IMPROVED CONTROL OF WELL BORE TRAJECTORIES Russian patent published in 2018 - IPC E21B44/02 E21B44/04 E21B7/04 

FIELD: soil or rock drilling; mining.

SUBSTANCE: invention relates to directional drilling wells. In particular, there is provided a method for controlling the direction of a wellbore trajectory during directional sliding drilling by means of a drill string having a drill bit rotatable, by means of a mud motor, around a drill bit rotation axis at its lower end, the direction of the drill bit rotation axis defining a tool face. Said method comprises the following steps: a1) estimating pressure loss on the mud motor by measuring mud pressure; b1) using the result of estimating pressure loss obtained in step a1) to calculate the torque of the mud motor and c1) calculating the reactive twist angle of the drill string by multiplying torque calculated at step b1) by the torsional drill string compliance, wherein step a1) further comprises the step of including any transfer mud pressure into said estimate. In addition, the method further comprises step d1) of rotating the drill string by means of a drill string rotation means, wherein the angle substantially equal to but in the opposite direction of the calculated reactive twist angle, wherein direct supply of the calculated reactive twist angle to the control circuit of the rotating means of the drill string for instantaneous adjustment of the tool face is performed. System for realising this method is also provided.

EFFECT: technical result is to provide fast and accurate control of the tool face, which simultaneously allows changing the injection rate and load on the bit to optimise the penetration rate.

15 cl, 5 dwg