南方典型古油藏沥青来源和形成时代的Re-Os-PGE示踪研究

The absolute ages of petroleum generation and migration and the source of hydrocarbons are the key scientific issues for the hydrocarbon accumulation studies. Reservoir bitumen records the important information of petroleum generation, migration, accumulation, reconversion and destruction, which plays a significant role in understanding the formation and evolution of hydrocarbon reservoirs. In this study, three representative lower Paleozoic paleo-reservoirs bitumen with different causes and their potential source rocks are chosen as the research objects in the Southern China. The key technologies mainly are the Re-Os isotope and platinum group elements (PGE) tracer. The study will carry out the chronological framework construction of multiple evolution and hydrocarbon accumulation process for the typical paleo-reservoirs bitumen, and explore the new method for the oil-source correlation using Os isotope and PGE. As a representative, our study attempts to establishment the isotopic direct dating methods and technologies for the multiple hydrocarbon accumulation and destruction of the marine carbonate petroleum reservoirs, set up the new methods for oil-source correlation using the Os isotopes and Pt/Pd ratios, which will contribute to the study on the mechanism and process of hydrocarbon accumulation from the carbonate strata in the China.

油气生成和运移的绝对年龄以及烃类来源是油气成藏过程研究中最为关注的核心科学问题。沥青记录了油气生成、运移、聚集、改造和破坏的重要信息，对正确认识油气藏的形成和演化具有重要的作用。研究挑选我国南方典型古油藏不同成因的沥青和潜在的烃源岩作为研究对象，采用Re-Os同位素和铂族元素(PGE)示踪等关键技术，开展典型古油藏（沥青）多期形成演化时序和油气成藏过程的年代学重建、探索油源对比的锇同位素和铂族元素联合示踪分析的新方法。研究试图建立我国海相碳酸盐岩油气多期成藏的直接定年方法和技术组合，建立利用锇同位素初始比值、利用锇同位素和铂族元素Pt/Pd相关性进行油源对比的新方法和思路，从而促进我国海相碳酸盐岩油气成藏过程和成藏机理的研究。

油气生成和运移的绝对年龄以及烃类来源是油气成藏过程研究中最为关注的核心科学问题。这对这一问题，研究挑选我国南方下古生界三个典型的、具有不同成因的古油藏沥青和潜在的烃源岩作为研究对象，开展Re-Os同位素分析，有机地球化学分析，储层流体包裹体分析，并结合磷灰石裂变径迹分析，以及其它一些相关的测试 (如沥青反射率，烃类物理性质等)，探讨了Re-Os同位素年代学在我国海相油气成藏改造过程中的适用性，并提供了相关的研究实例。研究通过对油气演化过程中不同类型的烃类(原油、沥青、焦沥青) 的Re-Os同位素分析，不仅进一步证实了前人提出的原油及沥青质沥青的Re-Os同位素定年代表原油初始生成时间的观点，并且提出了高成熟度焦沥青的Re-Os同位素年龄与原油裂解天然气形成的时间相关。研究进一步证实了Re-Os同位素年代学在我国海相油气多期成藏改造过程中具有适用性，将具有广泛的应用前景。