【作者】 刘敏；

【导师】 李爱芬；

【作者基本信息】 中国石油大学 ， 油气田开发工程， 2008， 硕士

【摘要】 低渗油藏孔隙细小,渗流不符合达西定律,流体在其中流动存在启动压力。目前,国内外对低渗渗流规律的研究基本都集中在理论研究层面,实验规律很少。本文在前人的研究基础上,利用胜利油区某油田低渗透油藏的天然岩心,通过大量的渗流实验以及对实验数据的分析,对低渗透油藏的渗流规律做了进一步深入的研究。在分析低渗油藏单相渗流启动压力产生机理及渗流规律的基础上,设计了单相渗流启动压力及渗流规律的测定方法。通过对实验数据的回归,分别得出了油相与水相最小启动压力梯度、拟启动压力梯度、最大启动压力梯度及描述流量压差的曲线参数同岩石气测渗透率、流体粘度之间的经验公式,建立了确定最小、最大启动压力梯度的图版。得到了单相渗流启动压力的规律、特点及渗流特征的描述方法;在分析低渗油藏中两相渗流启动压力产生的机理和变化规律的基础上,设计了两相渗流启动压力及渗流规律的测定方法。通过实验研究了两相启动压力的特征及影响因素,建立了两相启动压力同渗透率和饱和度之间的函数关系式。建立了描述两相渗流规律的经验方法。通过单相及两相启动压力及渗流规律的研究,使低渗-特低渗油藏渗流规律的描述更加的系统化、定量化。低渗岩心流速与压力梯度曲线不过原点且不是直线,基于达西公式的不稳定相渗曲线测定方法已不再适应。本文用稳定法测定低渗岩心相渗曲线,并分析了影响相渗曲线的因素;通过分析测定的相渗曲线的特点,得出了平均及反求相渗曲线的新的归一化方法。研究表明:低渗岩心的启动压力及渗流规律与岩石的性质、渗透率和流体的性质有关;两相渗流启动压力与岩心渗透率、含水饱和度有关;低渗岩心相渗曲线参数与岩心渗透率、粘度都有很好的定量描述关系。本文在这些研究的基础上建立了一系列的定量描述低渗渗流规律的预测模型。更多还原

【Abstract】 The pore and throat of low permeable reservoir are very small, and the fluids flowing in it do not abide Darcy’s law, and there is threshold pressure when fluids begin to flow. Now the studies about threshold pressure are mainly in theory but little in laboratory. On the base of the study of predecessor, this paper do a great deal of flowing experiments and analysis by using the natural low permeability rock of Shengli oil field, and makeing more studies in the flowing law of the low permeability reservoir.On the base of the research of single flowing law and the reason of the threshold pressure in the low permeability reservoir,this paper design the equipment to study single flowing law and the threshold pressure. By regression the experimental data, the relationships between the threshold pressures and the ratio of gas permeability of rock to the viscosity of fluids are obtained. The parameters modifying the shape of velocity-pressure gradient are also obtained. Then the empirical figure for determining the min- and max-threshold pressures are built. the feature of the threshold pressures and the depicting way of single flowing are also obtained.On the base of the research of two-phase flowing threshold pressure in the low permeability reservoir, this paper design the equipment to study two-phase flowing law and the threshold pressure, and study the feature and the influential factor of the two-phase flowing threshold pressure, build the functional relationship of the two-phase flowing threshold pressure vs. permeability and Sw , and build the empirical method to depict the rule of two-phase flowing. By these results the description of the fluids flowing in low- permeability reservoir are quantitatively and more accurately.The curve of velocity-pressure gradient is not straight line or passes through origin. So the formula used to calculate relative permeability by non-steady state method based on the Dacy’s low is not suitable. The stead state method of determining the relative permeability curve(RPC) is improved based on the study of the characteristic of low permeable reservoir rock (LPRR). The unitary or standardization method is put forward to average and calculate RPC.The study shows that the threshold pressures and the flowing law are in connection with the rock nature and permeability and fluid nature, the two-phase threshold pressure is in connection with rock permeability and the Sw, the relative permeability curve parameters have good relationship with the rock permeability and the fluid velocity. This paper build a series of forecasting formulas for quantitatively depicting the flowing law of the low permeability reservoir.更多还原