Well deliverability in most gas condensate reservoirs is reduced by condensate banking when the pressure falls below the dew point, but the impact of condensate banking may be reduced due to improved mobility at high capillary number in the near-well region. Fevang and Whitson have shown that the key parameter in determining well deliverability is the relationship between k sub rg and the ratio k sub rg/k sub ro. They also suggested an experimental technique for measuring k sub rg as a function of k sub rg/k sub ro using core plugs. We have applied the experimental pseudo-steady-state technique proposed by Fevang and Whitson to long cores at high pressure and temperature, measuring relative permeabilites under conditions which are similar to the near-well region of a gas condensate reservoir. A gas condensate fluid is introduced into a core whose pressure is below the dew point of the fluid. The condensate saturation in the core builds up until it becomes mobile and a steady state is reached, reproducing the mechanism which occurs in the reservoir. By varying the fluid composition, core pressure and flow rate, it is possible to measure all of the relative permeability data needed to predict well deliverability, including the increase in mobility at high capillary number. We describe the experimental techniques and present results for a sandstone core from a North Sea gas condensate reservoir, using a 5-component synthetic fluid. The results show a clear increase in mobility with capillary number, at flow rates which are typical of the near-well region. The pseudo-steady-state technique measures relative permeabilities and does not require saturations to be measured. The dependence of k sub rg on k sub rg/k sub ro can be used directly in pseudopressure methods to calculate well deliverability. We also deseribe how the date for k sub rg versus k sub rg/k sub ro can be used to define parameters for empirical correlations of relative permeability versus saturation, so that the results can be used in reservoir simulators.
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机译：当压力降至露点以下时，大多数凝析气藏的井产能会因凝析作用而降低，但由于近井区高毛细管数下流动性的改善，凝析作用的影响可能会降低。 Fevang和Whitson表明，确定油井产能的关键参数是k sub rg与比率k sub rg / k sub ro之间的关系。他们还提出了使用芯塞测量k sub rg与k sub rg / k sub ro的函数的实验技术。我们已将Fevang和Whitson提出的实验性拟稳态技术应用于高压和高温下的长岩心，并在类似于凝析气藏近井区域的条件下测量相对透水石。气体冷凝液被引入到压力低于流体露点的岩心中。岩心中的凝结水饱和度不断累积，直到它变得可移动并达到稳态为止，从而重现了储层中发生的机理。通过改变流体成分，岩心压力和流速，可以测量预测井产能所需的所有相对渗透率数据，包括在高毛细管数下的迁移率增加。我们描述了使用5组分合成流体从北海凝析气藏中获取砂岩岩心的实验技术和结果。结果表明，在近井区域的典型流速下，流动性随毛细管数的增加而明显增加。拟稳态技术测量相对渗透率，不需要测量饱和度。 k sub rg对k sub rg / k sub ro的依赖关系可直接用于拟压方法中，以计算井的产能。我们还希望如何使用k sub rg相对于k sub rg / k sub ro的日期来定义相对渗透率与饱和度的经验相关性的参数，以便将结果用于储层模拟器中。
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