高含气井下气液混合输送技术研究

为了确保油田开采过程中电潜泵在高含气油井的正常运行,结合气液分离技术和引射技术,该文运用CFD模拟软件FLUENT研究了一种高含气井下气液混合输送技术.该技术通过建立气体及液体分采通道,利用引射原理将增压后的高压动力液携带富气流举升至地面,以实现利用生产井自身流体实现自我举升.研究表明:经过对比分析发现,对于不同入口气体含量的工况,由于射流泵引射装置的引射比影响,入口气体体积含量40%是一拐点,当入口气体含量超过40%时,引管内的气相含量以及流速基本达到一定值;对于不同入口流量,随着流量的增加,气液分离效果亦逐渐变佳,取气管内的气相含量基本稳定在一定的范围,而取气管内的流速则随着流量的增加而增大.该研究结果对提高电潜泵在油田开采高含气油井中的应用范围具有重要意义

双同向旋流场中液液变质量流动压降特性研究

轴流式井下旋流油水分离器是一种可用于油井中进行油水分离的新型分离器,在室内对影响其压降的因素(入口流量、分流比、含油率等)进行了试验研究。结果表明,与压降相关的无量纲参数Eu主要与Re_m、F和导流片结构有关。当导流片结构一定时,Re_m为主控参数。采用无量纲参数分析法还得到了压降的计算关系式,该关系式综合考虑操作参数、物性参数等对压降的影响,适用范围更广,为轴流式井下旋流油水分离器在井下应用时的压降预测提供了指导

Investigation on downhole gas-liquid two phase separation and mixing transportation characteristics with high gas fraction

Abstract Produced fluids in oilfields usually contains water, natural gas and other substances. With development of oilfields, formation energy decreases and oil reservoir degases, therefore high gas content wells increase. When the produced liquid is lifted by the Electric Submersible Pump (ESP), high gas content will impact pump working performance, and even leads to cavitation and gas lock, which greatly impact lifting efficiency and interrupt well production. To solve the problems caused by high gas content, this paper puts forward an idea of &ldquo;separating - mixed transporting&rdquo;, in which the separating is conducted by a flat deflector, and the mixed transporting is achieved by an ejector. According to this idea, an indoor experimental device and a numerical model were established. Laboratory experiments and numerical simulations were carried out simultaneously. The Euler-Euler multiphase flow model and Reynolds stress turbulence model (RSM) are used in the numerical simulation. It is found that a stable gas core formed by the guide vane appears near the swirl field center, and the gas core width decreases with the gas-liquid mixing flow rate increases. With the increase of inlet void fraction, the gas core width increases gradually. When the inlet gas fraction increases to 70%, the gas core can be taken out by the air pipe to achieve the purpose of complete separation. The distribution of the gas-liquid two-phase in the swirl field and the pressure drop during gas-liquid mixed transportation are compared and analyzed by numerical simulation and experimental testing, it is found that the numerical simulation results are in good agreement with the experimental results, which verifies the rationality of the selection of numerical simulation model. The research results are of great significance to broaden the application scope of ESP in high gas fraction oil wells.</p

基于气液分离的天然气双入口优化设计

天然气井采出的天然气通常含一定量的液体，这些液体不仅会堵塞管线、阀门，影响流量计计量的精确度，而且还会腐蚀设备、管道、仪表，易引起振动，破坏管道结构，严重影响集输生产管道寿命与安全，因此需尽快对采出液进行气液分离。为此，根据油气田现场采出液工况，设计了双入口气液分离器，并采用欧拉多相流模型，耦合标准k-ε湍流模型，对分离器内部的流场分布和分离特性开展了数值模拟研究。研究结果表明：(1)由于双入口的存在，分离器入口处湍流强度较小，流动较为平稳，能够增加入口气液混合液的分层程度，减少分离器下部发生折返的气体流量，进而减少气体出口带液量；(2)当入口液滴粒径大于0.1 mm时，仅有极少量的气体从液体出口流走，能够取得较好的分离效果；(3)随着分流比的减小，液体出口液体体积分数迅速增加，气体出口液体体积分数缓慢增加；(4)入口液体体积分数的变化主要影响分离后气体的纯度，对分离后液体的纯度影响较小。结论认为，在实际应用过程中，对于液滴粒径较小的来液工况，无论入口液体体积分数如何变化，均应调节分流比小于入口液体体积分数，使其液位略高于液体出口，以提高气液分离的效果