The Pearl River Mouth Basin(PRMB)is one of the most petroliferous basins on the northern margin of the South China Sea.Knowledge of the thermal history of the PRMB is significant for understanding its tectonic evoluti...The Pearl River Mouth Basin(PRMB)is one of the most petroliferous basins on the northern margin of the South China Sea.Knowledge of the thermal history of the PRMB is significant for understanding its tectonic evolution and for unraveling its poorly studied source-rock maturation history.Our investigations in this study are based on apatite fission-track(AFT)thermochronology analysis of 12 cutting samples from 4 boreholes.Both AFT ages and length data suggested that the PRMB has experienced quite complicated thermal evolution.Thermal history modeling results unraveled four successive events of heating separated by three stages of cooling since the early Middle Eocene.The cooling events occurred approximately in the Late Eocene,early Oligocene,and the Late Miocene,possibly attributed to the Zhuqiong II Event,Nanhai Event,and Dongsha Event,respectively.The erosion amount during the first cooling stage is roughly estimated to be about 455-712 m,with an erosion rate of 0.08-0.12 mm/a.The second erosion-driven cooling is stronger than the first one,with an erosion amount of about 747-814 m and an erosion rate between about 0.13-0.21 mm/a.The erosion amount calculated related to the third cooling event varies from 800 m to 3419 m,which is speculative due to the possible influence of the magmatic activity.展开更多
The reconstruction of thermal history is an important component of basin evolution and hydrocarbon exploration.Based on vitrinite reflectance data,we integrate the paleo-temperature gradient and paleo-heat flow method...The reconstruction of thermal history is an important component of basin evolution and hydrocarbon exploration.Based on vitrinite reflectance data,we integrate the paleo-temperature gradient and paleo-heat flow methods to reconstruct the thermal history of Junggar Basin.Compared with present thermal state,the Junggar Basin experienced much a higher heat flow of ca.80–120 mW/m2 during the Carboniferous.This feature can be attributed to large-scale volcanic events and related thermal effects.The hydrocarbon maturation history of Carboniferous source rocks indicates that the temperature rapidly reached the threshold of hydrocarbon generation during the Late Carboniferous and has never achieved such a high level since then.This characteristic resulted in the early maturation of hydrocarbons in Carboniferous source rocks.Meanwhile,the results reveal that hydrocarbon maturities are different among various tectonic units in Junggar Basin.The kerogen either rapidly broke through the dry gas period so that cracking of gas occurred or remained in the oil maturation window forming oil reservoirs,which depended on the tectonic background and depositional environment.In this study,we present the thermal and hydrocarbon maturation history since the Carboniferous,which has important implications for further hydrocarbon exploration in Junggar Basin.展开更多
基金This study is financially supported by the National Natural Science Foundation of China(42072181).
文摘The Pearl River Mouth Basin(PRMB)is one of the most petroliferous basins on the northern margin of the South China Sea.Knowledge of the thermal history of the PRMB is significant for understanding its tectonic evolution and for unraveling its poorly studied source-rock maturation history.Our investigations in this study are based on apatite fission-track(AFT)thermochronology analysis of 12 cutting samples from 4 boreholes.Both AFT ages and length data suggested that the PRMB has experienced quite complicated thermal evolution.Thermal history modeling results unraveled four successive events of heating separated by three stages of cooling since the early Middle Eocene.The cooling events occurred approximately in the Late Eocene,early Oligocene,and the Late Miocene,possibly attributed to the Zhuqiong II Event,Nanhai Event,and Dongsha Event,respectively.The erosion amount during the first cooling stage is roughly estimated to be about 455-712 m,with an erosion rate of 0.08-0.12 mm/a.The second erosion-driven cooling is stronger than the first one,with an erosion amount of about 747-814 m and an erosion rate between about 0.13-0.21 mm/a.The erosion amount calculated related to the third cooling event varies from 800 m to 3419 m,which is speculative due to the possible influence of the magmatic activity.
基金supported by the National Natural Science Foundation of China(No.41502236 and 41877210)the National Foundation for Science and Technology Development(No.2017ZX05008-004).
文摘The reconstruction of thermal history is an important component of basin evolution and hydrocarbon exploration.Based on vitrinite reflectance data,we integrate the paleo-temperature gradient and paleo-heat flow methods to reconstruct the thermal history of Junggar Basin.Compared with present thermal state,the Junggar Basin experienced much a higher heat flow of ca.80–120 mW/m2 during the Carboniferous.This feature can be attributed to large-scale volcanic events and related thermal effects.The hydrocarbon maturation history of Carboniferous source rocks indicates that the temperature rapidly reached the threshold of hydrocarbon generation during the Late Carboniferous and has never achieved such a high level since then.This characteristic resulted in the early maturation of hydrocarbons in Carboniferous source rocks.Meanwhile,the results reveal that hydrocarbon maturities are different among various tectonic units in Junggar Basin.The kerogen either rapidly broke through the dry gas period so that cracking of gas occurred or remained in the oil maturation window forming oil reservoirs,which depended on the tectonic background and depositional environment.In this study,we present the thermal and hydrocarbon maturation history since the Carboniferous,which has important implications for further hydrocarbon exploration in Junggar Basin.
