Effect of Micropore Structure on Macroscopic Water Cut Changing Law in Strongly Heterogeneous Reservoirs

Reservoir rock type (RRT) classification is commonly used for the fine characterization of strongly heterogeneous reservoirs. Many research focused on proposing different RRT methods, while few studies focused on the relationship between micropore structure and macroscopic seepage law of fluid trans...

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Main Authors: Renfeng Yang, Ruizhong Jiang, Guangwei Liu, Han Chen, Peiyuan Chen, Zhaobo Sun
Format: Article
Language:English
Published: Hindawi-Wiley 2020-01-01
Series:Geofluids
Online Access:http://dx.doi.org/10.1155/2020/8873903
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spelling doaj-aaa7b68c8b7c4a73827baecc06f3b9c22020-11-30T09:11:22ZengHindawi-WileyGeofluids1468-81151468-81232020-01-01202010.1155/2020/88739038873903Effect of Micropore Structure on Macroscopic Water Cut Changing Law in Strongly Heterogeneous ReservoirsRenfeng Yang0Ruizhong Jiang1Guangwei Liu2Han Chen3Peiyuan Chen4Zhaobo Sun5China University of Petroleum (East China), Qingdao 266580, ChinaChina University of Petroleum (East China), Qingdao 266580, ChinaCNOOC International Co., Ltd., No. 6, Taiyang Gong South Street, Chaoyang District, Beijing 100028, ChinaCNOOC International Co., Ltd., No. 6, Taiyang Gong South Street, Chaoyang District, Beijing 100028, ChinaCNOOC International Co., Ltd., No. 6, Taiyang Gong South Street, Chaoyang District, Beijing 100028, ChinaCNOOC International Co., Ltd., No. 6, Taiyang Gong South Street, Chaoyang District, Beijing 100028, ChinaReservoir rock type (RRT) classification is commonly used for the fine characterization of strongly heterogeneous reservoirs. Many research focused on proposing different RRT methods, while few studies focused on the relationship between micropore structure and macroscopic seepage law of fluid transporting through different types of formation. Considering the different diagenesis degrees of rock types in different sedimentary facies, the quadrant unit method and FZI method were applied to classify and evaluate the strongly heterogeneous reservoirs. The corresponding capillary pressure curves and relative permeability curves for different rock types could be obtained. A set of theoretical models that could describe the macroscopic seepage law are proposed, and numerical simulation case studies were carried out to explore the superimposed seepage law in reservoirs under different degrees of heterogeneity. Results show that water cut rises faster in poor-property RRT formation than in good-property RRT formation, with a lower recovery factor under the same conditions. The water cut rising rate increases firstly and then decreases with water cut and recovery degree increasing. The poorer the rock property is, the earlier and higher the peak value of water cut rising rate is. Also, based on numerical simulation case studies, the superimposed seepage law is close to that in the poor-property formation as the heterogeneity degree strengthens. The newly proposed method not only could provide a reference for rock type classification based on micropore structure but also could expound the influence of micropore structure on the change law of macroscopic water cut and elaborates the macroscopic change law after the superposition of different types of reservoirs. The conventional normalization of relative permeability curves is only applicable to relatively homogeneous reservoirs and not applicable to strongly heterogeneous reservoirs, especially when the permeability variation is higher than 0.7. The newly proposed approach is capable of analyzing the effect of micropore structure on macroscopic seepage law and improving the prediction accuracy of the production profile.http://dx.doi.org/10.1155/2020/8873903
collection DOAJ
language English
format Article
sources DOAJ
author Renfeng Yang
Ruizhong Jiang
Guangwei Liu
Han Chen
Peiyuan Chen
Zhaobo Sun
spellingShingle Renfeng Yang
Ruizhong Jiang
Guangwei Liu
Han Chen
Peiyuan Chen
Zhaobo Sun
Effect of Micropore Structure on Macroscopic Water Cut Changing Law in Strongly Heterogeneous Reservoirs
Geofluids
author_facet Renfeng Yang
Ruizhong Jiang
Guangwei Liu
Han Chen
Peiyuan Chen
Zhaobo Sun
author_sort Renfeng Yang
title Effect of Micropore Structure on Macroscopic Water Cut Changing Law in Strongly Heterogeneous Reservoirs
title_short Effect of Micropore Structure on Macroscopic Water Cut Changing Law in Strongly Heterogeneous Reservoirs
title_full Effect of Micropore Structure on Macroscopic Water Cut Changing Law in Strongly Heterogeneous Reservoirs
title_fullStr Effect of Micropore Structure on Macroscopic Water Cut Changing Law in Strongly Heterogeneous Reservoirs
title_full_unstemmed Effect of Micropore Structure on Macroscopic Water Cut Changing Law in Strongly Heterogeneous Reservoirs
title_sort effect of micropore structure on macroscopic water cut changing law in strongly heterogeneous reservoirs
publisher Hindawi-Wiley
series Geofluids
issn 1468-8115
1468-8123
publishDate 2020-01-01
description Reservoir rock type (RRT) classification is commonly used for the fine characterization of strongly heterogeneous reservoirs. Many research focused on proposing different RRT methods, while few studies focused on the relationship between micropore structure and macroscopic seepage law of fluid transporting through different types of formation. Considering the different diagenesis degrees of rock types in different sedimentary facies, the quadrant unit method and FZI method were applied to classify and evaluate the strongly heterogeneous reservoirs. The corresponding capillary pressure curves and relative permeability curves for different rock types could be obtained. A set of theoretical models that could describe the macroscopic seepage law are proposed, and numerical simulation case studies were carried out to explore the superimposed seepage law in reservoirs under different degrees of heterogeneity. Results show that water cut rises faster in poor-property RRT formation than in good-property RRT formation, with a lower recovery factor under the same conditions. The water cut rising rate increases firstly and then decreases with water cut and recovery degree increasing. The poorer the rock property is, the earlier and higher the peak value of water cut rising rate is. Also, based on numerical simulation case studies, the superimposed seepage law is close to that in the poor-property formation as the heterogeneity degree strengthens. The newly proposed method not only could provide a reference for rock type classification based on micropore structure but also could expound the influence of micropore structure on the change law of macroscopic water cut and elaborates the macroscopic change law after the superposition of different types of reservoirs. The conventional normalization of relative permeability curves is only applicable to relatively homogeneous reservoirs and not applicable to strongly heterogeneous reservoirs, especially when the permeability variation is higher than 0.7. The newly proposed approach is capable of analyzing the effect of micropore structure on macroscopic seepage law and improving the prediction accuracy of the production profile.
url http://dx.doi.org/10.1155/2020/8873903
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