流动改进剂降低含水原油转相点的实验研究

An Experimental Study of Reducing Phase Inversion Point of Watercut Crude Oil Using Flow Improver

为了了解流动改进剂对大庆含水原油在集输管路中流动的影响，在具有长20m水平工作段的管道流动实验装置上，在40℃测量了流动改进剂DODE加量分别为0、150、200和250mg／L、含水率分别为30％～90％的高含水原油不同流量下的流动参数，计算出剪切速率和表观黏度。在直径76和50mm管道内，剪切速率691／s的表观黏度～含水率关系曲线均按先上升，达到最大值后又下降的规律变化，表观黏度最大值对应的含水率即转相点含水率，转相点含水率随剪切速率降低而减小，在同一剪切速率下随流动改进剂加量增大而减小，最后基本趋于稳定不变。不加剂含水原油的转相点含水率为50％～70％，加剂250mg／L时的稳定值在35％～45％，即流动性改进剂可使W／O原油乳状液提前转相。将实验数据用S函数进行拟合，得到了可预测加入一定量流动改进剂的含水原油转相点含水率的方程。认为流动改进剂的作用是形成O／W乳状液或拟乳状液及在管壁形成亲水膜。图5参8。

To understand the effects of chemical flow improver （FI） on flow behavior of high watercut crude oil in oil-gathering pipelines in Daqing, the flow characteristics of crude oil containing 30% -90% water with FI DODE added at dosage of 0,150,200, and 250 mg/L are measured at 40℃ at various flow rate on an experimental conduit pipe flow installation with horizontal working section 20 m long and its shear rate and app viscosity are caloalated. The app viscosity vz watercut curves at shear rate 69 1/s obtained in conduit pipe 76 and 50 mm in diameter demonstrate similar changes： the app viscosity rises, reach a peak value and then lowers with increasing watercut, the percentage watercut at peak app viscosity, i.e. the phase inversion point （PIP） for W/O emulsions, decreases with decreasing shear rate and, at equal shear rate, decreases with increasing FI dosage and eventually levels out. The PIP for watercut crude oil without FI added is in range 50% -70% watercut and decreases to a steady value in range 35% -45% watercut at FI dosage 250 mg/L, which indicates an advanced phase inversion caused by FI. The experimental flow data are fitted well to S-function, giving an equation to predict the PIP-watercut for a W/O emulsion with FI added at a definite dosage. It is stated that the FI added acts to promote formation of O/W emulsion or/and pseudoemulsions and of hydrophilic films on pipe walls.