Measurement and revised interpretation of gas flow behavior in tight reservoir cores
Measurement and revised interpretation of gas flow behavior in tight reservoir cores
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DOI：
10.1016/j.petrol.2008.12.017
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发表时间：
2009-03-01
影响因子：
--
通讯作者：
Li, Z.
中科院分区：
文献类型：
--
作者：
Li, S.;Dong, M.;Li, Z.
随着低渗透油气资源日益受到重视，工业和研究机构都需要一种可靠、快速的方法来确定致密储层岩心的渗透率。由于气体滑脱现象的存在，致密岩心中的气体流动在实验室条件下更加复杂。世纪以来，Klinkenberg相关式在实验室中被广泛用于通过将测量的视渗透率线性外推到无限平均测试压力来获得致密多孔介质中的气体渗透率。本文提出了一种在低渗透岩心气体渗透率测量中，通过在试样出口处施加反压来研究滑脱效应的实验方法。通过逐步增加背压，气体滑移效应逐渐减小，当背压达到或超过一个临界值时，气体滑移效应可以忽略不计。该压力定义为本研究中的最小背压。因此，可以在背压等于或大于最小背压的情况下不使用Klingkenberg相关性来确定防滑气体渗透率。对于渗透率极低的岩心，Klinkenberg渗透率和非滑动渗透率之间也存在明显的差异。该研究提供了一种利用气体实验确定致密储层岩心渗透率的简单方法。所开发的技术也可以应用于测量的相对气液渗透率在多相流系统中的困难时，发现使用Klinkenberg相关。(c)2009爱思唯尔有限公司版权所有。
As more attention has been paid to low permeability hydrocarbon resources, a reliable and fast method to determine permeability of tight reservoir cores is required by both industry and research organizations. Gas flow in tight cores presents more complications under laboratory conditions due to gas slip phenomenon. For over half a century, the Klinkenberg correlation has been widely used in laboratories to obtain gas permeability in tight porous media through linear extrapolation of measured apparent permeabilities to infinite mean test pressure. This paper presents an experimental method to study the slip effects in gas permeability measurements for low permeability cores by applying a backpressure at the outlet of test sample. By increasing backpressure step by step, the gas slip effect is gradually reduced and finally becomes negligible when backpressure reaches or exceeds a critical value. This pressure is defined as minimum backpressure in this study. Therefore, the non-slip gas permeability can be determined without using Klingkenberg correlation with backpressures equal to or greater than minimum backpressure. Evident discrepancies were also found between the Klinkenberg permeability and non-slip permeability for very low-permeability cores. This study provided a straightforward method to experimentally determine permeability of tight reservoir cores by using gases. The developed technique can also be applied in the measurement of relative gas-liquid permeabilities in multiphase flow systems where difficulties were found when using Klinkenberg correlation. (c) 2009 Elsevier B.V. All rights reserved.