钻井泥浆滤液侵入储集层的理论计算模型

A THEOKETICAL M0DEL FOR MUD-FILTRATE INVASION IN RESERVOIR FORMATIONS DRILLING

利用多孔介质中两相渗流理论和岩电理论，建立了钻井泥浆滤液侵入孔隙性和渗透世地层的理论模型。利用数值计算方法可以得到水饱和度、水矿化度、水电阻率、地层电阻率等一系列物理量的径向侵入剖面分布特征，结果表明，泥浆侵入储集层后流体及地层的物世参数并非像传统的阶跃模型所描述的那样呈阶梯状突变，而是与时间有关的动态过程，沿径向呈较为复杂的分布。本文研究了侵入剖面随时间的动力学变化过程以及地层参数对侵入剖面的影响。

A theoretical model for mud-filtrare invasion in a porous and permeable formation dur-ing drilling is suggested through the application of the theory of fluid flow tbrough porous media and rock physics.A series of radial distribution of parameters around the borehole,such as water saturation,water salinity watet resistivity,formation resistivity and so on,will be obtained with a numerical method.These distributions are not in a perfectly piston-like shapes described by the“step profile”model,rather that they vary with the invasion time and show eomplex behaviors. In the present work,both the dynamic process of the invasion varying with time and the effect of the formation parameters on their distributions are stud-ied.