底部钻具组合力学特性模拟试验研究

Simulation and Experimental Research on Mechanical Properties of Bottom Hole Assembly

底部钻具组合(BHA)的力学特性直接影响井身质量、钻井安全与钻速,因此,需要从理论和试验2个方面去研究BHA的力学特性,然而目前试验方面的研究很少。根据相似理论,利用底部钻柱力学装置,模拟研究了钻压和转速对井斜力、方位力、钻头合侧向力及其方向角的影响规律。结果表明:合侧向力随钻压的增大而增大,转速对合侧向力的影响较小;随钻压增大,井斜力增大,转速越大,井斜力越大;方位力随钻压增大而增大,转速对方位力的影响较小;合侧向力方向角随钻压增大而减小,随转速增大而增大。研究结果可为井斜控制机理研究和防斜打快提供理论依据。

The mechanical properties of bottom hole assembly （BHA） directly affect wellbore quality, drilling speed and safety,thus it is necessary to study the mechanical properties of BHA based on theories and experiments. However,the experimental study is inadequate so far. According to the similarity theory, the bottom drill string mechanics device is used to simulate the effect of weight on bit （WOB） and rotary speed on inclinational force, azimuthal force, total side forces and directional angle. The results indicate that total side forces at bit increases with the increase of WOB, but the rotary speed affects it slightly; the incli- nation force increases with the increase of WOB, and the higher the rotary speed; the greater the inclination force, too, azimuthal force increases with the increase of WOB, and rotary speed affects it slightly; the direc- tion angle caused by total side forces decreases with the increase of WOB, and increases with the increase of rotary speed. It can provide basis for the study on mechanism of well deviation control and fast drilling.