ZHANG Juncheng, LI Jun, XIE Shiyuan, WANG Xuegang, ZHANG Hao, SONG Lin. Risk assessment method for cementing program considering well integrity[J]. Oil Drilling & Production Technology, 2024, 46(1): 53-59. DOI: 10.13639/j.odpt.202304024

考虑井筒完整性的固井方案风险评价方法

Risk assessment method for cementing program considering well integrity

  • 摘要: 在吉木萨尔页岩油藏开发过程中,压裂导致井筒完整性失效的问题严重,不同固井方案下的失效位置和比例差异较大。为研究固井方案对压裂时井筒完整性的影响,基于该地区固井现状构建了二开特征水平井Ⅰ井和Ⅱ井,分别选取这2口井在一开、二开井段的相同位置及Ⅰ井水泥环与钻井液的固液交界处作为关键节点进行研究。采用有限元软件模拟压裂施工对井筒的影响,明确了压裂时不同固井方案下井筒不同位置处套管和水泥环的应力分布规律,分析了全井筒多节点的失效风险,优选了固井方案。研究结果表明:B环空内是钻井液时油层套管的Mises应力明显大于是水泥环时,损伤风险更大;B环空中水泥环的受力大于C环空,且顶部有较高拉伸破坏风险,底部有较高压缩破坏风险;固井方案Ⅰ相较于方案Ⅱ完整性失效风险低。风险评价及优选结果可为拟压裂井的固完井方案设计提供指导,为优选安全经济的固完井方案提供参考。

     

    Abstract: The development of the Jimsar shale oil is found with severe issues of well integrity failure due to fracturing, and the failure position and rate are highly differentiated among different cementing programs. To investigate the effects of cementing programs on well integrity during fracturing, two horizontal well models (Ⅰ and Ⅱ) were built in accordance with the characteristics of the cementing for the horizontal wells with two casing sections in the study area. The same positions of the 1st and 2nd casing sections and the solid-fluid interface between the cement sheath and drilling fluids in Well Ⅰ were selected for analysis. The effects of fracturing on the well were simulated using a finite element simulator. In cases of different cementing programs, the stress distribution patterns of the casing and cement sheath along the well during fracturing were clarified, the full-well multi-node failure risks were assessed, and the cementing program was optimized. The results showed that with the B annulus filled with drilling fluids, the Mises stress of the production casing is considerably higher than that with the B annulus occupied by the cement sheath, indicating higher damage risks. The stress of the cement sheath in the B annulus is higher than that in the C annulus. Moreover, the top of the B annulus cement sheath is prone to tensile failure, while the bottom is prone to compressive failure. The Ⅰ cementing program is found with lower risks of well integrity failure, compared with the Ⅱ cementing program. The performed risk assessment and optimization provide guidance for the designs of cementing and well completion of wells to be fractured to deliver safe and cost-effective cementing and well completion programs.

     

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