高压砾石充填防砂工艺参数优化设计方法研究

高压砾石充填防砂施工过程中砾石尺寸、携砂比、充填排量、携砂液黏度、筛管参数等是影响施工成败和防砂效果的主要因素.讨论了地层砂侵入砾石层的特性以及砾石层压降计算方法,用以评价其挡砂效果和对产能的影响;建立了砾石尺寸综合评价方法,用以优选最佳砾石尺寸;以水平射孔孔眼中砾石颗粒不发生沉积堵塞为目标,建立了给定携砂比、携砂液黏度条件下的最小临界排量计算方法,用以对施工参数进行组合优化设计;最后研究了绕丝筛管尺寸和管柱结构的设计.给出了一套高压砾石充填施工参数优化设计方法,用该方法对涩北气田涩49井进行了高压充填设计,施工后防砂效果较好,产能降低率11.6%,目前稳产在(4.7～5.0)×104m3/d.

Optimization design of the parameters of high- rate gravel-packing sand-preventing technology

High-rate gravel-packing sand-preventing technology is an effective sand-control measures for serious sand oil/gas wells at present. The size of gravel, the ratio of sand to sand-carrying fluid, the flow rate of sand-carrying fluid, the viscosity of sand-carry fluid, the parameters of screen pipe are all the important factorswhich decide the success or failure of the technology and influence the result of sand prevention. The characteristic of formation sand invading into gravel packing zone and the calculation method of the pressure drop through the gravel packing zone are analyzed for evaluating the sand-retention result of the gravel packing zone and the influence of the gravel packing zone on the productivity of oil/gas wells. The comprehensive evaluation method of the size of gravel is established for obtaining optimal size of gravel. Under the presupposition of gravel not depositing in horizontal perforation tunnels, the calculation method of minimum critical flow rate of sand-carrying fluid is put forward with the ratio of sand to sand-carrying fluid and the viscosity of sand-carrying fluid being given for the integrated optimization design of technological parameters. Finally, the size of screen pipe and the structure of sand-preventing pipe string are designed. The parameters of high-rate gravel-packing sand-preventing technology of Se 4-9 gas well in Sebei Gasfield are designed by using the method presented in this paper, and the sand-preventing result of the gas well is very good. Its productivity is only decreased by 11.6% , and its output stabilizes in (4.7～5.0) ×104 m3/d.