基于提高钻速的待钻井眼轨道设计方法

Wellbore Trajectory Design Method of the Hole to Be Drilled Based on ROP Increasing

目前待钻井眼轨道设计时,通常以最短井段或最小摩阻/扭矩为设计目标,在通用轨道设计方法的基础上,依据现场人员工程经验进行轨迹调整,现用方法存在待钻井眼设计轨道工程适用性差、设计过程随意性及经验性强等问题。为此,利用定向钻井机械钻速预测模型,结合螺杆钻具造斜能力预测与计算,建立了以工程实际为限制准则的约束条件,采用通用井眼轨道计算模型,构建了以钻进时间最短为优化目标的待钻井眼轨道设计方法。该方法可根据组合剖面类型确定优化轨道设计参数,使之适用性更佳,同时解决了常规设计方式随意性及经验性强的问题,而且该方法可实现避开难钻地层定向、提高复合钻进比例、提高定向钻井效率、缩短钻进周期的效果。应用该设计方法的鄂尔多斯气田某侧钻水平井,复合钻进比例达到49.53%,较邻井提高19.3%,摩阻在10 t以内,相同地质条件下较邻井节省钻进时间约24 h,使该井具备了由侧钻点至A靶点"一趟钻"完成的提速潜力,实现了优快钻井。

At present,when the drilling trajectory is designed,it is usually with the shortest well interval or minimum friction drag/Torque is the design objective.On the basis of the general trajectory design method,the trajectory is adjusted according to the engineering experience of field personnel.However,the existing method has some problems,such as poor applicability of the trajectory engineering to be designed for drilling holes and strong randomness and experience in the design process.Therefore,based on the prediction model of the drilling rate of directional drilling and the prediction and calculation of the build rate of the positive displacement motor,the constraint conditions based on the engineering practice were established,and the general borehole trajectory calculation model was adopted to construct the design method of the borehole trajectory to be drilled with the shortest drilling time as the optimization objective.This method can determine the optimal trajectory design parameters according to the combination profile type,which makes it more applicable,and solves the problems of arbitrariness and high experience of conventional design methods.In addition,this method can orientate to avoid the difficult-to-drill formation,improve composite drilling ratio,improve directional drilling efficiency and shorten drilling cycle.A lateral horizontal well was drilled in the Ordos gas field by using this method.The compound drilling ratio reached 49.53%,which was 19.3%higher than the adjacent well,and the friction drag was less than 10T.Under the same geological conditions,the drilling time was saved by about 24h compared with the adjacent well.The well has the potential to accelerate in one run from the sidetrack drilling out point to target A,thus achieving optimal and fast drilling.