基于正交实验的海上疏松砂岩油藏防砂参数优选方法

摘要

针对海上疏松砂岩油藏防砂完井设计中防砂参数多导致的实验工作量大和费用高等问题,以渤海南堡35-2油田某防砂井为例进行了正交实验法防砂参数优选,开展了基于正交实验的防砂参数化设计,结果表明该油田影响产能的防砂参数主次顺序为生产压差、原油黏度、挡砂精度和砾石层厚度,而影响出砂量的主次顺序为挡砂精度、生产压差、砾石层厚度和原油黏度;最优防砂方式为优质筛管+砾石充填,以产能最大为优选标准时的防砂参数最优组合为生产压差3 MPa+挡砂精度150 μm(10/30目)+原油黏度50 mPa·s+砾石层厚度52 mm,以出砂量最小为优选标准时的防砂参数最优组合为生产压差1 MPa+挡砂精度120 μm(20/40目)+原油黏度50 mPa·s+砾石层厚度52 mm.本文提出的基于正交实验的防砂参数优选方法在南堡35-2油田4口热采实验井防砂作业中取得了成功应用,具有较好的推广应用价值.%In order to solve the problem of heavy experimental tasks and hence the high cost due to the large number of parameters involved in the design of sand control completion for offshore unconsolidated sandstone reservoirs,optimization of parameters and sand control design was conducted based on orthogonal experiments.This methodology was applied in NB 35-2 oilfield in Bohai sea.The results indicated that the factors influencing productivity are drawdown pressure,oil viscosity,sand retention precision and gravel layer thickness;and the factors influencing sand production rate are sand retention precision,drawdown pressure,gravel layer thickness and oil viscosity.The optimal sand control completion is the combination of premium screen and gravel packing.If the maximum productivity is taken as the criteria,the optimum sand control parameters are 3 MPa of drawdown pressure + 150 μm (10/30 mesh) of sand retention precision+ 50 mPa·s of crude oil viscosity+ 52 mm of gravel layer thickness;but if the minimum sand production rate is taken as the criteria,the optimum sand control parameters are 1 MPa of drawdown pressure + 120 μm (20/40 mesh) of sand retention precision + 50 mPa· s of crude oil viscosity + 52 mm of gravel layer thickness.The optimization method presented here based on orthogonal experiments has been successfully applied in the sand control design of four thermal recovery wells in NB 35-2 oilfield.The results show that this method is worthy to be popularized.