预弯钟摆BHA在不同钻井介质中的动力学特征及其应用

Dynamic characteristics and application of the prebent pendulum BHA in different drilling media

带预弯结构的钟摆钻具组合(简称预弯钟摆BHA)既可适用于气体钻井,也适用于泥浆钻井,并在直井控斜、提速方面得到了较好的应用。但在不同钻井介质中,预弯钟摆BHA的应用效果体现出了较大的差异。从动力学角度出发研究钻井介质对预弯钟摆BHA力学特性的影响鲜有报道。通过研究钻井液附加质量引起的非线性惯性力及流体阻力特征,分析了气体钻井和泥浆钻井中预弯钟摆BHA动力学模型的差异。基于旋转Rayleigh梁模型,推导了预弯钟摆BHA钻头上的动态侧向力和动态轴向力,研究在不同钻井介质中预弯钟摆BHA的运动特征及受力特征,分析其对实际钻井的控斜、提速效果的影响,并研究了弯角大小对不同介质中预弯钟摆BHA的动力学特征的影响规律。结果表明,预弯钟摆BHA在不同钻井介质中的动态特征差异显著,气体钻井中的运动特征更为稳定,动态侧向力和轴向力较高;不同介质中的弯角影响规律有其各自的特点,在现场实际应用中,应根据需要进行合理的选择。

The pendulum drill assembly with prebent structure(prebent pendulum BHA for short)can be used in both gas drilling and mud drilling, and has been well applied in vertical wells for controlling inclination and increasing drilling speed. However, in different drilling media, the application effect of prebent pendulum BHA has shown a big difference. Especially from the perspective of dynamics, there are few reports on the impact of drilling media on prebent pendulum BHA. By studying the characteristics of nonlinear inertia force and fluid resistance caused by the added mass of drilling fluid, this paper analyzes the difference between the dynamic models of prebent pendulum BHA in gas drilling and mud drilling. Based on the rotating Rayleigh beam model, this paper deduces the dynamic lateral force and dynamic axial force on the prebent pendulum BHA bit, studies the motion characteristics and stress characteristics of the prebent pendulum BHA in different drilling media, and also analyzes its impact on the effect of controlling inclination and increasing drilling speed in actual drilling and the influence rule of the bending angle on the dynamic characteristics of prebent pendulum BHA in different media. The results show that the dynamic characteristics of prebent pendulum BHA in different drilling media are significantly different. The motion characteristics in gas drilling are more stable, and the dynamic lateral and axial forces are higher. The influence law of the bending angle in different media has its own characteristics. In the field, a reasonable choice should be made according to the needs.