生物酶可解堵钻井液生物降解评价方法探讨

Methods for the Evaluation of Drilling Fluids' Biodegradability.

生物酶可解堵钻井液是一种新型的环保钻井液,它利用生物酶能将钻井液处理剂降解为二氧化碳和水的生物催化特性,使井壁先前形成的泥饼自动破除而解堵。由钻井液处理剂的降解特点衍生出4种评价方法,并依据处理剂的生物降解性对处理剂进行了分类。考虑试验设备复杂程度以及现场推广应用等实际情况,主要采用DO衰减法和黏度衰减法对处理剂和钻井液生物降解程度进行了评价,在评价试验基础上优选出了生物酶可解堵钻井液所用处理剂,并形成复配的钻井液。最后指出黏度衰减法适合评价处理剂以及生物酶可解堵钻井液的生物降解性,但DO衰减法只适合评价处理剂的生物降解性。

Mud cakes formed on borehole wall by drilling fluids can be removed by degrading the drilling fluid additives in the mud cakes to carbon dioxide and water with a bio-enzyme. Four evaluation methods were designed based on the degradation of drilling fluid additives which were in turn classified according to their bio-degradation behavior. A drilling fluid formulated with additives that are biodegradable with bio-enzymes are evaluated with DO attenuation and viscosity attenuation methods. It is pointed out that the viscosity attenuation method is suitable for evaluating the biodegradability of both additives and drilling fluids, while the DO attenuation method is only suitable for evaluating the biodegradability of additives.