罗玉财,王佳佳,谭天宇,等. 薄盐层套损防控技术及其在河套盆地的应用[J]. 石油钻采工艺,2026,48(4):456-464. DOI: 10.13639/j.odpt.202508009
引用本文: 罗玉财,王佳佳,谭天宇,等. 薄盐层套损防控技术及其在河套盆地的应用[J]. 石油钻采工艺,2026,48(4):456-464. DOI: 10.13639/j.odpt.202508009
LUO Yucai, WANG Jiajia, TAN Tianyu, et al. Technology for casing damage prevention and control in thin salt layers and its application in Hetao Basin[J]. Oil Drilling & Production Technology, 2026, 48(4): 456-464. DOI: 10.13639/j.odpt.202508009
Citation: LUO Yucai, WANG Jiajia, TAN Tianyu, et al. Technology for casing damage prevention and control in thin salt layers and its application in Hetao Basin[J]. Oil Drilling & Production Technology, 2026, 48(4): 456-464. DOI: 10.13639/j.odpt.202508009

薄盐层套损防控技术及其在河套盆地的应用

Technology for casing damage prevention and control in thin salt layers and its application in Hetao Basin

  • 摘要: 为解决河套盆地薄盐层蠕变引起的套管非均匀挤毁问题,并兼顾井筒完整性与经济性,开展了针对性的套损防控研究。通过盐岩室内蠕变实验揭示了高温深部薄层盐岩的蠕变规律,实验表明在150 ℃条件下盐岩稳态蠕变应变量(0.69%)为常温(0.15%)的4.6倍;建立了地层-水泥环-套管复合力学模型,引入非均匀载荷系数Kp,完善了非均匀载荷下套管抗外挤强度计算方法,明确了套损的主要原因是盐岩蠕变的外挤力超过了套管在非均质地应力下的抗外挤强度。基于此建立了适配河套盆地薄盐层的套损综合防控技术体系,在薄盐层段采用Ø206.36 mm、钢级140HC、壁厚17.25 mm套管,显著增强了井筒抗外挤强度、抗弯刚度,并配合随钻扩眼工艺增加环空间隙,提升了薄盐层井段的固井质量。该技术在河套盆地X11-15井等5口井进行了现场应用,有效指导了封盐套管选型,组合套管柱顺利下入,扩眼后盐层井段固井质量均合格,完井1~3年后均未发生套损问题。该方法有效解决了薄盐层套损问题,无需调整原井身结构,节省了钻井周期与费用,可为类似盐下油气藏的安全高效开发提供参考。

     

    Abstract: Aiming at the uneven casing collapse caused by the creep of thin salt layers in Hetao Basin, considering the wellbore integrity and economy, a targeted research on casing damage prevention and control was conducted. The laboratory creep experiments on salt rock revealed the creep behavior of high-temperature, deep, and thin salt rock. The experiments showed that the steady-state creep strain (0.69%) of salt rock at 150 ℃ is 4.6 times of that (0.15%) at room temperature. A formation-cement sheath-casing composite mechanical model was established, introducing uneven load factor Kp to improve the calculation method for casing collapse resistance under uneven loads. It was clarified that the main cause of casing damage is that the external collapse force from salt rock creep exceeds the casing’s collapse strength under uneven in-situ stress. Based on these findings, a comprehensive casing damage prevention and control technology system adapted to the thin salt layers in Hetao Basin was developed. In the thin salt layer interval, casing with an outer diameter of Ø206.36 mm, steel grade 140HC, and wall thickness of 17.25 mm was adopted, which significantly enhanced the collapse resistance and bending stiffness of the wellbore. Combined with a reaming process to increase the annular clearance, the cementing job quality in the thin salt layer interval was improved. This technology has been applied in five wells, including Well X11-15 in Hetao Basin, effectively guiding the selection of salt-sealing casing. The mixed casing string was run smoothly, the cementing job quality in the salt layer intervals after reaming met the standards, and no casing damage occurred within 1 to 3 years after completion. Moreover, this technology effectively addresses the challenge of casing damage in thin salt layers, without adjustment of the original wellbore configuration, offering significant advantages in controlling drilling costs and shortening the drilling operation cycle. It can provide theoretical reference for the safe and efficient development of similar sub-salt oil and gas reservoirs.

     

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