Development and mechanism of plugging agent while drilling for rotary guide
JIA Yonghong, GUO You, ZHANG Wei, YE Anchen, HE Yinbo
1 Drilling fluid Branch of CNPC Western drilling Engineering Co., Ltd., Karamay 834000, China 2 College of Petroleum Engineering, China University of Petroleum-Beijing, Beijing 102249, China
With the increasing difficulty of oil and gas resources extraction, rotary guided drilling has become an important technology for controlling the trajectory of the borehole and connecting the reservoir. In the process of rotary guided drilling, it is often necessary to add plugging agent with drilling when encountering formation leakage, but the small-sized plugging materials mainly used nowadays may reduce the plugging effect, especially fiber-based materials, which, due to their large length-to-diameter ratios and easy to be intertwined, will lead to an increase in the viscosity of the drilling fluid, and in serious cases, trigger stuck drilling. In this paper, a kind of plugging fiber with drilling was developed and compared with the fiber material for plugging rotary guide screen in the field. The results show that the developed fiber complies with the industry standard and has good performance of over-spinning conductivity and pressure-bearing plugging performance. After adding 3% modified fiber to the drilling fluid system, it can effectively block 20~40 mesh quartz sand at 150 ℃ and 6 MPa, and the cumulative leakage is only 4 mL in 30 min. This study is of great significance for the selection of plugging materials for rotary guided drilling tools.
