Dolomite mapping as a first step towards a carbonate diagenetic modelling, is critical for understanding the dolomitization mechanism, and reservoir quality prediction. Stratigraphically discordant dolomite bodies within the Upper Jurassic intervals have long been studied on the Arabian Shelf. The proposed dolomitization mechanisms show that fluid movement is a key factor in dolomitization processes, and fracture as conduits of fluid movement controlling dolomite geometry. Therefore, faults/fractures served as migration conduits, determine dolomitization distribution by controlling fluid movement. Dolomite delineation in the study area is driven by the diagenetic mechanisms and comprehensive characterization of fracture systems in multiple scales. The complex fracture in the subsurface are categorized into macroscale, mesoscale, and microscale fractures according to the fracture size and seismic wavelength. Macroscale fractures, i.e. faults, are much greater than seismic wavelength and can be easily picked on seismic sections due to obvious seismic response. Mesoscale fractures are slightly greater or equal to seismic wavelength and can be recognized using seismic attributes. Microscale fractures are far smaller than seismic wavelength and can be observed mainly on core samples and thin-sections. The dolomite mapping workflow includes three steps: 1) calibrate seismic attribute characteristics with borehole image logs and core interpretations; 2) implement multiscale fracture characterization using multiple seismic attributes; and 3) interpret dolomite bodies based on fracture characterization and geological modelling. The mapping results show that massive dolomite bodies are heterogeneously developed and distributed mainly in the northeastern part of the study area, with a southward decrease in dolomite content, which is validated by well-based geological model. The results clearly demonstrate that multiscale fracture systems play critical roles in the massive dolomitization, which provides new insights on the dolomitization mechanism and subsurface reservoir and seal.
{"title":"Regional Stratigraphically Discordant Dolomite Mapping Based on Dolomitization Mechanism on the Arabian Carbonate Shelf","authors":"Sihai Zhang","doi":"10.1190/int-2022-0116.1","DOIUrl":"https://doi.org/10.1190/int-2022-0116.1","url":null,"abstract":"Dolomite mapping as a first step towards a carbonate diagenetic modelling, is critical for understanding the dolomitization mechanism, and reservoir quality prediction. Stratigraphically discordant dolomite bodies within the Upper Jurassic intervals have long been studied on the Arabian Shelf. The proposed dolomitization mechanisms show that fluid movement is a key factor in dolomitization processes, and fracture as conduits of fluid movement controlling dolomite geometry. Therefore, faults/fractures served as migration conduits, determine dolomitization distribution by controlling fluid movement. Dolomite delineation in the study area is driven by the diagenetic mechanisms and comprehensive characterization of fracture systems in multiple scales. The complex fracture in the subsurface are categorized into macroscale, mesoscale, and microscale fractures according to the fracture size and seismic wavelength. Macroscale fractures, i.e. faults, are much greater than seismic wavelength and can be easily picked on seismic sections due to obvious seismic response. Mesoscale fractures are slightly greater or equal to seismic wavelength and can be recognized using seismic attributes. Microscale fractures are far smaller than seismic wavelength and can be observed mainly on core samples and thin-sections. The dolomite mapping workflow includes three steps: 1) calibrate seismic attribute characteristics with borehole image logs and core interpretations; 2) implement multiscale fracture characterization using multiple seismic attributes; and 3) interpret dolomite bodies based on fracture characterization and geological modelling. The mapping results show that massive dolomite bodies are heterogeneously developed and distributed mainly in the northeastern part of the study area, with a southward decrease in dolomite content, which is validated by well-based geological model. The results clearly demonstrate that multiscale fracture systems play critical roles in the massive dolomitization, which provides new insights on the dolomitization mechanism and subsurface reservoir and seal.","PeriodicalId":51318,"journal":{"name":"Interpretation-A Journal of Subsurface Characterization","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2023-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42464417","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The joint interpretation of geophysical data provides an increasingly important integration of information able of characterizing our subsurface planetary resources. This paper is a demonstration of a case study, situated in an extremely limited water resources region, allowing to develop hydrogeological provinces. An integrated geophysical approach was implemented to clarify the structuring, the extension and geometry of the Miocene aquifer system located to the Sbetla basin (Central Tunisia, southern Mediterranean arid province).#xD;This significant hydrogeological basin is connected to the Tunisian North Water Transmission System for achieve sustainable drinking water supply of Sfax region with at least 1 million residents. The seismic, gravity and electrical methods were used together using advanced analysis (Residual-regional gravity separation, Electrical Resistivity Tomography generation form 1D Vertical Electrical Sounding, etc.). This specific methodology allowed us to reveal a NE-SW strategic deep Miocene aquifer valley segmented by NW-SE faulting corridors. This valley can record the maximum thickness of sandstone Miocene aquifer levels named respectively from deep to shallow levels G1, G2 and G3 separated by two aquitards called from deep to shallow levels A1 and A2. It can be considered as a preferential target zone to carry out new deep exploration drilling.
{"title":"STRATEGIC DEEP AQUIFER VALLEY CHARACTERIZATION USING AN INTEGRATED GEOPHYSICAL APPROACH (CENTRAL TUNISIA, SOUTHERN MEDITERRANEAN ARID PROVINCE)","authors":"Chrifa Meftahi, H. Gabtni","doi":"10.1190/int-2022-0101.1","DOIUrl":"https://doi.org/10.1190/int-2022-0101.1","url":null,"abstract":"The joint interpretation of geophysical data provides an increasingly important integration of information able of characterizing our subsurface planetary resources. This paper is a demonstration of a case study, situated in an extremely limited water resources region, allowing to develop hydrogeological provinces. An integrated geophysical approach was implemented to clarify the structuring, the extension and geometry of the Miocene aquifer system located to the Sbetla basin (Central Tunisia, southern Mediterranean arid province).#xD;This significant hydrogeological basin is connected to the Tunisian North Water Transmission System for achieve sustainable drinking water supply of Sfax region with at least 1 million residents. The seismic, gravity and electrical methods were used together using advanced analysis (Residual-regional gravity separation, Electrical Resistivity Tomography generation form 1D Vertical Electrical Sounding, etc.). This specific methodology allowed us to reveal a NE-SW strategic deep Miocene aquifer valley segmented by NW-SE faulting corridors. This valley can record the maximum thickness of sandstone Miocene aquifer levels named respectively from deep to shallow levels G1, G2 and G3 separated by two aquitards called from deep to shallow levels A1 and A2. It can be considered as a preferential target zone to carry out new deep exploration drilling.","PeriodicalId":51318,"journal":{"name":"Interpretation-A Journal of Subsurface Characterization","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2023-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49233757","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. McCaffrey, A. Kornacki, C. Laughrey, B. Patterson
There is a standard method for rigorously using geochemical data to identify the source of stray gas. “Stray gas” is defined as gaseous material of undetermined origin found in an area where the gas has impacted the shallow-subsurface, potable water supplies, or has the potential to present a threat to public health and safety. Stray gas is composed of hydrocarbons or other gases, such as CO2. Previous studies have used geochemical data, including molecular and isotopic gas compositions, to empirically constrain the source of stray gas present in samples collected from specific locations (sometimes called “receptors”). On a more granular level than presented previously, we have discussed the interpretive workflow that should be followed to interpret geochemical data in the context of a stray gas investigation. A key concept is that geochemical data should be used impartially to evaluate all potential sources of the stray gas and, where possible, identify the most likely source. Focusing on only a subset of potential gas sources can lead to erroneous conclusions regarding gas sources. Furthermore, to accurately identify the gas source, geochemical data must be interpreted in the context of the site-specific geology, including evidence of previous gas migration events in the area. We illustrate these points using examples from Parker County, Texas, and from Lycoming County, Pennsylvania.
{"title":"Stray gas source determination using forensic geochemical data","authors":"M. McCaffrey, A. Kornacki, C. Laughrey, B. Patterson","doi":"10.1190/int-2023-0005.1","DOIUrl":"https://doi.org/10.1190/int-2023-0005.1","url":null,"abstract":"There is a standard method for rigorously using geochemical data to identify the source of stray gas. “Stray gas” is defined as gaseous material of undetermined origin found in an area where the gas has impacted the shallow-subsurface, potable water supplies, or has the potential to present a threat to public health and safety. Stray gas is composed of hydrocarbons or other gases, such as CO2. Previous studies have used geochemical data, including molecular and isotopic gas compositions, to empirically constrain the source of stray gas present in samples collected from specific locations (sometimes called “receptors”). On a more granular level than presented previously, we have discussed the interpretive workflow that should be followed to interpret geochemical data in the context of a stray gas investigation. A key concept is that geochemical data should be used impartially to evaluate all potential sources of the stray gas and, where possible, identify the most likely source. Focusing on only a subset of potential gas sources can lead to erroneous conclusions regarding gas sources. Furthermore, to accurately identify the gas source, geochemical data must be interpreted in the context of the site-specific geology, including evidence of previous gas migration events in the area. We illustrate these points using examples from Parker County, Texas, and from Lycoming County, Pennsylvania.","PeriodicalId":51318,"journal":{"name":"Interpretation-A Journal of Subsurface Characterization","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2023-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47026255","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Guangui Zou, Yanhai Liu, De-Lin Teng, Fei Gong, Jiasheng She, Ke Ren, Chengyang Han
Well-logging-constrained impedance inversion is an effective process for predicting the thickness and bifurcation of coal seams. Wavelet changes in a complex region achieve the best match between the inverse and source wavelets, affecting the accuracy of the inversion solution and the ability to obtain accurate inverted acoustic impedance (AI) data. We have conducted the joint inversion of wavelet and AI data using iterative methods, which combined the conjugate gradient (CG) method and particle swarm optimization (PSO) algorithm. The Marmousi AI model was used to prove the reliability of the method. The CG-PSO algorithm achieved excellent results compared with the statistical wavelet pickup method. The wavelet obtained by the CG-PSO algorithm is preferred for inversion operations. We applied a new method to invert field data and predict the thickness and bifurcation of coal seams in the karst region. The results find that the wavelet spectrum obtained by the CG-PSO matches the spectrum map of the coal seam in the Yuwang colliery. We determined the distribution of the thickness and bifurcation of the 101 panel, Yuwang Colliery, Yunnan Province. The average error of the predicted coal thickness is 0.17 m (14.4%), which verifies the feasibility and effectiveness of the method. The method provides insights into the AI inversion of constrained waves in complex regions.
{"title":"Log-Constrained Inversion Based on CGPSO Algorithm","authors":"Guangui Zou, Yanhai Liu, De-Lin Teng, Fei Gong, Jiasheng She, Ke Ren, Chengyang Han","doi":"10.1190/int-2022-0109.1","DOIUrl":"https://doi.org/10.1190/int-2022-0109.1","url":null,"abstract":"Well-logging-constrained impedance inversion is an effective process for predicting the thickness and bifurcation of coal seams. Wavelet changes in a complex region achieve the best match between the inverse and source wavelets, affecting the accuracy of the inversion solution and the ability to obtain accurate inverted acoustic impedance (AI) data. We have conducted the joint inversion of wavelet and AI data using iterative methods, which combined the conjugate gradient (CG) method and particle swarm optimization (PSO) algorithm. The Marmousi AI model was used to prove the reliability of the method. The CG-PSO algorithm achieved excellent results compared with the statistical wavelet pickup method. The wavelet obtained by the CG-PSO algorithm is preferred for inversion operations. We applied a new method to invert field data and predict the thickness and bifurcation of coal seams in the karst region. The results find that the wavelet spectrum obtained by the CG-PSO matches the spectrum map of the coal seam in the Yuwang colliery. We determined the distribution of the thickness and bifurcation of the 101 panel, Yuwang Colliery, Yunnan Province. The average error of the predicted coal thickness is 0.17 m (14.4%), which verifies the feasibility and effectiveness of the method. The method provides insights into the AI inversion of constrained waves in complex regions.","PeriodicalId":51318,"journal":{"name":"Interpretation-A Journal of Subsurface Characterization","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2023-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47833040","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Junping Cui, Z. Ren, Hua Tao, Kai Qi, Hao Liu, Kezhang Chen, Jingjing Liu
The Weibei uplift in the Ordos Basin has a distinctive tectonic setting and intricate evolutionary history. Along these lines, we have used the stratum temperature, apatite fission track, and vitrinite reflectance data to restore the thermal and hydrocarbon generation histories of the Weibei uplift. The average value of the present geothermal gradient of the Weibei uplift was 27.9°C/km, and the heat flow was 64.9 mW/m2. The Weibei uplift exhibited a moderate geothermal field. Three uplift cooling events occurred in the Weibei uplift during the Mesozoic era: the late Jurassic-early Cretaceous (162–125 Ma), the late Cretaceous (105–65 Ma), and the Eocene-Oligocene (40–27 Ma). The uplift history indicates an early uplift in the south region and a late uplift in the later stage. The thermal evolution history simulation demonstrates that the lower Palaeozoic Ordovician source rocks began to enter the hydrocarbon generation threshold in the middle Permian-late Permian (270 Ma) era and joined the hydrocarbon generation peak in the early-middle Jurassic event (180 Ma). The upper Palaeozoic Carboniferous-Permian source rocks began to enter the hydrocarbon generation threshold in the later period of the middle Permian period (235 Ma). They joined the hydrocarbon generation peak in the late Jurassic-early Cretaceous period (150 Ma). In addition, Triassic source rocks entered the hydrocarbon generation threshold in the early Cretaceous era (135 Ma) and did not enter the hydrocarbon generation peak until now. The low geothermal gradient of the Weibei uplift in the Palaeozoic-early Mesozoic reached the maximum paleotemperature in the early Mesozoic era (100 Ma) because of tectonic thermal events. The highest geothermal gradient of the early Cretaceous reached 51.5°C/km. The peak period of the hydrocarbon generation of source rocks of the different horizons in the Weibei uplift was regulated by the geothermal field of the early Cretaceous event. Since the late Cretaceous period, the stratum has been uplifted and cooled rapidly, and the hydrocarbon generation process of the source rocks has ceased.
{"title":"Thermal evolution and hydrocarbon generation history of the Weibei uplift in the Ordos Basin","authors":"Junping Cui, Z. Ren, Hua Tao, Kai Qi, Hao Liu, Kezhang Chen, Jingjing Liu","doi":"10.1190/int-2022-0073.1","DOIUrl":"https://doi.org/10.1190/int-2022-0073.1","url":null,"abstract":"The Weibei uplift in the Ordos Basin has a distinctive tectonic setting and intricate evolutionary history. Along these lines, we have used the stratum temperature, apatite fission track, and vitrinite reflectance data to restore the thermal and hydrocarbon generation histories of the Weibei uplift. The average value of the present geothermal gradient of the Weibei uplift was 27.9°C/km, and the heat flow was 64.9 mW/m2. The Weibei uplift exhibited a moderate geothermal field. Three uplift cooling events occurred in the Weibei uplift during the Mesozoic era: the late Jurassic-early Cretaceous (162–125 Ma), the late Cretaceous (105–65 Ma), and the Eocene-Oligocene (40–27 Ma). The uplift history indicates an early uplift in the south region and a late uplift in the later stage. The thermal evolution history simulation demonstrates that the lower Palaeozoic Ordovician source rocks began to enter the hydrocarbon generation threshold in the middle Permian-late Permian (270 Ma) era and joined the hydrocarbon generation peak in the early-middle Jurassic event (180 Ma). The upper Palaeozoic Carboniferous-Permian source rocks began to enter the hydrocarbon generation threshold in the later period of the middle Permian period (235 Ma). They joined the hydrocarbon generation peak in the late Jurassic-early Cretaceous period (150 Ma). In addition, Triassic source rocks entered the hydrocarbon generation threshold in the early Cretaceous era (135 Ma) and did not enter the hydrocarbon generation peak until now. The low geothermal gradient of the Weibei uplift in the Palaeozoic-early Mesozoic reached the maximum paleotemperature in the early Mesozoic era (100 Ma) because of tectonic thermal events. The highest geothermal gradient of the early Cretaceous reached 51.5°C/km. The peak period of the hydrocarbon generation of source rocks of the different horizons in the Weibei uplift was regulated by the geothermal field of the early Cretaceous event. Since the late Cretaceous period, the stratum has been uplifted and cooled rapidly, and the hydrocarbon generation process of the source rocks has ceased.","PeriodicalId":51318,"journal":{"name":"Interpretation-A Journal of Subsurface Characterization","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2023-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47153726","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
As the petroleum industry builds long-term production histories in major liquid-rich unconventional resource (UCR) plays, development geologists and engineers have come to realize the production GOR, petroleum type, and ultimate recoveries do not always match the predictive petroleum system models. Early studies suggested the UCR petroleum systems neither require traditional petroleum traps nor major migration systems, but simply an organic-rich source within the optimal maturity window. Possible explanations for these production discrepancies that were not fully characterized in the initial models include uncertainties in source rock characteristics, primary migration fractionation, fractionation related to storage, and production fractionation. Long term empirical observations suggest off-structure migration contribution, trapping mechanisms, and reservoir phase (single versus two) play an important role in the liquid rich UCR production. If the liquid-rich UCR petroleum system is a well-behaved predominantly local charge system, then the generation product can be estimated with an understanding of the local organic matter type and in-situ level of maturity, but if the UCR play is hybrid with significant migrated down-dip charge contribution, then a more complicated work program will be required to estimate well rates and volumes. The liquid rich unconventional resource play evaluation should reflect these additional factors which can greatly impact surface production rate and liquid recovery.
{"title":"Understanding multiple factors which impact unconventional production: Guidelines to evaluate liquid rich unconventional resource plays","authors":"M. Abrams","doi":"10.1190/int-2022-0120.1","DOIUrl":"https://doi.org/10.1190/int-2022-0120.1","url":null,"abstract":"As the petroleum industry builds long-term production histories in major liquid-rich unconventional resource (UCR) plays, development geologists and engineers have come to realize the production GOR, petroleum type, and ultimate recoveries do not always match the predictive petroleum system models. Early studies suggested the UCR petroleum systems neither require traditional petroleum traps nor major migration systems, but simply an organic-rich source within the optimal maturity window. Possible explanations for these production discrepancies that were not fully characterized in the initial models include uncertainties in source rock characteristics, primary migration fractionation, fractionation related to storage, and production fractionation. Long term empirical observations suggest off-structure migration contribution, trapping mechanisms, and reservoir phase (single versus two) play an important role in the liquid rich UCR production. If the liquid-rich UCR petroleum system is a well-behaved predominantly local charge system, then the generation product can be estimated with an understanding of the local organic matter type and in-situ level of maturity, but if the UCR play is hybrid with significant migrated down-dip charge contribution, then a more complicated work program will be required to estimate well rates and volumes. The liquid rich unconventional resource play evaluation should reflect these additional factors which can greatly impact surface production rate and liquid recovery.","PeriodicalId":51318,"journal":{"name":"Interpretation-A Journal of Subsurface Characterization","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2023-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49097781","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Adolfo Barbosa da Silva, Rafael Pires de Lima, Karelia La Marca
Airborne gamma-ray spectrometry (AGRS) data provide valuable information about the distribution of radiometric elements on Earths surface. However, the presence of noise can hinder the interpretation or the identification of subtle variations of radioelement concentrations that can be economically attractive. Previous research demonstrated that techniques based on matrix factorization, such as Noise Adjusted Singular Value Decomposition (NASDV) and Minima Noise Fraction (MNF), can reduce noise when applied to AGRS raw spectra. Nevertheless, the raw spectra are often unavailable for end-users, limiting the widespread adoption of such techniques. In this context, we propose using Principal Component Analysis (PCA) with the flight-line data before interpolating the data onto a regular grid as a means to reduce noise when the raw spectra are no longer available. We used our approach on two AGRS datasets located in Brazil and one in the United States of America (U.S.A). For Brazils AGRS data, results show that noise can be attenuated through eigendecomposition projection and recovery of the radiometric variables. Furthermore, the technique we propose can highlight some geological features dependent on the number of eigenvectors used to reconstruct the database. For the U.S.A's AGRS dataset previously filtered with NASDV, the proposed methodology seems to produce only marginal improvement. Therefore, our methodology might be particularly successful for AGRS data whose acquisitions were conducted before NASDV and MNF were proposed as radiometric data processing techniques.#xD;
{"title":"Decomposing and recovering airborne radiometric data through principal component analysis applied on flight-line data: An alternative to reduce noise","authors":"Adolfo Barbosa da Silva, Rafael Pires de Lima, Karelia La Marca","doi":"10.1190/int-2022-0110.1","DOIUrl":"https://doi.org/10.1190/int-2022-0110.1","url":null,"abstract":"Airborne gamma-ray spectrometry (AGRS) data provide valuable information about the distribution of radiometric elements on Earths surface. However, the presence of noise can hinder the interpretation or the identification of subtle variations of radioelement concentrations that can be economically attractive. Previous research demonstrated that techniques based on matrix factorization, such as Noise Adjusted Singular Value Decomposition (NASDV) and Minima Noise Fraction (MNF), can reduce noise when applied to AGRS raw spectra. Nevertheless, the raw spectra are often unavailable for end-users, limiting the widespread adoption of such techniques. In this context, we propose using Principal Component Analysis (PCA) with the flight-line data before interpolating the data onto a regular grid as a means to reduce noise when the raw spectra are no longer available. We used our approach on two AGRS datasets located in Brazil and one in the United States of America (U.S.A). For Brazils AGRS data, results show that noise can be attenuated through eigendecomposition projection and recovery of the radiometric variables. Furthermore, the technique we propose can highlight some geological features dependent on the number of eigenvectors used to reconstruct the database. For the U.S.A's AGRS dataset previously filtered with NASDV, the proposed methodology seems to produce only marginal improvement. Therefore, our methodology might be particularly successful for AGRS data whose acquisitions were conducted before NASDV and MNF were proposed as radiometric data processing techniques.#xD;","PeriodicalId":51318,"journal":{"name":"Interpretation-A Journal of Subsurface Characterization","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2023-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45232591","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Since the early 2000s, the exploitation of unconventional reservoirs has become very important to the oil and gas industry because of their high potential source of energy and economic value. Venezuela possesses a world-class hydrocarbon source rock in one of the most prolific hydrocarbon basins in the world, namely the Cretaceous La Luna Formation in the Maracaibo Basin. Outcrop and core samples collected from the northwestern Maracaibo Basin provided the database for this study. A comprehensive multiscale characterization of the samples was undertaken to unravel the stratigraphic properties of the petroleum system. In addition, a geochemical approach was taken to evaluate the prospectivity of the La Luna Formation as an unconventional resource in the Maracaibo Basin. Rock-Eval pyrolysis and biomarker data indicate that the La Luna Formation is dominated by type II kerogen, indicating an oil-prone marine organic matter origin. Total organic carbon values ranged between 3.85 wt% and 9.10 wt%. Distributions of isoprenoids, steranes, and terpanes including gammacerane and monoaromatic steroid hydrocarbons indicated a hypersaline, marine carbonate anoxic depositional environment. Thermal maturity parameters indicate that most of the cores are currently in the oil window. This combined stratigraphic geochemical study indicates that the La Luna Formation has excellent potential as an unconventional reservoir for oil and gas in the study area.
{"title":"La Luna Formation, Venezuela. A Prospective Unconventional Reservoir","authors":"A. Liborius-Parada, R. Philp, R. Slatt","doi":"10.1190/int-2023-0010.1","DOIUrl":"https://doi.org/10.1190/int-2023-0010.1","url":null,"abstract":"Since the early 2000s, the exploitation of unconventional reservoirs has become very important to the oil and gas industry because of their high potential source of energy and economic value. Venezuela possesses a world-class hydrocarbon source rock in one of the most prolific hydrocarbon basins in the world, namely the Cretaceous La Luna Formation in the Maracaibo Basin. Outcrop and core samples collected from the northwestern Maracaibo Basin provided the database for this study. A comprehensive multiscale characterization of the samples was undertaken to unravel the stratigraphic properties of the petroleum system. In addition, a geochemical approach was taken to evaluate the prospectivity of the La Luna Formation as an unconventional resource in the Maracaibo Basin. Rock-Eval pyrolysis and biomarker data indicate that the La Luna Formation is dominated by type II kerogen, indicating an oil-prone marine organic matter origin. Total organic carbon values ranged between 3.85 wt% and 9.10 wt%. Distributions of isoprenoids, steranes, and terpanes including gammacerane and monoaromatic steroid hydrocarbons indicated a hypersaline, marine carbonate anoxic depositional environment. Thermal maturity parameters indicate that most of the cores are currently in the oil window. This combined stratigraphic geochemical study indicates that the La Luna Formation has excellent potential as an unconventional reservoir for oil and gas in the study area.","PeriodicalId":51318,"journal":{"name":"Interpretation-A Journal of Subsurface Characterization","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2023-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41304795","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tong Sun, Yiqing Zhu, B. Ran, Ke Liang, C. Luo, Yuyue Han
This destruction mechanism of organic matter enrichment plays an important role in improving the mudstone sedimentary structure system. For the lower Silurian marine mudstone in the western South China Block, the destruction mechanism of organic matter enrichment is unclear, with previous studies ignoring the control from paleogeography and spatial differences. Lamination is a typical sedimentary structure in mudstone and different types of lamination in mudstones can reflect a range of depositional environments. Lenticular lamination, composed of arranged lenses of variable composition, is a common type of lamination in marine mudstone and mainly occurs in organic-lean mudstone (Schieber et al., 2010). The origin of lenticular lamination remains controversial, and a multidisciplinary approach is needed that integrates sedimentology, petrography, and paleogeography. The main objectives of this approach are to (1) interpret the formation mechanism of lenticular laminations in the Longmaxi marine mudstone, and (2) discuss the significance of lenticular lamination to organic matter destruction. The results not only allow for a complete understanding of the destruction mechanisms of the Silurian marine mudstones but also provide new insights into the sedimentary processes of marine mudstone.
这种有机质富集的破坏机制对改善泥岩沉积构造体系具有重要作用。对于华南地块西部下志留统海相泥岩，有机质富集的破坏机制尚不清楚，以往的研究忽略了古地理和空间差异的控制。层理是泥岩中一种典型的沉积构造，泥岩中不同类型的层理可以反映一系列沉积环境。透镜状层叠是海相泥岩中一种常见的层叠类型，主要发生在有机贫泥岩中(Schieber et al.， 2010)。透镜状层叠由不同组成的排列透镜组成。透镜状层压的成因至今仍有争议，需要综合沉积学、岩石学和古地理学的多学科研究。本研究的主要目的是:(1)解释龙马溪海相泥岩透镜状层理的形成机制;(2)探讨透镜状层理对有机质破坏的意义。研究结果不仅有助于全面认识志留系海相泥岩的破坏机制，而且为海相泥岩的沉积过程提供了新的认识。
{"title":"Destruction mechanism of organic matter enrichment controlled by tectonism in the Lower Silurian organic-rich marine mudstone in the western South China Block","authors":"Tong Sun, Yiqing Zhu, B. Ran, Ke Liang, C. Luo, Yuyue Han","doi":"10.1190/int-2023-0006.1","DOIUrl":"https://doi.org/10.1190/int-2023-0006.1","url":null,"abstract":"This destruction mechanism of organic matter enrichment plays an important role in improving the mudstone sedimentary structure system. For the lower Silurian marine mudstone in the western South China Block, the destruction mechanism of organic matter enrichment is unclear, with previous studies ignoring the control from paleogeography and spatial differences. Lamination is a typical sedimentary structure in mudstone and different types of lamination in mudstones can reflect a range of depositional environments. Lenticular lamination, composed of arranged lenses of variable composition, is a common type of lamination in marine mudstone and mainly occurs in organic-lean mudstone (Schieber et al., 2010). The origin of lenticular lamination remains controversial, and a multidisciplinary approach is needed that integrates sedimentology, petrography, and paleogeography. The main objectives of this approach are to (1) interpret the formation mechanism of lenticular laminations in the Longmaxi marine mudstone, and (2) discuss the significance of lenticular lamination to organic matter destruction. The results not only allow for a complete understanding of the destruction mechanisms of the Silurian marine mudstones but also provide new insights into the sedimentary processes of marine mudstone.","PeriodicalId":51318,"journal":{"name":"Interpretation-A Journal of Subsurface Characterization","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2023-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48873673","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-25DOI: 10.1190/int-2023-0420-fe.1
V. Egorov, Antony Price
{"title":"Be aware of black geomagic: Revisiting L. W. Blau and Greg Hodges","authors":"V. Egorov, Antony Price","doi":"10.1190/int-2023-0420-fe.1","DOIUrl":"https://doi.org/10.1190/int-2023-0420-fe.1","url":null,"abstract":"<jats:p> </jats:p>","PeriodicalId":51318,"journal":{"name":"Interpretation-A Journal of Subsurface Characterization","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2023-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45460491","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：