STUDY AND APPLICATION OF THE POLYOL DRILLING FLUID SYSTEM

When using the conventional water based drilling fluid for high angle deviated directional well drilling, high friction is often caused by the high deviation angle during rotary drilling and tripping. Experimental study is carried out on the polyol drilling fluid system, and results show that there are minor changes found on the rheological property and fluid loss; the aging resistance is greatly improved, and the temperature resistance reaches 120℃, friction rate reduces by 50%. Field using indicates that the system has good lubricity, and the clay hydration is inhibited, which effectively prevents the hole from collapsing. The rock permeability improved by 20%, which is 87.3%, and this is beneficial for formation protection.