This study analyzes Brazilian stromatolites in Lagoa Salgada,serving as analogs for pre-salt rocks in the Santos and Campos basins.Despite their excellent petrophysical properties,such as high porosity and permeabilit...This study analyzes Brazilian stromatolites in Lagoa Salgada,serving as analogs for pre-salt rocks in the Santos and Campos basins.Despite their excellent petrophysical properties,such as high porosity and permeability,these reservoirs present challenges in fluid flow modeling and simulation.The research investigates various factors influencing the development of carbonate reservoirs,including diagenetic processes employing several techniques,such as microcomputed tomography(micro-CT)and digital rock physics(DRP),to study petrophysical and geological characteristics.Additionally,through numerical simulations,the properties of fluid flow in different microfacies of stromatolites are estimated,with particular emphasis on understanding and highlighting changes in the direction of fluid flow in the three characterized microfacies.These findings offer crucial insights into optimizing oil and gas exploration and production techniques in carbonate reservoirs,providing a comprehensive understanding of the dynamics of fluid transport in porous media,especially in terms of directional changes within stromatolites.展开更多
Santos Basin contains the major hub of oil and gas exploration in Brazil. Consequently, knowledge of ocean surface winds in this area is very important for operational and planning activities. In addition, the importa...Santos Basin contains the major hub of oil and gas exploration in Brazil. Consequently, knowledge of ocean surface winds in this area is very important for operational and planning activities. In addition, the importance of renewable energies is nowadays unquestionable, specifically in the case of the wind energy. In this paper, a data clustering technique is applied in order to obtain representative local wind patterns in Santos Basin. Reanalysis data from the National Centers for Environmental Prediction (NCEP) and National Center for Atmospheric Research (NCAR) have been used in this study.展开更多
Petroleum and Natural Gas still represent a considerable share in terms of energy consumption in the current global matrix, so that its exploration/exploitation is present in the market and driving activities in locat...Petroleum and Natural Gas still represent a considerable share in terms of energy consumption in the current global matrix, so that its exploration/exploitation is present in the market and driving activities in locations of specific complexities, as the ones along unconventional hydrocarbon resources from the Brazilian pre-salt. The daily cost of well drilling under harsh conditions can exceed US $1 million a day, turning any type of downtime or necessary maintenance during the activities to be very costly, moment in which processes optimization starts to be a key factor in costs reduction. Thus, new technologies and methods in terms of automating and optimizing the processes may be of great advantages, having its impact in total related project costs. In this context, the goal of this research is to allow a computation tool supporting achieving a more efficient drilling process, by means of drilling mechanics parameters choosiness aiming rate of penetration (ROP) maximization and mechanic specific energy (MSE) minimization. Conceptually, driven by the pre-operational drilling test curve trends, the proposed system allows it to be performed with less human influences and being updateable automatically, allowing more precision and time reduction by selecting optimum parameters. A Web Operating System (Web OS) was designed and implemented, running in online servers, granting accessibility to it with any device that has a browser and internet connection. It allows processing the drilling parameters supplied and feed into it, issuing outcomes with optimum values in a faster and precise way, allowing reducing operating time.展开更多
This work aims to improve the understanding of how fracture zones affect carbonate reservoir properties based on observations of a pre-salt well located in the Santos Basin,Brazil.The identification of fracture zones ...This work aims to improve the understanding of how fracture zones affect carbonate reservoir properties based on observations of a pre-salt well located in the Santos Basin,Brazil.The identification of fracture zones allowed for the observation of a relationship between the occurrence of rock fractures and the silicification,as the latter plays an important role in determining porosity(higher silica content may increase brittleness of the rocks therefore increasing the likelihood of creating fractures zones and fractures may be filled up reducing the total porosity).To support the proposed observation,an integrated study was conducted using borehole imaging,spectroscopy logs,and sidewall core samples.The porosities were defined using nuclear magnetic resonance log analysis,alongside sidewall core samples,and thin sections.The integration of rock samples and well data with seismic analysis was performed to analyze the presence of a regional fault system that could explain high fracture densities as well as observed silica content characteristics.The results show how different types of cement filling up the formation pores affect fracture densities and total porosity.Furthermore,it was possible to infer that the amount of silica content observed in well logs and thin sections relates to hydrothermal fluids reaching out the reservoir through regional fault systems detected in the seismic section.Therefore,this paper supports the comprehension of how diagenetic processes can significantly affect the properties of presalt reservoirs.展开更多
The opening of the Central South Atlantic and the consequent formation of the eastern Brazilian continental margin was marked by a complex history of mafic magmatism,carbonate sedimentation,and deposition of a thick s...The opening of the Central South Atlantic and the consequent formation of the eastern Brazilian continental margin was marked by a complex history of mafic magmatism,carbonate sedimentation,and deposition of a thick salt layer.The carbonates underlying the salt layer(pre-salt carbonates)were formed in restricted lacustrine basins.Here,the timing and fluid sources of deposition,diagenetic,and hydrothermal alterations of the pre-salt carbonate rocks are defined through in-situ U-Pb dating,87Sr/86Sr,and trace element analyses of samples from the Santos Basin.The very alkaline nature of the Aptian lake(s)produced characteristically unique and widely distributed carbonate rocks such as Mg-clays with calcite spherulite and calcite crystal shrub limestones transitioning laterally and vertically into travertines formed by hydrothermal pulses during basin evolution.Hydrothermalism caused extensive replacement,dissolution,and calcite cementation.REE+Y PAAS-normalised patterns and 87Sr/86Sr ratios indicate that deposition/eo-diagenesis of the primary carbonates occurred in a lacustrine environment primarily controlled by evaporation,pH,and continental water source,with 2%–10%hydrothermal fluid input.Trace elements and Sr-isotope of travertines and burial diagenetic phases show that they are produced from a hot mixture of mafic/mantle-derived fluids and dissolution/alteration of older carbonate formations.U-Pb dating indicates that carbonate deposition occurred between 124.8±2.6 Ma and 120.0±1.6 Ma,earlier than previously proposed,followed closely by the circulation of hydrothermal fluids.Replacement and cementation ages range from 120.5±2.4 Ma to 80.4±2.4 Ma.展开更多
Based on the achievements and research advances in oil and gas exploration in the Persian Gulf Basin,this study analyzes the orderliness of oil and gas distribution and main controlling factors of hydrocarbon accumula...Based on the achievements and research advances in oil and gas exploration in the Persian Gulf Basin,this study analyzes the orderliness of oil and gas distribution and main controlling factors of hydrocarbon accumulation with reservoir-forming assemblage as the unit.In the Persian Gulf Basin,the hydrocarbon-generating centers of source rocks of different geological ages and the hydrocarbon rich zones migrate in a clockwise direction around the Ghawar Oilfield in the Central Arabian Subbasin.Horizontally,the overall distribution pattern is orderly,showing“oil in the west and gas in the east”,and“large oil and gas fields dense in the basin center and sparse at the basin edges”.Vertically,the extents of petroleum system compounding and sources mixing increase from west to east,the pattern of tectonic strength(weak in the west and strong in the east)forming the distribution characteristics of“gas rich in the Paleozoic,oil rich in the Mesozoic,and both oil and gas rich in the Cenozoic”.The large scale accumulation and orderly distribution of oil and gas in the Persian Gulf Basin are controlled by three factors:(1)Multiple sets of giant hydrocarbon kitchens provide a resource base for near-source reservoir-forming assemblages.The short-distance lateral migration determines the oil and gas enrichment in and around the distribution area of effective source rocks.(2)The anhydrite caprocks in the platform area are thin but have experienced weak late-stage tectonic activities.Their good sealing performance makes it difficult for oil and gas to migrate vertically to shallow layers through them.The thrust faults and high-angle fractures formed by intense tectonic activities of the Zagros Orogenic Belt connect multiple source-reservoir assemblages.However,the Neogene Gachsaran Formation gypsum-salt rocks are thick and highly plastic,generally with good sealing performance,so large-scale oil and gas accumulations are still formed beneath the salt;(3)Each set of reservoir-forming assemblages is well matched in time and space in terms of the development of source rocks and reservoir-caprock assemblages,the maturation and hydrocarbon generation of source rocks,and the formation of traps,thus resulting in abundant multi layer hydrocarbon accumulations.At present,the Persian Gulf Basin is still in the stage of structural trap exploration.The pre-salt prospective traps in effective hydrocarbon kitchens remain the first choice.The areas with significant changes in Mesozoic sedimentary facies have the conditions to form large scale lithologic oil and gas reservoirs.The deep Paleozoic conventional oil and gas reservoirs and the Lower Silurian Qusaiba Member shale gas have great exploration potential and are expected to become important reserve growth areas in the future.展开更多
基金the Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior of the Ministry of Education(CAPES/MEC/BRAZIL)-Finance Code 001,Equinor Energy of Brazil Company(Project No.4600025270)the Brazilian National Agency of Petroleum,Gas,and Biofuels(ANP),and Petrobras(Project No.46000579151)+1 种基金INCT/Petroleum Geophysics for financial supportthe National Council for Scientific and Technological Development (CNPq) for their Research Grants of Productivity in Technological Development and Innovation-DT II (313522/2019-7 and 313746/ 2019-2)
文摘This study analyzes Brazilian stromatolites in Lagoa Salgada,serving as analogs for pre-salt rocks in the Santos and Campos basins.Despite their excellent petrophysical properties,such as high porosity and permeability,these reservoirs present challenges in fluid flow modeling and simulation.The research investigates various factors influencing the development of carbonate reservoirs,including diagenetic processes employing several techniques,such as microcomputed tomography(micro-CT)and digital rock physics(DRP),to study petrophysical and geological characteristics.Additionally,through numerical simulations,the properties of fluid flow in different microfacies of stromatolites are estimated,with particular emphasis on understanding and highlighting changes in the direction of fluid flow in the three characterized microfacies.These findings offer crucial insights into optimizing oil and gas exploration and production techniques in carbonate reservoirs,providing a comprehensive understanding of the dynamics of fluid transport in porous media,especially in terms of directional changes within stromatolites.
文摘Santos Basin contains the major hub of oil and gas exploration in Brazil. Consequently, knowledge of ocean surface winds in this area is very important for operational and planning activities. In addition, the importance of renewable energies is nowadays unquestionable, specifically in the case of the wind energy. In this paper, a data clustering technique is applied in order to obtain representative local wind patterns in Santos Basin. Reanalysis data from the National Centers for Environmental Prediction (NCEP) and National Center for Atmospheric Research (NCAR) have been used in this study.
文摘Petroleum and Natural Gas still represent a considerable share in terms of energy consumption in the current global matrix, so that its exploration/exploitation is present in the market and driving activities in locations of specific complexities, as the ones along unconventional hydrocarbon resources from the Brazilian pre-salt. The daily cost of well drilling under harsh conditions can exceed US $1 million a day, turning any type of downtime or necessary maintenance during the activities to be very costly, moment in which processes optimization starts to be a key factor in costs reduction. Thus, new technologies and methods in terms of automating and optimizing the processes may be of great advantages, having its impact in total related project costs. In this context, the goal of this research is to allow a computation tool supporting achieving a more efficient drilling process, by means of drilling mechanics parameters choosiness aiming rate of penetration (ROP) maximization and mechanic specific energy (MSE) minimization. Conceptually, driven by the pre-operational drilling test curve trends, the proposed system allows it to be performed with less human influences and being updateable automatically, allowing more precision and time reduction by selecting optimum parameters. A Web Operating System (Web OS) was designed and implemented, running in online servers, granting accessibility to it with any device that has a browser and internet connection. It allows processing the drilling parameters supplied and feed into it, issuing outcomes with optimum values in a faster and precise way, allowing reducing operating time.
文摘This work aims to improve the understanding of how fracture zones affect carbonate reservoir properties based on observations of a pre-salt well located in the Santos Basin,Brazil.The identification of fracture zones allowed for the observation of a relationship between the occurrence of rock fractures and the silicification,as the latter plays an important role in determining porosity(higher silica content may increase brittleness of the rocks therefore increasing the likelihood of creating fractures zones and fractures may be filled up reducing the total porosity).To support the proposed observation,an integrated study was conducted using borehole imaging,spectroscopy logs,and sidewall core samples.The porosities were defined using nuclear magnetic resonance log analysis,alongside sidewall core samples,and thin sections.The integration of rock samples and well data with seismic analysis was performed to analyze the presence of a regional fault system that could explain high fracture densities as well as observed silica content characteristics.The results show how different types of cement filling up the formation pores affect fracture densities and total porosity.Furthermore,it was possible to infer that the amount of silica content observed in well logs and thin sections relates to hydrothermal fluids reaching out the reservoir through regional fault systems detected in the seismic section.Therefore,this paper supports the comprehension of how diagenetic processes can significantly affect the properties of presalt reservoirs.
基金C.Lana and F.F.Alkmim benefit from the Brazilian National Research Council(CNPq)research grants 3073353/2019-2 and 311543/2020-0.C.Lana,F.F.Alkmim,and Maria Eugênia Souza are part of the Instituto GeoAtlântico,a National Institute of Science and Technology,CNPq-Brazil process 405653/2022-0We acknowledge Petrobras’s support during the investigation and permission to publish this study.I.Figueiredo acknowledged the Brazilian Federal Agency for Support and Evaluation of Graduate Education(CAPES)for Master's scholarship 88887.816343/2023-00.
文摘The opening of the Central South Atlantic and the consequent formation of the eastern Brazilian continental margin was marked by a complex history of mafic magmatism,carbonate sedimentation,and deposition of a thick salt layer.The carbonates underlying the salt layer(pre-salt carbonates)were formed in restricted lacustrine basins.Here,the timing and fluid sources of deposition,diagenetic,and hydrothermal alterations of the pre-salt carbonate rocks are defined through in-situ U-Pb dating,87Sr/86Sr,and trace element analyses of samples from the Santos Basin.The very alkaline nature of the Aptian lake(s)produced characteristically unique and widely distributed carbonate rocks such as Mg-clays with calcite spherulite and calcite crystal shrub limestones transitioning laterally and vertically into travertines formed by hydrothermal pulses during basin evolution.Hydrothermalism caused extensive replacement,dissolution,and calcite cementation.REE+Y PAAS-normalised patterns and 87Sr/86Sr ratios indicate that deposition/eo-diagenesis of the primary carbonates occurred in a lacustrine environment primarily controlled by evaporation,pH,and continental water source,with 2%–10%hydrothermal fluid input.Trace elements and Sr-isotope of travertines and burial diagenetic phases show that they are produced from a hot mixture of mafic/mantle-derived fluids and dissolution/alteration of older carbonate formations.U-Pb dating indicates that carbonate deposition occurred between 124.8±2.6 Ma and 120.0±1.6 Ma,earlier than previously proposed,followed closely by the circulation of hydrothermal fluids.Replacement and cementation ages range from 120.5±2.4 Ma to 80.4±2.4 Ma.
基金Supported by the CNPC Major Science and Technology Project(2023ZZ07).
文摘Based on the achievements and research advances in oil and gas exploration in the Persian Gulf Basin,this study analyzes the orderliness of oil and gas distribution and main controlling factors of hydrocarbon accumulation with reservoir-forming assemblage as the unit.In the Persian Gulf Basin,the hydrocarbon-generating centers of source rocks of different geological ages and the hydrocarbon rich zones migrate in a clockwise direction around the Ghawar Oilfield in the Central Arabian Subbasin.Horizontally,the overall distribution pattern is orderly,showing“oil in the west and gas in the east”,and“large oil and gas fields dense in the basin center and sparse at the basin edges”.Vertically,the extents of petroleum system compounding and sources mixing increase from west to east,the pattern of tectonic strength(weak in the west and strong in the east)forming the distribution characteristics of“gas rich in the Paleozoic,oil rich in the Mesozoic,and both oil and gas rich in the Cenozoic”.The large scale accumulation and orderly distribution of oil and gas in the Persian Gulf Basin are controlled by three factors:(1)Multiple sets of giant hydrocarbon kitchens provide a resource base for near-source reservoir-forming assemblages.The short-distance lateral migration determines the oil and gas enrichment in and around the distribution area of effective source rocks.(2)The anhydrite caprocks in the platform area are thin but have experienced weak late-stage tectonic activities.Their good sealing performance makes it difficult for oil and gas to migrate vertically to shallow layers through them.The thrust faults and high-angle fractures formed by intense tectonic activities of the Zagros Orogenic Belt connect multiple source-reservoir assemblages.However,the Neogene Gachsaran Formation gypsum-salt rocks are thick and highly plastic,generally with good sealing performance,so large-scale oil and gas accumulations are still formed beneath the salt;(3)Each set of reservoir-forming assemblages is well matched in time and space in terms of the development of source rocks and reservoir-caprock assemblages,the maturation and hydrocarbon generation of source rocks,and the formation of traps,thus resulting in abundant multi layer hydrocarbon accumulations.At present,the Persian Gulf Basin is still in the stage of structural trap exploration.The pre-salt prospective traps in effective hydrocarbon kitchens remain the first choice.The areas with significant changes in Mesozoic sedimentary facies have the conditions to form large scale lithologic oil and gas reservoirs.The deep Paleozoic conventional oil and gas reservoirs and the Lower Silurian Qusaiba Member shale gas have great exploration potential and are expected to become important reserve growth areas in the future.
