Design and Validation of a Numerical Model for Inclined Oil-Water Flow

该研究旨在开发和验证倾斜油水管流的时间相关的三维数值模型。井下油井中经常会遇到倾斜的油水流动，这些油井的静水压力太高，不能让溶解的气体从溶液中出来。石油公司使用“生产测井仪器”(PLT)在这类油井中进行流体流量测量，这是最大化英国油层石油产量的过程的一部分，该数值模型将极大地方便解释来自这些PLT的测量数据。由于Kelvin-Helmholtz(K-H)波的存在，倾斜的油水流动非常复杂，它间歇性地形成和衰减。这些波的作用是引起油和水的局部速度矢量的大小和方向随时间发生很大的变化，以及引起两相的局部体积分数分布随时间发生很大的变化。该数值模型将预测倾斜油水流动结构的细节，包括(I)两相局部速度矢量分布随时间的变化；(Ii)两相局部体积分数分布随时间的变化；(Iii)流动中间歇性K-H波的结构和传播速度。如果该模型能够在很大的流动条件下预测K-H波的传播速度，这将极大地方便解释一种新的生产测井技术，该技术通过测量K-H波速度来估计油水混合物的表面速度。该数值模型将在水包油流动中使用实验室流动回路和两种独立的、最先进的测量技术进行验证，这两种技术能够对分散相(油)的局部速度矢量和待测量的两相的局部体积分数进行随时间变化的测量。这些技术是：(I)高速双平面电阻抗断层扫描(EIT)和(Ii)局部多传感器电导探头。这两种技术都可以在平均分散相体积分数的高值下操作(例如，对于水包油流动，EIT操作高达约45%的石油体积分数，而本地探头操作高达约30%的石油体积分数)，在这种情况下，由于来自多个油滴表面的光散射的影响和油水混合物的不透明度，通常不能使用PIV和LDA等光学技术。鉴于高速、双平面EIT和本地多传感器电导探头的高度新颖性和创新性，将开展工作来开发这些技术，以使从它们获得的测量具有足够的精度，以用于验证数值模型。由于这两种测量技术都是新的，拟议的研究的一个重要特点将是这些技术相互交叉验证。

The proposed research seeks to develop and validate a time dependent, 3D numerical model of inclined oil-water pipe flow. Inclined oil-water flows are commonly encountered downhole in oil wells at depths where the hydrostatic pressure is too high to allow dissolved gases to come out of solution. 'Production Logging Tools' (PLTs) are used by oil companies to make fluid flow measurements in such oil wells, as part of the process of maximising oil production from UK reservoirs, and the numerical model will greatly facilitate interpretation of measurement data from these PLTs. Inclined oil-water flows are highly complex due to the presence of Kelvin-Helmholtz (K-H) waves which intermittently form and decay. The effect of these waves is to induce large, time dependent variations in the magnitude and direction of the local velocity vector of both the oil and water as well as causing large time dependent variations in the local volume fraction distribution of both phases. It is intended that the numerical model will predict the fine detail of the structure of inclined oil-water flows including (i) time dependent variations in the local velocity vector distribution of both phases; (ii) time dependent variations in the local volume fraction distribution of both phases; and (iii) the structure and propagation speed of intermittent K-H waves in the flow. If the model is successful in predicting the propagation speed of K-H waves for a wide range of flow conditions this will greatly facilitate interpretation of a novel Production Logging technique which estimates the oil-water mixture superficial velocity from measurements of the K-H wave speed. The numerical model will be validated in oil-in-water flows using a laboratory flow loop and two independent, state of the art measurement techniques which enable time dependent measurements of the local velocity vector of the dispersed phase (oil) and the local volume fraction of both phases to be measured. These techniques are; (i) high speed dual-plane Electrical Impedance Tomography (EIT) and (ii) the local, multi-sensor conductance probe. Both techniques can operate at high values of the mean dispersed phase volume fraction (e.g. for oil-in-water flows EIT operates up to about 45% oil volume fraction and the local probe operates up to about 30% oil volume fraction) where optical techniques such as PIV and LDA cannot generally be used due to the effects of light scattering from multiple oil droplet surfaces and the opacity of the oil-water mixture. Given the highly novel and innovative nature of both high speed, dual-plane EIT and the local multi-sensor conductance probe, work will be undertaken to develop these techniques such that measurements obtained from them are of sufficient accuracy to be useful in validating the numerical model. Since both measurement techniques are novel, an important feature of the proposed research will be the cross-checking of these techniques against each other.