Application of Nanotechnology on Borehole Wall Stability in Gas-Liquid Medium Transition during Gas Drilling

Abstract

Abstract Gas drilling has many advantages such as high drilling speed, low damage to reservoir and avoiding circulation lose, etc. However, when gas drilling encounters geological risks, drilling fluid must be filled, which may lead to serious borehole wall collapse. These problems severely restrict the application of gas-drilling technology. Thus, this paper puts forward using nano technology to reverse the wetting characteristics of borehole-wall surrounding rock before filling water based drilling fluid into the well. In this way, the capillary effect can prevent further penetration of drilling fluid, and avoid the swelling of shale and propagating of fractures on the surrounding rock. The strength of the borehole wall can be improved by taking advantage of this technology. The author puts forward that the application of the high-speed gas current to atomize the solution. The atomized solution will carry nano wetting reverse agent and anti-swelling agent rise with gas along borehole wall. Instead of the previous research method from perspective of drilling fluid, this technology can directly change the surface character of fracture surface with small amount of treating agent to avoid the propagating of fractures. Besides, the technique can effectively reduce the friction of the drill string and the impact of the drill string on the borehole wall. The technology is expected to achieve the goal of keeping the wellbore stability in gas liquid medium transition during gas drilling process.