井下局部反循环清砂系统研究

为了解决传统的正循环或反循环冲砂工艺在漏失井和深井中清砂难度大、成本高的问题,提出利用射流泵在油井下形成局部反循环的清砂工艺,并对其进行工艺流程优化设计,通过多级沉砂而提高清砂效率。以某油田油井为研究对象,设计一套井下局部反循环和多级沉砂的清砂管柱系统,包括对其中清砂用射流泵、集砂器2个核心工具进行结构设计。选用固定式、正循环式的射流泵结构,计算得到其喷嘴出口直径为4.4 mm,喉管直径为7.7 mm。通过CFD数值模拟方法对清砂用射流泵内流场进行仿真分析,对其喉嘴距和喉管长度2个关键结构参数进行优化,并为现场清砂作业提供依据。对所设计加工的工具进行了下井应用试验,试验结果可为后续清砂工艺的持续优化提供参考。

Study on Oil Well Sand Cleaning System Based on Downhole Partial Reverse Circulation

In order to solve the problem of the difficulty and high cost of sand cleaning in lost wells and deep wells with traditional positive circulation or reverse circulation sand washing methods, the idea of sand removal technology using jet pumps to form a local reverse circulation in the oil well was put forward, and the process flow was optimized to improve the sand removal efficiency through multi-stage sand settling. Taking the oil well in an oil field as the research object, a set of downhole partial reverse circulation and multi-stage sand-settling sand cleaning pipe string system was designed, including the structure design of two key tools, a jet pump for sand cleaning and a sand collector. The fixed and positive circulation jet pump structure is selected, and the nozzle outlet diameter is calculated to be 4.4 mm, and the throat diameter is 7.7 mm. Through the Three-dimensional modeling and CFD numerical simulation method, the flow field of the jet pump for sand cleaning was simulated and analyzed, and the two key structural parameters of the throat distance and the throat length were optimized, and the basis for the on-site sand cleaning operation was provided. On this basis, the downhole application test was carried out by using the designed and processed tools. The analysis of the test results provides a reference for the continuous optimization of the later sand cleaning process.