Phase behavior of gas condensate in porous media using real-time computed tomography scanning

作     者：Wen-Long Jing Lei Zhang Ai-Fen Li Jun-Jie Zhong Hai Sun Yong-Fei Yang Yu-Long Cheng Jun Yao 

作者机构：Institute of Petroleum EngineeringChina University of Petroleum(East China)Qingdao266580ShandongChina National Key Laboratory of Deep Oil and GasChina University of Petroleum(East China)Qingdao266580ShandongChina 

出 版 物：《Petroleum Science》 (石油科学（英文版）)

年 卷 期：2024年第21卷第2期

页      面：1032-1043页

核心收录：

学科分类：0820[工学-石油与天然气工程] 08[工学] 0805[工学-材料科学与工程（可授工学、理学学位）] 080502[工学-材料学] 

基　　金：the National Natural Science Foundation of China(Nos.52122402,12172334,52034010,52174051) Shandong Provincial Natural Science Foundation(Nos.ZR2021ME029,ZR2022JQ23) Fundamental Research Funds for the Central Universities(No.22CX01001A-4)。 

主　　题：Gas condensate Pressure depletion Real-time micro-computed tomography scanning Distribution of condensate liquid 

摘      要：The phase behavior of gas condensate in reservoir formations differs from that in pressure-volume-temperature(PVT)cells because it is influenced by porous media in the reservoir formations.Sandstone was used as a sample to investigate the influence of porous media on the phase behavior of the gas condensate.The pore structure was first analyzed using computed tomography(CT)scanning,digital core technology,and a pore network model.The sandstone core sample was then saturated with gas condensate for the pressure depletion experiment.After each pressure-depletion state was stable,realtime CT scanning was performed on the sample.The scanning results of the sample were reconstructed into three-dimensional grayscale images,and the gas condensate and condensate liquid were segmented based on gray value discrepancy to dynamically characterize the phase behavior of the gas condensate in porous media.Pore network models of the condensate liquid ganglia under different pressures were built to calculate the characteristic parameters,including the average radius,coordination number,and tortuosity,and to analyze the changing mechanism caused by the phase behavior change of the gas condensate.Four types of condensate liquid(clustered,branched,membranous,and droplet ganglia)were then classified by shape factor and Euler number to investigate their morphological changes dynamically and elaborately.The results show that the dew point pressure of the gas condensate in porous media is 12.7 MPa,which is 0.7 MPa higher than 12.0 MPa in PVT cells.The average radius,volume,and coordination number of the condensate liquid ganglia increased when the system pressure was between the dew point pressure(12.7 MPa)and the pressure for the maximum liquid dropout,Pmax(10.0 MPa),and decreased when it was below Pmax.The volume proportion of clustered ganglia was the highest,followed by branched,membranous,and droplet ganglia.This study provides crucial experimental evidence for the phase behavior changing process of gas condensate in porous media during the depletion production of gas condensate reservoirs.