Optimization Design Of The Stepped Horizontal Wellbore Trajectory And Hole Assembly Based On Friction Analysis

With the increase difficulty of oil and gas exploration, to meet the development demand of fault block reservoirs and thin reservoir, the stepped horizontal well drilling technology in the proportion of oil drilling is becoming higher and higher. So it is particularly important to tackle with the confronted problems caused by stepped horizontal well drilling.For stepped horizontal wells is level divide big, long, large sliding friction in the process of drilling, the characteristics of optimizing the friction calculation model for stepped horizontal Wells, combined with the optimization model created friction reduction stepped horizontal well track design software, the software calculation results with the commercial software LANDMARK are basically identical.By the analysis of the casing string and hole assembly, the combination design of drilling string are selected to achieve the purpose of reducing the frictional resistance.Results show that the vertical well section should optimize the large size drilling tool; The influences of the technology casing depth, the friction coefficient of the casing are not obvious; Stepped horizontal well section is the most strongly influenced by the friction coefficient, which should choose small diameter to carry out drilling; In hole assembly design, combine the 101.6 mm with 139.7 mm drill pipe are good for friction reduced.In view of the large friction of stepped horizontal well drilling, the target displacement,build-up rate, ladder made slope and height difference of stepped horizontal well are optimized. Results show that when the horizontal section length is determined, the three different building type, the size of the slope profile build-up rate low well track can reduce friction and torque; the friction is small when the ladder section have larger build rates at upper section and small build rates at lower section.B2HF Well is analyzed based on the low frictional resistance wellbore trajectory and the optimized hole assembly. Results show that the frictional resistance of the optimized design is 24.6% lower than the original design, which means the optimized design can reduce the drilling risks and costs.