钻井液携屑的双流体模型

井筒中的岩屑颗粒群在细观上是离散的,其运动具有极大的随机性.但是,在时间与空间的宏观尺度下,其分布及运动又具有统计连续性与规律性,并可将其视为一种特殊的连续介质──拟流体.依据这一基本观点,本文深入地探讨了在实际岩屑运移过程中客观存在的、对钻井液携屑起主导作用的一系列关键性问题,例如:岩屑-岩屑间的随机碰撞及剪切效应、岩屑-钻井液的相间作用及岩屑-井壁的作用等等.从细观分析入手,揭示了钻井液携屑机理;应用统计理论及方法建立了描述其动力学特性的双流体模型.

A TWO-FLUID MODEL FOR THE TRANSPORT OF CUTTINGS CARRIED BY DRILLING-MUD

In microscopic view, the group of cuttings is discrete, its motion and collision between the cuttings are strongly random. In macro-scale of time and space,the dispersed cuttings phase is assumed to behave as continuous medium,which is termed "pseudo-fluid", and its dynamic regularity is shown in the view of statistics. Based on this concept, a serious of important problems in the transport of the cuttings carried by drilling-mud are studied systematically,such as the shearing and the random collision effects between the cuttings,the interaction between the drilling-mud and the cuttings phase, the interaction between the cuttings and a wall. The dynamics mechanism of the cuttings transport carried by the drilling-mud is revealed,and a two-fluid governing model for the drilling-mud and cuttings mixture flow is generated .