四川盆地双鱼石区块深井钻井井斜规律研究

A Study on Deep Well Deviation in Shuangyushi Block,Sichuan Basin

针对双鱼石区块井斜控制问题,考虑钻头与地层互作用、地层倾角、井斜角、地层各向异性指数、地层自然造斜力、钻头侧向力,综合建立了钻头侧向力模型,根据不同影响因素探讨了井斜变化规律,通过实钻资料验证了模型的正确性。结果表明,与常规钻井方式相比,空气钻井条件下地层自然造斜力增加,且增加幅度较大。随着地层倾角增加,地层自然造斜力增加。随着井斜角的增大,钻头综合侧向力减小,在空气钻井中和常规泥浆钻井中,钻头综合侧向力均存在零值平衡点。随着地层各向异性指数的增加,地层自然造斜能力增大导致井斜角增大。结合理论研究,通过钻具组合优化、钻井参数优选提出井斜控制措施,将该区块深层易斜地层井斜角降低至0.50°~1.15°,机械钻速提高了40%~85%。研究结果可为超深层井斜规律的研究和高效控制提供重要的参考和指导。

To solve the problem of well deviation in Shuangyushi Block,We establish a model of drill bit deflection force with consideration of interaction between bit and formation,formation dip,inclination,angle,formation anisotropy index,formation deflection force and drill bit deflection force.And we explore the law of well deviation change under different influencing factors and verify the correctness of the model based on actual drill data.The results show that,compared with drilling fluid drilling,the formation deflection force increases under air drilling conditions.When the inclination angle is smaller than the formation dip,the formation force is a deflection force,which causes the drill bit to deviate upwards.Increasing the drilling pressure will cause the inclination angle to increase.As the formation dip angle increases,the natural forming force of the formation increases.As the inclination angle increases,the combined lateral force decreases.The resultant force of the bit has a balanced point.With the increase of the formation anisotropy index,the natural deflection ability of the formation increases,leading to the increase of the well inclination angle.According to the results of theoretical analysis,an integrated quantitative measure is proposed for drilling tool assembly,bit optimization,and drilling parameters,which reduces the inclination angle of ultra-deep formations with easy deflection to 0.50°~1.15°and increases the ROP by 40%~85%.The results of this paper can provide important reference and guidance for the study and efficient control of ultra-deep well deviation rules.