泥饼结构物理模型与数学模型研究

Mathematical & physical models for drilling fluid filter cake

通过对泥饼结构的物理模型与数学模型进行研究,可以准确地定量分析出14项泥饼质量参数。将钻井液静态滤失形成的真实泥饼的针入度曲线归结为5种类型,各反映不同泥饼内在质量的差别。通过分析泥饼在纵向压力作用下发生破坏的过程中力学特征的变化,建立了泥饼层状结构物理模型,解释了虚泥饼以及泥饼的可压缩层、密实层和致密层间的差别及其物理意义。将各类泥饼针入度曲线视为由4段连续光滑的直线和曲线组成的同一种典型曲线演变而成,建立了其数学模型。用数字化仪读入实测泥饼针入度曲线后,用泥饼质量评价软件CSEFCP可定量求解涉及泥饼厚度、强度和弹塑性等的14项泥饼质量参数,以快速、准确、方便地对泥饼质量进行定量评价。

To classify the true penetrating curves of drilling fluid filter cakes into 5 kinds by a definite shape and every kind reflects a definite behavior of a filter cake from static filtration test. According to the change of mechanical characteristic of a filter cake in penetrated courses with a longitudinal pressure, the paper advanced a physical model of layered structure of filter cake, and explained what the physical means of false filter cake vs true filter cake, and the difference of compressive, dense and solid of filter cake, By regarding all shapes of penetrating curves as a typical developed curve that forms from a curve and four lines smoothly, a mathematical model of its was build. After inputting the data of a penetrating curve with a digital instrument, a Computer Software Evaluates Filter Cake Performances (CSEFCP) outputted 14 parameters of a filter cake including strength, thickness, and plas-toelasticity, etc. . These parameters can be used to evaluate the filter cake qualities quantitatively, quickly and easily.