Research and Application of High-Pressure Deep-Well Coiled Tubing Plugging Removal and Production Restoration Technology

The exploration and development of CNPC has moved towards ultra-deep wells. The completion and production of deep wells and the later stages of production face the problem of oil pipeline scaling and formation sanding, which seriously affects the production of oil and gas wells. However, conventional continuous pipe plugging has generally been plagued by low operational efficiency and poor reliability. This paper focuses on the problem of plugging removal using continuous tube jet flow in high-pressure deep wells, focusing on complex operating conditions such as high temperature, high confining pressure, and small well bore. Starting from the study of high confining pressure jet flow, a 105 MPa ultra-high confining pressure laboratory test was conducted to develop a theory of high confining pressure jet flow attenuation. Based on theoretical research models, the jet striking mode, energy focusing method, and full-scale tool flow field simulation were carried out to form two types of jet plugging removal tools, namely internal swirling flow and nozzle rotating. Combined with high-temperature sealing and small-size design, a series of high-pressure deep-well coiled tubing plugging removal and production tools were developed. The field test was completed in Kuche piedmont of Tarim oilfield with the complete set of operation process, achieving efficient plugging removal in deep wells, meeting the requirements of on-site construction, and effectively supporting the development of ultra-deep wells.