GFT型防塌减阻剂的性能评价与现场应用

Performance Evaluation and Field Application of GFT Anti-collapse and Drag Reduction Agent

摘要:

为解决现有沥青软化点高、分散性差、较低温度条件下润滑性差及稳定孔壁能力不强等问题，研制了以沥青及树脂材料为主要原料，软化点为35 ℃的GFT型防塌减阻剂。这种防塌减阻剂具有稳定性好，润滑能力强，在不增加钻井液粘度的同时，可有效降低钻井液的滤失量；沥青质粒子的附着能力强，可有效充填与封堵孔壁微裂缝、微孔隙，粘接破碎岩块或颗粒，提高孔壁稳定性。淡水膨润土基浆中加入1%的GFT型防塌减阻剂，其润滑系数降低率达80%以上。经青海鱼卡煤田勘探区ZK30-7孔及ZK30-8孔2个钻孔的现场应用，证明了GFT型防塌减阻剂对破碎地层具有良好的护壁效果；同时能显著降低钻具扭矩，体现出优良的润滑性能。

关键词:孔壁稳定;防塌减阻剂;软化点;润滑性

Abstract:

In order to solve the high asphalt softening point, poor dispersibility, poor lubricity at relatively low temperature and weak borehole wall stability, GFT anti-collapse and drag reduction agent was developed mainly preparing by asphalt and resin material with the softening point at 35℃. This agent exhibits its advantages of good stability and lubrication; it can effectively reduce the filtration of drilling fluid without the viscosity increasing; due to the strong adhesion ability of asphaltene particle, the agent can effectively fill and seal the microcracks and microporosity of borehole wall and bond broken rocks or particles to increase the stability. With 1% GFT anti-collapse and drag reduction agent adding into freshwater bentonite slurry, the lubricating coefficient decreases is up to more than 80%. Through field application of GFT in boreholes of ZK30-7 and ZK30-8 in Yuqia coalfield exploration region, it is proved that GFT anti-collapse and drag reduction agent has good wall protection effect in broken formation, and can significantly reduce the torque of drilling tool with its excellent lubricity being present.

Key words:borehole stability; anti-collapse & drag reduction agent; softening point; lubricity