Model flow in a capping, containment, and collection system and comparison to available data from the Macondo well incident.

A computer program (included as an EXCEL spreadsheet) was generated to model flow in capping, containment, and collection system and evaluated using available data from the Macondo well incident. Flow modeling is essential to determine the pipe and component sizes needed or conversely, the flow rate and pressure capabilities required, when applying a capping system to a particular set of conditions. The program consists of 10 multiphase correlations and 5 PVT correlations that have been published over the years. The computational technique used by multiphase correlations is an iterative algorithm, one length increment at a time. The pipe is divided into equal length intervals (50 in the case of the computer program), and the pressure is iterated in each interval until self-consistency is achieved, using the pressure calculated in the interval directly above as a starting point. Once pressure and temperature are predicted as a function of depth, the question of whether hydrates could form in the pipe at any interval of depth is evaluated. A limitation of the computer program is it is a black oil model, that is, the oil in the reservoir has gas in solution and this gas is liberated as pressure and temperature decrease, yielding a multiphase flow of fluids in whatever pipe is in use.

本研究开发了一个计算机程序（以EXCEL电子表格形式提供），用于模拟封盖、围堵及收集系统（capping, containment, collection system）中的流动，并利用马孔多井事故的现有数据对其进行了评估。流动建模（flow modeling）对于确定封盖系统应用于特定工况时所需的管道及组件尺寸，或反之，所需的流量及压力能力至关重要。该程序包含多年来发表的10种多相流关联式（multiphase correlations）及5种PVT关联式（PVT correlations）。多相流关联式采用的计算方法为迭代算法（iterative algorithm），即逐段增量计算：管道被划分为等长区间（本程序中设为50个），并以正上方区间计算得到的压力为初始值，在每个区间内迭代计算压力直至达到自洽性（self-consistency）。当压力与温度随深度的变化关系被预测后，将评估管道内任意深度区间是否可能形成水合物（hydrates）。该计算机程序的一个局限性在于其采用黑油模型（black oil model），即储层中的原油溶解有气体，且随着压力与温度降低，这些气体将析出，导致所用管道内出现流体多相流。