用门限流动压差和渗透率恢复值评价钻井液对储层的损害

Evaluating reservoir damage caused by drilling fluid based on threshold differential pressure of flow and the return permeability

渗透率恢复值在一定程度上受返排压差的影响,随返排压差的增加,渗透率恢复值逐渐增大。从门限流入压差和渗透率恢复值两方面评价储集层钻井液对储层的损害更准确。试验结果表明,3种储集层钻井液体系在同一条件下的性能相比,正电胶型的门限流动压差最低,渗透率恢复值最大,对储层的损害也最低,复合金属聚合物型的门限流动压差居中,渗透率恢复值居中,对储层的损害也居中;两性离子聚合物型的门限流动压差最大,渗透率恢复值最小,对储层的损害也最大。

Based on the determination of threshold differential pressure of flow and the return permeability in flow test, the reservoir damage caused by drill- .in fluid is evaluated, including (i) mixed metal hy-droxide fluid, (ii) amphoteric ion polymer fluid and (iii) compound metal amphoteric ion polymer fluid. Tests indicate that in the same condition (i) possesses the low threshold differential pressure of flow and the high return permeability, (iii) possesses the high threshold differential pressure of flow and the low return permeability, (ii) is the medium in the determination of two values.