水力喷射径向水平井回灌增注特性可视化试验研究

Visual experimental study on the recharge enhancement characteristics of radial jet drilling technology

针对砂岩热储开采回灌过程中经常发生严重的地层堵塞,降低了回灌率的问题,设计了模拟砂岩回灌可视化试验装置,开展了径向水平井可视化回灌试验,研究了近井地带颗粒运移规律以及径向水平井增灌特性。结果显示,在仅中心井情况下,示踪粒子堵塞区域主要呈现圆形,随着注入流量的增加(900~2100 mL/min),示踪粒子的运移半径和堵塞面积都呈增大趋势;当流量进一步增大时(2100~3000 mL/min),堵塞形状转变成为圆环形;在径向井存在的条件下,示踪粒子的堵塞形状为沿着径向井分支分布的锥形堵塞,且从径向井根端到趾端堵塞程度呈降低趋势;随着径向井分支数的增加,单分支井堵塞面积呈减小趋势,形态为细长锥形,堵塞总面积呈增大趋势,但相对堵塞程度降低,证明径向井技术有利于减少储层堵塞。研究结果可为径向水平井技术应用于砂岩热储回灌过程提供理论支撑。

In response to the frequent occurrence of severe formation blockage during the process of sandstone thermal storage recovery and reinjection,which reduces the reinjection rate,a visualization experimental device for simulating sandstone reinjection was designed,and radial horizontal well visualization reinjection experiments were carried out to study the particle transport law near the wellbore and the characteristics of radial horizontal well injection enhancement.The results show that in the case of only the central well,the blockage area of the tracer particles is mainly circular.With the increase of injection flow rate(900~2100 mL/min),the migration radius and blockage area of the tracer particles show an increasing trend;When the flow rate further increases(2100~3000 mL/min),the blockage shape changes into a circular ring shape;Under the presence of radial wells,the blockage shape of tracer particles is a conical blockage distributed along the radial well branches,and the degree of blockage decreases from the root to the toe of the radial well;As the number of radial well branches increases,the blockage area of single branch wells shows a decreasing trend,with a slender conical shape.The total blockage area shows an increasing trend,but the relative blockage degree decreases,proving that radial well technology is beneficial for reducing reservoir blockage.The research results are expected to provide effective theoretical support for the application of radial horizontal well technology in the process of sandstone thermal storage and reinjection.