PROPERTY EVALUATION ON PRE-BENDING BHA AND ITS APPLICATION

To improve the penetration rate of directional drilling,and minimize the tripping frequencies,pre-bending BHA is usually used for drilling the angle building and holding sections.The properties of pre-bending BHA were evaluated,and the influences of such factors as clearance between stabilizer and hole,distance between stabilizer and bottom hole and hole inclination on BHA properties were also described in detail.Based on the theoretical analysis,the union lateral forces in Xifeng and Huachi of Changing Oilfield were calculated,and the corresponding pre-bending BHAs were also optimized.The optimized BHAs were tested in the drilling of three wells,with average penetration rate improved by 43% to 55.9%.