Abstract: The effective degradation of bioenzymatic can make the polymer changed from longchain to shortchain and the viscosity will be decreased, and the mud cake can be well cleared up. For this purpose, the viscosity exhaustion method was used, the bioenzymatic corresponding to different polymer were preferred, and four recipes of biodegradable drilling fluid were settled. The properties of drilling fluid have been obtained through the filter cake removal experiments and the permeability recovery experiments. The results show that the different kinds of polymers correspond to different optimal biological enzymes, X1, X6, X3 and X6 are the optimal enzyme corresponds to CMC, PACLV, HEC and guar gum drilling fluid respectively; Four recipes of enzyme biodegradable drilling fluid preferred are of higher practical value, which could clean up the mud cake after drilling process, and the degree of injury of the reservoirs is smaller.

Key words: Soft coal seam,    , Enzyme,    ,  Polymer,    , Stable borehole,    ,  Effective degradation

摘要： 生物酶的高效降解作用可使聚合物由长链变短链, 黏度减小, 清除聚合物泥饼效果较好。为此, 采用黏度衰减法, 优选了不同聚合物所对应的生物酶, 配置了4组生物酶可解堵钻井液, 通过滤饼清除实验和渗透率恢复实验测定了所配钻井液的解堵性能。结果表明, 不同聚合物对应不同的最佳生物酶, CMC、 P AC - LV、 HE C和胍胶钻井液的最佳生物酶分别为 X 1、 X 6、 X 3和 X 6; 优选出的4组生物酶可解堵钻井液配方, 均能在钻进后清除泥饼, 并对储层伤害率较小, 具有较高的实用价值。

关键词: 松软煤层,    ,  , 生物酶,    ,  聚合物,    ,  , 护壁,    ,  , 解堵