This study reversed the developing environments of hydrocarbon-source rocksin the Ordos Basin and evaluated carbonate rocks as hydrocarbon-source rocks and their distributionson account of the fact that China''...This study reversed the developing environments of hydrocarbon-source rocksin the Ordos Basin and evaluated carbonate rocks as hydrocarbon-source rocks and their distributionson account of the fact that China''s marine carbonate rocks as hydrocarbon-source rocks arecharacterized by intensive thermal evolution and relatively low abundance of organic matter, bytaking the Lower Paleozoic of the Ordos Basin for example and in light of the calculated enrichmentcoefficients of trace elements, the REE distribution patterns, the mathematical statistics analysisof elements and carbon isotopes and their three-dimensional diagrammatization in combination withthe necessary organic parameters. As for the Ordos Basin, TOC=0.2% is an important boundary value.Studies have shown that in the strata where TOC is greater than 0.2%, Ba is highly enriched withpositive δ^(13)C_(carb) shifts and δ^(13)C_(org) less than -28per thousand, reflecting a thighpaleo-productivity, high burial amounts of organic matter, relatively good hydrocarbon-generatingpotentiality and intensive REE fractionation. All these indicated that the settlement rates are lowand the geological conditions are good for the preservation of organic matter, hence favoring thedevelopment of hydrocarbon-source rocks. The Klimory and Wulalik formations show certainregularities in those aspects and, therefore, they can be regarded as the potential effectivehydrocarbon-source rocks. In the strata where total TOC is less than 0.2%, the contents of Ba arelow, δ^(13)C_(carb) values are mostly negative, and δ^(13)C_(org) values range from -24perthousand—-28per thousand, demonstrating low burial amounts of organic matter, poor potentialitiesof hydrocarbon generation, weak REE fractionation and rapid settlement rates. These facts showedthat most of the hydrocarbon-source rocks were formed in shallow-water, high-energy oxidizingenvironments, thus un-favoring the development of hydrocarbon-source rocks. It is feasible to makeuse of the geochemical method to comprehensively asse展开更多
The present paper mainly studies the petroleum system of the Sufyan Depression in the Muglad Basin of central Africa and analyzes its control of hydrocarbon accumulation. On the basis of comprehensive analysis of effe...The present paper mainly studies the petroleum system of the Sufyan Depression in the Muglad Basin of central Africa and analyzes its control of hydrocarbon accumulation. On the basis of comprehensive analysis of effective source rock, reservoir bed types and source-reservoir-seal assemblages, petroleum system theory has been used to classify the petroleum system of the Sufyan Depression. Vertically, the Sufyan Depression consists of two subsystems. One is an Abu Gabra subsystem as a self generating, accumulating and sealing assemblage. The other subsystem is composed of an Abu Gabra source rock, Bentiu channel sandstone reservoir and Darfur group shale seal, which is a prolific assemblage in this area. Laterally, the Sufyan Depression is divided into eastern and western parts with separate hydrocarbon generation centers more than 10 000 m deep. The potential of the petroleum system is tremendous. Recently, there has been a great breakthrough in exploration. The Sufyan C-1 well drilled in the central structural belt obtained high-yielding oil flow exceeding 100 tons per day and controlled geologic reserves of tens of millions of tons. The total resource potential of the Sufyan Depression is considerable. The central structural belt is most favorable as an exploration and development prospect.展开更多
文摘This study reversed the developing environments of hydrocarbon-source rocksin the Ordos Basin and evaluated carbonate rocks as hydrocarbon-source rocks and their distributionson account of the fact that China''s marine carbonate rocks as hydrocarbon-source rocks arecharacterized by intensive thermal evolution and relatively low abundance of organic matter, bytaking the Lower Paleozoic of the Ordos Basin for example and in light of the calculated enrichmentcoefficients of trace elements, the REE distribution patterns, the mathematical statistics analysisof elements and carbon isotopes and their three-dimensional diagrammatization in combination withthe necessary organic parameters. As for the Ordos Basin, TOC=0.2% is an important boundary value.Studies have shown that in the strata where TOC is greater than 0.2%, Ba is highly enriched withpositive δ^(13)C_(carb) shifts and δ^(13)C_(org) less than -28per thousand, reflecting a thighpaleo-productivity, high burial amounts of organic matter, relatively good hydrocarbon-generatingpotentiality and intensive REE fractionation. All these indicated that the settlement rates are lowand the geological conditions are good for the preservation of organic matter, hence favoring thedevelopment of hydrocarbon-source rocks. The Klimory and Wulalik formations show certainregularities in those aspects and, therefore, they can be regarded as the potential effectivehydrocarbon-source rocks. In the strata where total TOC is less than 0.2%, the contents of Ba arelow, δ^(13)C_(carb) values are mostly negative, and δ^(13)C_(org) values range from -24perthousand—-28per thousand, demonstrating low burial amounts of organic matter, poor potentialitiesof hydrocarbon generation, weak REE fractionation and rapid settlement rates. These facts showedthat most of the hydrocarbon-source rocks were formed in shallow-water, high-energy oxidizingenvironments, thus un-favoring the development of hydrocarbon-source rocks. It is feasible to makeuse of the geochemical method to comprehensively asse
基金supported by the CNPC Science and Technology Study Financing Project (EDR/CN-01-102)
文摘The present paper mainly studies the petroleum system of the Sufyan Depression in the Muglad Basin of central Africa and analyzes its control of hydrocarbon accumulation. On the basis of comprehensive analysis of effective source rock, reservoir bed types and source-reservoir-seal assemblages, petroleum system theory has been used to classify the petroleum system of the Sufyan Depression. Vertically, the Sufyan Depression consists of two subsystems. One is an Abu Gabra subsystem as a self generating, accumulating and sealing assemblage. The other subsystem is composed of an Abu Gabra source rock, Bentiu channel sandstone reservoir and Darfur group shale seal, which is a prolific assemblage in this area. Laterally, the Sufyan Depression is divided into eastern and western parts with separate hydrocarbon generation centers more than 10 000 m deep. The potential of the petroleum system is tremendous. Recently, there has been a great breakthrough in exploration. The Sufyan C-1 well drilled in the central structural belt obtained high-yielding oil flow exceeding 100 tons per day and controlled geologic reserves of tens of millions of tons. The total resource potential of the Sufyan Depression is considerable. The central structural belt is most favorable as an exploration and development prospect.
