煤层气水平井玻璃钢管固井居中度分析

摘要

在煤层气水平井水平段采用玻璃钢套管可以提高后期采煤作业的安全性.为了揭示固井顶替过程中不同时刻玻璃钢管的居中度变化规律,根据玻璃钢管的浮重分析,建立考虑扶正器影响的水平井眼内玻璃钢管居中度计算模型.研究结果表明:由于玻璃钢管密度较低,随着管内外流体密度的变化,顶替过程中水平段玻璃钢管由井眼低边逐渐上浮,偏向井眼高边,其在水平井眼内的位置及居中度处于动态变化之中;减小水泥浆的密度有利于减小顶替结束时玻璃钢管所受向上的浮重,提高玻璃钢管在水平段的居中度.该研究为煤层气水平井玻璃钢管固井套管居中度的改进提供了理论依据.%Using fiber reinforced plastic (FRP) pipe in the coalbed methane horizontal well can enhance the security of later coal mining. For revealing centrality change rules of FRP pipe at different stages of cement slurry displacement at different time during coalbed methane horizontal well cementing, on the basis of analysis on buoyant weight of FRP pipe, a centrality calculation model is established by considering the influence of centralizers. The result of the research shows that, because of the low density of the FRP pipe, it will float upward instead of sinking when fluid density changes inside and outside of casing, and its location and centrality may dynamically change. So a lower density of slurry is in favor of reducing buoyant weight of FRP pipe and enhancing its centrality. This research provides theoretical basis for the improvement of centralizer for the FRP pipe.