A Novel Semi-Analytical Model for Multi-branched Fractures in Naturally Fractured-Vuggy Reservoirs
In the past few decades, scholars have made great breakthroughs in the study of well test analysis of carbonate rock. The previous studies are based on horizontal wells, straight wells, fractured wells, and inclined wells. With the development of fracturing technology, acid fracturing technology is...
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ftpubmed:oai:pubmedcentral.nih.gov:6072746 2023-05-15T15:52:59+02:00 A Novel Semi-Analytical Model for Multi-branched Fractures in Naturally Fractured-Vuggy Reservoirs Wang, Lei Chen, Xiaoxia Xia, Zunyi 2018-08-02 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6072746/ http://www.ncbi.nlm.nih.gov/pubmed/30072702 https://doi.org/10.1038/s41598-018-30097-2 en eng Nature Publishing Group UK http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6072746/ http://www.ncbi.nlm.nih.gov/pubmed/30072702 http://dx.doi.org/10.1038/s41598-018-30097-2 © The Author(s) 2018 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/. CC-BY Article Text 2018 ftpubmed https://doi.org/10.1038/s41598-018-30097-2 2018-08-12T00:26:54Z In the past few decades, scholars have made great breakthroughs in the study of well test analysis of carbonate rock. The previous studies are based on horizontal wells, straight wells, fractured wells, and inclined wells. With the development of fracturing technology, acid fracturing technology is considered to be the most effective measure to develop carbonate reservoirs. As the carbonate rock is easily dissolved in carbonic acid, multi-branched fractures will be produced near a vertical well. This article presented a semi-analytical model for multi-branched fractures in naturally fractured-vuggy reservoirs for the first time, which laid a theoretical foundation for solving well test analysis for finite conductivity multi-branched fractures. The model can quantify the wellbore flow pressure and applied to obtain more parameters reflecting comprehensive flow characteristics through using history matching procedure. The results were compared with numerical simulation and the existing analytical solutions of a single fracture model. Then in this paper, flow characteristics are recognized and there are five flow regimes found in the type curves, e.g. bi-linear flow region, linear flow region, inter-porosity flow region between vugs and fractures, inter-porosity region between matrix and fractures, and radial flow region. Finally, the influence factors analysis shows fracture number will mainly affect flow behavior of bi-linear flow and linear flow. The angle analysis showed that as the fractures were closer, their interaction became stronger. The conductivity would seriously affect the flow behavior in the early time. Linear flow cannot be observed when the conductivity is less than 1 and bi-linear flow cannot be observed when the conductivity is more than 20. And the effect of fracture length on flow behavior occurs in the early time. Bi-linear flow and linear flow characteristics cannot be observed when the fracture length is reduced. Text Carbonic acid PubMed Central (PMC) Scientific Reports 8 1 |
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Article Wang, Lei Chen, Xiaoxia Xia, Zunyi A Novel Semi-Analytical Model for Multi-branched Fractures in Naturally Fractured-Vuggy Reservoirs |
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In the past few decades, scholars have made great breakthroughs in the study of well test analysis of carbonate rock. The previous studies are based on horizontal wells, straight wells, fractured wells, and inclined wells. With the development of fracturing technology, acid fracturing technology is considered to be the most effective measure to develop carbonate reservoirs. As the carbonate rock is easily dissolved in carbonic acid, multi-branched fractures will be produced near a vertical well. This article presented a semi-analytical model for multi-branched fractures in naturally fractured-vuggy reservoirs for the first time, which laid a theoretical foundation for solving well test analysis for finite conductivity multi-branched fractures. The model can quantify the wellbore flow pressure and applied to obtain more parameters reflecting comprehensive flow characteristics through using history matching procedure. The results were compared with numerical simulation and the existing analytical solutions of a single fracture model. Then in this paper, flow characteristics are recognized and there are five flow regimes found in the type curves, e.g. bi-linear flow region, linear flow region, inter-porosity flow region between vugs and fractures, inter-porosity region between matrix and fractures, and radial flow region. Finally, the influence factors analysis shows fracture number will mainly affect flow behavior of bi-linear flow and linear flow. The angle analysis showed that as the fractures were closer, their interaction became stronger. The conductivity would seriously affect the flow behavior in the early time. Linear flow cannot be observed when the conductivity is less than 1 and bi-linear flow cannot be observed when the conductivity is more than 20. And the effect of fracture length on flow behavior occurs in the early time. Bi-linear flow and linear flow characteristics cannot be observed when the fracture length is reduced. |
format |
Text |
author |
Wang, Lei Chen, Xiaoxia Xia, Zunyi |
author_facet |
Wang, Lei Chen, Xiaoxia Xia, Zunyi |
author_sort |
Wang, Lei |
title |
A Novel Semi-Analytical Model for Multi-branched Fractures in Naturally Fractured-Vuggy Reservoirs |
title_short |
A Novel Semi-Analytical Model for Multi-branched Fractures in Naturally Fractured-Vuggy Reservoirs |
title_full |
A Novel Semi-Analytical Model for Multi-branched Fractures in Naturally Fractured-Vuggy Reservoirs |
title_fullStr |
A Novel Semi-Analytical Model for Multi-branched Fractures in Naturally Fractured-Vuggy Reservoirs |
title_full_unstemmed |
A Novel Semi-Analytical Model for Multi-branched Fractures in Naturally Fractured-Vuggy Reservoirs |
title_sort |
novel semi-analytical model for multi-branched fractures in naturally fractured-vuggy reservoirs |
publisher |
Nature Publishing Group UK |
publishDate |
2018 |
url |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6072746/ http://www.ncbi.nlm.nih.gov/pubmed/30072702 https://doi.org/10.1038/s41598-018-30097-2 |
genre |
Carbonic acid |
genre_facet |
Carbonic acid |
op_relation |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6072746/ http://www.ncbi.nlm.nih.gov/pubmed/30072702 http://dx.doi.org/10.1038/s41598-018-30097-2 |
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© The Author(s) 2018 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/. |
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CC-BY |
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https://doi.org/10.1038/s41598-018-30097-2 |
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