Abstract The response of gas condensate reservoirs is directly influenced by heterogeneity. In such reservoirs, condensate is created around wellbore areas, when the reservoir pressure falls below the dew point pressure. Consequently, the distribution of this condensate bank makes fluid flow in the reservoir even more complicated by changing rock-fluid properties (e.g., relative permeability). This alteration can be assumed as a new heterogeneity, called fluid heterogeneity. The separation of fluid heterogeneity from rock heterogeneity is a challenging task. The main idea of this study is to investigate the transient pressure responses of a gas condensate reservoir to separate rock and fluid heterogeneities. Different homogeneous and heterogeneous reservoir models of a reservoir were constructed by the geostatistical approach. A commercial reservoir simulator was used to simulate the behavior of different drawdown and buildup scenarios. The fluid is a lean gas condensate selected from one of the Middle East formations. The wavelet transform (WT) approach was implemented to characterize the behavior of condensate banks for both homogeneous and heterogeneous models. Analyzing the wavelet approximate and detail coefficients of the pressure-transient responses enabled us to distinguish the rock and fluid heterogeneities. The results showed that the wavelet detail coefficient could be a good indicator of reservoir heterogeneity. Moreover, the WT could be successfully used to distinguish different regions of a condensate bank inside the reservoir under study. The implemented approach showed promising results in analyzing the pressure-transient responses of gas condensate reservoirs.

中文翻译：

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通过压力瞬态响应的小波变换评估凝析气藏的流体和岩石非均质性

摘要 凝析气藏的响应直接受到非均质性的影响。在这样的油藏中，当油藏压力低于露点压力时，会在井筒区域周围产生凝析油。因此，通过改变岩石流体特性（例如，相对渗透率），该凝析油堤的分布使储层中的流体流动更加复杂。这种改变可以假设为一种新的异质性，称为流体异质性。流体非均质性与岩石非均质性的分离是一项具有挑战性的任务。本研究的主要思想是研究凝析气藏对分离岩石和流体非均质性的瞬态压力响应。通过地质统计学方法构建了不同的均质和非均质储层模型。使用商业油藏模拟器来模拟不同压降和堆积场景的行为。该流体是选自中东地层之一的贫气凝析油。实施小波变换 (WT) 方法来表征同质和异质模型的凝析油库的行为。分析压力瞬态响应的小波近似系数和细节系数使我们能够区分岩石和流体的非均质性。结果表明，小波细节系数可以很好地反映储层非均质性。此外，WT 可以成功地用于区分正在研究的储层内凝析油库的不同区域。