页岩气长水平井筒流动冲蚀及沉砂规律研究

发布时间：2018-03-03 12:42

本文选题：页岩气　切入点：长水平井筒　出处：《西南石油大学》2017年硕士论文　论文类型：学位论文

【摘要】：目前,水平井开采已经成为国内外页岩气开发的最主要方式,尤其是针对产层薄、渗透率极低同时孔隙度小的页岩气储层。在现有的页岩气开发技术条件下,尽管常规防砂技术工艺的精度日益提高,且能够阻挡大部分来自地层的砂粒,但仍会有一定粒径的地层砂粒随页岩气进入井筒,当采出页岩气气量足够大时,高速含砂气流将会对井筒以及井口地面设备造成强烈的冲蚀和磨损;当采出气量不够大时,则会有一部分砂粒不能被携带出井口,造成砂粒在井底堆积,引起砂堵井筒等严重事故,在页岩气长水平井筒中则尤为严重。因此,为探究页岩气长水平井筒冲蚀失效和沉砂原理,本文开展了对页岩气长水平井筒冲蚀及砂沉积模拟计算,研究了各参数对它的影响,为实际生产中页岩气长水平井筒冲蚀失效和沉砂提供依据和方向。主要包括以下内容:(1)本文对现有的一套可循环的冲蚀装置进行了升级和改造,使实验装置能够模拟出更加贴切真实管道内环冲蚀情况,并开展了相关冲蚀实验。(2)自主设计了一套可视化水平管沉砂实验装置,砂粒沿着“L”型导管从水平管中部并在来流的作用下运移和沉积到水平管底部,对于砂粒的运移轨迹,实验将利用高速摄像机进行捕捉。(3)开展与实验同尺寸的管内环冲蚀和水平管砂沉积数值模拟,处理并分析模拟结果,与实验结果对比,分别验证冲蚀和砂沉积模型。(4)在对实际生产中的页岩气长水平井筒的调研基础上,对井筒的关键部位开展符合实际生产工况的多组次冲蚀与砂沉积数值模拟计算,结果分析表明,长水平井筒中接箍和封隔器部位极易受到冲蚀,且随着气体进口质量流量、砂粒直径以及砂粒含量增加冲蚀量也越来越大。而在其他工况不变的条件下随着砂粒浓度的增加,相同的运移距离下,砂粒浓度明显增加并最终达到稳定。(5)对整体井筒进行实尺寸冲蚀和砂沉积数值模拟,开展不同工况下整体井筒的冲蚀和砂沉积模拟,结果显示,在相同工况下,沿着气流方向井筒受到的最大冲蚀速率逐渐减小,而在相同位置上,冲蚀量随着进口质量流量、砂粒直径和含砂量的增加而增大,砂粒运移的距离逐渐减小。
[Abstract]:At present, horizontal well production has become the most important way of shale gas development at home and abroad, especially for shale gas reservoirs with thin layers, very low permeability and small porosity. Although the accuracy of conventional sand control technology is improving day by day and can block most of the sand grains from the formation, there will still be sand particles of certain diameter entering the wellbore with shale gas, when the shale gas production is large enough, The high speed sand bearing air flow will cause strong erosion and wear to the wellbore and the surface equipment of the wellhead. When the gas production rate is not large enough, some sand particles will not be carried out from the wellhead, resulting in sand particles accumulating at the bottom of the well. Serious accidents such as sand plugging are especially serious in shale gas long horizontal wellbore. Therefore, in order to explore the failure of shale gas long horizontal wellbore erosion and sand sinking principle, the simulation calculation of shale gas long horizontal shaft erosion and sand deposition is carried out in this paper. The influence of various parameters on it is studied, which provides the basis and direction for the erosion failure and sand sinking of shale gas horizontal horizontal wellbore in actual production. The main contents include the following contents: 1) this paper has upgraded and reformed a set of circulating erosion devices in this paper. So that the experimental device can simulate the erosion of the inner ring of the pipe more accurately, and carry out the related erosion experiment. (2) A set of visualized horizontal pipe sand sinking experimental device is designed independently. Sand particles are transported and deposited along the "L" tube from the middle of the horizontal tube to the bottom of the horizontal pipe under the action of the incoming flow. The experiment will use high-speed camera to capture. 3) numerical simulation of inner ring erosion and horizontal tube sand deposition of the same size as the experiment will be carried out. The simulation results will be processed and analyzed, and the results will be compared with the experimental results. Based on the investigation of shale gas long horizontal wellbore in actual production, numerical simulation of erosion and sand deposition of key parts of wellbore in accordance with actual production conditions is carried out. The results show that the coupling and Packer parts in the long horizontal wellbore are vulnerable to erosion, and with the mass flow rate of the gas inlet, The diameter of sand and the amount of erosion increased with the increase of sand content, and under the same moving distance with the increase of sand concentration in other conditions, Sand concentration increased obviously and finally reached stability. 5) numerical simulation of solid size erosion and sand deposition was carried out on the whole wellbore. The results showed that under the same working conditions, the erosion and sand deposition of the whole wellbore were simulated under different working conditions. The maximum erosion rate along the air flow direction decreases gradually, while at the same position, the erosion rate increases with the increase of inlet mass flow rate, sand diameter and sand content, and the distance of sand grain migration decreases gradually.
【学位授予单位】：西南石油大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TE37

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