水平井、大位移井连续管高效清砂过程中摩擦学行为与作用机制研究

Sand washing with high efficiency by coiled tubing in horizontal wells and extended reach wells has become an important part as the cleanout operation during the process of oil and gas exploitation. Due to the lack of systematic and in-depth understandings on the underlying mechanisms and theoretical guidance, problems during sand washing always have a great influence on the efficiency and safety of oil and gas exploitation in China. Towards solving these problems, the present project will carry out investigations on the action mechanism of sand washing by coiled tubing in horizontal wells and highly deviated wells. In this project, particle actions in situ observation testing system and a friction performance testing platform will be developed. Using the particle actions in situ observation testing system and the comprehensive friction testing platform, the frictional sliding characteristics of deposited particles and its influencing factors will be investigated, the moving and evolution behavior and of particles in horizontal annular space will be researched, and the frictional characteristics between particles and washing tools will be studied. Based on multi-disciplines of tribology, surface and interface science, material and chemistry, the interaction mechanism of deposited particles with tools under the water-based washing fluids will be constructed. Thereby, theoretical supports will be provided for sand washing operation during oil and gas exploitation.

水平井与大位移井连续油管高效清砂已经成为油气开采过程的重要环节。由于缺乏系统深入的机理研究和理论指导，砂沉积卡堵等问题始终影响着油气井的开采效率与安全。本项目针对这些问题，开展水平井与大位移井连续油管高效清砂过程中的摩擦学行为与作用机制研究，主要包括：研制水平井和大位移井清砂过程中颗粒运动在线观测系统和清砂液条件下颗粒与工具/套管间摩擦滑动综合试验平台；利用所研制平台，研究清砂过程中水平环空沉积颗粒运移规律，清砂液条件下沉积颗粒与清砂工具/套管间的摩擦滑动特性及其稳定性，以及单个沉积颗粒和沉积颗粒层间的摩擦运动特性。在摩擦学、表界面科学、材料学和化学等多学科综合交叉的基础上，揭示环空中清砂液、沉积颗粒和工具/套管之间的相互作用机制，为油气井高效清砂洗井作业提供理论支持。

随着油气开采力度加大，高效开采和水平井技术的发展，水平井开采逐渐普及，随之水平段颗粒沉积卡堵问题成为一个关注的焦点。砂堵对油气井生产有非常大的危害，易引起井下设备严重磨蚀，砂埋储层，造成油气井停产，甚至井壁坍塌等问题。因此，水平井与大位移井连续油管高效清砂已经成为油气开采过程的重要环节。本项目针对这些问题，开展了水平井与大位移井连续油管高效清砂过程中的摩擦学行为与作用机制研究。研制并搭建了水平井和大位移井清砂过程中颗粒运动在线观测系统和清砂液条件下颗粒与工具/套管间摩擦滑动综合试验平台。通过所搭建的试验平台，模拟研究了清砂过程中水平环空沉积颗粒运移规律。进行了水平井沉砂床工具携砂数值模拟研究，分析了喷嘴结构参数和作业参数对环空流场影响规律。研究了清砂液条件下沉积颗粒与清砂工具/套管间的摩擦滑动特性及其磨损机理。.本项目依据工具对水平井段沉砂床作业工况，对洗井作业过程工具水平环空段携砂作用进行综合分析和机理研究，结合作业参数下的工具摩擦学行为，探索在携砂作业过程中工具的优化结构和作业参数，为油气井高效清砂洗井作业提供理论支持。