| Abstract |
Most oil and gas fields possess abundant geothermal resources and a large number of idle abandoned wells. Repurposing these abandoned wells for geothermal development can effectively revitalize their value and reduce drilling costs for geothermal projects. This study analyzes the wellbore structural characteristics of abandoned wells in the Dongpu Sag of the Zhongyuan Oilfield, compares the similarities and differences between abandoned wells and geothermal wells, and develops downhole operation tools required for the retrofitting of abandoned wells in this region.Two casing cutting solutions were selected, and specialized tools were developed, including a dedicated tool for reshaping the casing fish mouth using energy-concentrated cutting, a hydraulic jet casing cutting tool, and a sand-carrying fluid for hydraulic jet cutting. Based on the sealing and water-blocking requirements after casing cutting, two types of water-blocking tools were designed for sealing the top of the cut casing. A sand control process suitable for retrofitted geothermal wells was studied, and a precision microporous composite sand screen was designed according to the particle size analysis of regional geothermal reservoir sand samples, meeting the sand control requirements of repurposed abandoned wells.The key supporting tools developed for converting abandoned wells into geothermal wells are suitable for the technical requirements of regional abandoned well retrofitting and provide technical readiness for the engineering implementation of repurposing abandoned wells in the region. |