METHOD FOR DIRECTED DRILLING OF INCLINED WELLS WITH GUIDE ROD Russian patent published in 1996 - IPC

FIELD: inclined and horizontal well drilling. SUBSTANCE: when drilling axle of guide rod lower and a bit is retained in the center of well cross section by the frame of support-centering member. Well deviation is achieved by shifting and assured retaining upper end of guide rod by decentralizing device at well shaft wall that is opposite to deviation direction. Retaining force /F_r/ of the above end is determined by expression as follows: F_r≥ f_a•l_в/l_r+(M_d+M_up)/l_r, where F_a= 0,5 σ_rock•S_c•h•sin2(θ -Φ) id deviating force acting on the bit in anisotropy rocks, kN; l_d is arm of deviation force action, m; l_r is arm of F_r force action, m; M_up is moment of resistance forces acting on upper end of guide rod in plane of well shaft deviation, kNm; M_d= 2D•σ_rock•s_c/9π- is moment of rock resistance to bit rotation in plane of well shaft deviation, kNm; σ_rock is strength of rock to be drilled, kN per square mm; h is index of anisotropy of the rock to be drilled; θ angle of seam dip angle of the rock to be drilled, degree; v well shaft zenith angle, degree; D is bit diameter, m. EFFECT: high efficiency. 1 dwg