【作者】 蔡勋育；

【导师】 沈忠民；

【作者基本信息】 成都理工大学 ， 矿产普查与勘探， 2005， 博士

【摘要】 本文针对第三系残留型盆地的油气成藏动力学理论与方法研究中存在的有关主要问题,以广西百色盆地例,从盆地区域地质资料入手,在百色盆地石油地质条件综合研究的基础上,采用现代有机地球化学研究方法与盆地模拟方法以及油气生成与运聚的实验模拟新技术手段相结合,对百色第三系残留型盆地的油气成藏动力学基本特征进行了深入系统研究。 应用有机地球方法系统地分析了百色第三系残留型盆地不同地区烃源岩和原油的地球化学特征,划分原油的成因类型,并且通过生物标志化合物的油-油对比、油-岩对比,明确指出百色盆地已发现的原油主要来源于那读组湖相暗色泥岩,而煤层与碳质泥岩的贡献较小,确认盆地内东部与西部地区油源有所差异,即东部坳陷原油主要来源于那二段和那一段源岩,西部坳陷原油则来源于那三段源岩。 采用分步连续加热方式,在温压釜内对盆地主力烃源岩的未成熟样品生烃特征进行热压模拟实验研究。通过各模拟温度点的气相产物和液态烃产物系统分析,首次建立了盆地主力烃源岩有机质的生烃演化模式。结合盆地的地质条件,指出那读组高效烃源岩有机质在低成熟、成熟阶段具有油源岩的生烃特征,并且在低成熟阶段有机质具有较强的成烃能力。 在盆地现今地温场、流体压力场和水化学场分布特征研究基础上,系统地分析了异常低压形成机制,提出了异常低压的形成是限流因素和降压因素共同作用结果的认识。以盆地东部坳陷仑16块那读组油藏为例,对油水体系的异常低压形成演化进行深入研究,认为无气顶异常低压油藏的形成不仅与晚期地层抬升-剥蚀作用有关,并且砂体受到限制而失去与地表水的静水柱压力作用也有重要影响。 通过油气运聚模拟实验的研究,发现砂体输导体系的储层物性、砂体与断层的组合方式以及烃源岩向输导体系充注油气的强度,对油气运聚成藏方式具有重要影响。在层间非均质砂层输导体系中,从源岩中排驱出来的烃类进入砂岩储集体以后,首先充注层间非均质砂层中孔隙度和渗透率较高的砂层,随着油气充注强度的不断增加,油气才能进入储层物性较差的砂层中运移和聚集。在砂体与断层的不同组合方式中,由断层和非均质砂体组成的油气输导网络导致油气运移的复杂性和多样性。 应用盆地模拟技术对百岗组和那读组古流体势进行模拟计算。百色盆地百岗组和那读组的古流体势的高势区分布坳陷中心南侧,在区域大断层两盘等势线不相连,表现为两个相对独立的流体系统。 在百色盆地油气成藏动力学特征的研究基础上,综合分析了油气成藏的主要控制因素,指出百色盆地油气成藏的相态主要受到烃源岩有机质类型和古地温场控制,古、今流体流动样式控制油气运聚方向,并且在盆地东部坳陷归纳总结出四种成藏模式。这不仅对百色盆地的油气勘探具有重要指导意义,我国其它第三系残留型盆地的油气成藏研究也有重要借鉴意义。更多还原

【Abstract】 To solving some main problems of the theory and method of dynamic Systems of Petroleum Accumulation in relict basin of Tertiary, the author takes Baise basin in Guangxi as an example. The basic characteristics of dynamic systems of petroleum accumulation are systemically studied in this paper by the using of the method of modern organic geochemistry and basin simulation with new technology of simulation experiment for migration and accumulation, which based on the comprehensive study of petroleum geologic condition in Baise basin with the material of regional geology.The characteristics of geochemistry on source rock and crude oil of different area in relict basin of Tertiary in Baise basin are systematic analyzed and the genetic type of oil have been classified by means of organic geochemistry. Moreover, based on the oil—oil and oil—rock correlation of biomarker, it is pointed out that the surveyed crude oil is originated from lake-facies dark mudstones in Nadu formation, while coal and carbonaceous mudstones have rather less contribution. It is determined that oil-source from west area is different from east area in basin, the crude oil of east depression is mainly from the second and first members of Nadu formation and the one of west depression is from the third members of Nadu formation.The hydrocarbon-generating characteristics of immature samples about main source rock in basin are systemically studied through thermal simulation experiment under continual heating. According to the systematic analysis of product of gas and liquid hydrocarbon, the hydrocarbon-generating model of organic about main source rock in basin is established for the first time. Based on the geologic condition, it points out that the organic of source rock in Nadu formation have the hydrocarbon-generating characteristics at low maturity or maturity stage, and especially have a strong hydrocarbon-generating capability at low maturity stage.The author analyzed the mechanisms of controlling formation on abnomal subpressure in a systematic way and put forward to the formation of abnomal subpressure which is the result of limited-entry and pressure drops based on the characteristics of modern geothermal、 fluid pressure field and hydrochemical field. Take the reservoir of Nadu formation in East depression as a example, the author indicated that the formation of reservoir which is non-gas cap abnomal subpressure not only gets something to do with function of reflection about uplift and erosion of late strata, but also to do with limited sand body which loses the function of hydrostatic pressure with the ground water.According to the systematic analysis of the simulation experimente about migration and accumulation,it is discovered that the reservoir properties of sands conduit systems、 the association pattern of sand body and fault and entering the oil poor which is from source rock to liquid conduit systems play a significant role to the reservoir-generating pattern of migration and accumulation. In the heterogeneous sand conduit systems, when the hydrocarbon which is from source rock entered the reservoir, it enters the heterogeneous sand body which permeability and porosity is rather high at first, and then enter the one which reservoir properties is poor with the increase density of entering the oil poor. Among the different association pattern of sand body and faults, oil conduit web formed by sands and heterogeneous sand leads to the complexity and variety of migration and accumulation.更多还原