保护冻土层的真空隔热套管性能试验与数值模拟研究

Performance Test and Numerical Simulation Research on Vacuum Insulated Casings for Permafrost Protection

周晓晖 苏义脑 牛成成 程远方 魏佳

ZHOU Xiaohui SU Yinao NIU Chengcheng CHENG Yuanfang WEI Jia

中国石油大学(华东)石油工程学院，山东青岛 266580 中国石化石油工程技术研究院，北京 102206

School of Petroleum Engineering, China University of Petroleum (East China), Qingdao, Shandong, 266580, China Sinopec Research Institute of Petroleum Engineering, Beijing, 102206, China

针对冻土层钻井过程中可能引发的冻土融沉和井口下沉等问题，研究采用真空隔热套管保护冻土层，并采用试验和数值模拟方法研究了真空隔热套管的保温性能。试验结果显示：真空隔热套管能在限制径向传热的同时限制表面的轴向传热，减小套管表面的升温幅度和升温范围；其视导热系数远小于传统套管，在不同环境温度和钻井液温度下都具有保温性能；降低真空度可以提高其保温性能，强化其对冻土层的保护。数值模拟结果表明，真空隔热套管可以减小冻土层融化区域，降低冻土融沉和井口下沉的可能性。在此基础上，提出了降低真空度、加大套管总成内的隔热套管段长度和接箍处包裹隔热泡沫等提高真空隔热套管保温性能的工程措施。研究结果验证了真空隔热套管对冻土层保护的有效性和稳定性，对开发极地油气资源具有一定的指导作用。

Because permafrost settles as it thaws, there is a risk that the wellhead will sink while drilling, and therefore, vacuum insulated casings were introduced to protect the permafrost, and their thermal insulation performance was analyzed through experiments and numerical simulations. The field test results showed that the vacuum insulated casings could limit both the radial and the axial heat transfer on the surface simultaneously, which restricts the range and magnitude of temperature increase on the casing surface. Because the vacuum insulated casings have much lower apparent thermal conductivity than that of traditional casings, their thermal insulation performance can be maintained at various ambient temperatures and drilling fluid temperatures. In addition, decreasing the vacuum degree can improve their thermal insulation performance and strengthen their protection of the permafrost. The numerical simulation results indicated that the vacuum insulated casings could greatly reduce the permafrost thaw zone and lower the possibility of settling and wellhead sinking due to permafrost thaw. Furthermore, the following measures were adopted to enhance the thermal insulation performance of the vacuum insulated casings, including vacuum degree reduction, insulated casings length increase in the casing assembly, and insulation foam wrapping at the coupling. The research results have verified the effectiveness and stability of vacuum insulated casings in protecting the permafrost, so as to guide the development of oil and gas resources in the Arctic region.

国家重点研发计划项目“钻井工艺及井筒工作液关键技术研究”（编号：2016YFC0303303）资助

https://doi.org/10.11911/syztjs.2021050