四川盆地东部大中型气藏成烃条件分析

应用含油气系统理论和气藏地球化学方法,研究了四川盆地东部石炭系和下三叠统飞仙关组大中型气藏的烃源地球化学控制因素。指出:川东地区发育的下志留统和上二叠统两套大中型泥质烃源岩是石炭系和下三叠统飞仙关组大中型天然气藏的烃源保障,石炭系和下三叠统飞仙关组大中型气藏的形成受开江印支―燕山期古隆起的控制,喜山运动形成的圈闭对天然气成藏具有调整作用。     

四川盆地三叠系天然气地球化学特征及资源潜力分析

简要介绍了四川盆地三叠系的总体勘探形势,认为该层系资源发现率和探明率不高,仍具有很好的勘探前景。通过分析四川盆地三叠系天然气的地球化学特征,指出该层系可划分为2个含油气系统,即志留系—中三叠统含油气系统和上三叠统—侏罗系含油气系统。通过研究四川盆地三叠系烃源岩地球化学特征、生气强度、展布特征等，定量评价出该层系油气资源总量为8.01×10¹²m³，同时指出了该层系天然气有利勘探领域。     

GEOCHEMISTRY OF LITHUANIAN OILS AND SOURCE ROCKS: A PRELIMINARY ASSESSMENT

A series of oils and potential petroleum source-rock samples has been analysed from exploration wells on-and offshore Lithuania. Despite the limited amount of data, the results indicate the possible existence of partly-exhausted source rocks within the Cambrian succession. Furthermore, possible source rocks are present within the Ordovician succession, and excellent source rocks occur within the Silurian in several wells. The source rocks are all present within a few hundred metres of stratigraphic succession, and the thermal maturity roughly follows the actual depth of burial, despite the fact that most of the subsidence and maturation took place in the latest Palaeozoic. The most important reservoir rocks are Middle Cambrian sandstones, but petroleum accumulations also occur in Ordovician limestones and Silurian reefal carbonates. Petroleum accumulations in Lithuania probably result from the pooling of oil derived from several sources, with the Lower Silurian (Llandoverian) shales being the most important single contributor.     

BIOMARKER CHARACTERISTICS OF POTENTIAL SOURCE ROCKS IN THE JABAL NAFUSAH AREA,NW LIBYA: PETROLEUM SYSTEMS SIGNIFICANCE

The Jifarah Arch of NW Libya is a structurally prominent feature at the eastern end of the regional Talemzane Arch, separating the Ghadamis hydrocarbon province to the south from the offshore Pelagian province to the north. The Arch has experienced a complex structural history with repeated episodes of uplift, exhumation and burial. This paper provides a provisional assessment of its hydrocarbon habitat based on detailed geochemical analyses of potential Triassic, Silurian and Ordovician source rocks encountered by wells drilled in the area. Twenty‐seven core and cuttings samples of marine shales were collected from eight widely‐ dispersed wells and analyzed using standard Rock‐Eval pyrolysis techniques. Kerogen types II‐III were identified in the majority of Triassic samples analysed, indicating a low hydrocarbon generation potential, but oil‐prone Type II kerogen was found in the basal Silurian Tanezzuft Formation and Ordovician Memouniat Formation. The presence of steranes and acyclic isoprenoids suggested variable inputs of algal, bacterial and terrestrial organic matter, while biomarkers including C₃₀‐gammacerane and β–carotene and selected biomarker ratios (Pr/Ph ratio and homohopane index) were used to assess their depositional environment. Results indicate that extended zones with periodic (if not continuous) oxygen‐deficient conditions existed throughout the basin during Late Ordovician and Early Silurian time, favouring the preservation of organic matter. The thermal maturity of the samples was assessed by Rock‐Eval pyrolysis, zooclast reflectance, molecular ratios including C_32‐22S/(22S+22R)‐homohopanes, Ts/(Ts+Tm), C₂₉‐steranes and parameters based on the relative abundance of methylphenanthrene, methyldibenzothiophene and methylnaphthalene isomers. The results indicate significant variability in thermal maturity, with Ordovician and Silurian source rocks ranging from 0.6% to 0.7% VR_o equivalent increasing to 1.0% locally. These values represent palaeo‐maturities achieved at different times in the past and are considered too low to have generated significant volumes of hydrocarbons directly. However the downdip equivalents of these source rocks in the adjacent Ghadamis Basin contributed to prolific petroleum systems. The absence of large petroleum accumulations on the Jifarah Arch contrasts with the western part of the geologically similar Talemzane Arch, which harbours several giant and supergiant oil and gas fields. This difference is attributed both to the complex structural history of the Jifarah Arch, which permitted post‐charge leakage of palaeo‐accumulations, and stratigraphic migration barriers which restricted migration between Tanezzuft source rocks and Ordovician and Triassic reservoirs.     

塔里木盆地寒武系两类优质烃源岩及其形成的含油气系统

寒武系烃源岩是塔里木盆地主要烃源岩之一,包括泥页岩和碳酸盐岩。泥页岩类烃源岩有机碳平均含量为1.87%,发育于欠补偿盆地环境,主要分布于盆地的东部,有效厚度120～415m;碳酸盐岩类烃源岩有机碳平均含量为0.42%,发育于台地内的蒸发泻湖环境,主要分布于盆地西部,有效厚度288～324m。两类烃源岩形成了不同的油气系统,盆地相泥页岩类烃源岩的油气系统以满加尔凹陷为生烃中心,储层主要为寒武系-奥陶系碳酸盐岩和志留系、石炭系、三叠系和侏罗系砂岩;台地相碳酸盐岩烃源岩油气系统的生烃中心可能在巴楚凸起一带,主要储集层为下奥陶统和石炭系。     

上扬子地台北缘古生界海相烃源岩有机地球化学特征

上扬子地台北缘古生代广泛沉积了一套海相碳酸盐岩和泥质岩。通过对16条沉积剖面系统采样,结合样品有机地球化学分析结果,认为该区有效烃源岩主要发育在下二叠统、下志留统下部、上奥陶统和下寒武统地层中;烃源岩以I型、Ⅱ 型为主,生烃能力较强,未丧失生气能力。综合评价认为下寒武统及下二叠统是区内的主力烃源岩;下志留统下部及上奥陶统在局部地区可能存在有利的烃源岩发育层段。     

贵州页岩气源岩特征及页岩气勘探远景分析

贵州在地质历史时期长期处于海洋沉积环境,特别是缺氧沉积环境发育,形成多层位黑色泥页岩。根据黑色泥页岩分布范围及厚度,主要划分出震旦系陡山沱组、下寒武统牛蹄塘组、奥陶系五峰组、下志留统龙马溪组、中泥盆统罐子窑组-火烘组、下石炭统大塘组、二叠系栖霞组-龙潭组。页岩气烃源岩具有层位多\,厚度大\,有机质含量高,成熟度高等特点。同时,根据页岩气烃源岩分布、厚度、有机质含量、成熟度等综合分析,划分出有利的页岩气成藏区,即武陵褶皱、黔中-黔北、南盘江紫云-册亨页岩气有利发育区,并认为南盘江坳陷的册亨-望谟一带是最有利的页岩气勘探远景区。     

塔里木盆地叠合演化与油气聚集

根据前人成果和石油勘探资料,对塔里木盆地进行了解剖,认为自寒武纪以来,它经历了寒武纪-志留纪-泥盆纪、石炭纪-二叠纪、三叠纪-侏罗纪、白垩纪-新生代等四大构造演化阶段.寒武纪-泥盆纪盆地演化阶段受周缘板块裂离与汇聚的控制,以碳酸盐岩、膏盐岩和碎屑岩建造为特征,盆地基底整体由早期的西高、东低向东高西低翘倾转变,中奥陶世末的构造事件形成了沙雅、塔中和塔西南古隆起,志留纪晚期的构造事件导致了盆地的整体隆升与剥蚀.石炭纪-二叠纪进入陆表海盆地和陆内坳陷演化阶段,以碳酸盐岩和膏泥岩建造为主要特征,整体表现为西南降、东北抬的构造格局.二叠纪沉积末的构造事件导致了盆地隆升与剥蚀,北部构造变形、剥蚀强烈.三叠纪形成了南、北山前坳陷和台内坳陷盆地,侏罗纪沉积主要在山前坳陷.自白垩纪-古近纪,盆地整体沉降,发生了海侵,逐渐形成大型陆内坳陷盆地,白垩纪末构造事件导致了巴楚隆起的初步形成和地层的剥蚀,新近纪晚期的构造事件形成库车、塔西南前陆盆地和中央隆起带.盆地叠合演化形成了中-下寒武统、中-上奥陶统、三叠系-侏罗系等多套富含有机质的烃源岩,与盆地内叠合联片发育的中-下寒武统膏泥岩、上奥陶统泥岩、石炭系膏泥岩、三叠系-侏罗系泥岩、煤系和古近系-新近系膏盐岩、泥岩构成了盆地内最佳的源盖组合,成为油气富集的基础.碳酸盐岩岩溶储层、碎屑岩中的砂岩储层与构造作用形成的圈闭形成了盆地良好的储-圈组合,成为油气富集的必要条件.盆地的多期叠合演化形成了台盆区下组合、中组合和山前坳陷区上组合三大勘探层系.勘探成果显示,古隆起、古斜坡和烃源岩的分布控制盆地内油气分布.     

四川盆地二叠系烃源岩及其天然气勘探潜力(二)——烃源岩地球化学特征与天然气资源潜力

四川盆地二叠系发育中二叠统海相碳酸盐岩和上二叠统海陆交互相碎屑岩两套烃源岩,由于其热演化程度高,造成对烃源岩原始生烃潜力及天然气资源潜力认识不清。为此,通过研究该盆地内探井及盆地周缘剖面大量二叠系烃源岩样品的地球化学特征及生烃潜力随成熟度的变化规律,探讨了二叠系烃源岩的原始生烃潜力以及在地质历史时期生排烃量、干酪根与原油裂解生成天然气的资源潜力。研究结果表明:(1)上二叠统龙潭组泥岩和碳质泥岩总有机碳含量高、原始生烃潜力大,是二叠系中最主要的油气烃源岩,龙潭组煤层也是非常重要的气源岩,上二叠统大隆组有机碳含量和生烃潜力也很高,是四川盆地北部重要的油气源岩,中二叠统碳酸盐岩烃源岩总有机碳含量与原始生烃潜力低,是次要的油气源岩;(2)二叠系烃源岩在地质历史时期生成原油3 290×10~8 t,生成天然气420×10~(12) m~3,龙潭组烃源岩对原油和天然气的贡献率分别为80%和85%;(3)二叠系烃源岩形成的古油藏原油资源量为580×10~8 t,原油裂解气资源量为4.45×10~(12) m~3,干酪根直接生成的天然气资源量约为2.10×10~(12) m~3,天然气资源总量可达6.55×10~(12) m~3,其中原油裂解气占70%。结论认为,四川盆地北部和中部—东南部是二叠系的两个生烃中心,也是最有利的二叠系油气成藏和天然气勘探区域,古油藏是最具天然气资源潜力的勘探目标。     

HYDROCARBON SOURCE ROCKS AND GENERATION HISTORY IN THE LUNNAN OILFIELD AREA, NORTHERN TARIM BASIN (NW CHINA)

In this paper we report on source rocks and maturation history at the Lunnan oilfield, northern Tarim Basin (NW China), using a combination of organic petrographic and geochemical techniques. Three separate source rock intervals are present here: Cambrian mudstones and argillaceous limestones; Middle and Upper Ordovician argillaceous limestones; and Triassic mudstones. Reservoir rocks comprise Lower Ordovician carbonates, Carboniferous sandstones, and Triassic and Jurassic sandstones. Structural traps were formed principally during the Silurian and Jurassic.
The Lunnan field is located on a small-scale palaeo uplift which developed during the Early Palaeozoic. Hydrocarbons migrated updip from source areas in surrounding palaeo-lows along faults and unconformities. Major phases of hydrocarbon generation and migration occurred in the Early Silurian — Late Devonian, Cretaceous — Early Tertiary and Late Tertiary. Uplift and intense erosion at the end of the Devonian destroyed Early Palaeozoic oil and gas accumulations sourced from the Cambrian source rocks, but hydrocarbons generated by Middle and Upper Ordovician source rocks during the Mesozoic and Tertiary have been preserved. At the present day, accumulations are characterized by a range of crude oil compositions because source rocks from different source areas with different maturation histories are involved.     

Processes and causes of Phanerozoic tectonic evolution of the western Tarim Basin,northwest China

This paper addresses the Phanerozoic tectonic evolution of the western Tarim Basin based on an integrated stratigraphic,structural and tectonic analysis.P-wave velocity data show that the basin has a stable and rigid basement.The western Tarim Basin experienced a complex tectonic evolutionary history,and this evolution can be divided into six stages:Neoproterozoic to Early Ordovician,Middle Ordovician to Middle Devonian,Late Devonian to Permian,Triassic,Jurassic to Cretaceous and Paleogene to Quaternary.The western Tarim Basin was a rift basin in the Neoproterozoic to Early Ordovician.From the Middle Ordovician to Middle Devonian,the basin consisted of a flexural depression in the south and a depression that changed from a rift depression to a flexural depression in the north during each period,i.e.,the Middle-Late Ordovician and the Silurian to Middle Devonian.During the Late Devonian to Permian,the basin was a depression basin early and then changed into a flexural basin late in each period,i.e.,the Late Devonian to Carboniferous and the Permian.In the Triassic,the basin was a foreland basin,and from the Jurassic to Cretaceous,it was a downwarped basin.After the Paleogene,the basin became a rejuvenated foreland basin.Based on two cross sections,we conclude that the extension and shortening in the profile reflect the tectonic evolution of the Tarim Basin.The Tarim Basin has become a composite and superimposed sedimentary basin because of its long-term and complicated tectonic evolutionary history,highly rigid and stable basement and large size.     

塔里木盆地中央隆起带油气突破领域与勘探方向

塔里木盆地中央隆起带以发育多套烃源层系、多种储集类型、多类圈闭与油气藏、多期油气充注、多种成藏组合为基本特征,是典型的大型油气聚集带。基于当前钻井与地震勘探等资料以及地质综合研究,推论塔里木盆地中央隆起带油气新突破与新发现的主要领域是奥陶系礁滩相和加里东期古岩溶、志留系和泥盆系"不整合三角带"、寒武系盐下白云岩等。在加强重点勘探的同时,要进一步强化上述领域的针对性研究和做好勘探技术配套攻关,形成行之有效的综合勘探技术。     

南黄海古生代盆地原型演变与烃源岩发育特征

钻井及露头证实下扬子陆区发育下寒武统幕府山组、上奥陶统五峰组—下志留统高家边组、二叠系3套烃源岩。盆地发育时期的动力学环境决定该时期的盆地原型，盆地原型影响盆内岩相及烃源岩展布。幕府山组沉积时期，南黄海盆地表现为张裂背景下的被动陆缘克拉通盆地，盆地相及深水陆棚相呈环带状围绕古隆起或台地发育，为烃源岩发育优势相带，推测南黄海盆地中部隆起及北部幕府山组烃源岩发育较好；五峰组—高家边组沉积时期，南黄海盆地表现为挤压背景下的前陆盆地，盆地相、斜坡相、深水陆棚相由西北向东南依次呈条带状分布，盆地相、深水陆棚相为烃源岩发育优势相带，预测五峰组—高家边组烃源岩主要在南黄海地区中北部发育且有一定厚度；上二叠统龙潭组沉积时期，南黄海盆地表现为挤压背景下的活动大陆边缘坳陷型盆地，在该盆地中各沉积相带呈环带状分布，三角洲相、潮坪相、沼泽相为烃源岩发育优势相带，发育龙潭组品质中等—好的烃源岩；预测龙潭组烃源岩在南黄海盆地中部发育，是南黄海盆地古生界的次要烃源岩。      

川西北地区海相烃源岩地球化学特征、分布规律及天然气勘探潜力

川西北地区为近年来四川盆地天然气勘探的热点地区,但时至今日对该区海相烃源岩的地球化学特征和分布仍缺乏全面的研究.选取8条露头剖面对川西北地区下震旦统陡山沱组、上震旦统灯三段、下寒武统筇竹寺组、下志留统龙马溪组、中泥盆统、中二叠统茅口组、上二叠统龙潭组/吴家坪组和大隆组8套海相烃源岩进行了系统的有机地球化学分析,探讨了该...     

塔河油田志留系成藏条件分析

塔河油田地理位置处于新疆维吾尔自治区库车县和轮台县境内,构造位置位于塔里木盆地沙雅隆起阿克库勒凸起西南部斜坡.受加里东晚期、海西早期、海西晚期和燕山早期构造运动影响,阿克库勒凸起主体部位及南部斜坡的大部分地区缺失志留系、泥盆系、上石炭统、二叠系、侏罗系中上统,另外中-上奥陶统也遭受不同程度剥蚀,以至局部地带缺失.塔河油田大部分地区缺失志留系,目前主要在其西南部钻遇该套地层,且主要保存柯坪塔格组(S₁k)和塔塔埃尔塔格组(S₁t).区域烃源岩、储盖及圈闭条件分析表明,塔河油田及其邻区志留系圈闭多属于与地层削截或与超覆尖灭有关的地层-岩性、地层-构造复合型圈闭,少数为构造圈闭与岩性圈闭.综合研究认为志留系具备成藏的地质条件.      

南方海相油气勘探中的烃源条件分析——以江汉平原区为例

中国南方海相油气地质条件和特点给烃源条件分析提出了新内容和新要求。对于晚期成藏来说,烃源岩的时效性比其原有品质条件更为重要,烃源条件分析和烃源岩评价应该打破"唯指标论"的习俗,立足于烃源岩演化史研究,突出"阶段性"和"时效性"分析,在确定有效烃源岩及其发育区的基础上,进行资源潜力分析并指导对勘探目标的选择。对于以晚燕山—早喜山期重建的封存体系为主要勘探对象的江汉平原区海相,断陷盆地的叠覆是促成二叠系烃源岩成熟和下古生界烃源岩二次(晚期)生烃的主要原因。初步研究表明,二叠系(碳酸盐岩)烃源岩为主要的有效烃源岩,其次为上奥陶统五峰组—下志留统龙马溪组烃源岩;而主要的供烃区则是江陵凹陷、潜江凹陷等几个晚期断陷深凹的地区。      

次生孔隙形成期次与溶蚀机理——以塔中地区志留系沥青砂岩为例

显微镜鉴定结果塔中地区志留系沥青砂岩次生孔隙可分为石英及硅质岩屑颗粒边缘溶孔、石英次生加大边溶孔、长石及火山岩岩屑溶孔以及粒间碳酸盐胶结物溶孔4种类型。根据成岩序次研究，结合烃源岩成熟史、油气成藏史以及流体包裹体数据分析，它们分别形成于志留纪末-泥盆纪初、泥盆纪-二叠纪末、白垩纪和第三纪4个时期。第一、三、四期的溶蚀作用主要与下伏寒武-奥陶系烃源岩成熟产生的有机酸有关，第二期的溶蚀作用与古油藏破坏烃类微生物降解产生的有机酸有关。溶蚀作用受岩性、古油藏抬升受破坏程度以及与断层的关系控制。溶蚀型优质储层主要分布于前滨相带，尤其是塔中I号断层附近或志留系抬升暴露较严重的地区。     

RESERVOIR AND SOURCE-ROCK CHARACTERISATION OF THE EARLY PALAEOZOIC INTERVAL IN THE PERIBALTIC SYNECLISE, NORTHERN POLAND

Detailed investigations have been conducted on samples from 2,750m of conventional cores from 18 wells penetrating the Cambrian siliciclastics in northern Poland. The results of sedimentological, petrological and geochemical analyses were combined with a computeraided regional evaluation of the Polish onshore sector of the Peribaltic Syneclise. Our results may help in the successful future identification of Cambrian prospects in northern Poland. The Middle Cambrian reservoir sandstones consist of quartzites in which low porosities (5% - 8%) and permeabilities (5 to 24 mD) were preserved only in oil-bearing structures in the more deeply-buried, western part of the Peribaltic Syneclise. Isotopic studies suggest crystallisation temperatures for the pore-plugging quartz cement of between 53d?C and 78 d?C. These temperatures were not reached in the shallower, eastern part of the basin, where porosities of up to 20% are present in the quartz arenites which constitute potential reservoir units. A 150-m thick, organic-lean (0.1-l.0 wt. % TOC) Middle Cambrian shale below the quartzites, and an up to 20-m thick, organic-rich (4.5–10 wt. % TOC) Late Cambrian shale unit above the quartzites, are regarded as source rocks for the oil accumulations in the Cambrian reservoirs. The organic matter in these two shale units consists of abundant grey, lenticular particles and finely-dispersed bituminite-like constituents. The reflectance intensity of these bitumen particles is a useful parameter for evaluating the source rocks' maturity. Geochemical investigations have proved the (potential) source rocks to be immature in the shallower, eastern part of the Peribaltic Syneclise, and to have reached the “oil window ” in the more deeply-buried western part of the basin. The extractable organic matter is dominated by saturated hydrocarbons. Late Cambrian extracts can be differentiated from Middle Cambrian samples by their higher content of aromatic compounds. Reservoired Cambrian oils and extracts from Cambrian source rocks could not be distinguished by triterpane “fingerprints ”. Both are characterised by a well-developed sequence of tri- and pentacyclic compounds, with no variation in their relative abundances. Burial-history modelling indicates that rapid subsidence of the Cambrian deposits to depths of more than 2,500m occurred during the Silurian in the western part of the basin. In the eastern part, however, a much more moderate burial history is inferred. Here, the Cambrian interval lies at depths of only 1,500 to 2,200m. An analysis of the basin's geothermal history indicates that porosity-plugging quartz cementation in the Cambrian quartzites commenced in the western Peribaltic Syneclise during this rapid Silurian burial. In this western region, the source rocks reached the “oil window” during the Devonian. Hence, migration and accumulation of the generated hydrocarbons could preserve only the remaining pore space, which had already been drastically reduced. This genetic model implies that petroleum traps were formed before or during the Carboniferous. Because the thick Silurian marlstones acted as an efficient regional seal, the generated hydrocarbons must have been trapped somewhere in the underlying Early Palaeozoic sequence. Oil stains in Cambrian quartz arenites in the organic-geochemically immature eastern part of the basin point to long-distance, up-dip migration towards the basin's eastern margin. A scarcity of structural traps and reduced shalyness of the eastwards-coarsening, Early Palaeozoic sequence are adverse features, relative to a high degree of preservation of the hydrocarbons generated. The search for subtle diagenetic traps, however, may prove to be challenging.     

塔里木盆地塔中地区奥陶系油气成藏主控因素及勘探选区

通过对塔中地区钻遇奥陶系的60余口探井油气成藏及失利原因的综合分析,提出该区奥陶系油气成藏的主控因素为:①中、上奥陶统(相当于黑土凹组—萨尔干组的层位)主力烃源岩控制了塔中地区的油气分布,其主要分布于塔中凸起北部斜坡区;②4套碳酸盐岩储层(志留纪—泥盆纪古潜山岩溶储层、中奥陶世晚期—晚奥陶世早期古潜山岩溶储层、上奥陶统良里塔格组棚缘礁滩体埋藏溶蚀储层及下奥陶统内幕白云岩储层)的分布及其非均质性对成岩—岩性圈闭油气藏的形成起到了至关重要的作用;③二叠纪—早三叠世是塔中地区现今工业性油藏的主要成藏期;④圈闭及其封盖—保存条件决定了油气藏的规模。针对塔中地区奥陶系油气勘探选区及勘探步骤,提出具体的勘探工作可分3个层次进行:①近期主攻塔中I号断裂带南侧良里塔格组棚缘礁滩体成岩圈闭特大型岩性油气藏,兼探中央断垒带东段(塔中401—塔中9井区)下奥陶统古潜山岩溶储层油气藏;②对塔中10号构造带及其与中央断垒带之间的中奥陶世晚期—晚奥陶世早期形成的下奥陶统鹰山组中上部古潜山岩溶储层油气藏及塔中1—塔中7—塔中48井区下奥陶统古潜山岩溶储层油气藏进行勘探;③在存在沟通油源断裂的前提下,对满加尔凹陷区上奥陶统浊积砂岩—陆棚—三角洲—滨岸潮坪砂岩的构造及岩性圈闭油气藏进行勘探。     

STRATIGRAPHIC CONTROLS ON PALAEOZOIC PETROLEUM SYSTEMS, GHADAMES BASIN, LIBYA

The distribution of oil‐ and gasfields in the Libyan Ghadames Basin is strongly influenced by the stratigraphic architecture of the Silurian‐Devonian succession. This interval encompasses part of two (second‐order) super‐sequences separated by the Caledonian unconformity: (i) a late Ashgillian‐Silurian super‐sequence, comprising the Melez Chograne‐Memouniat periglacial lowstand, the Tanezzuft transgressive to early highstand shales and the Acacus Formation late highstand systems tracts; and (ii) the lower part of a composite Devonian‐Carboniferous super‐sequence terminated by the Hercynian unconformity, which includes the lowstand Tadrart fluvial‐shallow marine sands, the Ouan Kasa (transgressive) and the Aouinet Ouinene transgressive to early highstand systems tracts of Devonian age. Hydrocarbon accumulations in Acacus, Tadrart and later Devonian reservoirs have been charged from a basal Silurian (Tanezzuft Formation) “hot” radioactive shale source rock. The Acacus and Tadrart sandstones provided regional migration conduits sealed by intra‐Acacus, intra‐Devonian (Emghaet Formation) and Permian (Bir Al Jaja Formation) shales. Regional stratigraphic continuity of these migration conduits permitted the development of low to moderate impedance petroleum systems dominated by lateral migration. Basin reconstructions and burial history modelling suggest three expulsion peaks from the basal Tanezzuft Formation source rock, preceding major periods of Hercynian, Austrian and Alpine (mid‐late Tertiary) uplift and exhumation. Hydrocarbons trapped prior to the Hercynian event were dispersed during later periods of structural deformation. Some pre‐Austrian accumulations may have survived locally in more robust traps. However, most if not all of the oil‐ and gasfields discovered in the Late Silurian ‐ Devonian succession were probably charged during the Late Cretaceous—Early Tertiary, only to suffer partial dispersal during later uplift, tilting and flushing. Three petroleum systems can be distinguished within the basin: (i) a Tanezzuft ‐Acacus system to the north; (ii) a Tanezzuft ‐ Tadrart system to the south; and (iii) a Tanezzuft ‐Acacus/Tadrart(+) system in the centre, with some leakage into overlying Devonian and Carboniferous sandstones locally.