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模拟井眼条件研究了不同剪切速梯、温度、压差条件下钻井液对油层的损害程度。结果表明 ,钻井液中的固相粒子在级配合理的情况下 ,对高渗透率的岩心损害深度浅 ,反排易于解除损害 ;而对低渗透率的岩心 ,细微粒子和液相进入油层深部后不易用反排方式解除 ,损害较严重 ;速梯增加以及温度升高也会加大损害程度 ;随压差的增大 ,岩心渗透率恢复值没有一定的规律。用动失水法评价钻井液对油层的损害半径 ,更接近于井下实际情况。
The wellbore conditions were simulated to study the damage degree of the drilling fluid to the oil layer under different shear velocity ladders, temperature and pressure difference conditions. The results show that the solid particles in the drilling fluid, with the grading rationale, have shallow damage to the core of high permeability and easy release of the reverse row. For cores with low permeability, fine particles and the liquid phase enter the deep part of the reservoir Which is not easy to be dislocated by the anti-row mode, resulting in more serious damage. The increase of the speed ladder and the increase of the temperature also increase the degree of damage. With the increase of the pressure difference, there is no certain law of the recovery value of the core permeability. The dynamic loss of water method to evaluate the drilling fluid damage radius of the reservoir, closer to the actual situation downhole.