新疆博孜区块空气钻井关键技术研究及应用

Research and Application of Air Drilling Key Technologies in Bozi Block,Xinjiang

博孜区块位于新疆库车坳陷克拉苏构造带西部,是塔里木油田“十四五”期间3500×104 t油气产量建设工作的重点区块之一。该区域内分布有巨厚砾石层,其抗压强度高、非均质性强、可钻性差,从而导致常规钻井机械钻速低,钻头耗用多,钻井周期长,严重制约了该区块的增储上产进程。文章采用离散元方法,对砾石层空气钻井井壁失稳机理进行了分析,通过优化空气钻井参数和钻具组合,进行了注气量优化和防斜打直探索,通过试验连续循环钻井技术,解决了井底沉砂多易造成井下复杂的难题。2013年以来,在新疆博孜区块开展了9井次空气钻井提速探索试验,平均机械钻速达4.81 m/h,取得了良好成效。

Bozi block is located in the west of Kelasu structural belt in Kuche depression,Xinjiang.It is one of the key blocks for the construction of 35 million tons of oil and gas production in Tarim Oilfield during the 14th Five Year Plan period.There are very thick gravel layers in this area,which have high compressive strength,strong heterogeneity and poor drillability,resulting in low ROP,high bit consumption and long drilling cycle of conventional drilling methods,which seriously restricts the process of increasing reserves and production in this block.In this paper,the discrete element method is used to analyze the instability mechanism of air drilling in gravel layer.By optimizing the air drilling parameters and BHA,the optimization of gas injection and the exploration of deviation prevention and fast drilling are carried out.Through the test of continuous circulation drilling technology,the problem of downhole complexity resulted from sand sinking at the bottom hole is solved.Since 2013,nine exploratory tests of air drilling speed increase have been carried out in Bozi block,Xinjiang,with an average ROP of 4.81m/h,and good results have been achieved.