【作者】 王威；

【导师】 徐国盛；

【作者基本信息】 成都理工大学 ， 矿产普查与勘探， 2009， 博士

【摘要】 本论文针对中扬子地区海相地层年代老、后期构造活动强、原生油气藏经历多次破坏改造,油气演化和富集规律复杂的特点,从基础工作入手,针对海相地层油气保存研究之重点和难点,开展了大量的文献调研和基础资料收集工作。以构造地质学、流体化学及流体封存箱等石油地质学理论为指导,以构造形成与演化为主线,分析构造演化过程中的流体化学-动力学响应特征,恢复与重现流体化学-动力学运移轨迹,建立了中扬子区海相地层现今流体封存箱系统油气保存有效性综合评价指标体系,分析流体封存箱演变史,明确流体封存箱油气成藏主控因素,预测出有利于油气保存的勘探区带。取得的主要认识及创新性成果如下:(1)中扬子区的构造演化具有多期性,构造变形具有多层性,先后经历了加里东整体沉降期、海西-印支大隆大坳期、早燕山强烈变形变位期、晚燕山-喜马拉雅伸展-拗陷期等四个阶段,早燕山期为中扬子区构造主要形成时期。(2)采用古水动力场恢复与流体动力学数值模拟技术,根据中扬子区域构造运动的多期性、沉积与剥蚀作用、水动力条件,把研究区不同海相储层地下径流演化过程划分为加里东期、海西-早印支期、晚印支-早燕山期、晚燕山-喜马拉雅期2-4个水文地质旋回,恢复和重建了海相储层的古水动力场。根据储层水动力场态势及地下水径流汇聚特点,提出了研究区有利于油气聚集的水动力学模式:低势圈闭型、低势半圈闭型、势梯度陡变型与台缘型和流势马鞍型等。通过储层流体势场剖析,揭示出研究区不同构造带水文地质条件的差异性和复杂性,以储层水汇流模型、径流继承性、埋藏封闭条件和水化学特征等作为评价因子,预测了中扬子区海相储层油气聚集有利区。(3)利用地下水地球化学因子转化分析技术,通过大量薄片之矿物成分与孔洞缝充填物的鉴定与统计,中扬子区海相地层识别出:大气淡水溶蚀、溶洞、溶缝、泥质充填去白云化及淡水白云石组合;黄铁矿、泥岩压释水及白云石溶蚀重结晶组合;构造破裂、石英沉淀、黄铁矿沉淀、异形白云石、有机溶蚀组合等,与之相对应的水化学环境分为:准同生期近地表蒸发超盐度水介质环境;浅埋藏低温咸水环境;深埋藏中-高温卤水环境等。在解剖储层水动力场和水化学特征的基础上,首次提出与建立了地层水化学成因演化序列和模式。(4)采用流体地球化学示踪技术,经流体碳、氧、锶同位素和包裹体的综合研究表明:湘鄂西大部分地区寒武系流体向下伏震旦系灯影组运移和向上覆奥陶系储层运移,由于所分析样品主要形成于石油热裂解后,说明下组合中分隔流体的封隔层已失效,湘鄂西区下组合及下伏震旦系已无形成大规模油气藏的可能。鄂西渝东区三叠系和二叠系中的流体主要来自于上二叠统,且受地表渗入水影响小,海相上组合中未见下伏早古生界流体加入,如果以古生界作为勘探目的层,下组合具有相对较好的保存条件。江汉平原区在早期流体充注时,流体来自于下伏寒武系,下伏古生界与上覆三叠系的流体相互连通,早期古生界的保存条件相对较差;晚期流体充注时,早古生代地层与中生代地层中的流体互不连通,即晚期保存条件相对较好。但流体包裹体拉曼分析表明,海相地层中可能缺少较大规模的油气充注。探讨了流体化学-动力学运移轨迹,分析了与流体运移轨迹具成生联系的油气保存体系的完整性与继承性。(5)依照有效烃灶对中扬子区海相地层流体封存箱进行统一划分,将中扬子区海相地层在纵向上划分为4个主要的流体封存箱单元,自下而上分别为Ⅰ-流体封存箱单元(∈1-Z)、Ⅱ-流体封存箱单元(O-∈2)、Ⅲ-流体封存箱单元(S)和Ⅳ-流体封存箱单元(T1-D)。(6)采用成藏动力学理论,探讨油气成藏主控因素。研究结果表明:保存条件是中扬子区海相油气成藏的关键因素,而构造隆升剥蚀、断裂活动、流体保存的继承性是影响油气保存的三大要素。综合考虑了地层出露情况,特别是侏罗系覆盖程度;后期构造作用强度及断裂的封堵性;水文地质条件与流体化学-动力学行为特征;流体封存箱的现今压力与古压演化;古流体来源、古流体跨层运移层位与运移规模、古流体的封存性好坏及流体保存条件演变等诸因素及其成因联系,建立了中扬子区海相地层现今流体封存箱系统油气保存有效性综合评价指标体系。(7)按照已建立的中扬子区海相地层现今流体封存箱系统油气保存有效性综合评价指标体系为标准,结合流体封存箱油气成藏主控因素分析,在流体封存箱单元内对中扬子区海相地层油气有利勘探区带进行预测。其中江汉平原区1个区块为II-封存箱单元油气有利勘探区带;江汉平原区2个区带和鄂西渝东区2个区带为III-封存箱单元油气有利勘探区带;鄂西渝东区3个区块为IV-封存箱单元油气有利勘探区带。湘鄂西区无勘探有利区带。更多还原

【Abstract】 In this paper, the features of marine strata in the middle Yangtze region are that the strata is old, the post-tectonic activity was strong, a number of original reservoir damaged reconstruction happen, the evolution and enrichment of oil and gas is complex. To these features, it starts from the basic work for oil and gas preservation’s research focus and difficult in marine strata, and carry out a large number of literature investigation and basic data collection. Regard the petroleum geology theory as guidelines, for example, structural geology, fluid chemistry and fluid compartment etc. , taking structure formation and evolution as the main line, analyze the fluid chemistry - the characteristics of dynamic response in the process of tectonic evolution, restore and reproduce the fluid chemistry - kinetics migration trajectory, construct the marine strata in the middle Yangtze region’s current index system of oil and gas fluid compartment to preserve the effectiveness of comprehensive evaluation, analyze the evolution of fluid compartment, definite the main controlling factors of oil and gas preservation system, and forecast the favorable exploration region. The main outcomes and innovation are as follows:(1)In the middle Yangtze region, the tectonic evolution is multi-phase, structure deformation is multi-storey. and it has gone through four phases, such as Caledonian, Hercynian - Tai Au Dalong Indosinian period, as early as a strong deformation of the Yanshan period shift, night Yanshanian - Himalayan extension , early Yanshanian is the main forming period of middle Yangtze region.(2)By using ancient water dynamic field recovery and fluid dynamics simulation technology, according to the multi-phase of tectonic movement in the Yangtze region, the role of deposition and erosion, hydrodynamic conditions, dividing different marine reservoir’s underground runoff evolution of the study area into Caledonian period, Hercynian - Indosinian early, late Indo-Chinese - as early as Yanshanian late Yanshanian - Himalayan hydrogeological cycles 2-4, the rehabilitation and reconstruction of the ancient marine reservoir hydrodynamic field. Dynamic field in accordance with reservoir water and groundwater runoff trend convergence characteristics of the study area is conducive to accumulation of oil-gas-water hydrodynamic model: low-power trap-type, low-power semi-trap type, variant steep potential gradient and the platform margin and saddle-shaped, such as streaming potential. Potential field through the fluid analysis of the study area reveals a different structure with different hydrogeological conditions and the complexity of the convergence model to reservoir water, runoff succession, burying the closure conditions and chemical characteristics of water as a rating factor, forecast Yangtze marine areas of favorable reservoir of natural gas gathering section.(3) By using groundwater geochemical factor transformation analysis technique, observing a large number of thin section and identification and statistics the mineral composition and pore filling material, the marine strata in the Yangtze region identified: atmospheric corrosion of fresh water, cave, dissolved joints, muddy and filled to Baiyun combination of fresh dolomite; pyrite, shale discharged ballast water and dolomite recrystallization solution portfolio; tectonic rupture, quartz precipitation, precipitation of pyrite, dolomite shaped, organic composition, such as corrosion. Corresponding to the chemical environment of the water are: quasi-phase with the near-surface evaporation of ultra-salinity aqueous environment; shallow water buried in low-temperature environment; buried deep in - high-temperature brine environment. Reservoir in the anatomy of the hydrodynamic characteristics of field and water chemistry on the basis of the first with the establishment of the causes of the formation water chemistry and mode of sequence evolution.(4) By using fluid geochemical tracer technique, through the comprehensive study about the fluid of carbon, oxygen and strontium isotopes indicate that: the West in most areas of Hunan, Hubei, Cambrian V fluid downward migration Sinian Dengying Formation and upward review of Ordovician reservoir migration, mainly as a result of the analysis of samples formed in the pyrolysis oil, the description under the portfolio of letters separated by insulating fluid is invalidated, under the combination of Western Hunan, Hubei, and the underlying Sinian formation of large-scale oil and gas reservoirs is no longer possible . Western Hubei-Eastern Chongqing Triassic and Permian fluid in the main from the Upper Permian, and the infiltration of surface water by the impact of small, marine portfolio not on the underlying Paleozoic fluid as early as by adding, if the ancient Health sector as exploration for the purpose of layer, under the portfolio has a relatively good preservation conditions. Jianghan Plain area in the early filling fluid, the fluid from the underlying Cambrian, Paleozoic underlying and overlying Triassic connected fluid, early Paleozoic relatively poor preservation conditions; advanced fluid-filled when, as early as the Paleozoic and Mesozoic strata of the fluid are not connected, that is relatively good preservation conditions late. However, Raman analysis of fluid inclusions indicate that the lack of marine strata may be large-scale oil and gas filling. Of fluid chemistry - Kinetics of migration trajectory, analysis of fluid behavior and the trajectory associated with oil and gas into Health System preservation of the integrity and inheritance.(5) According to effective hydrocarbon kitchen, the fluid compartment in middle Yangtze region on marine strata is divided into four major units in vertically: bottom-up, respectivelyⅠ-fluid compartment unit (∈1-Z),Ⅱ- fluid compartment unit (O-∈2),Ⅲ- fluid compartment unit (S) andⅣ- fluid compartment unit (T1-D).(6) Through accumulation dynamic theory to explore the main controlling factors of accumulation. The results show that: to preserve the condition that in the Yangtze area marine hydrocarbon accumulation a key factor, and the tectonic uplift erosion, faulting, fluid to preserve the impact of the succession is the preservation of the three elements of oil and gas. Considering the exposed strata, in particular the extent of the Jurassic cover; late tectonism and fracture strength of the closure; hydro-geological conditions and fluid chemistry - the characteristics of dynamic behavior; fluid compartment of the present pressure and pressure evolution of the ancient ; palaeo-fluid source, cross-layer of palaeo-fluid migration and transport layer the size of the archive of paleo-fluid and fluid quality of the evolution of storage conditions and the causes of various factors such as contact was established in present-day marine strata in the Yangtze area fluid compartment the effectiveness of oil and gas preservation system comprehensive evaluation index system.(7) Regarding the having been established preservation oil and gas preservation efficiency comprehensive evaluation index system of currency fluid compartment system in middle Yangtze marine strata region as standard, combination of fluid compartment controlling factors of oil and gas reservoir analysis, forecast the favorable exploration region in fluid compartment unit. Of which: Jianghan Plain area for a block of unit II-compartment favorable oil and gas exploration zone; Jianghan plain area of zone 2 and Western Hubei-Eastern Chongqing zone 2 for III-compartment unit favorable oil and gas exploration zone; Western Hubei-Eastern Chongqing three blocks for the IV-compartment unit favorable oil and gas exploration zone. Western Hunan, Hubei, no favorable area for exploration.更多还原