Key Technologies of Directional Drilling in the Moxi-Gaoshiti Area of the Sichuan Basin

Due to the deep kick-off point, high formation temperature and drilling fluid density, and complex reservoir characteristics in the Moxi-Gaoshiti area of the Sichuan Basin, directional well drillings with ϕ215.9 mm wellbore combining screw and measurement while drilling (MWD) are faced with many challenges such as difficulty in well trajectory control, severe supporting pressure, and low rate of penetration (ROP). Regarding these problems, new key drilling technologies for directional well with ϕ215.9 mm wellbore were developed by means of optimizing the wellbore trajectory, selecting personalized drill bits, customizing the speed-up tools for hydraulic oscillators, and formulating technical measures such as friction reduction and the prevention of differential pressure sticking. With the applications of directional drilling technologies in the ϕ215.9 mm directional well section of the Moxi-Gaoshiti area in the Sichuan Basin, the trajectory control was strategically optimized, and the directional drag was effectively reduced. Besides, the average ROP was effectively improved, and the risk of downhole sticking was reduced. The drilling time of the ϕ215.9 mm directional well section was shortened from 44.75 d to 27.51 d depending on this technology. The results showed that the key directional drilling technologies with ϕ215.9 mm wellbore could effectively solve the technical difficulties in the drilling of the Moxi-Gaoshiti area, and thus the technology merits promotion in this block.