KCl—有机盐钻井液在高石梯—磨溪区块上部井段钻井提速中的应用

四川盆地川中地区高石梯—磨溪区块因上部地层出水而使气体钻井受到限制,在上部大尺寸(311.2mm)长井段(500~2 300m)采用钻井液钻进情况下,如何提高钻井速度成为加快该区深部气藏勘探开发进程的主要问题。为此,从加强钻井液抑制性能的研究入手,在保证井眼稳定的前提下,采用降低钻井液密度的技术路线,来实现钻井提速。措施如下:①在KCl—聚合物钻井液的基础上,通过对引入有机盐的钻井液综合性能测试与经济性评价,优选出5%KCl+10%有机盐聚合物钻井液配方,该配方具有抑制性能强、封堵性能好、流变性能优良且易于调控等优点;②现场钻井液管理,按钻进速度来调整控制钻井液性能和钻井液的维护补充量,以及防塌抑制剂的浓度;③同时做好钻井液劣质固相的清除,保证入井钻井液的清洁及低密度钻井液的回收利用。磨溪11等井现场应用的效果表明,采用该钻井液技术顺利钻过了上三叠统须家河组,井眼畅通、井壁稳定,井径规则、电测顺利,助推了震旦系钻井提速目标的实现。

Application of KCl organic salt drilling fluids to the ROP enhancement in the top section of wells in the Gaoshiti Moxi block,Sichuan Basin

In the Gaoshiti Moxi exploration block, central Sichuan Basin, water cut has become an obstacle for gas drilling especially in the top sections of strata. How to improve the ROP of drilling a well there with a hole size of 311.2 mm and laterals as long as 500 2300 m is a major issue to speed up the exploration of deep gas reservoirs. To solve this problem, a technology of strengthening the study of drilling fluid inhibition performance and reducing the density of drilling fluid was put forward. First, a type of drilling fluid formulation with 5% KCl and 10% organic salt was optimized based on the KCl polymer drilling fluid after the comprehensive performance and economy were tested and evaluated through the introduction of organic salt into the drilling fluid. This newly formulated drilling fluid has many advantages such as strong inhibitive properties, good sealing and rheological performance, and great operability. Second, it makes the site drilling fluid management easy by adjusting and controlling drilling fluid performance and maintains the concentration of inhibiting agents according to the drilling rate. Meanwhile, it is also important to get rid of the inferior solid phases in the drill in fluid to guarantee its cleanliness and the recycle use of such low density drilling fluids. With this drilling fluid technology, such clean and stable boreholes through the Upper Triassic Xujiahe Fm like Moxi 11, etc. were all drilled with regular and consistent borehole gauge and successful electrical measurement, which have boosted the goal realization for the ROP enhancement in the Sinian strata.