Optimization of a drill-pipe string’s bottom-hole assembly parameters for horizontal wells drilling
Analysis of horizontal wellbores drilling carried out at the fields of Timan-Pechora oil and gas province shows that actual trajectory deviation from the project one is of the alternating nature. This means that the angle and well azimuth values are bigger or smaller than the projected ones. Continuous wellbore trajectory correction leads to a deterioration of its quality, hence, the problem of finding the optimum parameters of a drill-pipe string’s well bottom assembly arrangement is very relevant. Design of parameters of a drill-string bottom assembly which includes a 155,6 mm diameter drill bit and two centralizing-supporting elements (CSE) (the first one is mounted on the spindle’s body while the second one-behind the check valve) under which deviations from the projected path are minimal. To receive a curvature zero intensity when rotating the assembly with a downhole drilling motor (DDM) by rotor and to provide its normal operating conditions that means a lack of interaction between the «heel» of the skew angle controller and the well’s wall as well as presence of a support on the first and second CSE, the permissible angularity angles of 0,39 and 0,78° between the engine sections are substantiated, diameters of the supporting-centralizing elements make 142 and 146 mm and the optimal axial load on the bit are 30 and 50 kN.