학술논문
我国中西部盆地深层-超深层烃源岩热演化研究 / Maturation history of deep and ultra-deep source rocks,central and western basins,China
Document Type
Academic Journal
Author
邱楠生; 常健; 冯乾乾; 曾帅; 刘效妤; 李慧莉; 马安来; QIU Nansheng; CHANG Jian; FENG Qianqian; ZENG Shuai; LIU Xiaoyu; LI Huili; MA Anlai
Source
地学前缘 / Earth Science Frontiers. 30(6):199-212
Subject
Language
Chinese
ISSN
1005-2321
Abstract
我国中西部盆地深层、超深层油气相态、分布深度和油气贫富差异大,盆地温度场是制约油气成藏及烃源岩成熟演化的关键要素.本文以塔里木盆地和四川盆地寒武系为研究对象,系统解析盆地古、今温度场特征,明确寒武系烃源岩热演化及其差异性,探讨热演化对油气生成及油气相态的控制作用.结果表明,塔里木盆地和四川盆地现今平均热流为(42.5士7.6)和(53.8士7.6)mW/m2,反映了"冷盆"和"温盆"特征.塔里木盆地热流自早寒武世以来呈下降趋势,早二叠世受岩浆活动的影响,出现短暂的峰值.四川盆地寒武纪至早二叠世为稳定低热流,早二叠世末受峨眉山地幔柱热效应的深刻影响,热流快速上升,晚二叠世以来热流下降.由于四川盆地的热状况一直高于塔里木盆地,同时受二叠纪岩浆活动的差异影响,盆地寒武系烃源岩成熟演化、油气生成和相态存在差异.塔里木盆地寒武系烃源岩的热演化具有3种类型:(1)古生代迅速成熟演化定型;(2)早古生代快速演化-后期持续演化型;(3)早古生代和中生代快速演化型.四川盆地寒武系烃源岩的热演化具有3种类型:(1)持续演化型;(2)加里东期热演化停滞-中生代持续演化型;(3)加里东期和印支期热演化停滞-后期持续演化型.极低的地热背景使得塔里木盆地深层-超深层仍存在液态烃保存的有利温度条件.
There are significant differences in the oil and gas phase behavior,distribution depth,and content in deep and ultra-deep strata in the central and western basins in China where the temperature field plays an essential role in hydrocarbon generation and conservation.Focusing on the Cambrian of the Tarim and Sichuan Basins,this study summarizes and contrasts the present-day and ancient temperature fields,and clarifies the maturation history and differences of the Lower Cambrian source rocks.The effect of thermal evolution on hydrocarbon generation and phase behavior is also discussed.The average heat flows in the Tarim and Sichuan basins are(42.5+7.6)mW/m2 and(53.8+7.6)mW/m2,respectively,reflecting the characteristics of"cold"and"warm"basins.In the Tarim Basin the paleo heat flow decreased since the Early Cambrian and only peaked abruptly in the Early Permian in response to the Tarim Large Igneous Province.Whilst the Sichuan Basin experienced steady,low heat flow in the Cambrian-Early Permian,rapid rising heat flow at the end of the Early Permian due to the Emeishan mantle plume,and declining heat flow since the Late Permian.The Sichuan Basin's consistent higher thermal regime,and the differential effect of Permian magmatic activity,resulted in the differential oil and gas generation and conservation in the ancient,ultra-deep strata between the two basins.The maturation history of source rocks of the Lower Cambrian Yuertusi Formation in the Tarim Basin can be classified into three kinds:(1)Paleozoic rapid maturation and finalization;(2)Early Paleozoic rapid maturation followed by continuous heating;and(3)Early Paleozoic and Mesozoic rapid maturation.Similarly,three maturation patterns are identified for the source rocks of the Lower Cambrian Qiongzhusi Formation in the Sichuan Basin:(1)continuous maturation;(2)Silurian-Permian cessation followed by Mesozoic maturation;and(3)Silurian-Permian and Triassic cessation and later continuous maturation.Due to its low thermal regime,the Tarim Basin has favorable temperature conditions for the liquid hydrocarbon preservation in ultra-deep strata.
There are significant differences in the oil and gas phase behavior,distribution depth,and content in deep and ultra-deep strata in the central and western basins in China where the temperature field plays an essential role in hydrocarbon generation and conservation.Focusing on the Cambrian of the Tarim and Sichuan Basins,this study summarizes and contrasts the present-day and ancient temperature fields,and clarifies the maturation history and differences of the Lower Cambrian source rocks.The effect of thermal evolution on hydrocarbon generation and phase behavior is also discussed.The average heat flows in the Tarim and Sichuan basins are(42.5+7.6)mW/m2 and(53.8+7.6)mW/m2,respectively,reflecting the characteristics of"cold"and"warm"basins.In the Tarim Basin the paleo heat flow decreased since the Early Cambrian and only peaked abruptly in the Early Permian in response to the Tarim Large Igneous Province.Whilst the Sichuan Basin experienced steady,low heat flow in the Cambrian-Early Permian,rapid rising heat flow at the end of the Early Permian due to the Emeishan mantle plume,and declining heat flow since the Late Permian.The Sichuan Basin's consistent higher thermal regime,and the differential effect of Permian magmatic activity,resulted in the differential oil and gas generation and conservation in the ancient,ultra-deep strata between the two basins.The maturation history of source rocks of the Lower Cambrian Yuertusi Formation in the Tarim Basin can be classified into three kinds:(1)Paleozoic rapid maturation and finalization;(2)Early Paleozoic rapid maturation followed by continuous heating;and(3)Early Paleozoic and Mesozoic rapid maturation.Similarly,three maturation patterns are identified for the source rocks of the Lower Cambrian Qiongzhusi Formation in the Sichuan Basin:(1)continuous maturation;(2)Silurian-Permian cessation followed by Mesozoic maturation;and(3)Silurian-Permian and Triassic cessation and later continuous maturation.Due to its low thermal regime,the Tarim Basin has favorable temperature conditions for the liquid hydrocarbon preservation in ultra-deep strata.