To comprehensively utilize the valuable geological map,exploration profile,borehole,and geochemical logging data and the knowledge on the formation of the Jinshan Ag-Au deposit for forecasting the exploration targets ...To comprehensively utilize the valuable geological map,exploration profile,borehole,and geochemical logging data and the knowledge on the formation of the Jinshan Ag-Au deposit for forecasting the exploration targets of concealed ore bodies,three-dimensional Mineral Prospectivity Modeling(MPM)of the deposit has been conducted using the weights-of-evidence(WofE)method.Conditional independence between evidence layers was tested,and the outline results using the prediction-volume(P-V)and Student's t-statistic methods for delineating favorable mineralization areas from continuous posterior probability map were critically compared.Four exploration targets delineated ultimately by the Student's t-statistic method for the discovery of minable ore bodies in each of the target areas were discussed in detail.The main conclusions include:(1)three-dimensional modeling of a deposit using multi-source reconnaissance data is useful for MPM in interpreting their relationships with known ore bodies;(2)WofE modeling can be used as a straightforward tool for integrating deposit model and reconnaissance data in MPM;(3)the Student's t-statistic method is more applicable in binarizing the continuous prospectivity map for exploration targeting than the PV approach;and(4)two target areas within high potential to find undiscovered ore bodies were diagnosed to guide future near-mine exploration activities of the Jinshan deposit.展开更多
This study examines the molecular and isotopic composition of 193 gas samples collected from oil and gas fields across Colombia's onshore basins with active hydrocarbon production.Comparative analyses were conduct...This study examines the molecular and isotopic composition of 193 gas samples collected from oil and gas fields across Colombia's onshore basins with active hydrocarbon production.Comparative analyses were conducted on both isotopic and molecular compositions across the Lower Magdalena Basin(LMB),Middle Magdalena Basin(MMB),Upper Magdalena Basin(UMB),Putumayo Cagu an Basin(PUTCAB),Catatumbo Basin(CATB),Eastern Llanos Basin(LLAB),and Eastern Cordillera Basin(ECB).The primary objectives were to classify the gases produced,characterize their origins,assess transformation processes such as biodegradation and migration,and analyze the statistical distribution patterns of their components.This geochemical characterization aims to support the discovery of new reserves for both natural gas(NG)and liquefied petroleum gas(LPG),given Colombia's potential risk of diminished energy selfsufficiency in gas resources.The basins under study produce dry gas,wet gas,and liquefied petroleum gas(LPG/C_(3+)),all associated with oil and gas fields of commercial hydrocarbon production.Notably,the LLAB contains the highest proportions of heavy isotopic carbon and C_(3+)(LPG)concentrations,whereas LMB is characterized by isotopically lighter methane,indicative of dry gas predominance.Results suggest a predominantly thermogenic origin for the gases studied,generated within the oil and gas windows,with several samples originating from secondary oil cracking,while some samples from LMB display a likely biogenic origin.Additionally,evidence of gas migration and biodegradation was observed in a significant subset of samples.The analysis of statistical distributions and compositional trends reveals a prevalent high methane content,with substantial C_(2)-C_(5)(C_(2+))gas concentrations across all basins studied.This composition underscores the potential for both natural gas(NG)and LPG production.The C_(3+)(LPG)content varies between 1%and 92%,with 35%of the samples containing less than 5%LPG.High original gas-in-place(OGIP)volumes and substantial LPG content in the Eastern Llanos foothills,encompassing fields such as Cusiana and Cupiagua,highlight the prospective potential of this region.Near-field exploration could further add reserves of both NG and LPG.展开更多
基金financially supported by the Ministry of Science and Technology of China(Nos.2022YFF0801201,2021YFC2900300)the National Natural Science Foundation of China(Nos.41872245,U1911202)the Guangdong Basic and Applied Basic Research Foundation(No.2020A1515010666)。
文摘To comprehensively utilize the valuable geological map,exploration profile,borehole,and geochemical logging data and the knowledge on the formation of the Jinshan Ag-Au deposit for forecasting the exploration targets of concealed ore bodies,three-dimensional Mineral Prospectivity Modeling(MPM)of the deposit has been conducted using the weights-of-evidence(WofE)method.Conditional independence between evidence layers was tested,and the outline results using the prediction-volume(P-V)and Student's t-statistic methods for delineating favorable mineralization areas from continuous posterior probability map were critically compared.Four exploration targets delineated ultimately by the Student's t-statistic method for the discovery of minable ore bodies in each of the target areas were discussed in detail.The main conclusions include:(1)three-dimensional modeling of a deposit using multi-source reconnaissance data is useful for MPM in interpreting their relationships with known ore bodies;(2)WofE modeling can be used as a straightforward tool for integrating deposit model and reconnaissance data in MPM;(3)the Student's t-statistic method is more applicable in binarizing the continuous prospectivity map for exploration targeting than the PV approach;and(4)two target areas within high potential to find undiscovered ore bodies were diagnosed to guide future near-mine exploration activities of the Jinshan deposit.
文摘This study examines the molecular and isotopic composition of 193 gas samples collected from oil and gas fields across Colombia's onshore basins with active hydrocarbon production.Comparative analyses were conducted on both isotopic and molecular compositions across the Lower Magdalena Basin(LMB),Middle Magdalena Basin(MMB),Upper Magdalena Basin(UMB),Putumayo Cagu an Basin(PUTCAB),Catatumbo Basin(CATB),Eastern Llanos Basin(LLAB),and Eastern Cordillera Basin(ECB).The primary objectives were to classify the gases produced,characterize their origins,assess transformation processes such as biodegradation and migration,and analyze the statistical distribution patterns of their components.This geochemical characterization aims to support the discovery of new reserves for both natural gas(NG)and liquefied petroleum gas(LPG),given Colombia's potential risk of diminished energy selfsufficiency in gas resources.The basins under study produce dry gas,wet gas,and liquefied petroleum gas(LPG/C_(3+)),all associated with oil and gas fields of commercial hydrocarbon production.Notably,the LLAB contains the highest proportions of heavy isotopic carbon and C_(3+)(LPG)concentrations,whereas LMB is characterized by isotopically lighter methane,indicative of dry gas predominance.Results suggest a predominantly thermogenic origin for the gases studied,generated within the oil and gas windows,with several samples originating from secondary oil cracking,while some samples from LMB display a likely biogenic origin.Additionally,evidence of gas migration and biodegradation was observed in a significant subset of samples.The analysis of statistical distributions and compositional trends reveals a prevalent high methane content,with substantial C_(2)-C_(5)(C_(2+))gas concentrations across all basins studied.This composition underscores the potential for both natural gas(NG)and LPG production.The C_(3+)(LPG)content varies between 1%and 92%,with 35%of the samples containing less than 5%LPG.High original gas-in-place(OGIP)volumes and substantial LPG content in the Eastern Llanos foothills,encompassing fields such as Cusiana and Cupiagua,highlight the prospective potential of this region.Near-field exploration could further add reserves of both NG and LPG.
