【作者】 王韶华；

【导师】 叶加仁；

【作者基本信息】 中国地质大学 ， 能源地质工程， 2010， 博士

【摘要】 中扬子经历了多幕构造演化、多期盆地叠加改造,同时经历了多期生、：排烃和复杂的油气成藏过程,是一个典型的复杂油气聚集区。上震旦统是中扬子地区重要的勘探目的层系之一。本文以构造学、沉积学和多旋回盆地分析等现代石油地质理论为指导,充分应用地质、地震、钻井、测井和测试分析化验等资料,以综合分析及计算机模拟为手段,把握野外宏观观测与室内微观分析相结合、地表地质与地下地质及地震分析相结合、静态描述与动态研究相结合的原则,应用区域封盖层控气论、古隆起控气论等天然气成藏与富集理论的观点,强调源是“根”,盖是“本”,系统总结了中扬子上震旦统油气成藏基本特征,动态分析了上震旦统的油气成藏演化过程,探讨了其油气成藏机理与成藏控制因素,建立了可能的油气成藏模式,并进一步综合评价了上震旦统的油气勘探潜力,指出了有利的勘探区带,明确了下步主要勘探方向。盆地充填及构造演化分析表明,中扬子总体经历了两大演化阶段——原型盆地演化阶段及强烈变形、变位演化阶段。各演化阶段又可分为多个演化时期,即加里东期克拉通(Z1—O2)及前陆膨隆盆地(O3—S)、海西—早印支期(D—T2)克拉通盆地、晚印支—早燕山期(T3—J2)前陆盆地的原型盆地沉积演化时期,以及早燕山末期(J3—K1)陆内盆地强烈褶皱变形、晚燕山—早喜山期(K2—E)盆地伸展改造、晚喜山期(N—Q)盆缘强烈挤压的变形变位演化时期。以南北碰撞造山及前陆盆地理论为指导,通过对区域构造格架剖面的地震资料精细解释,认为中扬子区海相地层存在南北分带、东西分块的构造格局。印支期及以前以差异隆升为主要特征,形成了与基底隆升有关的构造样式；燕山早期以南北挤压下形成的陆内造山带为主体,可划分为南、北两个大的陆内挤压推覆造山带,以及处于南、北两个逆冲褶皱带之间中部对冲过渡带,并可进一步划分为7个二级单元和17个三级单元。综合应用地表露头、钻井、测井、测试与化验分析等资料,系统分析了上震旦统油气成藏要素基本特征。分析结果表明,烃源层以上震旦统陡山沱组碳质泥岩、泥灰岩及下寒武统牛蹄塘组(水井沱组)泥岩、碳质泥岩为主,储集层以上震旦统灯影组颗粒白云岩、溶蚀孔洞白云岩为主,盖层以下寒武统泥质岩、泥灰岩为主。上震旦统、下寒武统两套烃源层演化程度高,均以产气为主；纵向上,下寒武统烃源岩优于上震旦统；平面上,上震旦统烃源岩以湘鄂西鹤峰地区最发育,具备形成大、中型油气藏的烃源条件；下寒武统烃源岩存在湘鄂西区的恩施—鹤峰一带、江汉平原区南部两个主要生烃中心区,具备形成大型油气藏的烃源条件。上震旦统灯影组储层横向分布相对稳定且广泛发育,储集空间以次生成因的溶蚀孔、洞为主,储层类型以裂缝—孔洞型为主,并以兴山—宜昌地区储层厚度大,物性较好。下寒武统盖层基本连片分布,累计厚度大,且盖层均质程度高,湘鄂西区具备形成高效气藏的封闭能力,江汉平原区较湘鄂西区逊色。保存条件以石柱复向斜为有利保存单元,沔阳干涉断褶带、宜昌稳定带、花果坪复向斜、桑植—石门复向斜及利川复向斜为较有利保存单元。从区域封盖层控气论和古隆起控气论等观点出发,动态分析了上震旦统油气成藏演化历程。研究表明,上震旦统、下寒武统烃源岩在加里东期进入生、排烃的鼎盛期,此时古构造表现为“大隆大坳”(北缘隆起带、中部斜坡带、南缘坳陷带)的格局,因此“斜坡”为油气运移的主要指向,尤其是距离烃源岩生、排烃中心较近的鄂西渝东、湘鄂西区以及江汉平原南部最为有利,此时下寒武统盖层的封闭性以中扬子西南部湘鄂西区最好,油气成藏以鄂西渝东的石柱地区最好；在海西—印支期,上震旦统和下寒武统烃源岩的生、排烃强度有所降低,此时古构造格局由鄂西渝东隆起、湘鄂西坳陷、黄陵-洪湖隆起、当阳坳陷带、钟祥隆起和鄂东坳陷组成,其中“隆起”成为油气运移的有利指向区,且此时下寒武统盖层封闭性好的位置较加里东时期向西迁移,鄂西渝东区有利于油气保存；在早燕山期,上震旦统和下寒武统烃源岩的生、排烃进入尾声,该时期形成的大量圈闭成为先期储备在隆起中或斜坡上的油气或古油藏中油型裂解气再次分配的目标,此时下寒武统盖层的封闭能力与海西—印支运动期相差无几,鄂西渝东区有利于油气保存；在晚燕山期—喜山期,烃源岩早已结束生烃,但有部分先期震旦系古油藏中石油裂解气的供给,由于拉张断陷和早期挤压断裂的反转对油气保存体系具有破坏和建设双重作用,此时鄂西渝东区下寒武统盖层封闭性持续好,石柱、利川、花果坪最有利于油气保存。应用圈闭形成时间法、生排烃史法、流体包裹体分析法等多种方法,综合分析了上震旦统油气成藏的期次。基于圈闭形成时间确定出上震旦统大规模的油气成藏发生在侏罗纪末期的燕山运动时期,同时也是油气大量散失和气藏遭受破坏与改造的主要时期；根据生排烃史法确定出加里东期、海西-印支期以及早燕山期是上震旦统、下寒武统两套烃源层有机质热演化的重要变革时期；从流体包裹体分析确定出加里东晚期—早印支期是上震旦统灯影组内包裹体形成的时间,而此时区内并无局部构造形成,古隆起、古构造为油气运移的有利指向区。应用烃源岩发育及生烃动力学和成藏动力学相结合的分析方法,探讨了中扬子上震旦统成藏的烃源岩有效供烃能力及控制因素。分析认为,烃源岩以泥质类烃源岩为主,是主要的生烃母质；构造-沉积类型影响油气生成-排驱、运移-聚集和破坏-保存的整个成藏过程；生排烃强度是烃源灶初始排烃能力的表征；烃源灶性质演变为天然气成藏提供了多种供烃途径；烃类散失速率影响烃源灶的有效供烃能力；有效供烃效率是烃源岩性质、构造-沉积类型、烃源灶类型及其叠合、生烃强度历史演化和天然气散失速率诸控制要素的综合效应。有效供烃能力影响因素的分析及其定量描述为中扬子海相油气藏演化历史的定量描述提供了新的思路。综合应用地层沉积、储层与成岩演化分析等方法,指出了上震旦统灯影组优质储层形成机理及控制因素。研究表明,上震旦统灯影组优质储层发育与古岩溶作用、埋藏溶蚀作用、白云石化作用关系密切。平面上,灯影组储集条件好的沉积相为潮下高能带和台地边缘,而潮下低能带的储集条件相对较差。纵向上,高位体系域发育潮坪相藻云岩、颗粒云岩以及台缘滩相颗粒云岩。白云石化作用主要表现为准同生白云石化、回流渗透白云石化、和混合水白云石化,其中准同生白云石化作用主要发育于灯三段,回流渗透白云石化作用主要发育于灯影组中上部,混合水白云石化作用以灯一段和灯三段较发育。由于灯影末期受海平面变化与地壳运动影响,致使灯影组顶部出现了不同程度的古表生溶蚀作用。现今灯影组储集体规模以及孔渗性是沉积、古岩溶以及埋藏阶段的选择性溶蚀作用综合影响的结果。通过典型油气藏解剖,结合区域成藏背景分析,应用天然气成藏与富集理论,研究了上震旦统油气成藏富集规律。上震旦统灯影组油气成藏具有多源、多期的特点,并存在三种可能的油气成藏模式,即早期聚集晚期调整成藏型、持续演化原生成藏型、早期运聚晚期破坏改造成藏型。烃源灶的变迁是油气藏形成的首要物质基础,两套优质烃源岩的发育控制了油气多期成藏和混源特征；继承性古隆起及其斜坡控制了油气富集,是最佳油气聚集区；构造运动,特别早燕山构造活动是油气成藏定型的关键；后期优越的封盖条件是油气得以保存的关键。在成藏条件和主控因素分析的基础上,对上震旦统的有利区带进行了评价与优选,并应用地质类比法预测了油气资源勘探潜力。结果表明,中扬子上震旦统油气勘探前景广阔,预测上震旦统总资源量为11422.10×108m3；油气成藏条件以石柱复向斜最为优越,是中扬子上震旦统油气勘探的首选有利区带。更多还原

【Abstract】 As a typical complex hydrocarbon accumulation area, the Middle Yangtze underwent a multi-stage tectonic evolutions, superimposed alterations and hydrocarbon generation and expulsion, and complex petroleum accumulation process. The Upper Sinian is a important sequence for hydrocarbon exploration in the Middle Yangtze area. Under the guidence of modern petroleum geology theories as tectonics, sedimentology and multi-cycle basin analysis, using the data of geological, seismic, drilling, logging and laboratory test analysis, by means of comprehensive analysis and computer simulation technology, based on the principles of combined the field macroscopic observation with office microscopic analysis, combined the surface geology and subsurface geology with seismic analysis, combined static description with dynamic research, and applying the viewpoints about natural gas accumulation and enrichment controlled by regional seal, and by palaeohigh,especially emphasizing the important actions of source and caprock, this paper has studied the basic characteristics, evolution processes, mechanisms, controlling factors, possible models of hydrocarbon accumulation of the Upper Sinian in the Middle Yangtze area, evaluated the exploration potential synthetically, and also pointed out the favorable exploration zones and directions.The analysis about basin filling and tectonic evolution showed that the Middle Yangtze basin underwent two evolution stages of the prototype basin, and strong deformation and dislocation. The first stage can further be divided into four phases as craton (Z1-O2) and foreland swell basin (O3-S) during the Caledonian period, craton basin from the Hercynian to the early Indosinian (D-T2) and foreland basin from the Late Indo-China to the early Yanshan (T3-J2), whereas the second stage contained intracontinental basin with fold and deformation strongly at the end of the early Yanshan (J3-K1), extension and alteration from the late Yanshan to the early Himalayan (K2-E), and compression deformation and dislocation strongly in basin’s margin during the late Himalayan period (N-Q).Under the guidence of the theories of collision orogenesis and foreland basin, the interpretation of regional structural frame section on seismic data indicated that the structural frame of the Middle Yangtze marine strata are north-south zonation and east-west blocking. The main character before the Indo-China epoch is differential uplift, and its tectonic style associated with the basement rising; The main character of the early Yanshan is the intracontinental orogenic belt, which resulted from south-north compression, and it consists of two large overthrust orogenic belts with intracontinental compression in the south and north, and a transition belt in the middle. The tectonic units of the marine strata can be divided into three first-level units, seven second-level units and seventeen third-level units.The basic features of the Upper Sinian hydrocarbon accumulation have been studied in this paper by using the data of surface outcrops, drilling, logging, testing and laboratory analysis. The results show that the source rock mainly contain carbonaceous mudstone and marl of the Upper Sinian Doushantuo Formation, and mudstone and carbonaceous mudstone of the Lower Cambrian Niutitang Formation. The main reservoirs are granular dolomite and corrosion vugular dolomite of the Upper Sinian Dengying Formation. The main caprock are the Lower Cambrian mudstone and marl. The source rock in the Upper Sinian and Lower Cambrian evolved a hign level, and mainly producted gas. The Lower Cambrian source rock is better than that of the Upper Sinian. In the plane, the Upper Sinian source rock was distributed mainly in the the Hefeng area, the western of the Hunan and Hubei provinces, whereas the Lower Cambrian source rock was developed mostly in the areas of the Enshi-Hefeng and the north of the Jianghan plain, where have the condition of forming large-size oil and gas pools. The reservoirs in the Upper Sinian Dengying Formation distributed relatively stable and extensive in the lateral. Its reservoir spaces consisted mainly of the secondary corroded pore and hole, and the major reservoir type is the fracture-pore-hole. This reservoir height in the Lichuan and Xingshan-yichang areas is greater, and physical property is also better. The caprock in the Lower Cambrian is charatered as continuous distribution, large total thickness, and high homogeneous. Comparing with the Jianghan plain, the caprock in the western Hunan-Hubei is more effectively to develop high efficiency gas accumulation. The Shizhu synclinorium is the most favorable preservation unit, and the Mianyang interference bruchfalten, Yichang stable belt, Huaguoping synclinorium, Sangzhi-Shimen synclinorium and Lichuan synclinorium are also favorable preservation unit.Based on the viewpoints of gas distribution controlled by regional seal and paleohigh, the hydrocarbon accumulation evolution history of the Upper Sinian was analyzed dymanically in this study. It is shown that the Upper Sinian and Lower Cambrian source rocks entered the peak of hydrocarbon generation and expulsion during the Caledonian period, while the paleo-tectonic presented as great uplift and great depression (North marign uplift belt, Central slope zone, Sourth margin depression zone). Thus, The slope is the favorable direction of hydrocarbon migration, i.e., the areas as the western Hubei-eastern Chongqing, western Hubei and Hunan, and sourthern Jianghan Plain due to near the hydrocarbon generation and expulsion center of source rock, while the seal ability of the Lower Cambrian caprock in the southwest of the western Hubei and Hunan is the best, and hydrocarbon accumulation condition of the Shizhu area in the western Hubei-eastern Chongqing is the best. The generation and expulsion intensities of the Upper Sinian and Lower Cambrian source rocks decreased during the Hercynian-Indochina period, while the paleo-tectonic units consisted of the western Hubei-eastern Chongqing uplift, western Hubei and Hunan depression, Huangling-Honghu uplift, Dangyang depression zone, Zhongxiang uplift and eastern Hubei depression. The uplifts situated on the direction of hydrocarbon migration. Comparing with the Caledonian period, the area of good seal ability moved to west, so the western Hubei-eastern Chongqing area is favourable to hydrocarbon preservation. During the early Yanshanian period, the hydrocarbon generation and expulsion intensities of the Upper Sinian and Lower Cambrian source rock can be neglected, and the traps forming in this period became the re-distribution targets of ancient oil reservoir in the uplift or on the slope and paleo-oil pools pyrolysis gas. The seal ability of the Lower Cambrian caprock is almost the same as it in the Hercynian-Indo-China movement, and the western Hubei-eastern Chongqing area is favourable to hydrocarbon preservation. During the middle Yanshanian-Himalayan period, the source rock can not be generated hydrocarbon again, however, it can be supplyed by some oil cracking gas from the Pre-Sinian ancient reservoir. As a result of the extensional rift and the reversal of early compression fault has the dual role of destruction and construcion for oil and gas preservation system, the seal ability of the Lower Cambrian caprock in the western Hubei-eastern Chongqing area is continuously well, and the areas of Shizhu, Lichuan, Huaguoping are favourable to hydrocarbon preservation.Hydrocarbon accumulation period of the Upper Sinian was analyzed comprehensively by using the methods of trap formation time, hydrocarbon generation and expulsion history, and fluid inclusion analysis. The large-size hydrocarbon accumulation of the Upper Sinian occurred during the Yanshan movement period at the Late Jurassic on the trap formation time analysis, while much of oil and gas were lost, and gas reservoirs were destructed and transformed. With the hydrocarbon generation and expulsion history analysis, it indicatedt that the Caledonian, Hercynian-Indosinian and early Yanshan periods are the key moments to the thermal evolution of the source rocks of the Upper Sinian and the lower Cambrian. From the fluid inclusion analysis, the fluid inclusions in the Upper Sinian Dengying Formation were formed from the Late Caledonian to the early Indo-China period, while the paleo-uplifts and paleo-structures were favorable for hydrocarbon migration due to no local structures in this area at that time.The effective hydrocarbon supplying ability of source rock and controlling factors of the Upper Sinianin hydrocarbon accumulation in the Middle Yangtze area were dicussed by using the methods of source rock devoloping, hydrocarbon generation kinetics, and hydrocarbon accumulation process kinetics comprehensively. It indicated that the muddy source rock is the main hydrocarbon-generating matter, and the tectonic-sedimentary type influenceed the whole process of hydrocarbon generation, expulsion, migration, accumulation, destruction amd preservation. The hydrocarbon generation and expulsion intensities represented the initial ability of hydrocarbon expelled from hydrocarbon kitchen, and the evolving nature of hydrocarbon kitchen offered a variety of sources for gas accumulation. The hydrocarbon loss rate affected the effective supplying ability of hydrocarbon kitchen. The effective hydrocarbon supplying efficiency was the comprehensive function of source rock properties, tectonic-sedimentary types, hydrocarbon kitchen types and their combination, hydrocarbon generation intensity evolution history and gas loss rate. And the analysis and quantitative description of influencing factors of the effective hydrocarbon supplying ability provided a new idea to reconstruct the hydrocarbon history of the oil and gas pools in the Middle Yangtze area quantitatively.With the comprehensive analysis of strata deposition, reservoir and its diagenesis evolution history, the formation mechanism and controlling factors of the high-quality reservoir in the Upper Sinian Dengying Formation were studied. It is shown that the high-quality reservoir developing of the Upper Sinian Dengying Formation was closely related with the palaeoepigenetic dissolution, burial dissolution and dolomitization. In the planar, the reservoirs of the Dengying Formation developing at the subtidal high-energy zone and platform margin had good quality, whereas at the the subtidal low-energy had a relatively poor quality. In the vertical, the highstand system tract developed algae dolomite and particle dolomite of tidal flat facies, and particle dolomite of platform margin bank facies. The dolomitization was dominated by penecontemporaneous dolomitization, seepage-reflux dolomitization and mixed water dolomitization, which occurred mainly at the Third Member, the top and middle parts, and the First and Third members of the Dengying Formation respectively. Being influence of sea level change and crustal movement at the end of the Dengying Formation deposition, ancient supergene dissolution appeared at the top of the Dengying Formation in varying degrees. However, the size, and the porosity and permeability of the Dengying Formation reservoir at present should be influenced by the selective dissolution in the stages of sediment, ancient karst and bury.With the application of the theory about natural gas accumulation and enrichment, the hydrocarbon accumulation and concentration rules of the Upper Sinian were studied by dissecting the classic reservoirs combined with the regional background analysis of reservoir forming. The hydrocarbon accumulation in the Upper Sinian Dengying Formation was charactered as mixure sources and multi-periods, and would be develop three possible patterns as accumulation at early with adjusting at the later, initial accumulation with continuous evolution, and accumulation at early with destruction and alteration at the later. The migration of hydrocarbon kitchens was the primary material foundation for hydrocarbon accumulation, and the two high-quality source rocks dominated hydrocarbon multi-period accumulation and mixure sources. The inherited paleo-uplifts and slopes controlled the petroleum enrichment, where were the best favorable areas for hydrocarbon accumulation. The tectonic movement, especially the early Yanshan Movement is the key to hydrocarbon accumulation finally, and the late superior sealing condition was the most important for petroleum preservation.Based on the study about the basic consitions and main controlling factors of hydrocarbon accumulation, the structural zones of the Upper Sinian were evaluated furtherly and the exploration pontential of hydrocarbon resources was also predicted by using the method of geologic analogy. The results showed that the exploration prospect of the Upper Sinian in the Middle Yangtze is broad with the total quantity resources of 11422.10×108m3, and the Shizhu synclinorium should be the preferred area for hydrocarbon exploration due to its most favorable conditions to hydrocarbon accumulation in the Middle Yangtze.更多还原