Research on the Stability of Directional Drilling through Rock

With construction of long-distance pipeline in China, the horizontal directional drilling of many pipeline is often through the rock, and the stability of the drilling is the key factor that pipeline successful pass through the rock. On the basis of previous experiences in engineering, the various factors of affecting stability were analyzed from rock mechanics point of view in this paper, including the in-situ rock stress and the hole fluid pressure and so on. Moreover, the formula of hole fluid pressure was deduced according to the compression-shear pressure and tension-fracture pressure, and an evaluation of the directional drilling through the rock mass stability criterion was established ultimately. This research can lay the foundation for theoretical studies of similar projects and it is guidance for practical engineering.