稠油相对渗透率实验中管线死体积校正方法

Correction Method for the Dead Volume of Core Exit End Pipeline in Heavy Oil Relative Permeability Experiment

稠油相对渗透率曲线是稠油油藏开发动态预测过程的重要基础数据,稠油相对渗透率实验测量过程中的误差将会给油田开发分析传递错误信息。在稠油油藏相渗实验过程中,由于实验温度高,出口端计量管线长,系统死体积较大,死体积孔隙中水驱油规律和死体积校正方法会对实验结果产生重要影响。在常规实验管线中进行的水驱油实验发现,死体积管线中的原油不能全部被驱替出来,且管线中存在油水两相流动过程。油水黏度越高、驱替速度越快,则管线中的原油采出程度越低;实验过程还存在压力测量和体积计量不同步现象,产出流体体积计量滞后于压力测量。采用简单扣除管线孔隙体积来处理死体积的常规方法会使产油量计量产生较大误差,导致实验结果偏离真实流动情况,对此给出了相应的校正方法。

The heavy oil relative permeability curve is an important parameter in heavy oil reservoir performance prediction. The error in the relative permeability test caused by experimental factors will result in wrong information for reservoir devel- opment analysis. Due to the long exit end pipeline and more dead volume in the high temperature relative permeability test, the oil-water phases flowing law in the exit end pipeline of core holder and method of dead volume calibration will have important effect on relative permeability experimental results. The phenomenon of non-piston like displacement and pressure hysteresis effect have been discovered based on the water flooding experiment of heavy oil in the exit end pipeline. The breakthrough recovery and ultimate recovery factor decrease with increasing oil viscosity and water drive velocity, and the metering oil vol- ume is behind the data corresponding to the pressure. The conventional data correction by oil volume deducting space volume of pipeline may lead to the deviation of experimental results from the actual flow behavior, so a new method of data calibration is proposed.