江苏金坛盐穴储气库定向井轨道优化设计方法

A Trajectory Optimization Design Method for the Directional Wells in Jintan Salt-Cavern Underground Gas Storage of Jiangsu

针对盐穴储气库定向井下部直井段过短导致后期造腔管柱因不垂直而出现的盐腔严重偏溶的情况,采用五段式井眼轨道设计方法,结合材料力学相关理论,得出盐穴储气库定向井下部直井段最小长度计算方法,并对不同尺寸、不同钢级的造腔管所要满足的下部直井段最小长度进行了计算,完成了该方法在金坛地区11井次的应用。盐穴储气库定向注采井下部直井段的长度对后期造腔管柱的影响较大,盐穴储气库定向井第2直井段计算方法可以定量确定下部直井段最小长度,使造腔管成自然垂直状态,一定程度上避免了造腔过程中腔体偏溶情况的发生,保证了腔体体积,提高了盐层的利用率,符合现场实际要求。该方法对盐穴储气库定向井钻井设计及现场施工具有一定的指导作用。

The lower vertical section in the directional well of salt-cavern underground gas storage is too short,which leads to partial solution of salt cavity because the solution mining string is not vertical in the late stage.In order to deal with this situation,a method for calculating the minimum length of the lower vertical section in the directional well of salt-cavern underground gas storage was developed by means of the five-section borehole trajectory design method,combined with the related theories of material mechanics.In addition,the minimum length of the lower vertical section to satisfy the solution mining pipes of different sizes and steel grades was calculated.And this method has been applied in Jintan area 11 well times.It is indicated that the length of the lower vertical section in the directional injection/production well of salt-cavern underground gas storage has greater influences on the solution mining string in the late stage,and the method for calculating the section vertical section in the direction well of salt-cavern underground gas storage can be used to quantitatively determine the minimum length of the lower vertical section,which can avoid the occurrence of partial cavity solution in the process of solution mining to some extent,ensure the cavity volume,increase the utilization rate of salt beds and meet the field actual requirements.This method plays a certain role in guiding the drilling design and field construction of directional wells in salt-cavern underground gas storages.