预弯曲动力学防斜打快技术在塔里木盆地台前区应用研究

Research and Application of Pre-bending Dynamic Defl ection Control and Fast Drilling Technology in Platform Area of Tarim Basin

塔里木盆地直井段井斜不易控制,严重影响油气资源的经济高效开发。通过分析塔里木盆地台盆区井斜不易控制的地质原因,建立数学和数值计算模型优化设计预弯曲动力学防斜打快底部钻具组合和配套钻头,结合现场实际制定防斜打快施工方案。结果显示:志留系下部-桑塔木组等大倾角地层及裂缝广泛发育是直井易斜的主要地质原因;钻具组合弯角、弯角到下扶正器距离、弯角到上扶正器距离逐渐增大,降斜力先增大后减小最后趋于平稳,分别在0.9°~1.25°,0.5~0.7 m和4~6 m取得极值。PDC钻头造斜能力随保径长度和宽度的增加减弱,随保径倾角、内锥角、冠部旋转半径和高度的增大而增强。研究成果在塔里木盆地TK4-3X等井现场应用9口井,井斜控制良好,平均机械钻速较邻井同开次提高45.68%,实际钻井周期较设计周期累计节约周期105.64天,平均周期节约率21.43%。

The vertical well deviation is difficult to control in Tarim Basin,which seriously affects the economic and efficient development of oil and gas resources.Through analyzing the geological reasons why well deviation is difficult to control in the platform basin area of the Tarim Basin,a mathematical and numerical calculation model is established to optimize the design of pre-bending bottom hole assembly and matching bits,and a construction scheme for pre-bending dynamic deviation control and fast drilling is formulated in combination with the actual situation on the site.The results show that the main geological reasons for the inclination of straight wells in the Tarim Basin are the widely developed high dip strata such as the lower Silurian Sangtamu Formation and fractures;With the increases of bending angle of the drilling tool assembly,the distance from the bending angle to the lower stabilizer,and the distance from the bending angle to the upper stabilizer,the lowering force first increased and then decreased before stabilizing,reaching extreme values at 0.9°~1.25°,0.5~0.7 m,and 4~6 m,respectively.The inclination ability of PDC drill bits decreases with the increase of diameter maintaining length and width,but increases with the increase of diameter maintaining angle,inner cone angle,crown rotation radius,and height.The research results have been applied to 9 wells in the Tarim Basin TK4-3X and other wells.The deviation is well controlled.The average penetration rate is 45.68%higher than that of adjacent wells.The actual drilling cycle is 105.64 days less than the design cycle,with an average cycle saving rate of 21.43%。