定向钻井BHA力学分析及井斜控制技术研究

【作者】 孟凡生；

【导师】 初迎利； 邹野；

【作者基本信息】 大庆石油学院 ， 油气井工程， 2003， 硕士

【摘要】 本文根据定向井下部钻具工作状态，建立了下部钻具双重非线性力学分析模型，该模型除考虑钻具结构、井眼形态、各种外载荷等因素外，还考虑了钻具与井壁的初始间隙和随机多向接触摩擦、钻具自重分力和钻压引起的纵向弯曲。采用有限元法中的梁单元和多向接触摩擦间隙元，对钻具的双重非线性力学模型进行求解，为下部钻具力学分析提供了一种实用的计算方法。通过定向井常用钻具井斜性能影响因素分析，得到了近钻头稳定器与钻头间距的短距离变化，能够改变钻具井斜性能，为变距稳定器的设计和应用提供了可靠的理论依据。通过5口斜直井的现场试验表明，变距稳定器能够由地面调整钻压或泵压来改变稳定器至钻头距离，使钻具井斜性能发生变化，实现了定向井旋转钻井时的井斜连续控制。更多还原

【Abstract】 According to the work state of bottom hole assembly (BHA) in the directional well, the nonlinear mechanics model of BHA is presented in the paper. In the model, it is considered that the BHA structure, hole trajectory, various loads, the initial gap and contact friction between BHA and hole wall, and also the vertical bending to be caused by the BHA weight and drill pressure. In order to solve the model, the beam element and multi-directional contact gap element are adopted, which present a method so as to analyze the force and deformation of BHA. Through the inclined capacity analysis of BHA to be affected by various parameters, it is shown that the distance between drill bit and the first stabilizer to be changed a little, the inclined capacity of BHA can be changed, which provide the theory for the various distance stabilizer (VDS) to be designed and applied in drill engineer. The VDS has been used in 5 inclined straight wells. The test results show that the VDS work principle is reliable and the structure is reasonable, the distance between drill bit and the stabilizer can be changed by adjusting the drill pressure and pump pressure at the well head, which make the inclined capacity of BHA change, thus the continuous control of well bore inclination during rotary directional drilling was achieved.更多还原