无渗透无侵害钻井液及其渗滤性能评价方法的探讨

无渗透无侵害钻井液通过在常规钻井液中加入无渗透钻井液处理剂转化而成,是一种能够满足钻井工程要求的宾汉塑性流体,其滤液几乎不渗入地层,采用砂床评价方法测得的滤失量趋近于零,固相颗粒对地层几乎不产生侵害,能最大程度地防止储层渗透率降低,实现无损害钻井.介绍了一种无渗透钻井液处理剂OCL-BST及用其配制的无渗透钻井液,评价了该钻井液的渗滤性能.OCL-BST由水溶和油溶性聚合物及生物聚合物、阳离子胶体等原料组成,在常规钻井液中加入OCL-BST就可以将体系转换为无渗透钻井液,采用中国产FA型砂床无渗透滤失仪测得该体系滤失量趋近于零,从而实现了无损害钻井技术.无渗透钻井液是一种与传统钻井液不同的体系,需用新方法对其渗滤性能进行评价,国外用砂床代替滤纸作为渗滤介质对无渗透钻井液进行滤失试验并研制出了相应的仪器,中国也随之研制出了类似的评价仪器.对评价无渗透钻井液渗滤性能的方法进行了初步探讨.

The non-filtration, non-invasive drilling fluid and the infiltration evaluation method

The non-filtration drilling fluid with the base compositions of bentonite slurry, gel protector, flow pattern regulator, special additive for non-filtration drilling fluid is a Bingham plastic fluid fulfilling drilling requirements. An additive OCL-BST, and the non-filtration drilling fluid prepared by it were presented. The OCL-BST is composed of water soluble and oil soluble polymers, biopolymer, cationic colloid and other materials. Based on lab experiments, the conventional drilling fluid can be converted into a non-filtration drilling fluid by adding in OCL-BST. Measurement using the China made FA sand-bed filtration tester showed that the filtrate value is zero, making drilling operation free of damages possible. As the non-filtration drilling fluid is a novel fluid different form the conventional ones, new methods are required to evaluate its filtration. In abroad, sand-bed was used in place of filter paper in the filtration tests, and corresponding device was developed also. Similar devices were developed in China subsequently. Pilot study was carried out on the evaluation method for filtration property of non-filtration drilling fluid.