多功能煤储层钻井液动态污染评价系统

Research and Application of Multi-function Evaluation System for Dynamic Contamination of Drilling Fluid in Coal-bed Reservoir

多功能煤储层钻井液动态污染评价系统是一种模拟煤储层真三轴应力条件下的钻井液对煤储层的侵入、以及侵入储层的深度和程度,同时还可以进行各种真三轴应力条件下的煤储层各向异性特征研究的实验仪器,属煤层气钻井液保护与伤害评价测试技术研究领域。该评价系统具有测量煤层煤心在各向异性应力条件下渗透率变化以及在真三维压力状态下煤储层钻井液动态污染前后的渗流变化规律的功能;能模拟正压差、负压差、平衡钻井过程中的钻井液动态污染过程,实现煤储层污染过程和渗流测试过程一体化,避免多次装夹煤样产生应力效应;适用于煤储层气液两相渗透率测试,解决了目前评价实验中常用的伪三轴夹持器不能在3个轴向上加载不同轴压的问题以及流体驱替实验、钻井液污染试验、气液两相驱替试验要单独进行的缺陷,具有流程清晰、操作方便、实验软件模块化、实验数据标准化等特点。

The multifunction evaluation system for dynamic contamination of drilling fluid is a test instrument of drilling fluid protection and damage evaluation of coal reservoir,which is used for simulating coal formation invasion caused by drilling fluid and the extent and depth of contamination under the condition of true triaxial stress,and can research anisotropic characteristics of coal formation being stood various true triaxial stresses.The system can detect permeability variation of coal core in aeolotropic stress conditions and filtration law of coal reservoir before and after being contaminated by drilling fluid in true triaxial stress situation,simulate dynamic pollution history of drilling fluid during positive and negative differential pressure,balanced pressure drilling,realize integration between the process of formation pollution and flow event,thus avoid pressure effect caused by multiple loading sample,and is applied for testing gas/liquid two-phase permeability of coal formation.Moreover,it has the characteristics of clear flow chart,easy operation,modules of experimental software and standardization of experiment data.