用钻头与地层相互作用模式预测井眼轨道

PREDICTION OF BOREHOLE TRAJECTORY BY INTERACTION MODEL BETWEEN DRILLING BIT AND STRATUM

给出了沿钻头轴向力方向和侧向力方向，考虑岩石破碎方式和破岂门限力对相应方向钻速的影响而建立的三维钻速方程，及井眼曲率等预测计算模式，对实际应用时，钻头机械力和钻头偏转角、测斜参数、地层倾角和倾向角、岩石破碎方式指致、地层各向异性参数、钻头各向异性参数和地层法向钻进效率等参数的确定方法进行了说明。在实际轨道预测中，计算用参数的准确性及计算程序的可靠性对预测结果准确程度显得尤为重要。理论成果和计算软件在辽河油田冷平１井、冷平３井和齐４０－平１、齐４０－平２水平井井眼轨道控制中进行了试验性应用，预测井段井眼曲率平均误差控制在０．５°／３０ｍ，达到水平井井眼轨道控制施工的要求。

To present a 3- Ddrilling rate equation and prediction calculation for borehilecurvaturealong bit axial and lateral direction force,considering effects of rock broken manner and lim-it force on drilling rate. The determination methed for the included calculaiton parameterssuch as bit mechanical force and deviation angle,borehole deviation angle,stratum dip an-gle,rock broken manner index,stratum anisostropic index, bit drilling rate in normal direc-tion etc. are also describled.During practical borehole trajectory prediction,the accuracy forthese parameters and the reliability for the calcuIation program obviously affect precision ofthe prediction results.Theoretical results and computer software are succesfully used to pre-dict borehole traJectory for three horizontal wells.Prediction results meet the requirment ofborehole trajectory control for horitontal well iri Liaohe oilfield. The average error of bore-hole ctJrvature in ptediction section is equal to 0.5°/30 m.