塔里木盆地罗布泊地区石炭系混合沉积层序

对塔里木盆地罗布泊凹陷北部的石炭系露头剖面进行了野外详细实测,根据古生物特征,岩性、岩相分析和地层对比,对地层层位进行了划分、对比。由露头区向覆盖区进行了地震追踪,证实覆盖区内也有石炭系分布。古生物、岩性、岩相、沉积构造和粒度等资料证实,本区石炭系在垂向上发育典型的滨浅海碎屑岩和台地相碳酸盐岩互层的混合沉积层序。总结出了适合这种混合沉积层序的相模式,依据这种相模式对本剖面石炭纪的岩相古地理进行了简单分析。在这种典型的沉积层序中,发育着良好的烃源岩和储集层,使研究区内的石炭系具备了有利的生储盖组合条件,具有良好的油气勘探远景。     

和田河气田石炭系沉积相特征与演化

和田河气田石炭系主要发育混合台地、碎屑滨岸和浅海(陆棚)沉积相.混合台地是区内主要沉积相,可划分出4种亚相,当台内有水下隆起时,由岸向海4种亚相发育齐全;反之,则缺失局限台地和台内滩亚相.混合台地相具有物源近、水体浅、能量较弱的特点,总体上为以细粒为主的碎屑岩和碳酸盐互层沉积,当气候干燥炎热或水体受到局限时,还可形成大量石膏沉积.碎屑滨岸相分布在石炭系砂砾岩段,划分为后滨、前滨及临滨亚相,以细粒碎屑岩为主.浅海陆棚相分布在石炭系下泥岩段,主要为泥岩夹粉砂岩.在中、晚海西运动影响下,石炭系从巴楚期、卡拉沙依期到小海子期整体表现为一次大的海侵-海退旋回,沉积环境也表现为由碎屑滨海向混合浅水台地的演化.     

和田河气田石炭系沉积相特征与演化

和田河气田石炭系主要发育混合台地、碎屑滨岸和浅海(陆棚)沉积相.混合台地是区内主要沉积相,可划分出4种亚相,当台内有水下隆起时,由岸向海4种亚相发育齐全;反之,则缺失局限台地和台内滩亚相.混合台地相具有物源近、水体浅、能量较弱的特点,总体上为以细粒为主的碎屑岩和碳酸盐互层沉积,当气候干燥炎热或水体受到局限时,还可形成大量石膏沉积.碎屑滨岸相分布在石炭系砂砾岩段,划分为后滨、前滨及临滨亚相,以细粒碎屑岩为主.浅海陆棚相分布在石炭系下泥岩段,主要为泥岩夹粉砂岩.在中、晚海西运动影响下,石炭系从巴楚期、卡拉沙依期到小海子期整体表现为一次大的海侵-海退旋回,沉积环境也表现为由碎屑滨海向混合浅水台地的演化.     

伊犁盆地下石炭统阿克沙克组沉积特征及演化

伊犁盆地下石炭统阿克沙克组按岩性自下而上分为碎屑岩段、碎屑岩夹碳酸盐岩段以及碳酸盐岩段,通过详细的野外地质考察和室内分析,识别出6种沉积相、14种沉积亚相。碳酸盐沉积是伊犁石炭纪海相盆地重要沉积,发育有混积滨岸相、局限-开阔台地相、台盆相、台地边缘礁滩相、台地前缘斜坡-坡脚相。伊犁盆地早石炭世晚期沉积演化明显受构造活动、古地形、海平面升降、物源等影响,可分为3个阶段：①早期发育辫状河三角洲相,沉积物主要来自北天山一带;②中期发育辫状河三角洲相和混积滨岸相、开阔台地相、台盆相,靠近物源区的尼勒克水泥厂一带为辫状河三角洲相和混积滨岸相,昭苏阿克沙克沟一带为混积滨岸相,科克苏峡谷一带为开阔台地相,切克台沟一带为台盆相;③晚期盆地处于拗陷阶段,陆源物质输入少,为典型台地碳酸盐沉积时期,沉积相在平面上呈向西敞开、向东收敛的带状分布,由于靠近物源,尼勒克水泥厂一带仍存在混积滨岸相。     

龙门山地区中泥盆统观雾山组沉积相及其演化分析北大核心CSCD

以龙门山地区北川甘溪凉水洞剖面实测资料为基础,对中泥盆统观雾山组沉积相及其演化进行了分析,认为观雾山组底部以碎屑岩沉积为主,主要发育河流相和无障壁滨岸相;碎屑岩之上发育碳酸盐岩台地相和碳酸盐缓坡相。其中碳酸盐台地可划分为台地边缘生物礁、台地边缘浅滩和台地前缘斜坡等3种亚相,碳酸盐缓坡可划分为浅水缓坡、深水缓坡等2种亚相;碳酸盐台地和碳酸盐缓坡可以在特定的环境下发生相互转化,其识别标志主要有角砾礁灰岩和滑动变形构造。龙门山地区观雾山组经历了早期和晚期2个沉积演化阶段,早期旋回底部为碎屑岩沉积、中上部以碳酸盐台地为主,晚期以碳酸盐缓坡为主。本研究为龙门山地区观雾山组岩相古地理恢复提供了基础。     

龙门山地区中泥盆统观雾山组沉积相及其演化分析

以龙门山地区北川甘溪凉水洞剖面实测资料为基础,对中泥盆统观雾山组沉积相及其演化进行了分析,认为观雾山组底部以碎屑岩沉积为主,主要发育河流相和无障壁滨岸相;碎屑岩之上发育碳酸盐岩台地相和碳酸盐缓坡相。其中碳酸盐台地可划分为台地边缘生物礁、台地边缘浅滩和台地前缘斜坡等3种亚相,碳酸盐缓坡可划分为浅水缓坡、深水缓坡等2种亚相;碳酸盐台地和碳酸盐缓坡可以在特定的环境下发生相互转化,其识别标志主要有角砾礁灰岩和滑动变形构造。龙门山地区观雾山组经历了早期和晚期2个沉积演化阶段,早期旋回底部为碎屑岩沉积、中上部以碳酸盐台地为主,晚期以碳酸盐缓坡为主。本研究为龙门山地区观雾山组岩相古地理恢复提供了基础。     

湘西黔东寒武纪深水碳酸盐重力沉积

湘黔边境地区位于江南寒武纪边缘海盆和扬子碳酸盐台地的接壤地带。自早寒武世清虚洞期起,湘黔地区碳酸盐沉积相带发育良好而完整。从贵州中部至湖南中部依次发育台地蒸发相、局限海台地相、开阔海台地相、台地边缘浅滩相、台地边缘生物礁相、斜坡相、盆地边缘相和盆地平原相。台地边缘带是重力沉积的主要物源区。台地边缘浅滩相主要发育亮晶鲕粒云岩、砂屑云岩和生物屑灰(云)岩。台地边缘的兰绿藻礁具有完整的礁组合。礁核主要由表附藻骨架灰岩构成,次为葛万藻粘结岩、纤状藻障积岩等。礁前塌积带由粗砾至巨砾级的礁角砾、生物屑和灰泥组成。礁后带主要为暗色泥晶灰(云)岩、藻屑灰(云)岩,鸟眼构造发育。由于台地边缘的快速堆积及其向海推进而造成的不稳定性,是导致大规模重力沉积的基本因素。斜坡带和盆地边缘发育有类型繁多的重力再沉积碳酸盐岩。即①重力流沉积,包括a.碎屑流,b.浊流及c.颗粒流沉积;②孤立岩块;③滑塌沉积。它们在中、上寒武统各组段地层中普遍发育,其累积厚度超过400米。重力沉积与以纹层状碳酵盐岩为主的垂直降落沉积构成了颇具特色的组合。在各类重力沉积中,以碎屑流和浊流发育最好。碎屑流砾屑灰岩多属斜坡带的水道充填沉积,呈北西—南东向的带状分布。向盆地边缘方向,其层数、单层厚度和粒度均明显减小,但分布范围有所加宽,趋近于呈席状分布。本区低密度浊流和高密度浊流均甚发育。低密度浊流沉积的单层薄(<10厘米)、粒度细,以均匀递变的粒序层和鲍马序列发育为特征,在斜坡下部和盆地边缘广泛分布;高密度浊流沉积单层厚度大(>20厘米)、粒度粗(可达中砾级),以具粗尾递变和发育中～大型交错层为特征,并多构成“似鲍马序列”,其分布主要限于斜坡水道内。本区的颗粒流沉积具有三层结构:下部的反粒序段、中部的块状段和上部的正粒序段,其重要性远逊于浊流和碎屑流。孤立岩块是来自台地边缘的巨大的礁灰岩块体,四周为暗色纹层状灰岩所包围,主要分布于斜坡中部。本区还发育由①弯曲纹层、②同生褶皱、③原生错断、④滑塌角砾岩构成的完整的滑塌沉积系列、它是斜坡带的可靠相标志。碎屑流沉积的粒度概率曲线为下陡上缓的两段式或平缓的一段式,浊流以较陡的一段式为主,颗粒流则以下级上陡的两段式为特征。粒度参数离散图可将碎屑流与另两类重力流沉积区分开来;而用计算机进行数据处理所得的因子载荷图则能较好地将碎屑流、浊流、颗粒流三类沉积物相互区分开。在CM图上,不仅三类重力流沉积均有各自的集中分布带,而且国Ⅰ_m值可反映出分选性的好坏顺序,即浊流→颗粒流→碎屑流分选依次变差。根据本区可靠的地质记录可以得到如下认识:①碎屑流、浊流等不同类型重力流在运动过程中可以相互转化或部分转化;②粗粒浊积岩中出现中～大型交错层是不奇怪的,这与粒径大小对床沙形体的控制作用有关;③浅水碳酸盐碎屑流沉积的保存潜能大得足以使其留在地质记录中。     

塔里木盆地巴什托油气田石炭系碳酸盐岩沉积相特征

塔里木盆地巴什托区块石炭系包括3个组,自下而上为巴楚组、卡拉沙依组和小海子组.沉积相为碳酸盐岩台地,包括蒸发台地、局限台地、开阔台地3种亚相.岩石类型主要为碳酸盐岩,夹薄层碎屑岩和膏岩.巴楚组沉积晚期,本区陆源碎屑物质注入急剧减少,形成了一套富含生物碎屑的碳酸盐岩地层,发育局限台地亚相沉积.卡拉沙依早中期为蒸发台地夹局限台地亚相沉积,晚期为局限台地环境.小海子期海侵范围扩大,大部分地区为开阔台地沉积.由于海平面升降变化的周期性,使各种微相类型在垂向序列上呈规律性重复叠置,从而在空间上构成有规律的储盖组合,石炭系共发育3套良好储盖组合,其中小海子组发育2套,巴楚组发育1套.小海子组油气层主要分布在BK4H-麦4-麦6井一带的构造高部位.巴楚组油气层分布于麦10-BK4H-麦6井一带的构造高部位.     

川西北地区上二叠统吴家坪组沉积演化

通过大量岩心、薄片、测井、地震等资料的综合分析,研究了川西北地区上二叠统吴家坪组沉积相类型、分布特征及平面分布演化。川西北地区吴家坪组发育泥页岩、碳酸盐岩及火山碎屑岩等岩性,沉积相可划分为滨岸平原及沼泽、缓坡、开阔台地、台地边缘、斜坡和陆棚共6种。吴一段沉积初期,海水侵覆于下伏茅口组岩溶古地貌之上,研究区沉积水体较停滞,为较还原环境的滨岸平原与沼泽相,形成了吴一段底部的页岩等细粒沉积岩;吴一段沉积中晚期相对海平面上升,研究区内开始大范围发育缓坡沉积,St10井—Yb7井一带的西南部是以滩体沉积为主的浅缓坡亚相,西北部则是低能滩间洼地夹低能滩的深缓坡亚相;吴二段沉积期,受局部同沉积断层等影响,深缓坡沉积范围向西南方向扩大;持续的大规模滩体建造和构造沉降,使得吴三段沉积时期,在St9井—Lg70井—Yb7井一带出现亮晶颗粒灰岩夹微生物黏结岩等形成了弱镶边台地边缘沉积特征,其西南部为开阔台地相等浅水沉积,东北部为斜坡、陆棚等较深水沉积。因此,川西北地区的吴家坪组经历了滨岸平原及沼泽相、缓坡相、弱镶边台地相/斜坡相/陆棚相共3种沉积体系的演化。     

中上扬子地区碎屑岩—碳酸盐岩混积相发育特征及组合模式研究

混合沉积是沉积学中一个新的研究领域,研究区古生界沉积岩石类型多样,碳酸盐岩和碎屑岩交替出现,为混合沉积的研究提供了良好的实例。在古生代地层沉积格架系统研究基础上,对研究区各时期沉积格局及演化规律进行分析。经过基础性研究后,认为研究区发育以晚奥陶世、早志留世沉积为代表的碎屑岩—碳酸盐岩混积台地以及以早寒武世沉积为代表的碎屑岩—碳酸盐岩混积陆棚沉积2种混积相。碎屑岩—碳酸盐岩混积台地是主要发育于陆源碎屑滨浅海、砂泥质潮坪与碳酸盐缓坡或台地的过渡地带的台地沉积。混积陆棚是指同时发育碎屑岩与碳酸盐岩2种沉积的陆棚。研究区混合沉积主要发育于早古生代早期的镶边碳酸盐岩台地—欠补偿盆地组合和泥盆纪—二叠纪碎屑岩潮坪—碳酸盐岩台地组合内。     

新疆塔里木盆地沙雅隆起雅克拉断凸储层特征

雅克拉断凸储层主要有碎屑岩和碳酸盐岩两大类。下古生界以碳酸盐岩为主,主要储集空间类型为裂缝-孔洞型,为好-很好的储集岩。下石炭统、中新生界以碎屑岩为主,下石炭统以东河砂岩中等偏好的储层为主,自西向东储集性能明显变差;中新生界储层则为中等-较好的储层,储集性能的好与差受沉积环境的影响。      

THE GEOLOGY AND HYDROCARBON POTENTIAL OF THE PEEL AND SOLWAY BASINS, EAST IRISH SEA

Data from recent exploration campaigns by Elf Exploration UK plc and partners in the Peel and Solway Basins (East Irish Sea) have provided significant new information on the geology and hydrocarbon potential of these previously unexplored areas. In this paper, I present a regional geological framework for the basins based on outcrop studies, potential field data and regional seismic lines. The dominant NE-SW and NW-SE structural trends are probably inherited from the Caledonian Orogeny and show evidence of repeated reactivation. Seismic interpretation indicates that the NE-SW trending faults were important in controlling Early Carboniferous basin development, and that transpressional movement along these faults in response to N-S compression led to basin inversion during the Variscan Orogeny. New well data indicate that both the Peel and Solway Basins were subjected to major erosion at this time, causing the entire Upper Carboniferous stratigraphy to be removed. Preserved Dinantian facies comprise shallow-marine sandstones, shales and carbonates in the NE, passing into shallow-water, high energy carbonates in the SW. A change to E-W extension during the Permo-Triassic led to renewed extensional motion on the underlying Caledonian faults, and to the creation of a new system of faults oriented N-S. The Permian and Triassic sections present in the wells in the Peel and Solway Basins are very similar to those in the numerous exploration wells in the East Irish Sea Basin to the SE. Liassic rocks are partly preserved in both the Peel and Solway Basins. The intra-basinal highs which separate the basins in this region are thought to have been initiated during Late Cimmerian uplift, and to have been enhanced by Laramide and Alpine phases of uplift. Laramide uplift was also accompanied by the emplacement of WNW-ESE trending dykes. Regional stratigraphic information has been combined with apatite fission-track data and vitrinite reflectance data to constrain these phases of uplift. These data suggest that at the present day, the Peel and Solway Basins are isolated remnants of a previously more extensive cover of Mesozoic rocks. The three exploration wells drilled in the Peel and Solway Basins by Elf Exploration UK plc tested valid Triassic fault-block traps, but failed to encounter any significant hydrocarbon shows. Variable, but generally good quality reservoirs exist at the top of the Sherwood Sandstone Group. The main control on reservoir quality is the primary sedimentological character of the sandstones, with cementation and compaction locally reducing quality. Over most of the area, evaporites and shales in the Mercia Mudstone Group form a viable top and lateral seal. The main factor preventing development of a viable petroleum system appears to be the absence of significant Carboniferous source rocks.     

HYDROCARBON POTENTIAL OF THE INTRACRATONIC OGADEN BASIN, SE ETHIOPIA

The intracratonic Ogaden Basin, which covers one-third of the Democratic Republic of Ethiopia, developed in response to a tri-radial rift system which was active during Late Palaeozoic to Mesozoic times. Thick Permian to Cretaceous sequences, which principally occur in the SW and central parts of the basin, have proved petroleum potential. Reservoir rocks are mainly Permian to Lower Jurassic sandstones (the Calub and Adigrat Formations), and Callovian limestones (the Upper Hamanlei Formation). Source rocks are organic-rich Permian, Lower Jurassic and Callovian-Oxfordian lacustrine and marine shales.
This paper reviews the petroleum geology of the Ogaden Basin and assesses potential exploration targets. Successful exploration can be expected in view of the recent discovery of the Calub gas and gas/condensate field, and the occurrence of significant shows in the centre of the basin together with seeps along the margin.     

十万大山盆地北缘早三叠世碳酸盐重力流及其地质意义

广西十万大山盆地北缘下三叠统中广泛发育有碳酸盐重力流沉积,既有浊流,又有碎屑流及颗粒流。岩性以粗大的砾屑灰岩为主,少量砂屑灰岩。砾屑灰岩共数十层,累积厚百余米。已知分布范围:东自扶绥柳桥,西至宁明梅湾,东西延伸达50公里以上。研究这种碳酸盐重力流沉积,不仅对沉积环境的研究、岩相古地理图的编制有直接关系,而且在寻找石油、天然气和一些金属矿产方面均有重要意义。碳酸盐浊积岩也象碎屑浊积岩一样广泛发育。国外已多有报道^[1、2],国内的研究也逐渐开展起来^1)、[3]。     

THE MESOZOIC SEQUENCE IN SOUTH-WEST IRAN AND ADJACENT AREAS

New outcrop and subsurface data from SW Iran have permitted a review of the stratigraphy of the area to the SW of the Zagros Crush Zone and a comparison with neighbouing areas. The Triassic sequence consists mainly of an evaporite and dolomite sequence in the coastal areas of the Persian Gulf which is the extension of the evaporite basin of Saudi Arabia and Iraq. Towards the high Zagros in the northeast, the evaporites are replaced by dolomites. Two unconformities are found at the base and top of the Triassic. The Jurassic in Fars and eastern Khuzestan consists of an argillaceous interval representing early Liassic time, overlain by a thick development of neritic carbonates of early to late Jurassic age. An evaporite unit developed in the upper Jurassic is present in coastal/subcoastal areas of Fars and eastern Khuzestan and is the north-eastwards extension of Hith Anhydrite of Saudi Arabia. The end of the Jurassic was marked by uplift and erosion, giving rise to an unconformity over a large area. In western Khuzestan and Lurestan, the Lower Jurassic is a sequence of alternating evaporites and dolomites. The Middle Jurassic is represented by deeper water bituminous shales and argillaceous limestones of the Sargelu Formation, which is cut by a regional unconformity in this area. The Upper Jurassic is represented by the evaporites of the Gotnia Formation which is terminated by the possible Upper Jurassic unconformity. The Jurassic sequence of this area can be correlated well with that of eastern Iraq. In the high Zagros area to the south of the Crush Zone, the Jurassic consists of a thick development of shelf carbonates with no evaporites. The Cretaceous System in SW Iran is divided into Lower (Neocomian-Aptian), Middle (Albian-Turonian) and Upper (Coniacian-Maastrichtian). The Lower Cretaceous is mainly made up of two shelf carbonate unit separated by shales in Fars and eastern Khuzestan. Towards Lurestan, the carbonates pass into deeper water black shales and limestones with radiolaria. The top of the Lower Cretaceous is marked by a regional unconformity in Fars and the Persian Gulf area. The Middle Cretaceous began with a transgression forming the shales and limestones of the Kazhdumi Formation which was followed by a shallowing of the sea and the deposition of Cenomanian and Turonian shelf carbonates over the entire area of Fars and Khuzestan. The Lurestan basin retreated northwards and northwestwards and covered only central Lurestan during Albian- Turonian time, with the deposition of dark grey to black shales and pelagic limestones of the Garau and the Oligostegina bearing limestones of the Sarvak Formation. At least two pronounced regional unconformities have been recognized, between the Cenomanian and Turonian and between the Turonian and Coniacian. The Upper Cretaceous is represented by limestones at the base and a transgressive shale unit at the top, which is terminated by a regional unconformity at the Cretaceous/Tertiary boundary. Isopach and lithofacies maps of various units and correlations of outcrop and subsurface sections indicate several important unconformities and facies changes in SW Iran during the course of the Mesozoic. The general stratigraphy of the region shows similarities to the Mesozoic sequence of Iraq and Saudi Arabia, with a gradual facies change from carbonates to sandstone towards Saudi Arabia. This change is most evident in the Upper Triassic and in the Barremian-Cenomanian. The Upper Cretaceous sequence of SW Iran changes from mainly argillaceous sediments of deeper marine environment into carbonates of shallow water origin towards Saudi Arabia. The correlation of the Mesozoic sequence of SW Iran with those to the northeast of the Zagros Crush Zone indicates a rather abrupt change from the Upper Triassic onwards.     

THE HYDROCARBON PROSPECTIVITY OF LOWER OLIGOCENE DEPOSITS IN THE MARAGH TROUGH, SE SIRT BASIN, LIBYA

The main phase of rifting the Sirt Basin (Libya) had ceased by the mid-Cretaceous but Alpine-related tectonic pulses in the late Eocene resulted in northward tilting of the basin. In the Maragh Trough (SE Sirt basin), a regional unconformity consequently separates Eocene carbonates from the overlying Oligocene succession. The unconformity marks a change from Eocene carbonate sedimentation to more mixed shallow-marine deposition in the Oligocene. A regional transgression re-established fully marine conditions in the Miocene.
Deeply-buried (Triassic) source rocks in the Maragh Trough reached peak oil generation during the Oligocene. Two potential reservoir intervals have been identified: upper Eocene rudstones of the Augila Formation, and unconformably-overlying sandstones of the Lower Oligocene Arida Formation. Mid-Oligocene shales provide a regional seal.
Facies distributions and reservoir properties are related to rift-related structural highs. Despite the absence of a nearby source kitchen, Upper Eocene carbonates have been found to be oil-bearing in the Maragh Trough at wells D1- and F1–96. This indicates that hydrocarbons have migrated along graben-bounding faults from deeply-buried source rocks to platform and sub-platform areas. Traps are of combined structural and stratigraphic type.     

莺歌海盆地LD15-1构造莺黄组砂岩储层的成岩作用

LD15-1构造位于莺歌海盆地中部坳陷,是由泥底辟引起顶部地层向上拱曲而形成的背斜构造。天然气产自莺黄组中、上部砂岩中。粒间原生孔和粒间溶蚀扩大孔是砂岩中极其重要的储集空间。砂岩的成岩作用主要包括压实作用、胶结作用和溶蚀作用。研究表明,莺黄组地层所经受的成岩作用阶段为早成岩阶段及晚成岩阶段A—B期。溶蚀作用对砂岩成为高孔中渗储层贡献较大。深海盆地水道浊积砂、浅海陆架席状砂是良好的储集砂体。巨厚的烃源岩和良好的储集砂体及其与完整圈闭的有机组合,是莺歌海盆地天然气富集的基本因素。     

中国西北地区石炭系碎屑岩储集层研究

新疆北部地区石炭系碎屑岩主要为中粒级长石砂粉，岩屑长石砂岩，岩屑砂岩，凝灰质，泥含量高，结构成熟度低，处于晚成岩A期－晚成岩B、C期，局部达近变质阶段，早期方解石胶结发育，原生孔隙保存条件差，但长石，岩屑，早期方解石胶的的化学稳定性较差，古风化壳附近有望找到储集层，在火山岩中可形成裂缝－溶洞型信集层。安西红柳园地区碎屑岩火山岩屑含量较主（8％－17％），热成熟度高，埋藏溶蚀作用不发育，寄希望于次压实型集型层和古风化壳型储集层，祁连地区主要为（纯）石英砂岩，次长石岩屑砂岩，岩屑砂岩，储集空间为粒间（溶）孔，粒内溶也，高岭石晶间微孔及少量裂缝，总体为特低孔， 储集层，部分可达低孔，低渗或中孔，低渗储集层，在最大古埋深较浅，欠压实带以及古风化壳附近的较富含长石和岩屑的砂岩中，有望找到较好的储集层，上石炭统较好储集层主要分布于新疆准噶尔东北部的五彩湾，奇台双井子，准噶尔西部的车排子，百口泉及祁连地区的中卫下河沿，景泰红水堡等地。下石岩较好储集层分布于新疆的双井子和祁连地区的景泰红水堡等地。图1参3（朱如凯摘）。     

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。     

宜昌地区下寒武统沉积环境分析

宜昌地区早寒武世除天柱山期(南部和西部称岩家河期)岩性变化较大外,其他依次沉积了以黑色炭质页岩夹灰岩、细碎屑岩、石灰岩、白云岩等为主的岩性组合,反映了中扬子区岩性四分的特点。晚震旦世灯影末期区内是一个东高西低、东北高西南低的浅海沉积区。在此背景上,早寒武世早期(即天柱山期)遭受了短暂而快速海进之后,依次经历了浅海盆地边缘、斜坡带、浅海陆棚及潮坪等沉积环境的缓慢演化,显示了有规律的海退序列。在区内天柱山组、岩家河组及水井沱组等均首次发现了重力流沉积;在水井沱组下部炭质页岩所夹的薄层粉晶云岩中,首次发现了沉积型重晶石富集层。根据区内天柱山期为浅海斜坡带(岩家河期为浅海盆地边缘)、水井沱期为浅海盆地边缘至斜坡带等沉积环境判断。天柱山组(岩家河组)与水井沱组之问应为连续沉积、整合接触。图3表1参7