Numerical simulation and field application of diverting acid acidizing in the Lower Cambrian Longwangmiao Fm gas reservoirs in the Sichuan Basin
The Lower Cambrian Longwangmiao dolomite gas reservoirs in the Sichuan Basin are characterized by well-developed natural micro-fractures and dissolved pores and cavities. Due to the strong heterogeneity of reservoirs and the serious damage of drilling and completion fluids, acid placement is difficu...
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| Format: | Article |
| Language: | English |
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KeAi Communications Co., Ltd.
2018-06-01
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| Series: | Natural Gas Industry B |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2352854018300329 |
| _version_ | 1797283324990849024 |
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| author | Hong Yue Fei Liu Heng Xue Yu Sang Changlin Zhou Yezhong Wang |
| author_facet | Hong Yue Fei Liu Heng Xue Yu Sang Changlin Zhou Yezhong Wang |
| author_sort | Hong Yue |
| collection | DOAJ |
| description | The Lower Cambrian Longwangmiao dolomite gas reservoirs in the Sichuan Basin are characterized by well-developed natural micro-fractures and dissolved pores and cavities. Due to the strong heterogeneity of reservoirs and the serious damage of drilling and completion fluids, acid placement is difficult, and especially the acidizing stimulation of long-interval highly deviated wells or horizontal wells is more difficult. In this paper, the diverting mechanism and rheological behavior of viscoelastic surfactant (VES) based diverting acid was firstly investigated, and the diverting acid with good diversion performance and low secondary damage was selected as the main acid. Then, based on the experimental results of its rheological behaviors, an empirical model of effective viscosity was fitted and a two-scale wormhole propagation model was coupled. And accordingly, a mathematical model for the acidizing of self-diverting acid was established to simulate the pH value, Ca2+ concentration, effective viscosity and wormhole shape under the effect of diverting acid in long-interval highly deviated wells that are non-uniformly damaged. Finally, gelled acid and 5% VES diverting acid were compared in terms of their etched wormhole shapes, flow rate distribution and acid imbibition profiles. It is shown that the diverting acid can obviously improve the acid imbibition profile of strong-heterogeneity reservoirs to intensify low-permeability reservoir stimulation. In view of the strong heterogeneity of Longwangmiao dolomite reservoirs and the complexities of drilling and completion fluid damage in the Sichuan Basin, a placement technology was developed for variable VES concentration diverting acid in horizontal wells and long-interval highly deviated wells completed with slotted liners. This acid placement technology has been practically applied in 8 wells and their cumulative gas production rate tested at the wellhead is 1233.46 × 104 m3/d. The average production stimulation ratio per well is up to 1.95. It provides a support for the efficient development of the Longwangmiao giant gas reservoir. Keywords: Sichuan Basin, Early Cambrian, Longwangmiao Fm gas reservoir, Dolomite, Diverting acid, Rheological behavior, Matrix acidizing, Numerical simulation, Field application, Highly-efficient development |
| first_indexed | 2024-03-07T17:30:24Z |
| format | Article |
| id | doaj.art-b9bffcf7774f43a49528654879d1dd7e |
| institution | Directory Open Access Journal |
| issn | 2352-8540 |
| language | English |
| last_indexed | 2024-03-07T17:30:24Z |
| publishDate | 2018-06-01 |
| publisher | KeAi Communications Co., Ltd. |
| record_format | Article |
| series | Natural Gas Industry B |
| spelling | doaj.art-b9bffcf7774f43a49528654879d1dd7e2024-03-02T18:14:54ZengKeAi Communications Co., Ltd.Natural Gas Industry B2352-85402018-06-0153204211Numerical simulation and field application of diverting acid acidizing in the Lower Cambrian Longwangmiao Fm gas reservoirs in the Sichuan BasinHong Yue0Fei Liu1Heng Xue2Yu Sang3Changlin Zhou4Yezhong Wang5PetroChina Southwest Oil & Gas Field Company, Chengdu, Sichuan 610051, ChinaEngineering Technology Research Institute, PetroChina Southwest Oil & Gas Field Company, Chengdu, Sichuan 610017, China; Corresponding author.Zhenhua Oil Co., Ltd., Beijing 100031, China; Chengdu North Petroleum Exploration and Development Technology Co., Ltd., Chengdu, Sichuan 610051, ChinaPetroChina Southwest Oil & Gas Field Company, Chengdu, Sichuan 610051, ChinaEngineering Technology Research Institute, PetroChina Southwest Oil & Gas Field Company, Chengdu, Sichuan 610017, ChinaSichuan Shale Gas Exploration and Development Co., Ltd., Chengdu, Sichuan 610051, ChinaThe Lower Cambrian Longwangmiao dolomite gas reservoirs in the Sichuan Basin are characterized by well-developed natural micro-fractures and dissolved pores and cavities. Due to the strong heterogeneity of reservoirs and the serious damage of drilling and completion fluids, acid placement is difficult, and especially the acidizing stimulation of long-interval highly deviated wells or horizontal wells is more difficult. In this paper, the diverting mechanism and rheological behavior of viscoelastic surfactant (VES) based diverting acid was firstly investigated, and the diverting acid with good diversion performance and low secondary damage was selected as the main acid. Then, based on the experimental results of its rheological behaviors, an empirical model of effective viscosity was fitted and a two-scale wormhole propagation model was coupled. And accordingly, a mathematical model for the acidizing of self-diverting acid was established to simulate the pH value, Ca2+ concentration, effective viscosity and wormhole shape under the effect of diverting acid in long-interval highly deviated wells that are non-uniformly damaged. Finally, gelled acid and 5% VES diverting acid were compared in terms of their etched wormhole shapes, flow rate distribution and acid imbibition profiles. It is shown that the diverting acid can obviously improve the acid imbibition profile of strong-heterogeneity reservoirs to intensify low-permeability reservoir stimulation. In view of the strong heterogeneity of Longwangmiao dolomite reservoirs and the complexities of drilling and completion fluid damage in the Sichuan Basin, a placement technology was developed for variable VES concentration diverting acid in horizontal wells and long-interval highly deviated wells completed with slotted liners. This acid placement technology has been practically applied in 8 wells and their cumulative gas production rate tested at the wellhead is 1233.46 × 104 m3/d. The average production stimulation ratio per well is up to 1.95. It provides a support for the efficient development of the Longwangmiao giant gas reservoir. Keywords: Sichuan Basin, Early Cambrian, Longwangmiao Fm gas reservoir, Dolomite, Diverting acid, Rheological behavior, Matrix acidizing, Numerical simulation, Field application, Highly-efficient developmenthttp://www.sciencedirect.com/science/article/pii/S2352854018300329 |
| spellingShingle | Hong Yue Fei Liu Heng Xue Yu Sang Changlin Zhou Yezhong Wang Numerical simulation and field application of diverting acid acidizing in the Lower Cambrian Longwangmiao Fm gas reservoirs in the Sichuan Basin Natural Gas Industry B |
| title | Numerical simulation and field application of diverting acid acidizing in the Lower Cambrian Longwangmiao Fm gas reservoirs in the Sichuan Basin |
| title_full | Numerical simulation and field application of diverting acid acidizing in the Lower Cambrian Longwangmiao Fm gas reservoirs in the Sichuan Basin |
| title_fullStr | Numerical simulation and field application of diverting acid acidizing in the Lower Cambrian Longwangmiao Fm gas reservoirs in the Sichuan Basin |
| title_full_unstemmed | Numerical simulation and field application of diverting acid acidizing in the Lower Cambrian Longwangmiao Fm gas reservoirs in the Sichuan Basin |
| title_short | Numerical simulation and field application of diverting acid acidizing in the Lower Cambrian Longwangmiao Fm gas reservoirs in the Sichuan Basin |
| title_sort | numerical simulation and field application of diverting acid acidizing in the lower cambrian longwangmiao fm gas reservoirs in the sichuan basin |
| url | http://www.sciencedirect.com/science/article/pii/S2352854018300329 |
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