薄互层煤层气井出砂综合治理研究

    Research on sand control in thin interbed CBM wells

    • 摘要: 煤层气井出砂(煤粉)问题制约煤层气井生产寿命,造成高额维修费用、产能降低,而薄互层煤层因为与围岩接触面积大,出砂(煤粉)问题突出。澳大利亚苏拉特盆地储层胶结疏松,煤/泥/砂岩夹层复杂,在统计井中,100%的生产井都有不同程度的出砂问题,其中33.5%出砂严重,修井作业频繁,开采成本居高。在系统分析苏拉特盆地储层特征、出砂特点和生产规律的基础上,根据颗粒沉降规律研究,结合出砂层位预测和防砂工艺优选,采用“膨胀式封隔器+盲管”与“螺杆泵+浆式转子+自动分流阀+钻穿套管鞋”结合的综合防排砂技术,阶段性地解决了苏拉特盆地煤系地层出砂问题。现场应用结果表明:该技术使得单井平均连续生产时间由275 d增至近400 d,降低修井频率近50%。

       

      Abstract: Coalbed methane well sand (pulverized coal) problem restricts the production life of coalbed methane well, resulting in high maintenance costs, reduce productivity, and because of the large contact area between thin interbed coal seam and surrounding rock, the problem of sand production (pulverized coal) is prominent. In the Surat Basin of Australia, the coal seam cementation is loose and the coal/mud/sandstone interlayer is complex. In the statistical wells, 100% of the production wells have different degrees of sand production problems, and 33.5% of which have serious sand production, frequent workover operations, and high production costs. Based on the systematic analysis of the reservoir characteristics, sand production characteristics and production rules in Surat Basin, the comprehensive sand discharge prevention technology of “expansion packer + blind tube” and “screw pump + slurry rotor + automatic shunt valve + drilling through casing shoes” is adopted according to the research on the particle settlement law, combined with the prediction of sand production level and the optimization of sand control technology. The problem of sand production in coal measure strata in Surat Basin has been solved in stages. The field application results show that the average continuous production time of a single well increases from 275 days to nearly 400 days, and the workover frequency is reduced by nearly 50%.

       

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