高压砾石充填防砂工艺参数优化设计

高压一次充填是目前对严重出砂油气井十分有效的防砂工艺措施。砾石尺寸、携砂比、充填排量、携砂液黏度、筛管参数等是高压砾石充填施工过程中影响施工成败和防砂效果的主要因素。为了优化施工参数,改善施工效果,首先分析和研究了地层砂侵入砾石层的特性和砾石层压降计算方法,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,用来优选最佳砾石尺寸。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,可用来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,提出了一套高压砾石充填施工参数优化设计理论与方法。设计结果满足防砂基本要求并达到优化目的,防砂施工效果良好。

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 measure to 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 factors determining the success or failure of the technology and influence the result of sand prevention. The characteristics of formation sand invading into gravel packing zone and the method of calculation the pressure drop of gravel packing zone are analyzed first to optimize operation parameters and enhance operation effect, and the sand preventing effect of gravel and its effect on productivity are evaluated. Then a comprehensive method to evaluate gravel size is developed to select the optimal size of gravels. An approach to calculating minimum critical pumping rate, if given a ratio of sand to sand-carrying fluid and a low-rate sand-carrying fluid, is developed. It can be used for the optimization design of the operation parameters. At last, the design of the size of wrapping liners and the structure of strings is studied, as well as a set of theories and methods for the design of high-rate gravel-packing parameters are proposed. The design results fulfill the sand-preventing requirement and lead to good sand-preventing results.