【作者】 付静；

【导师】 李兆敏；

【作者基本信息】 中国石油大学 ， 油气田开发工程， 2009， 博士

【摘要】 气井生产应用井下气水分离技术可将气井的产出水直接在同井中回注,该项技术具有良好的经济效益和环保效果。本文首次提出采用螺旋旋流分离器进行井下气水分离,独创性地设计了一套采用螺旋旋流分离器将气水分离后注入同井水层的工艺系统。首先,结合常规气井排液工艺方法提出了采用螺旋旋流分离器进行井下气水分离的合理性。首次以螺旋分离器的螺距、螺旋圈数,以及液流和气流的流量等因素作为影响分离器的工作性能与分离效率的基本参数。其次,推导出实际的气液分离流场中分散相液滴的聚并计算公式;提出了天然气井积液诊断方法并编制了井筒积液预测软件;确定不同直径颗粒在不同加速度下所需螺距及螺旋圈数,为螺旋分离器设计提供了理论依据。再次,分析确定了Reynolds应力模型(RSM)为最适合螺旋旋流分离器分离性能数值模拟研究的湍流模型;针对设计的十一个模型应用FLUENT软件分别模拟了单相气体流场与气液两相流场,详细研究了结构参数变化对螺旋结构内气相湍流流动的影响关系以及影响分离器分离效率的影响因素。由结果分析得出了分离器螺距、螺旋圈数与分离器压降、截面压降、速度分布及分离效率之间的关系。重点讨论了结构参数与压降之间的关系:即在固定相同的入口速度与分离器螺旋圈数的情况下,螺距的大小与气体经过分离器产生的压降成反比;当螺距不变时,入口速度越大,气体经过分离器产生的压力降也越大;在相同的螺距长度下,分离器螺旋圈数越多,压力降越大。也可以看出入口流速对流场内过流断面气相速度分布影响较大。对分离器内气液两相流动模拟研究发现,在螺距、颗粒直径相同条件下,螺旋圈数越多,颗粒在分离器中分离效率越高。在螺旋结构相同条件下,颗粒直径越大越容易分离。根据数值模拟结果分析,得出最佳螺旋结构为Case1,即螺距为D1,螺旋圈数为N1。本文还自行设计了螺旋旋流分离器室内实验架,结合生产实际参数与数值模拟分析结果,证实了螺距为D1、螺旋圈数为N1的螺旋旋流器具有较好的气—水分离效果,分离效率在90%以上。最后,本文成功设计出螺旋旋流分离器分别结合螺杆泵与电潜泵两套井下气水分离回注装置,设计编制了井下气水分离回注生产系统设计软件。同时选取胜利油田水淹气井,采用螺旋旋流气液分离与螺杆泵增压进行同井回注现场试验,取得显著效果。更多还原

【Abstract】 This paper presents application of downhole gas-water separation technology can be output of water directly into the same well water recharge in gas well production. In this paper, put forward the use of spiral hydrocyclone for underground gas and water separation by the first time. Original design of a set of spiral hydrocyclone used to inject water and gas separation process with the well water system layer. The result shows that:First of all, the paper bring forward that using spiral cyclone separator for downhole gas-water separation is reasonable combination of conventional gas-well processes. The paper make the pitch of spiral separator, the number of spiral,as well as liquid flow and gas flow as the basic structure parameters impacting the performance and efficiency of separation in the first time.Second, the formula of droplet coalescence is derived by gas-liquid separation of flow field from the actual flow field. At the same time, the paper attempt to put forward the diagnosis of effusion of natural gas wells and the preparation of the wellbore fluid prediction software. Combination of underground conditions at the actual situation, it determines the pitch of spiral separator and the number of spiral under different acceleration of diameter of particle and founds the theoretical basis of spiral separator.Third, the paper analyzes the Reynolds Stress Model (RSM) as the most suitable model for the numerical simulation of turbulence. For 11 models parameters, respectively, it uses FLUENT software to simulate the single-phase of gas flow field and gas-liquid of two-phase flow field, and detailed study the relationship: the changes of structural parameters of spiral separator and the turbulent gas flows as well as the impact of separation efficiency factors. Results are obtained that the pitch, the number of spiral has relationship with separator pressure drop, cross-section pressure drop, velocity’s distribution and separation efficiency. As pressure drop is the important parameter of hydrocyclone energy consumption, so the structural parameters and the the pressure drop’s relationship is focused on the paper. The result shows that: when the speed of entrance and the number of spiral are fixed,the smaller the pitch, the greater the pressure drop with gas go through the separation; the greater the pitch, the smaller the pressure drop. When the pitch is fixed, the speed of entrance is greater, the pressure drop that gas pass the separator is greater. On the other hand when the pitch is not changed, the number of spiral is greater, the pressure drop is greater. At the same time, the law of pressure drop in cross-section is same with the whole separator by the simulation results. Also by the simulation results it can be seen that the velocity of entrances has greater impact on the velocity distribution in cross-section. The simulation study of gas-liquid separator and structure parameters and operating parameters of the relationship found that the number of spiral is more ,particles in the separator to isolate the time longer, higher separation efficiency when the pitch, particle diameter are under the same conditions. Under the structure in the same conditions, diameter of particles is larger, gas-liquid separated is more easily. According to single-phase of gas and gas-liquid two-phase analysis of simulation results, while overall energy consumption efficiency and separation factors, the paper obtains the best structure of Case1, that is, pitch for D1, the number of spiral for N1.This article also design spiral hydrocyclone laboratory frame, combined with the actual parameters of the production and results of numerical simulation, through experiments, confirmed the pitch for D1, the number of spiral for N1 has a good gas - water separation efficiency that the separation efficiency is more than 90%.Finally, the paper give the success of the design of the first: spiral hydrocyclone combination of helical screw pump, respectively, spiral hydrocyclone combination of electric submersible pump.With the combination of the two sets of downhole gas-water separation devices, it design software of underground gas-water separation and injection. At the same time, the paper select a wells in Shengli Oilfield, the use of gas-liquid separator with spiral frame and helical screw pump injection in field test, it achieved remarkable results.更多还原