塔中地区奥陶系储层烃包裹体特征及成藏分析

利用新发明的不同期次烃包裹体组份提取仪器"多功能烃包裹体取样机",分别提取了塔中地区5期烃包裹体组份,并成功地分析出组份生物标志化合物,论证了5期烃包裹体油气的来源:第Ⅰ期烃包裹体来源于满加尔坳陷的寒武系海相碳酸盐岩烃源岩、第Ⅱ期烃包裹体来源于满加尔凹陷的中奥陶系烃源岩、第Ⅲ期烃包裹体来源于塔中下部寒武系海相碳酸盐岩烃源岩、第Ⅳ期烃包裹体是由寒武系海相碳酸盐岩原油分解而成、第Ⅴ期烃包裹体来源于塔中上奥陶统良里塔格组烃源岩。其形成时间分别为:早海西期约383Ma、晚海西期约240~260Ma、燕山-早喜山期早期、23Ma喜山运动二幕、喜山运动晚期到现在。塔中奥陶系储层中不是每一个圈闭都含有以上5期烃包裹体,有的圈闭只含其中的一期或二期或三期。第Ⅰ期主要是油气运移的 "足迹",仅路过奥陶系,未成藏。第II、IV、V期成藏普遍影响塔中奥陶系,是油气成藏的"历史",使奥陶系的原油具有中奥陶统油源(第II期)、上奥陶统油源(第V期)和寒武系油源(第IV期)混源特征,第Ⅱ、Ⅳ期烃包裹体大量存在是塔中Ⅰ号坡折带凝析油气高产的"标志"。 第Ⅲ期包裹体的发育可能预示在塔中东部地区中下奥陶统及寒武系形成大油藏,塔中东部地区是找原生大型油藏的重要靶区。     

塔里木盆地塔中礁滩体大油气田成藏条件与成藏机制研究

中国海相碳酸盐岩油气勘探近年来进展很快,发现了一批大型油气田。塔中地区是塔里木盆地的重点勘探区和富油气区,奥陶系蕴藏了丰富的油气资源。奥陶系良里塔格组受塔中I号坡折带的控制发育陆棚边缘礁滩体,储层性质为低孔-特低孔、低渗灰岩储层,埋深在4500~6500m。储层的形成和分布受早期高能沉积相带、溶蚀作用和断裂作用等因素的控制,有效储层的空间展布控制了油气的分布与大面积成藏。油源对比认为,塔中良里塔格组礁滩体油气藏的原油主要来自于中上奥陶统烃源岩,并混有寒武系烃源岩成因的原油;天然气主要来自于寒武系油裂解气,沿塔中I号坡折带断裂向内充注。成藏过程分析表明,塔中地区曾存在三期主要成藏期,第一期为加里东晚期成藏,油气来自于寒武系-下奥陶统烃源岩,但早海西期的构造运动,对该期油气破坏严重,造成大范围油藏破坏。第二期成藏期是晚海西期,也是塔中地区最重要的油气充成藏期,油气来自于中上奥陶统烃源岩。第三期成藏期是晚喜山期,受库车前陆冲断影响,台盆区快速沉降,埋深急速增大,寒武系原油裂解气形成,沿深部断裂向浅部奥陶系充注,对油藏进行气洗改造,从而形成大面积分布的凝析气藏。     

中国海相油气田勘探实例之十五 塔里木盆地塔中北斜坡鹰山组凝析气田的发现与勘探

塔里木盆地塔中北斜坡中—下奥陶统鹰山组凝析气田发现于2006年,至2010年底探明石油地质储量3.81×108t(油当量)。气藏的储层为受层间岩溶缝洞型储集体控制的鹰山组大型准层状优质碳酸盐岩,主力烃源岩为中—下寒武统白云岩和上奥陶统碳酸盐岩及泥灰岩,油气主要分布于奥陶系不整合面之下0~200 m范围内。论述了气田的勘探历程、主要地质特征、勘探的技术创新,以及对海相碳酸盐岩凝析气田勘探的启示。     

塔里木盆地塔中奥陶系天然气的非烃成因及其成藏意义

塔里木盆地塔中北部斜坡带奥陶系海相碳酸盐岩油气勘探取得了重大突破,发现了台缘坡折带礁滩复合体大型凝析气藏和台内岩溶风化壳大型油气藏。利用有机地化指标与构造沉积演化紧密结合对有效烃源岩及成藏过程的研究取得了较好成果,但随着勘探的纵深发展,流体分布复杂的问题日趋突出,通过天然气组分以及相关同位素等分析化验数据,进行塔中北部斜坡带奥陶系油气成藏研究,建立了"三期成藏、两期调整,早期成油、晚期注气,复式聚集、普遍含油"成藏模式,明确了塔中天然气以原油裂解气为主,强调晚期气侵是形成塔中大型天然气田的关键。     

塔里木盆地古城墟隆起奥陶系油气成藏特征及主控因素

古城墟隆起奥陶系海相碳酸盐岩地层近年来相继发现了一些出油气井,已经成为塔里木盆地的重点勘探目标区。目前已证实古城墟隆起存在奥陶系一间房组顶部灰岩与鹰山组内幕灰质白云岩两套含油气层系。奥陶系主要为正常压力、高温的干气气藏,但顺南1井一间房组顶部的原油属低硫、低蜡轻质油,表现出典型的凝析油特征。综合油气性质、生物标志化合物特征及烃包裹体发育特征,认为该区主要存在两期油气充注过程:第一期油气充注发生在加里东晚期—海西早期,以来自寒武系—下奥陶统烃源岩的原油为主;第二期油气充注发生在喜马拉雅期,以寒武系过成熟的干气为主,气侵改造导致该区以纯气藏和凝析气藏为主。古城墟隆起已钻井均见到不同级别的油气显示,并且不含水,初步研究认为优质的碳酸盐岩储层是油气成藏的最关键因素,同时北东向断裂对油气成藏有重要影响。     

塔里木盆地和田河气田成藏条件及控制因素

和田河气田位于巴楚凸起南侧,晚加里东期以来始终处于构造高部位。主要烃源岩为寒武系、奥陶系及石炭系,天然气主要来源于寒武系古油藏的原油裂解气和干酪根裂解气,凝析油来源干石炭系烃源岩。主要储集层为石炭系生屑灰岩段、奥陶系古潜山碳酸盐岩、石炭系砂泥岩段和砂砾岩段碎屑岩,发育三套区域性盖层和多套区带性盖层,形成良好的储盖组合。成藏控制因素包括六个方面:①发育寒武系优质烃源岩,二叠纪火山活动使寒武系油源的古油藏裂解为干气,成为气田的主要气源。②构造运动使该区长期成为油气指向区并造成两侧的断裂发育,有利于形成断背斜圈闭;伴随断裂发育了裂缝系统,改善了储集物性。③断裂构成油气垂向运移的通道;奥陶系潜山不整合面成为油气横向长距离运移的通道。④三套区域性盖层和若干区带性盖层是和田河气田保存的关键因素之一。⑤溶蚀作用使缝洞系统发育,大大改善了碳酸盐岩的储集物性。⑥气田的构造形成期为早—中喜马拉雅期,晚期抬升运动只造成气田内山体出露,对主体构造没有造成影响,使气田得以保存完好。     

塔里木盆地和田河气田成藏条件及控制因素

和田河气田位于巴楚凸起南侧,晚加里东期以来始终处于构造高部位。主要烃源岩为寒武系、奥陶系及石炭系,天然气主要来源于寒武系古油藏的原油裂解气和干酪根裂解气,凝析油来源于石炭系烃源岩。主要储集层为石炭系生屑灰岩段、奥陶系古潜山碳酸盐岩、石炭系砂泥岩段和砂砾岩段碎屑岩,发育三套区域性盖层和多套区带性盖层,形成良好的储盖组合。成藏控制因素包括六个方面：①发育寒武系优质烃源岩,二叠纪火山活动使寒武系油源的古油藏裂解为干气,成为气田的主要气源。②构造运动使该区长期成为油气指向区并造成两侧的断裂发育,有利于形成断背斜圈闭;伴随断裂发育了裂缝系统,改善了储集物性。③断裂构成油气垂向运移的通道;奥陶系潜山不整合面成为油气横向长距离运移的通道。④三套区域性盖层和若干区带性盖层是和田河气田保存的关键因素之一。⑤溶蚀作用使缝洞系统发育,大大改善了碳酸盐岩的储集物性。⑥气田的构造形成期为早—中喜马拉雅期,晚期抬升运动只造成气田内山体出露,对主体构造没有造成影响,使气田得以保存完好。     

轮南低凸起油气输导体系格架及输导样式

多源多灶的生烃背景导致轮南地区的油气成藏过程高度复杂化.基于油气成藏动力学理论,综合运用钻井、地震以及地球化学等资料对轮南低凸起关键时期油气输导体系格架及典型油气藏输导样式的研究表明,由于志留系沥青砂盆地级的分布特征有力地证实了加里东晚期奥陶系岩溶缝洞体尚未形成,因此志留系砂体是加里东晚期源自寒武系烃源岩的烃类向轮南低凸起横向输导的主要通道;其次,海西早期的强烈抬升及长时间的暴露剥蚀导致表生岩溶作用深度改善了轮南地区碳酸盐岩层系的储集效能,而潜山风化壳之下的奥陶系岩溶缝洞储集体是这一时期源自满加尔坳陷内奥陶系烃源岩烃类的横向运载层;喜山期油气成藏的实质为海西晚期奥陶系整装油气藏形成后的调整改造过程,包括过量干气的气洗改造以及不同尺度断裂的垂向调整.轮南油田、桑塔木油田以及解放渠东油田三叠系油气藏的形成均受控于深大断裂的垂向输导.同时,上覆盖层的强制性封闭将喜山期干气的横向输导路径束缚于奥陶系内部,奥陶系油藏经气洗相分馏改造转变为次生的饱和凝析气藏.而由于桑塔木断垒带地区连接奥陶系与石炭系的层间断裂以及轮古东地区奥陶系层内断裂活动所诱发的泄压相分馏改造,不仅在石炭系圈闭形成了纯气相的不饱和凝析气藏,还直接控制了轮古东油田凝析气藏及其流体性质的分布.      

塔里木盆地塔中I号断裂带西缘奥陶系油气成藏与主控因素研究

塔中低凸起是塔里木盆地油气资源最丰富的地区之一,而塔中I号断裂带西缘也在多个层系中见到了不同程度的油气显示,并在上奥陶统良里塔格组获得了高产工业油气流,在下奥陶统鹰山组获得了低产油气流.本文通过油源对比、油气水物性对比、包裹体均一温度分析等方法并结合前人的研究成果,探讨了塔中I号断裂带西缘塔中86井区-塔中45井区奥陶系的油气成藏过程,认为该区奥陶系有过三期油气充注,即晚加里东期、晚海西期和燕山期-喜马拉雅期.晚加里东期的油气来自于寒武系-下奥陶统烃源岩,晚海西期的油气来自于中-上奥陶统烃源岩,两期油气均自塔中88井沿碳酸盐岩岩溶储层侧向运移而来;燕山期-喜马拉雅期主要以天然气为主,成因复杂.另外,认为该区油气富集的主控因素主要有3点:多源多期油气充注、优质的碳酸盐岩岩溶储层及各种成藏要素的优质配置.     

塔里木盆地塔中Ⅰ号断裂带西缘奥陶系油气成藏与主控因素研究

塔中低凸起是塔里木盆地油气资源最丰富的地区之一,而塔中I号断裂带西缘也在多个层系中见到了不同程度的油气显示,并在上奥陶统良里塔格组获得了高产工业油气流,在下奥陶统鹰山组获得了低产油气流。本文通过油源对比、油气水物性对比、包裹体均一温度分析等方法并结合前人的研究成果,探讨了塔中I号断裂带西缘塔中86井区—塔中45井区奥陶系的油气成藏过程,认为该区奥陶系有过三期油气充注,即晚加里东期、晚海西期和燕山期—喜马拉雅期。晚加里东期的油气来自于寒武系—下奥陶统烃源岩,晚海西期的油气来自于中—上奥陶统烃源岩,两期油气均自塔中88井沿碳酸盐岩岩溶储层侧向运移而来;燕山期—喜马拉雅期主要以天然气为主,成因复杂。另外,认为该区油气富集的主控因素主要有3点:多源多期油气充注、优质的碳酸盐岩岩溶储层及各种成藏要素的优质配置。     

Characteristics and differential accumulation of oil/gas in Lower Paleozoic marine carbonate on northern slope of Tazhong Low Rise,Tarim Basin,NW China: a case study of Lower Ordovician Yingshan Formation

Marine carbonate reservoirs, as a focus of petroleum exploration and development all over the world, are involved with high exploration risk and prediction difficulty owing to high heterogeneity and diversity of reservoir beds. In the Tarim Basin, NW China, carbonate reservoirs with resources about 38 % of the whole basin in a large prospecting area are mainly distributed in the Cambrian and Ordovician in central (Tazhong) and northern (Tabei) Tarim. Recently on the northern slope, Tazhong Low Rise, Central Uplift, Tarim Basin, a breakthrough has been made in the karsted weathering crust of Lower Ordovician Yingshan Formation and reef-flat reservoir of Upper Ordovician Lianglitag Formation. As a new frontier of exploration, oil/gas distribution and controlling factors of carbonate reservoirs in the Yingshan Formation are not clearly understood. In this work, play elements of the Yingshan Formation, such as seal-reservoir bed assemblage, oil/gas properties, and faulting, were studied by core and slice observation and field investigation. High-quality reservoir beds of Yingshan Formation are quasi-layer distributed in the interstratal karst belt about 250 m below the unconformity. The reservoir beds of fracture–void and void are formed by faulting, associated fracturing, and karstification. The Yingshan Formation is a large-scale condensate gas reservoir with partly oil. Owing to different oil–gas infilling periods, isolated pools far from the faults are primarily oil in the Hercynian; oppositely, condensate gas reservoirs near the faults are intensely influenced by gas invasion during the Himalayan movement. Laterally, oil/gas distribution is controlled by stratal pinch-out and strike-slip faults. Vertically, cap rock of the third to fifth members of the Lianglitag Formation and Yingshan interior high resistivity layers are superimposed with Yingshan reservoir beds to form several seal-reservoir bed assemblages. Oil and gas are superimposed and affected by gas invasion with characteristics of oil in the upper horizon and gas in the lower horizon.     

Early Palaeozoic carbonate reservoirs from the Yingshan Formation of Well block ZG‐43 in Tazhong Low Rise,Central Uplift,Tarim Basin,NW China: geological features and controlling factors

Marine carbonate reservoirs, as a focus of petroleum exploration and development in China, are involved with high exploration risk and prediction difficulty owing to high heterogeneity and diversity of reservoir beds. In the Tarim Basin, NW China, carbonate reservoirs host about 38% of the whole basin's hydrocarbon resources in a large prospecting area mainly distributed in the Cambrian and Ordovician rocks in central (Tazhong) and northern (Tabei) Tarim. Recently, a better understanding has been made of the karsted weathering crust at the top of the Lower Ordovician Yingshan Formation in the northern slope area of the Tazhong Low Rise, Central Uplift, Tarim Basin. As a new frontier of exploration, oil/gas distribution and controlling factors of carbonate reservoirs in the Yingshan Formation are not clearly understood. In this work, we investigated the reservoir beds and oil/gas properties in 13 wells in Well block ZG‐43 on the No. 10 structural belt in the Tazhong Low Rise, and studied hydrocarbon accumulation characteristics with seismic and geochemical data. The Yingshan Formation in Well block ZG‐43 is mainly composed of calcarenite, dolomitic limestone, dolomite, cryptite, as low porosity and low permeability reservoir beds, with fracture‐void porosity constituting the main reservoir pore space. Oil/gas is quasi‐layer distributed beneath the unconformity between the Yingshan and Lianglitag formations to a depth of 140 m. The oil in Well block ZG‐43 is condensate with low density, low viscosity, low sulphur, low resin, low asphaltene, and high wax. The gas is 87.3% methane, generally containing H₂S. The oil/gas distribution pattern is oil in the east and gas in the west, and H₂S content in the west is lower than that in the east. The controlling factors for hydrocarbon are multi‐source supply and multi‐phase charging, interstratal karstification, hydrothermal activity, structural location and sealing condition. A structural–lithological trap is the main type of oil/gas accumulation. Oil/gas distribution was clearly affected by strike–slip faults. Oil/gas with multi‐source supply and multi‐phase charging was controlled by favourable local palaeo‐highs, and affected by later karsting and hydrothermal activity, as well as gas invasion in the Himalayan (Cenozoic) period. Under the caprock of compact limestone in the third to fifth members of the Lianglitag Formation, oil/gas migrated up along the strike–slip fault planes, and moved laterally to both sides in a ‘T’ shape, and formed large‐scale quasi‐layer condensate gas reservoirs controlled by reservoir bed quality. Copyright © 2013 John Wiley & Sons, Ltd.     

Correlation of crude oils and oil components from reservoirs and source rocks using carbon isotopic compositions of individual n-alkanes in the Tazhong and Tabei Uplift of the Tarim Basin,China

Carbon isotopic compositions were determined by GC–IRMS for individual n-alkanes in crude oils and the free, adsorbed and inclusion oils recovered by sequential extraction from reservoir rocks in the Tazhong Uplift and Tahe oilfield in the Tabei Uplift of Tarim Basin as well as extracts of the Cambrian–Ordovician source rocks in the basin. The variations of the δ¹³C values of individual n-alkanes among the 15 oils from the Tazhong Uplift and among the 15 oils from the Triassic and Carboniferous sandstone reservoirs and the 21 oils from the Ordovician carbonate reservoirs in the Tahe oilfield demonstrate that these marine oils are derived from two end member source rocks. The major proportion of these marine oils is derived from the type A source rocks with low δ¹³C values while a minor proportion is derived from the type B source rocks with high δ¹³C values. Type A source rocks are within either the Cambrian–Lower Ordovician or the Middle–Upper Ordovician strata (not drilled so far) while type B source rocks are within the Cambrian–Lower Ordovician strata, as found in boreholes TD2 and Fang 1. In addition, the three oils from the Cretaceous sandstone reservoirs in the Tahe oilfield with exceptionally high Pr/Ph ratio and δ¹³C values of individual n-alkanes are derived, or mainly derived, from the Triassic–Jurassic terrigenous source rocks located in Quka Depression.The difference of the δ¹³C values of individual n-alkanes among the free, adsorbed and inclusion oils in the reservoir rocks and corresponding crude oils reflects source variation during the reservoir filling process. In general, the initial oil charge is derived from the type B source rocks with high δ¹³C values while the later oil charge is derived from the type A source rocks with low δ¹³C values.The δ¹³C values of individual n-alkanes do not simply correlate with the biomarker parameters for the marine oils in the Tazhong Uplift and Tahe oilfield, suggesting that molecular parameters alone are not adequate for reliable oil-source correlation for high maturity oils with complex mixing.     

中国海相油气田勘探实例之四 塔里木盆地塔河油田的发现与勘探

塔河油田位于塔里木盆地沙雅隆起阿克库勒凸起西部,目前井控含油气面积约1800km2。它发现于1990年,是我国发现的第一个陆上古生代海相大油田。2004年探明石油储量为5.3×108t,原油年产量为358×104t。油田的主要产层为奥陶系浅海台地—斜坡相碳酸盐岩,其盖层为下石炭统区域性泥岩和膏盐岩,油源为寒武系—下奥陶统碳酸盐岩烃源岩。岩溶储集体发育,油气藏圈闭类型多样。论述了油田的发现和勘探开发历程、油藏的地质特征、油气分布规律,以及寻找海相碳酸盐岩油气田的启示。     

Accumulation and Reformation of Silurian Reservoir in the Northern Tarim Basin

Silurian sandstone in Tarim Basin has good reservoir properties and active oil and gas shows, especially thick widely-distributed bituminous sandstone. Currently, the Silurian was found containing both bitumen and conventional reservoirs, with petroleum originating from terrestrial and marine source rocks. The diversity of their distribution was the result of "three sources, three stages" accumulation and adjustment processes. "Three sources" refers to two sets of marine rocks in Cambrian and Middle-Upper Ordovician, and a set of terrestrial rock formed in Triassic in the Kuqa depression. "Three stages" represents three stages of accumulation, adjustment and reformation occurring in Late Caledonian, Late Hercynian and Late Himalayan, respectively. The study suggests that the Silurian bitumen is remnants of oil generated from Cambrian and Ordovician source rocks and accumulated in the sandstone reservoir during Late Caledonian-Early Hercynian and Late Hercynian stages, and then damaged by the subsequent two stages of tectonic uplift movements in Early Hercynian and Pre-Triassic. The authors presumed that the primary paleo-reservoirs formed during these two stages might be preserved in the Silurian in the southern deep part of the Tabei area. Except for the Yingmaili area where the Triassic terrestrial oil was from the Kuqa Depression during Late Himalayan Stage, all movable oil reservoirs originated from marine sources. They were secondary accumulations from underlying Ordovician after structure reverse during the Yanshan-Himalayan stage. Oil/gas shows mixed-source characteristics, and was mainly from Middle-Upper Ordovician. The complexity and diversity of the Silurian marine primary properties were just defined by these three stages of oil-gas charging and tectonic movements in the Tabei area.     

塔北、塔中地区碳酸盐岩及其原油中的二苯并噻吩类化合物

塔里木盆地塔北、塔中地区四口井(库南1井,轮南46井,塔中12井和塔参1井)寒武-奥陶系12个碳酸盐岩烃源岩(泥灰岩,泥质灰岩和云岩)岩芯样品抽提物芳烃组分中的二苯并噻吩类化合物组成和丰度变化特征可分为三种类型:Ⅰ二苯并噻吩、甲基二苯并噻吩型;Ⅱ二苯并噻吩、甲基二苯并噻吩、二甲基二苯并噻吩+三甲基芴混合物型;Ⅲ二苯并噻吩、甲基二苯并噻吩、二甲基二苯并噻吩和三甲基二苯并噻吩型。研究的塔北、塔中隆起11个海相油二苯并噻吩类化合物分布类型均为二苯并噻吩、甲基二苯并噻吩、二甲基二苯并噻吩和三甲基二苯并噻吩型,和海相烃源岩二苯并噻吩类化合物第Ⅲ种分布类型完全相同。据此推断:塔北隆起8个海相油可能主要来源于塔北轮南地区下奥陶统;塔中隆起3个海相油可能来源于塔中地区中-上奥陶统。     

塔里木盆地北部奥陶系油气相态及其成因分析

塔里木盆地北部地区奥陶系是最重要的勘探层系,油气资源丰富;同时油气相态复杂多样,既有凝析气藏、正常油藏,也有稠油油藏、沥青等。通过对油气藏形成演化与保存过程的系统分析,结合油气地球化学和流体包裹体等分析数据,发现油气相态的多样性与油气多期次充注与次生蚀变作用有关。提出塔北隆起的东部奥陶系存在三期油气充注过程,分别发生在加里东运动晚期-海西早期、海西运动晚期、喜马拉雅运动晚期,原油主要来源于中、上奥陶统烃源岩,天然气主要来自与寒武系烃源岩有关的液态烃的裂解;塔北隆起的中西部奥陶系的油气充注主要发生在海西运动晚期。塔北奥陶系油藏形成以后,经历了三期明显的调整改造过程:海西早期构造抬升导致志留-泥盆系遭受剥蚀,东部源自寒武系油气的古油藏遭受破坏,形成沥青;三叠系沉积前的晚海西运动,使得奥陶系生源的油藏大范围遭受降解稠化;晚喜山期,来自于满加尔坳陷的天然气自东向西充注,致使隆起东部早期形成的油藏发生强烈的气侵改造,形成次生凝析气藏。而中西部奥陶系油藏在三叠系沉积前遭受降解稠化后,一直处于沉降深埋过程,油藏得到有效保存;由于成藏时间较早,轻质组分散失较多,气油比极低,油质较稠。研究认为,油气相态的多样性主要受晚海西期构造运动的抬升造成的生物降解作用和喜马拉雅晚期构造运动造成的天然气自东向西大规模充注对油藏进行气洗改造两大过程的控制。     

从塔里木盆地看中国海相生油问题

塔里木盆地厚达 5～ 7km的海相寒武、奥陶系 ,可划分出下、中寒武统和中、上奥陶统两套工业性烃源岩。油源对比证实 :盆地目前保存下来的海相成因工业性油藏 ,主要来源于中上奥陶统泥灰岩。正是因为塔里木盆地比四川、鄂尔多斯盆地多了一套中等成熟的中上奥陶统油源岩 ,所以能够找到海相油田。笔者认为 :海相工业性烃源岩不必很厚 ,但w (TOC)应≥0 .5% ,碳酸盐岩要含泥质 ;海相源岩往往并不发育在凹陷中心 ,而发育在 4种有利沉积相带上 ;碳酸盐岩具有“双重母质”的特点 ,浮游藻类偏油 ,底栖藻类偏气。海相源岩的形成模式有“保存模式”和“生产力模式”两种 ,分别对应于塔里木寒武系和中上奥陶统烃源岩。塔里木古生代克拉通早期活动、晚期稳定、持续降温的演化史 ,有利于海相油气的多期成藏和晚期保存。     

塔里木盆地和田河气田碳酸盐岩储层的多期次多来源油气聚集特征

高成熟度演化地区的海相碳酸盐岩储层易受到油气演化的影响 ,油气的聚集在储层中都留下了踪迹 ,既有对储层储集性能的改善有利的一面 ,也有对储层形成伤害的一面。对和田河气田的碳酸盐岩储层薄片观察、凝析油气的地球化学分析和储层沥青分析表明 ,主要有 3期油气运移 ,分别为 :晚加里东期—早海西期、晚海西期和喜山期。前两期都是寒武系来源的油气 ,均被生物降解或散失 ,喜山期是天然气的关键聚集时期。第一期以油相运聚的油气被降解 ,形成的沥青对储层造成了伤害 ,第二期以气相运移的油气多散失 ,仅在储层中留下凝析油 ,第三期油相运移的石炭系来源的油受到后期转移上来的寒武系干气的气侵 ,产生沥青质沉淀 ,使得寒武系凝析油被封堵 ,储层产出的凝析油的地球化学特征更接近石炭系源岩。