旋流井眼净化工具携岩性能影响因素研究

Research on Influencing Factors of Rock Carrying Performance of Swirl Wellbore Purification Tool

针对水平井段岩屑易沉积、安全隐患大的问题,提出了一种内外螺旋组合的复合旋流式井眼净化方案,旨在以螺旋流来抵抗岩屑颗粒的沉积,使岩屑保持悬浮态,进而提高岩屑的运移效率,保证钻井安全。利用Fluent-EDEM耦合模拟的方法探究螺旋叶片数量、钻井液排量以及岩屑粒径对旋流井眼净化效果的影响规律。研究发现:螺旋叶片数量对井眼净化效果存在较大的影响,叶片数量为3和4时井眼净化效果较好,螺旋叶片数量为4时携岩效率最大,可达96.14%,与单叶片工具体相比效率提升了近30%;旋流井眼净化工具体的临界启动排量在15~20 L s,临界轴向运移速度在0.8 m s左右,岩屑不沉积的临界角速度在250 rad s左右;从携岩效率来看,岩屑粒径并非越小越好,粒径与携岩效率之间呈现波峰变化,最佳携岩粒径在3~4 mm。

Aiming at the problems of easy deposition of cuttings in horizontal well sections and high potential safety hazards,a composite cyclone-type wellbore purification plan with a combination of inner and outer spirals is proposed,which aims to use spiral flow to resist the deposition of cuttings particles and keep cuttings in suspension.Therefore,it improves the efficiency of cuttings migration and ensures the safety of drilling.The Fluent-EDEM coupling simulation method is used to explore the influence of the number of spiral blades,the amount of drilling fluid and the particle size of cuttings on the purifying effect of swirling wells.The study shows that the number of spiral blades has a greater impact on the purification effect of the wellbore.When the number of blades is 3 and 4,the purification effect of the wellbore is better.When the number of spiral blades is 4,the rock carrying efficiency is the largest,and the efficiency value can reach 96.14%.Compared with the single blade tool body,the efficiency has increased by nearly 30%;the critical starting displacement of the swirling wellbore purification tool body is 15-20 L/s,the critical axial migration velocity is about 0.8 m/s,and the critical angular velocity for cuttings not deposited is 250 rad/s.From the perspective of rock carrying efficiency,the particle size of cuttings is not as small as possible.There is a peak change between the particle size and the rock carrying efficiency,and the best rock carrying particle size is 3-4 mm.