Multi-Factor Evaluation of Deep Karst Dolomite Reservoir Based on Paleogeomorphological Reconstruction, a Case Study From the 4th Member of the Dengying Formation in the Central Sichuan Basin, China
The evaluation of reservoirs is of great importance in exploration practices, and reservoir distribution is dependent on multiple geological factors. The carbonate platform of the fourth member (Z2dn4) of the Dengying Formation (Z2dn) in the Gaoshiti-Moxi area (GMA) was uplifted above sea level duri...
Main Authors: | , , , , , , , , |
---|---|
Format: | Article |
Language: | English |
Published: |
Frontiers Media S.A.
2022-06-01
|
Series: | Frontiers in Earth Science |
Subjects: | |
Online Access: | https://www.frontiersin.org/articles/10.3389/feart.2022.930269/full |
_version_ | 1818241268032995328 |
---|---|
author | Zikun Zhou Zikun Zhou Xingzhi Wang Xingzhi Wang Xiyan Yang Xiyan Yang Long Wen Wenzhi Wang Deming Zeng Deming Zeng Mingyang Wei Mingyang Wei Shengyang Xie Shengyang Xie Fei Huo Fei Huo |
author_facet | Zikun Zhou Zikun Zhou Xingzhi Wang Xingzhi Wang Xiyan Yang Xiyan Yang Long Wen Wenzhi Wang Deming Zeng Deming Zeng Mingyang Wei Mingyang Wei Shengyang Xie Shengyang Xie Fei Huo Fei Huo |
author_sort | Zikun Zhou |
collection | DOAJ |
description | The evaluation of reservoirs is of great importance in exploration practices, and reservoir distribution is dependent on multiple geological factors. The carbonate platform of the fourth member (Z2dn4) of the Dengying Formation (Z2dn) in the Gaoshiti-Moxi area (GMA) was uplifted above sea level during episode II of the Tongwan movement and underwent prolonged karstification by meteoric freshwater in the terminal Sinian, leading to a strong heterogeneity in reservoirs. Paleogeomorphology reflects hydraulic gradients that can affect the intensities of surface karstification and may be approximated by terrain slope gradients. Karst products (especially solution vugs and caverns) exist prevailingly in the Z2dn4; their development mirrors the extents of internal dissolution. Based on paleogeomorphological reconstruction using the elevation method, the slope angles of single boreholes were calculated through the digital elevation model (DEM). In accordance with single-borewell Fullbore Formation MicroImager (FMI) logging data, four electrofacies (host rock, vug, fracture, and cave) were identified in boreholes possessing FMI data. The identified electrofacies were matched with corresponding conventional logging curves to obtain the training data. A model generalized for other boreholes without FMI data was established with the random forest algorithm and the thicknesses of the four electrofacies in each borehole were determined to characterize the extent of karstification. Slope gradients and electrofacies thicknesses, together with multiple physical parameters of reservoirs in boreholes, were utilized for factor analysis. Four factors were obtained and fused into one comprehensive score based on their ratios of variance proportions. The favorability of reservoirs was described by the comprehensive scores of each borehole. These analyses showed that the most advantageous reservoirs are distributed in the vicinity of the platform margin in the west of the GMA, where they enjoy several benefits. Deposition of porous mound-shoal complexes occurs predominantly in the platform margin where large-scale caves are more developed in the mixing karst zone of seawater and freshwater. Meanwhile, the transmeridional lateral migration of hydrocarbons from the regional hydrocarbon-generating center abutting the west of the GMA contributes to earlier entrapment and accumulation in the mound-shoal complexes in the platform margin. |
first_indexed | 2024-12-12T13:26:38Z |
format | Article |
id | doaj.art-de8a892467d84db8872d3428e33ded20 |
institution | Directory Open Access Journal |
issn | 2296-6463 |
language | English |
last_indexed | 2024-12-12T13:26:38Z |
publishDate | 2022-06-01 |
publisher | Frontiers Media S.A. |
record_format | Article |
series | Frontiers in Earth Science |
spelling | doaj.art-de8a892467d84db8872d3428e33ded202022-12-22T00:23:10ZengFrontiers Media S.A.Frontiers in Earth Science2296-64632022-06-011010.3389/feart.2022.930269930269Multi-Factor Evaluation of Deep Karst Dolomite Reservoir Based on Paleogeomorphological Reconstruction, a Case Study From the 4th Member of the Dengying Formation in the Central Sichuan Basin, ChinaZikun Zhou0Zikun Zhou1Xingzhi Wang2Xingzhi Wang3Xiyan Yang4Xiyan Yang5Long Wen6Wenzhi Wang7Deming Zeng8Deming Zeng9Mingyang Wei10Mingyang Wei11Shengyang Xie12Shengyang Xie13Fei Huo14Fei Huo15School of Earth Science and Technology, Southwest Petroleum University, Chengdu, ChinaState Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu, ChinaSchool of Earth Science and Technology, Southwest Petroleum University, Chengdu, ChinaState Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu, ChinaSchool of Earth Science and Technology, Southwest Petroleum University, Chengdu, ChinaState Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu, ChinaExploration and Development Research Institute, PetroChina Southwest Oil and Gas Field Company, Chengdu, ChinaExploration and Development Research Institute, PetroChina Southwest Oil and Gas Field Company, Chengdu, ChinaSchool of Earth Science and Technology, Southwest Petroleum University, Chengdu, ChinaState Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu, ChinaSchool of Earth Science and Technology, Southwest Petroleum University, Chengdu, ChinaState Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu, ChinaSchool of Earth Science and Technology, Southwest Petroleum University, Chengdu, ChinaState Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu, ChinaSchool of Earth Science and Technology, Southwest Petroleum University, Chengdu, ChinaState Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu, ChinaThe evaluation of reservoirs is of great importance in exploration practices, and reservoir distribution is dependent on multiple geological factors. The carbonate platform of the fourth member (Z2dn4) of the Dengying Formation (Z2dn) in the Gaoshiti-Moxi area (GMA) was uplifted above sea level during episode II of the Tongwan movement and underwent prolonged karstification by meteoric freshwater in the terminal Sinian, leading to a strong heterogeneity in reservoirs. Paleogeomorphology reflects hydraulic gradients that can affect the intensities of surface karstification and may be approximated by terrain slope gradients. Karst products (especially solution vugs and caverns) exist prevailingly in the Z2dn4; their development mirrors the extents of internal dissolution. Based on paleogeomorphological reconstruction using the elevation method, the slope angles of single boreholes were calculated through the digital elevation model (DEM). In accordance with single-borewell Fullbore Formation MicroImager (FMI) logging data, four electrofacies (host rock, vug, fracture, and cave) were identified in boreholes possessing FMI data. The identified electrofacies were matched with corresponding conventional logging curves to obtain the training data. A model generalized for other boreholes without FMI data was established with the random forest algorithm and the thicknesses of the four electrofacies in each borehole were determined to characterize the extent of karstification. Slope gradients and electrofacies thicknesses, together with multiple physical parameters of reservoirs in boreholes, were utilized for factor analysis. Four factors were obtained and fused into one comprehensive score based on their ratios of variance proportions. The favorability of reservoirs was described by the comprehensive scores of each borehole. These analyses showed that the most advantageous reservoirs are distributed in the vicinity of the platform margin in the west of the GMA, where they enjoy several benefits. Deposition of porous mound-shoal complexes occurs predominantly in the platform margin where large-scale caves are more developed in the mixing karst zone of seawater and freshwater. Meanwhile, the transmeridional lateral migration of hydrocarbons from the regional hydrocarbon-generating center abutting the west of the GMA contributes to earlier entrapment and accumulation in the mound-shoal complexes in the platform margin.https://www.frontiersin.org/articles/10.3389/feart.2022.930269/fullreservoir evaluationpaleogeomorphological reconstructionrandom forest algorithmfactor analysisDeng memberGaoshiti-Moxi area |
spellingShingle | Zikun Zhou Zikun Zhou Xingzhi Wang Xingzhi Wang Xiyan Yang Xiyan Yang Long Wen Wenzhi Wang Deming Zeng Deming Zeng Mingyang Wei Mingyang Wei Shengyang Xie Shengyang Xie Fei Huo Fei Huo Multi-Factor Evaluation of Deep Karst Dolomite Reservoir Based on Paleogeomorphological Reconstruction, a Case Study From the 4th Member of the Dengying Formation in the Central Sichuan Basin, China Frontiers in Earth Science reservoir evaluation paleogeomorphological reconstruction random forest algorithm factor analysis Deng member Gaoshiti-Moxi area |
title | Multi-Factor Evaluation of Deep Karst Dolomite Reservoir Based on Paleogeomorphological Reconstruction, a Case Study From the 4th Member of the Dengying Formation in the Central Sichuan Basin, China |
title_full | Multi-Factor Evaluation of Deep Karst Dolomite Reservoir Based on Paleogeomorphological Reconstruction, a Case Study From the 4th Member of the Dengying Formation in the Central Sichuan Basin, China |
title_fullStr | Multi-Factor Evaluation of Deep Karst Dolomite Reservoir Based on Paleogeomorphological Reconstruction, a Case Study From the 4th Member of the Dengying Formation in the Central Sichuan Basin, China |
title_full_unstemmed | Multi-Factor Evaluation of Deep Karst Dolomite Reservoir Based on Paleogeomorphological Reconstruction, a Case Study From the 4th Member of the Dengying Formation in the Central Sichuan Basin, China |
title_short | Multi-Factor Evaluation of Deep Karst Dolomite Reservoir Based on Paleogeomorphological Reconstruction, a Case Study From the 4th Member of the Dengying Formation in the Central Sichuan Basin, China |
title_sort | multi factor evaluation of deep karst dolomite reservoir based on paleogeomorphological reconstruction a case study from the 4th member of the dengying formation in the central sichuan basin china |
topic | reservoir evaluation paleogeomorphological reconstruction random forest algorithm factor analysis Deng member Gaoshiti-Moxi area |
url | https://www.frontiersin.org/articles/10.3389/feart.2022.930269/full |
work_keys_str_mv | AT zikunzhou multifactorevaluationofdeepkarstdolomitereservoirbasedonpaleogeomorphologicalreconstructionacasestudyfromthe4thmemberofthedengyingformationinthecentralsichuanbasinchina AT zikunzhou multifactorevaluationofdeepkarstdolomitereservoirbasedonpaleogeomorphologicalreconstructionacasestudyfromthe4thmemberofthedengyingformationinthecentralsichuanbasinchina AT xingzhiwang multifactorevaluationofdeepkarstdolomitereservoirbasedonpaleogeomorphologicalreconstructionacasestudyfromthe4thmemberofthedengyingformationinthecentralsichuanbasinchina AT xingzhiwang multifactorevaluationofdeepkarstdolomitereservoirbasedonpaleogeomorphologicalreconstructionacasestudyfromthe4thmemberofthedengyingformationinthecentralsichuanbasinchina AT xiyanyang multifactorevaluationofdeepkarstdolomitereservoirbasedonpaleogeomorphologicalreconstructionacasestudyfromthe4thmemberofthedengyingformationinthecentralsichuanbasinchina AT xiyanyang multifactorevaluationofdeepkarstdolomitereservoirbasedonpaleogeomorphologicalreconstructionacasestudyfromthe4thmemberofthedengyingformationinthecentralsichuanbasinchina AT longwen multifactorevaluationofdeepkarstdolomitereservoirbasedonpaleogeomorphologicalreconstructionacasestudyfromthe4thmemberofthedengyingformationinthecentralsichuanbasinchina AT wenzhiwang multifactorevaluationofdeepkarstdolomitereservoirbasedonpaleogeomorphologicalreconstructionacasestudyfromthe4thmemberofthedengyingformationinthecentralsichuanbasinchina AT demingzeng multifactorevaluationofdeepkarstdolomitereservoirbasedonpaleogeomorphologicalreconstructionacasestudyfromthe4thmemberofthedengyingformationinthecentralsichuanbasinchina AT demingzeng multifactorevaluationofdeepkarstdolomitereservoirbasedonpaleogeomorphologicalreconstructionacasestudyfromthe4thmemberofthedengyingformationinthecentralsichuanbasinchina AT mingyangwei multifactorevaluationofdeepkarstdolomitereservoirbasedonpaleogeomorphologicalreconstructionacasestudyfromthe4thmemberofthedengyingformationinthecentralsichuanbasinchina AT mingyangwei multifactorevaluationofdeepkarstdolomitereservoirbasedonpaleogeomorphologicalreconstructionacasestudyfromthe4thmemberofthedengyingformationinthecentralsichuanbasinchina AT shengyangxie multifactorevaluationofdeepkarstdolomitereservoirbasedonpaleogeomorphologicalreconstructionacasestudyfromthe4thmemberofthedengyingformationinthecentralsichuanbasinchina AT shengyangxie multifactorevaluationofdeepkarstdolomitereservoirbasedonpaleogeomorphologicalreconstructionacasestudyfromthe4thmemberofthedengyingformationinthecentralsichuanbasinchina AT feihuo multifactorevaluationofdeepkarstdolomitereservoirbasedonpaleogeomorphologicalreconstructionacasestudyfromthe4thmemberofthedengyingformationinthecentralsichuanbasinchina AT feihuo multifactorevaluationofdeepkarstdolomitereservoirbasedonpaleogeomorphologicalreconstructionacasestudyfromthe4thmemberofthedengyingformationinthecentralsichuanbasinchina |