大修磨铣井反循环洗井装置的设计与结构优化

发布时间：2018-03-26 17:26

本文选题：大修磨铣井　切入点：反循环洗井　出处：《东北石油大学》2017年硕士论文

【摘要】：随着油气田开发时间增长,部分油水井受套管损坏及井下地质情况的影响,漏失严重,为落物鱼顶上碎屑的收集打捞带来了很大的困难。目前应用化学药剂暂堵的方法施工成本高、施工周期长并且对于漏失严重的井暂堵很难成功,最后往往导致修井失败及该井可能报废的结果。针对这种情况,油田现场研制出一种新型局部反循环打捞器,对漏失严重的井不进行暂堵作业便可收集磨铣过程中回落的砂子及碎屑。然而在实际应用中发现,该项新型装置在洗井作业时存在反循环能力不足、碎屑采取率低等问题。针对井下局部反循环洗井装置在实际应用过程中出现的问题,应用Fluent软件对此装置洗井作业时孔底固液两相流场进行数值模拟研究,研究表明:液相洗井介质在进入孔底流场在经过两次出水孔换向后,液相洗井介质的压力、流速以及湍动能耗散都较大,导致该装置对孔底中部的碎屑冲洗能力不足,最终在孔底生成碎屑“死区”。针对以上数值模拟分析结果,基于人工诱发龙卷风机理设计旋风式反循环洗井装置,对此装置洗井作业时孔底气固两相流场进行数值模拟研究,并对装置结构进行改进,研究表明:在改进装置结构前,装置对孔底中心部位碎屑抽吸能力良好,对孔底外围及环空部位碎屑反循环能力不足,在增设外喷孔后能够有效增加装置对孔底外围及环空部位碎屑的反循环能力,配合内旋喷孔能够完全将碎屑从孔底洗出。应用数值模拟的方法,对装置核心结构中喷孔直径d和喷孔角度θ这两项主要结构参数进行优化,研究结果表明:随着喷孔角度θ的增大,从孔底环空进入到装置内的气体质量流量单调递减,且前期递减严重;随着喷孔直径d的增大,从孔底环空进入到装置内的气体质量流量整体呈抛物线变化趋势,在d=4mm处质量流量最大,装置反循环能力最强。
[Abstract]:With the development time of oil and gas field increasing, some oil and water wells are seriously lost due to casing damage and downhole geological conditions. It is very difficult to collect and salvage debris from the top of the falling fish. At present, the method of temporary plugging with chemical agent is of high construction cost, long construction period and difficult to be successfully plugged in wells with serious leakage. In the end, it often leads to the failure of workover and the result that the well may be scrapped. In view of this situation, a new type of local reverse circulation fishing device has been developed in the oil field. Sand and debris falling back during grinding and milling can be collected without temporary plugging in wells with serious leakage. However, in practical application, it is found that the new device has insufficient reverse circulation capacity in well washing operation. In view of the problems in practical application of downhole local reverse circulation well washing device, the Fluent software is used to simulate the solid-liquid two-phase flow field at the bottom of hole during well washing operation. The results show that the pressure, velocity and turbulent kinetic energy dissipation of the liquid-phase well washing medium are large after entering the bottom flow field of the hole, and the pressure, velocity and turbulent kinetic energy dissipation of the liquid-phase washing medium are all large, which leads to the lack of the flushing capacity of the debris in the middle of the hole bottom. Finally, detritus "dead zone" is formed at the bottom of the hole. Based on the results of numerical simulation and analysis above, a whirlwind reverse circulation well washing device is designed based on the mechanism of artificial tornado, and the numerical simulation of the gas-solid two-phase flow field in the hole bottom during well washing operation is carried out. The research shows that before improving the structure of the device, the device has a good suction capacity to the debris in the center of the hole bottom, and the reverse circulation ability of the detritus on the periphery of the hole bottom and the annulus part is insufficient. The anti-circulation ability of the device to the detritus around the bottom of the hole and the annulus can be increased effectively after the addition of the external jet hole, and the debris can be completely washed out from the bottom of the hole with the internal rotating hole. The numerical simulation method is used. The two main structural parameters of nozzle diameter d and nozzle angle 胃 in the core structure of the device are optimized. The results show that with the increase of the nozzle angle 胃, the gas mass flow rate from the bottom annulus to the device decreases monotonously. With the increase of the nozzle diameter d, the mass flow rate from the bottom annulus of the hole to the device showed a parabolic trend, and the mass flow rate was the largest at d=4mm, and the reverse circulation capacity of the device was the strongest.
【学位授予单位】：东北石油大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TE925.1

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