【作者】 王斌；

【导师】 何生；

【作者基本信息】 中国地质大学 ， 矿产普查与勘探， 2022， 博士

【摘要】 顺托果勒低隆起是塔里木盆地12个一级构造单元之一,南北向夹持于塔北、塔中两大古隆起之间,东西向位于满加尔坳陷和阿瓦提坳陷间的低隆部位,东南方向延伸至古城墟隆起,是一个相对稳定的构造单元,面积约3.2×10⁴km²。2016年中石化在其北部地区中下奥陶统发现了世界首例超深层海相碳酸盐岩断溶体油藏,埋深大于7000m,油藏沿盆内走滑断裂带分布,属于典型的“三新”勘探领域,极具特色,具有较高的研究价值。顺托果勒低隆北部发育的顺北1号、3号、5号和7号走滑断裂带均获得了重大油气发现,现已建成百万吨轻质油年产能阵地,勘探证实该地区主干走滑断裂带碳酸盐岩储层整体含油,但油藏性质和富集程度存在较大的差异性,成藏过程十分复杂。目前的研究主要是从生产需要的角度出发,集中在断溶体地震识别,走滑断裂带结构和活动特征,断-储配置关系,油气藏特征及分布差异性等方面,但走滑断裂带多期断缝体系-复杂流体活动耦合与储层、成藏关系不清楚,流体对断控储层的改造机理研究不深入,断裂控藏、控富机理认识还不够全面。论文研究以克拉通盆地内部走滑断裂带动态成储-成藏为主线,聚焦碳酸盐岩储层成岩-流体-成藏耦合关系、多期油气成藏过程中的年代学判识两个关键科学问题,开展了顺托果勒低隆北部地区主干走滑断裂带（顺北1号、5号、7号断裂）构造解析与油气差异性分析,烃源岩热演化供烃、成岩流体来源与演化、成脉矿物与成藏期定年、断裂活动和输导体系等关键成藏要素时空匹配研究,恢复了研究区走滑断裂带油气动态成藏过程,建立了不同走滑构造样式下的成藏模式。利用三维地震小尺度滑移距走滑断裂精细解析技术开展了研究区3条主干走滑断裂构造变形样式和活动性分析,明确了走滑断裂“平面分段连结、纵向分层变形”的构造样式,即纵向上,T₇⁴界面以下碳酸盐岩地层为高陡走滑断层,上覆碎屑岩地层发育雁列正断层;平面上,主干走滑断裂带在中下奥陶统发育叠接拉分、叠接挤压和走滑平移3种不同分段样式相互连结。不同走滑断裂带、同一走滑断裂不同分段油藏性质和富集程度存在明显的差异性。断裂带钻井原油样品物性统计和地化特征分析表明,从顺北7号、5号断裂北段→5号断裂中段→1号断裂带、1号分支断裂气油比、H₂S含量、天然气干燥系数增加,原油密度变小,成熟度增加。利用重点钻井岩心观察、铸体薄片鉴定和阴极发光等技术手段确定研究区中下奥陶统碳酸盐岩储层缝洞充填物有方解石、沥青或硅质等,其中方解石充填最为常见、分布广泛。研究识别出C1、C2、C3与C4共四期方解石脉,激光原位方解石U-Pb同位素定年获得C1、C2与C3方解石脉体的年龄分别为460～446Ma、440～436Ma、421～420Ma,均形成于加里东期。通过示踪矿物鉴别、流体包裹体分析、同位素地球化学（碳、氧、锶、硅等）与稀土元素等分析识别出中下奥陶统储层成岩流体主要有富钙质流体、富硅流体、埋藏期封存海水、热液流体和烃类流体等类型,结合成岩序次和矿物年代学研究成果综合确定了不同流体的来源,认为依次有加里东中期Ⅲ幕来源于中上寒武统的海源地层水和地壳深部的富硅流体,加里东晚-海西早期来源于中下奥陶统的海源地层水和寒武系底部烃源岩供给的烃类流体,海西晚期的深部热液流体。结合储层岩相学和走滑断裂发育演化特征进一步揭示了研究区主干断裂带深层成岩流体演化过程与模式。应用烃类包裹体宿主矿物（方解石脉）U-Pb同位素年龄约束下的流体包裹体综合成藏期判识技术确定研究区奥陶系储层经历了三期原油充注过程,并确定了成藏时间。第1期原油充注时间约为436～421Ma,即加里东晚期,后被海西早期构造运动破坏改造而残留储层沥青;第2期原油充注时间约为385～363Ma左右,即海西早期;第3期原油充注时间约为258～235Ma左右,即海西晚期-印支期。主干断裂带深层成岩流体演化、断裂活动性与成藏期综合分析厘定了研究区走滑断控环境下一间房组-鹰山组储层成岩-流体-成藏耦合关系,即为泥晶化作用→胶结/重结晶作用→白云石化作用→构造破裂化作用→C1方解石充填（加里东中期Ⅲ幕）→硅化作用（隐晶质硅充填）→构造破裂化作用→C2方解石充填（加里东晚期）→第1期原油充注（加里东晚期）→C3方解石充填（加里东晚期）→储层致密化→古油藏破坏、沥青充填（海西早期）→构造破裂化作用→第2期原油充注（海西早期）→压实压溶作用→热液溶蚀作用→C4方解石、黄铁矿等充填→第3期原油充注（海西晚-印支期）→持续埋藏演化（燕山期-喜山期）。研究区中下奥陶统油藏为埋深大于7000m的超深层碳酸盐岩断溶体轻质-挥发油藏,走滑断裂控储、控藏、控富特征明显,整体具有“寒武供烃、断溶成储、垂向输导、多期成藏、走滑控富”的成藏模式。现今工业产出的原油主要为第2期和第3期充注成藏的原油,不同断裂带及同一断裂带不同位置经历了不同的油气充注混合过程,造成了现今复杂的油气分布面貌,而其主要受控于走滑断裂活动性及其与烃源岩生烃阶段的时空配置关系。顺北7号断裂带主要为海西早期成藏,充注发黄色荧光的相对低成熟度原油;顺北5号断裂带北段经历了海西早期和海西晚-印支期两次成藏,但以海西早期成熟度相对低的发黄色荧光的原油充注为主;顺北5号断裂带中段、顺北1号断裂分支和次级断裂同样经历了海西早期和海西晚-印支期两次成藏,但以海西晚-印支期成熟度相对高的发蓝绿色荧光的原油充注为主;顺北1号主干断裂带主要为海西晚-印支期成藏,充注成熟度相对高的发蓝绿色荧光的原油。不同断裂带及同一断裂带不同位置油气富集程度也存在较大的差异性,其主要受走滑断裂通源性、断裂演化程度及分段变形样式的控制,纵向贯穿性好的主干走滑断裂往往油气充注强度大,演化程度高则通常储集体发育规模大,同一走滑断裂带拉分段断裂宽度大、纵向储层深度大,油气富集程度最高,其次为挤压段和平移段。论文研究为揭示超深层碳酸盐岩断-储-藏关系提供一些新的思路,形成了基于U-Pb同位素定年约束下的成藏期综合判识技术,确定了油气成藏期次和时间,厘定了深层断控环境下成岩-流体-成藏耦合关系,恢复了不同走滑断裂带油气成藏动态过程,对推动海相叠合盆地碳酸盐岩成藏定年技术发展,深化塔里木盆地顺托果勒地区断溶体油气藏成藏机理与富集规律认识具有一定的指导作用。更多还原

【Abstract】 The Shuntuoguole Low Uplift is one of the 12 first-order structural units of the Tarim Basin.It is sandwiched between the two paleouplifts of the Tabei and the Tazhong in the north-south direction.It is located in the low uplift between the Manjiaer depression and the Awati depression in the east-west direction and extends to the Guchengxu uplift in the southeast.It is a relatively stable structural unit with an area of about 3.2×10⁴km².In 2016,Sinopec discovered the world’s first ultra-deep fault solution reservoir of marine carbonate in the Middle and Lower Ordovician of its northern region,with a buried depth of more than 7,000 m and distributed along a small-scale strike slip fault zone in the Tarim Basin,exhibiting unique characteristics and high research values.Significant oil and gas fields have been discovered in the Shunbei 1,3,5,and 7 strike-slip fault zones developed in the north of the Shuntuoguole Low Uplift,with an annual production of one million tons of light oil.The carbonate reservoirs in the main strike-slip fault zones of the Shuntuoguole Low Uplift are petroleum-bearing as a whole,but the reservoir properties and enrichment levels are quite different,thus the accumulation process is very complicated.Previous studies focused mainly on the seismic identification of fault solution,the structure and activity characteristics of strike slip fault zone,the relationship between fault and reservoir configuration,and oil and gas reservoir characteristics and distribution differences from a perspective of production demand.However,the relationship among multi-stage fault system,fluid activity,reservoir formation,and hydrocarbon accumulation mechanism in the strike slip fault zone is not clear,the transformation mechanism of fluid to fault-controlled reservoir is not deeply studied,and the control mechanism of faults on hydrocarbon accumulation is not well understood.Taking the dynamic reservoir-forming and hydrocarbon accumulation of the strike slip fault zone in the Shuntuoguole Low Uplift as the main line,this thesis focuses on two key scientific issues,including the relationship among diagenesis evolution,fluid activity,and hydrocarbon accumulation of carbonate reservoirs and the determination of oil charge timings in multi-stage hydrocarbon accumulation.Structural analysis,oil and gas property analysis,thermal and hydrocarbon generation history analysis of source rocks,evolution and source analysis of diagenetic fluids,absolute dating of calcite and oil charge,and correlation analysis between fault activity and transport system were carried out,the dynamic hydrocarbon accumulation process were reconstructed,and the accumulation models under different strike slip structural styles were established in the main strike slip fault zones（Shunbei 1,5,and 7）of the northern part of the Shuntuoguole Low Uplift.The structural deformation patterns and activity of three main strike-slip faults in the study area were analyzed by using the fine analysis technology of 3D seismic small-scale slip distance strike-slip faults,and the structural deformation style of“plane segmentation and vertical stratification”of strike slip faults was defined.Vertically,high-steep strike-slip faults are developed on the carbonate strata below the T₇⁴interface,and the overlying clastic strata develope en echelon normal faults Horizontally,the main strike-slip fault zone develope three different segmented splicing styles,including superimposed pull-apart style,superimposed compression style,and strike-slip translation style in the Middle and Lower Ordovician.There are obvious differences in the reservoir properties and enrichment degree of different strike-slip fault zones and different sections of the same strike-slip fault.The physical property statistics and geochemical characteristics analyses of crude oils in the fault zone show that the gas oil ratio,H₂S content,natural gas drying coefficient,and thermal maturity increase,whereas the crude oil density decreases from the north section of the Shunbei 5 fault zone to the middle section of the Shunbei 5 fault zone,and then to the Shunbei 1 fault zone.By means of core observation,cast thin section identification,and cathodoluminescence observation,calcite,bitumen,and silica were observed in the Middle and Lower Ordovician carbonate reservoir of the Shunbei Low Uplift,with calcite widely distributed.Four stages of calcite veins including C1,C2,C3,and C4were identified in this study.The timings of calcite veins C1,C2,and C3 formation obtained by laser in-situ calcite U-Pb isotope dating were 460～446Ma,440～436Ma,and421～420Ma,respectively,all of which were formed in the Caledonian.According to tracer mineral identification,fluid inclusion analysis,isotope geochemistry（carbon,oxygen,strontium,silicon,etc.）,and rare earth element analysis,multiple types of diagenetic fluids,such as calcium-rich fluids,silicon-rich fluids,sealed seawater in burial period,hydrothermal fluids,and hydrocarbon fluids were identified in the Middle-Lower Ordovician reservoirs.Combined with the results of diagenetic sequence and mineral chronology,the sources of different types of diagenetic fluids were comprehensively determined.It is believed that the diagenetic fluids of the third episode of Middle Caledonian came from the marine stratum water and the silicon-rich fluid of the Middle-Upper Cambrian,that of the late Caledonian-early Hercynian was sourced from marine stratum water of the Middle-Lower Ordovician,hydrocarbon fluids supplied by source rocks at the bottom of Cambrian,and the deep hydrothermal fluids in the Late Hercynian.Combined with reservoir petrography and the development and evolution characteristics of strike-slip faults,the evolution process and model of deep diagenetic fluids in the main fault zone of the study area were further revealed.Using the comprehensive identification technology of fluid inclusion accumulation period constrained by U-Pb isotopic age of hydrocarbon inclusion host mineral（calcite vein）,it is determined that the Ordovician reservoir in the study area has experienced three stages of crude oil charging process,and the accumulation time is determined.The timing of the first stage crude oil charge was about 436～421Ma,i.e.late Caledonian,which was damaged and transformed by the Early Hercynian tectonic movement to form residual reservoir bitumen;the timing of phase 2 crude oil charge was about385～363Ma,that is,the Early Hercynian period;the timing of phase 3 crude oil charge was about 258～235Ma,i.e.the Late Hercynian Indosinian period.The comprehensive analysis of fault activity,hydrocarbon accumulation period,and diagenesis fluid evolution in the main fault zone has determined the diagenetic-fluid-accumulation coupling relationship of the Yijianfang and Yingshan Formation under the strike slip fault controlled environment in the study area,which is clarified as argillization→cementation/recrystallization→dolomitization→structural rupture→C1 calcite filling（Episode III in the Mid-Caledonian）→silicification（cryptocrystalline silicon filling）→tectonic rupture→C2 calcite filling（the Late Caledonian）→phase 1 crude oil filling（the Late Caledonian）→C3 calcite filling（the Late Caledonian）→reservoir densification→paleoreservoir destruction and asphalt filling（the Early Hercynian）→tectonic rupture→phase 2 crude oil l charge（the Early Hercynian）→compaction and pressure solution→hydrothermal dissolution→C4 calcite Pyrite filling→phase 3crude oil charge（the Late Hercynian-Indosinian）→continuous burial evolution（Yanshan-Himalayan）.The Middle and Lower Ordovician reservoirs in the study area are ultra-deep carbonate fault solution light-volatile reservoirs with a buried depth of more than 7,000m,showing the obvious characteristics of strike slip faults controlling reservoir,storage and enrichment.As a whole,the reservoir forming mode of“Cambrian hydrocarbon supply,fault solution forming reservoir,vertical transportation,multi-stage accumulation,and strike slip controlling enrichment”was proposed.At present,the industrial crude oil production is mainly charged into reservoirs during the second and third stages.Different fault zones and different positions of the same fault zone have experienced different hydrocarbon charging and mixing processes,resulting in the current complex distribution of oil and gas plays,which is mainly controlled by the activity of strike-slip faults and their temporal-spatial allocation with the hydrocarbon generation stages of source rocks.The reservoirs of the Shunbei 7 fault zone were mainly accumulated in the Early Hercynian,filled with yellow fluorescent crude oil with relatively low maturity.The northern Shunbei 5 fault zone experienced two hydrocarbon accumulation processes in Early Hercynian and Late Hercynian,and was mainly filled the yellow fluorescent crude oil with relatively low maturity in the Early Hercynian;the middle Shunbei 5 fault zone,and the branch and the secondary fault of Shunbei 1 fault also experienced twohydrocarbon accumulation processes in the Early Hercynian and Late Hercynian,and was mainly filled with blue-green fluorescent crude oil with relatively high maturity in the Late Hercynian-Indosinian;The crude oil in the Shunbei 1 main fault zone was mainly accumulated in the Late Hercynian-Indosinian,and was filled with relatively high maturity crude oil that emits blue-green fluorescence.There are also great differences in oil and gas enrichment degrees in different fault zones and different locations of the same fault zone,which is mainly controlled by the continuity of strike slip faults,the degree of fault evolution,and segmented deformation style.The main strike slip faults with good longitudinal penetration tend to have high oil and gas filling intensity,high degree of evolution,and large scales of reservoir development.The pull section of the same strike-slip fault zone has large fault width and large longitudinal reservoir depth,and the oil and gas enrichment degree is the highest,followed by the compression section and translation section.This research provides some new ideas for revealing the fault-storage-reservoir relationship of ultra-deep carbonate rocks,forms a comprehensive identification technology of reservoir-forming period based on U-Pb isotope dating,determines the timing of oil and gas charge,clarifies the coupling relationship of diagenesis-fluids-reservoir forming under the deep fault controlling environment,and restores the dynamic process of reservoir forming in different strike slip fault zones.It plays an important role in promoting the development of carbonate reservoir-forming dating technology in marine superimposed basins and deepening the understanding of the accumulation mechanism and enrichment law of fault solution oil and gas reservoirs in the Shuntuoguole area,Tarim Basin.更多还原