Talang Akar Formation is a proven hydrocarbon source rock in South Sumatra basin. The formation contains dominant shale at the top, with some sandstone interbeds. Whereas it contains coarse to very coarse sandstone be...Talang Akar Formation is a proven hydrocarbon source rock in South Sumatra basin. The formation contains dominant shale at the top, with some sandstone interbeds. Whereas it contains coarse to very coarse sandstone beds at the bottom. The lower sandstone unit also contains carbonaceous shale and some coal seams. The geochemical analysis is important to identify a source rock quality in shale gas. The quality of source rock is determined by richness of the source rock and type of kerogen. 37 samples were collected from well cuttings in JML-1 and JML-2 wells. Samples we are received into the laboratories in the form of well site canned ditch cuttings, bagged ditch cuttings in various stages of preparation from wet, unwashed to dried, washed;sidewall cores, conventional cores, outcrop samples. The richness of a source rock can be defined by the content of organic carbon which is measured as total organic carbon (TOC). Based on geochemical result of analysis, quantity of shale hydrocarbon potential is indicated by the TOC value of 0.52 wt% - 6.12 wt% (fair to excellent criteria), with average of shale thickness more than 50 m. Tmax is an indication of the maturation stage of organic material and Hydrogen Index (HI) is a parameter used to explain the origin of organic material. HI versus Tmax crossplot was analysed for kerogen type determination and presence of type II/III kerogen was identified. This study concludes that the source rock contains abundant humic organic matter that was deposited in a transitional (Fluvio-deltaic) to marginal marine environment under oxic conditions.展开更多
Although various coaly source rocks widely developed in the Carboniferous-Permian(C-P)of the Bohai Bay Basin,their geochemical characteristics and hydrocarbon generation potential are poorly understood.This study aims...Although various coaly source rocks widely developed in the Carboniferous-Permian(C-P)of the Bohai Bay Basin,their geochemical characteristics and hydrocarbon generation potential are poorly understood.This study aims to discriminate the contribution of hydrocarbon generation from different C-P coaly source rocks and clarify the differences within generated oils using organic geochemistry,organic petrology,and thermal simulation experiments.The coaly source rocks containt coal clarain and durain,carbonaceous shale,and shale deposited in deltaic and lagoonal environment.The results indicated that clarain,durain,and carbonaceous shale exhibited higher hydrogen index and liquid-gas hydrocarbon yields than lagoonal and deltaic shales,which was mainly associated with the concentrations of sporinite,cutinite,and hydrogen-rich collodetrinite.Aliphatic hydro-carbons originated firom coal and carbonaceous shale presented lower Ts/(Ts+Tm),Ga/17α(H)21β(H)-C_(30)hopane,18α(H)-oleanane/17α(H)21β(H)-C_(30)hopane ratios,and higher 17β3(H)21α(H)-C_(30)Morane/17α(H)21β(H)-C_(30)hopane than deltaic lagoonal shales.Parameters of aromatic hydrocarbons generated from five lithologies of coaly source rocks trended as clear group distribution,e.g.,clarain and durain showing lower MNR,DBT/Fluorene(F)ratios and higher DBF/F ratio than coaly shales.The distinct descending trend of hydrocarbon potential is obtained from clarain,durain,carbonaceous shale to lagoonal and deltaic shales,implying dominated the petroleum and natural gas supplement from coal and carbonaceous shale.The difference between aliphatic and aromatic hydrocarbons provides a significant contribution to analyze the generic relationship between coaly source rock and lacustrine shale.Our results illustrate the importance of coaly source rocks for the in-depth oil-gas exploration of the Bohai Bay Basin and understanding hydrocarbon generation potential of source rocks in coal bearing strata.展开更多
文摘Talang Akar Formation is a proven hydrocarbon source rock in South Sumatra basin. The formation contains dominant shale at the top, with some sandstone interbeds. Whereas it contains coarse to very coarse sandstone beds at the bottom. The lower sandstone unit also contains carbonaceous shale and some coal seams. The geochemical analysis is important to identify a source rock quality in shale gas. The quality of source rock is determined by richness of the source rock and type of kerogen. 37 samples were collected from well cuttings in JML-1 and JML-2 wells. Samples we are received into the laboratories in the form of well site canned ditch cuttings, bagged ditch cuttings in various stages of preparation from wet, unwashed to dried, washed;sidewall cores, conventional cores, outcrop samples. The richness of a source rock can be defined by the content of organic carbon which is measured as total organic carbon (TOC). Based on geochemical result of analysis, quantity of shale hydrocarbon potential is indicated by the TOC value of 0.52 wt% - 6.12 wt% (fair to excellent criteria), with average of shale thickness more than 50 m. Tmax is an indication of the maturation stage of organic material and Hydrogen Index (HI) is a parameter used to explain the origin of organic material. HI versus Tmax crossplot was analysed for kerogen type determination and presence of type II/III kerogen was identified. This study concludes that the source rock contains abundant humic organic matter that was deposited in a transitional (Fluvio-deltaic) to marginal marine environment under oxic conditions.
基金supported by the Certificate of National Science and Technology Major Project of the Ministry of Science and Technology of China(No.2016ZX05006-007-004)National Natural Science Foundation of China(Grant Nos.41702139,420772164,42072130,and U1762217)+2 种基金Natural Science Foundation of Shandong Province(No.ZR2017BD036)the Fundamental Research Funds for the Central Universities(No.18CX02008A)Taishan Scholar Program of Shandong Province(No.TSQN201812030).
文摘Although various coaly source rocks widely developed in the Carboniferous-Permian(C-P)of the Bohai Bay Basin,their geochemical characteristics and hydrocarbon generation potential are poorly understood.This study aims to discriminate the contribution of hydrocarbon generation from different C-P coaly source rocks and clarify the differences within generated oils using organic geochemistry,organic petrology,and thermal simulation experiments.The coaly source rocks containt coal clarain and durain,carbonaceous shale,and shale deposited in deltaic and lagoonal environment.The results indicated that clarain,durain,and carbonaceous shale exhibited higher hydrogen index and liquid-gas hydrocarbon yields than lagoonal and deltaic shales,which was mainly associated with the concentrations of sporinite,cutinite,and hydrogen-rich collodetrinite.Aliphatic hydro-carbons originated firom coal and carbonaceous shale presented lower Ts/(Ts+Tm),Ga/17α(H)21β(H)-C_(30)hopane,18α(H)-oleanane/17α(H)21β(H)-C_(30)hopane ratios,and higher 17β3(H)21α(H)-C_(30)Morane/17α(H)21β(H)-C_(30)hopane than deltaic lagoonal shales.Parameters of aromatic hydrocarbons generated from five lithologies of coaly source rocks trended as clear group distribution,e.g.,clarain and durain showing lower MNR,DBT/Fluorene(F)ratios and higher DBF/F ratio than coaly shales.The distinct descending trend of hydrocarbon potential is obtained from clarain,durain,carbonaceous shale to lagoonal and deltaic shales,implying dominated the petroleum and natural gas supplement from coal and carbonaceous shale.The difference between aliphatic and aromatic hydrocarbons provides a significant contribution to analyze the generic relationship between coaly source rock and lacustrine shale.Our results illustrate the importance of coaly source rocks for the in-depth oil-gas exploration of the Bohai Bay Basin and understanding hydrocarbon generation potential of source rocks in coal bearing strata.
