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1.
《海洋地质前沿》2016,(3)
从生物礁碳酸盐岩的沉积特征、孤立台地生物礁沉积模式2个方面对巴哈马滩与西沙群岛进行对比分析:巴哈马滩礁区主要沉积粒状灰岩、泥质灰岩、斜坡发育生物碎屑灰岩,海底文石和镁方解石胶结作用强烈,致大部分原始孔隙度阻塞,孔隙度降低;西沙礁滩海滩岩以生物碎屑灰岩为主,地层主要发育生物碎屑灰岩和白云岩,各种藻类格架的杂乱分布增大岩石的孔隙度。巴哈马滩以孤立碳酸盐岩台地生物礁为主,发育台地边缘斜坡及滩礁型孤立台地,西沙孤立台礁区主要发育永乐、宣德2类环礁沉积系统,以及台地边缘礁、塔礁、马趾礁、环礁、点礁等多种生物礁类型。大巴哈马滩具有侧向生长的潜力和周期性进积作用的特征,西沙陡坡高能带发育进积型与侵蚀型2种沉积类型,风暴潮与盛行风作用成为灰沙岛的主要成因机制。 相似文献
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西非下刚果盆地为一典型被动大陆边缘含盐盆地,下刚果盆地北部海域在白垩系海相碳酸盐岩层系获得丰富油气发现。研究区海相碳酸盐岩领域油气勘探面临的核心瓶颈问题,即白垩系碳酸盐岩的沉积模式、演化规律、储层特征以及沉积储层发育控制因素。综合钻井、地震、区域地质等资料,分析认为自下向上相对海平面的上升控制了沉积演化,沉积体系演化模式为浅海碳酸盐岩台地→浅海混积陆棚→半深海-海底扇。下刚果盆地碳酸盐岩储层展布在纵向及平面上均可以划分为内中外3个储层发育带,碳酸盐岩储层最主要发育于下白垩统Albian阶下Sendji组。该时期研究区整体发育浅海碳酸盐岩混积缓坡台地沉积体系,沉积亚相可进一步划分为混积滨岸、后缓坡、浅水缓坡以及深水缓坡4种类型,其中浅水缓坡亚相颗粒滩微相与后缓坡亚相台内浅滩、砂质浅滩微相储层最为发育。碳酸盐岩储层岩性组合主要包括颗粒灰岩、砂岩、砂质灰岩、白云岩4种类型;储层发育主要受沉积相带的控制,并受成岩作用的影响。 相似文献
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研究区以生屑白云岩及含砂屑的鲕粒白云岩为主,相邻井区白云岩类型及厚度变化大。为确定各类白云岩的成因,通过孢粉及微体古生物化石、碳氧同位素、微量元素B含量等分析手段,对本区的古气候、古环境、古沉积介质的物理化学性质进行系统地分析,自沙三段以来,由温暖的亚热带气候变得逐渐干燥,水体逐渐咸化,为白云岩的形成提供了必要条件。具有硬的基底的滨浅湖台地,水体能长期保持清澈,有利于底栖生物生长繁殖,适宜碳酸盐岩的形成、沉积了巨厚的生屑白云岩,其生屑含量高、孔隙较发育、方解石也被交代的更加彻底,建立了该类白云岩滨浅湖台地渗透回流成因模式。滨浅湖隆起带区域,淡水与咸水在此交汇,易形成具雾心亮边的粉晶白云岩和具有同心圆结构的鲕粒云岩或生物碎屑云岩,但常常白云石化不彻底,方解石含量高,个别井段甚至发育云质鲕粒灰岩,建立了该类白云岩滨浅湖隆起带混合水成因模式。此研究丰富了湖相白云岩成因模式,对渤海湾盆地碳酸盐岩的勘探具有重要的指导意义。 相似文献
4.
北部湾盆地涠西南凹陷碳酸盐岩潜山储层特征与主控因素分析 总被引：1，自引：1，他引：0
北部湾盆地涠西南凹陷已发现多个碳酸盐岩潜山油田和含油构造，运用岩心、薄片、钻井、测井、地震等资料，对石炭系碳酸盐岩储层特征及主控因素进行了综合分析。研究认为涠西南凹陷碳酸盐潜山主要分布在一号断裂带至二号断裂带附近，其中一号断裂带碳酸盐岩潜山主要为上石炭统黄龙组，岩性为浅灰色灰岩、白云质灰岩、白云岩互层，沉积微相以碳酸盐台地-台缘生屑灰岩滩为主，发育裂缝、溶孔、溶洞等储集空间；二号断裂带碳酸盐岩潜山主要为下石炭统下部石磴子段、孟公拗段，岩性为灰色、深灰色灰岩，沉积微相以台内灰岩滩沉积和台缘生屑灰岩滩为主，发育良好的裂缝型储集层。碳酸盐岩潜山储层发育程度主要受碳酸盐岩沉积环境、地下水活动、古构造应力以及潜山上覆地层岩性等内因和外因诸多因素影响，在这些因素共同作用下，涠西南凹陷碳酸盐岩潜山发育孔隙、裂缝、溶洞等多种储集空间，具备良好的储集条件。 相似文献
5.
巢北地区黄龙组岩石学、元素地球化学特征及意义 总被引：1，自引：0，他引：1
安徽巢湖麒麟山中石炭统碳酸盐岩地层是研究碳酸盐岩沉积及成岩作用的理想剖面之一。文章采用岩相学及元素地球化学分析法,对该处剖面碳酸盐岩的特征做了深入研究。表明,黄龙组岩石以泥晶或亮晶颗粒灰岩为主;元素分布中稀土元素总量较低。分析认为,巢北地区中石炭统属于浅海碳酸盐台地相产物,其成岩序列属于海退序列,成岩环境主要为大气淡水成岩环境。 相似文献
6.
王圣柱 《海洋地质与第四纪地质》2013,(1):121-127
南盘江坳陷的海相油气勘探潜力巨大,至今未取得实质性的突破的重要原因之一就是储集岩特征的认识不清。在储层沉积学各种研究的基础上,利用大量地面和井下资料,论述了南盘江地区海相碳酸盐岩储集岩特征及储集空间类型,探讨了本区储层发育的主要控制因素,如沉积相带及成岩作用等,研究区储集岩类型以礁滩灰岩和白云岩较好,有利储层发育的层位主要集中于中泥盆统、中上石炭统和二叠系,总体储集性能评价为Ⅱ—Ⅲ类储层,有利储层分布区主要位于研究区西北部的碳酸盐台地边缘一线,以及孤立台地周缘的礁滩环境。 相似文献
7.
结合区域构造、地层概况、岩相古地理等方面的背景资料,对宣汉盘龙洞上二叠统长兴组生物礁地层剖面进行了观测描述。通过室内镜下岩石薄片鉴定分析,识别出主要岩石类型为礁灰岩、礁云岩、生屑灰岩、颗粒灰岩及晶粒白云岩。根据露头观察和室内镜下岩石薄片鉴定分析,结合岩石学、古生物等沉积相标志的研究,认为该剖面发育开阔台地、台地边缘生物礁和台地边缘浅滩三种沉积相类型,其中台地边缘生物礁发育,可进一步识别出礁基、礁核和礁前亚相,礁核以骨架礁和障积礁为主;台地边缘浅滩进一步划分为粒屑滩、鲕粒滩等亚相。初步总结出了该剖面的沉积相模式,并对该剖面的沉积演化序列和识别标志进行了讨论。 相似文献
8.
巴西盐下湖相碳酸盐岩是现今海外油气勘探的热点领域,但中国关于该类储层特征的研究相对薄弱。通过综合应用岩心、薄片、物性测试等资料,系统研究了储层岩石类型、储集空间类型、储层物性特征、成岩作用类型及其对物性的影响情况。研究表明微生物灰岩和生物碎屑灰岩是盆地的主要储层类型,其中微生物灰岩由叠层石和鲕粒灰岩互层组成,生物碎屑灰岩由贝壳灰岩组成。盐下微生物灰岩储层的孔隙类型以溶孔、晶间孔、粒间孔等次生孔隙和受过改造的原生孔隙为主;生物碎屑灰岩储层的孔隙类型以铸模孔、溶孔、溶洞及晶间孔为主。盐下湖相碳酸盐岩储层整体物性较好,具有中-高孔渗特征;白云岩化和溶蚀作用是改善盐下湖相碳酸盐岩储层的主要成岩作用类型,储层主要处于中成岩阶段,少量处于早成岩阶段。 相似文献
9.
南海北部海区珠江口盆地前渐新统找油的新领域 总被引：1，自引：0，他引：1
寇才修 《海洋地质与第四纪地质》1984,(2)
珠江口盆地是广东陆架裂谷盆地,其邻区普遍分布着晚海西—印支期基底(CP—T_(1 2)),东、南部岛弧区为千枚岩、板岩夹灰岩、大理岩组成的复理石建造;北部广东沿海陆地为浅海灰岩和滨海含煤碎屑岩系.燕山早期(J_1或T3—J_1)在岛弧区为杂砂岩、页岩复理石建造夹火山碎屑岩;北部沿岸为海相和海陆交互相含煤碎屑岩建造.中期(J_(2-3))岛弧区为杂砂岩,页岩复理石夹火山岩;北部沿海为中酸性火山岩夹砂岩、页岩陆相碎屑岩.晚期(K_1或K_1—K_2)岛弧区与中期沉积相似,北部沿岸为陆相复矿砂砾岩、泥灰岩夹火山碎屑岩.喜山早期(K_2—E_1)岛弧区为复理石碎屑岩和浅海火山碎屑岩,礁灰岩,北部沿海主要为陆相复矿红色碎屑岩,火山碎屑岩夹海相层.中期(E_2—E_3)岛弧区是复理石碎屑岩、浅海火山碎屑岩、礁灰岩;北部沿岸为陆相暗色泥岩、红色碎屑岩为主夹海相泥岩、砂岩和砂砾岩,含海生动物,和岸相植物红树科化石.晚期(N_1—N_2)岛弧区为浅海碎屑岩、港湾三角洲砂岩、泥灰岩、灰岩、凝灰岩、安山岩、玄武岩;北部沿岸缺失或变薄,为海相和陆相碎屑岩夹玄武岩.组成晚印支期(T_3—J_1)、燕山期(J_(2-3)—K_1)、喜山期(K_2—E N)等三组叠置含油气盆地. 相似文献
10.
中卫及周缘地区位于阿拉善地块、华北板块、北祁连加里东造山带之间,该区上古生代受区域构造和全球海平面变化影响,地层发育与华北地区有较大差异。通过收集整理3条野外实测地质剖面及19条剖面资料,根据剖面岩性、沉积结构、构造、沉积旋回等,对中卫及周缘地区石炭纪岸线变迁、沉积范围、主要海泛期沉积体系及沉积相的纵向演变规律进行了研究。将研究区石炭系地层划分为三角洲、堡岛、碳酸盐岩台地、浅海4类沉积体系。早石炭世早期,南秦岭洋的海水开始入侵研究区南部,沉积范围呈狭长带东西向展布;早石炭世晚期海侵范围逐步向北、向东扩大,于早石炭世形成由阿拉善古陆、鄂尔多斯、北祁连围成的祁连海沉积区。早石炭世海水较深,沉积物以厚层灰岩为主,碳酸盐岩台地和堡岛沉积体系较为发育。晚石炭世海侵继续向北、向东扩大,晚石炭世晚期研究区祁连海与华北陆表海在中央古隆起北部汇合;早二叠世早期,中央古隆起没于水下,祁连海与华北海已广泛连通。晚石炭世至早二叠世早期海平面变化频繁,海水较浅,沉积物以碎屑岩为主并夹有灰岩,主要发育三角洲沉积体系、堡岛沉积体系以及浅海沉积体系。 相似文献
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12.
古巴三区块是2005年中国石化获得的风险勘探开发合同区块，位于墨西哥湾西南部，是古巴西部的前陆盆地之一。结合该盆地勘探现状，对相关的钻井、物探以及地球化学等资料进行石油地质综合分析，评价了该盆地的油气成藏条件及其勘探潜力，预测了有利区带。三区块主要发育上侏罗统一下白垩统的泥灰岩、泥质灰岩和中-下侏罗统泥页岩两套主要烃源岩，储层以泥晶灰岩、灰岩和砂砾岩为主，区内早期形成的圈闭在造山期基本遭到破坏，有效的圈闭主要形成于晚古近纪，圈闭类型有背斜、断鼻、断块和地层圈闭等，推测可能发育多套储盖组合。据区域对比和钻井资料分析，区内的前陆冲断带是本区最有利勘探区带，南盆地北缘发育较厚的第三系，推测是本区有利远景区。 相似文献
13.
南沙岛礁区中西部海底岩石拖网和发现早第三纪半深海沉积的地质意义 总被引：2，自引：0，他引：2
在南沙岛礁区中西部实施海底岩石拖网,有3个站获得海底岩石样品。其中在巽它陆架东北缘水深200多米的NS99－17站见深灰色淤泥中有大量铁褐色含泥钙质结核,说明该区（可能在末次冰期时）处于滨海或海滩氧化环境形成结核,之后海平面上升了至少150m。在南威岛西北方康泰滩的NS99－57站1360m水深的海底获强溶蚀的白垩多孔灰岩,含底栖有孔虫化石,指示康泰滩是从早－中中新世或更早开始生长的生物礁。在永暑礁东北约55km处的NS99－52站新命名了“东生海山”,其西北坡获含第四纪钙质超微化石的礁灰岩,以及由抱球虫类等生物碎屑和胶磷矿组成的钙质磷块岩和含磷生物屑灰岩滚石,指示半深海环境,其中的钙质超微化石大部分时代为中始新世－渐新世,以始新世可能较大,小部分属第四纪。这次海底岩石拖网为研究南沙岛礁区中部写信为和油气资源评价提供了重要的“硬证据”,尤其是发现早第三纪半深海相钙质磷块岩离南海西南次海盆很近,不但证实了南沙海域广布下第三系海相沉积的推断,而且为判断南海的张开时间提供了补充依据。 相似文献
14.
Deeply buried (4500–7000 m) Ordovician carbonate reservoirs in the Tazhong area, Tarim Basin, NW China show obvious heterogeneity with porosity from null in limestones and sweet dolostones to 27.8% in sour dolostones, from which economically important oils, sour gas and condensates are currently being produced. Petrographic features, C, O, Sr isotopes were determined, and fluid inclusions were analyzed on diagenetic calcite, dolomite and barite from Ordovician reservoirs to understand controls on the porosity distribution. Ordovician carbonate reservoirs in the Tazhong area are controlled mainly by initial sedimentary environments and eo-genetic and near-surface diagenetic processes. However, vugs and pores generated from eogenetic and telogenetic meteoric dissolution were observed to have partially been destroyed due to subsequent compaction, filling and cementation. In some locations or wells (especially ZG5-ZG7 Oilfield nearby ZG5 Fault), burial diagenesis (e.g. thermochemical sulfate reduction, TSR) probably played an important role in quality improvement towards high-quality reservoirs. C2 calcite and dolomite cements and barite have fluid inclusions homogenization temperatures (Ths) from 86 to 113 °C, from 96 to 128 °C and from 128 to 151 °C, respectively. We observed petrographically corroded edges of these high-temperature minerals with oil inclusions, indicating the dissolution must have occurred under deep-burial conditions. The occurrence of TSR within Ordovician carbonate reservoirs is supported by C3 calcite replacement of barite, and the association of sulfur species including pyrite, anhydrite or barite and elemental sulfur with hydrocarbon and 12C-rich (as low as −7.2‰ V-PDB) C3 calcite with elevated Ths (135–153 °C). The TSR may have induced burial dissolution of dolomite and thus probably improved porosity of the sour dolostones reservoirs at least in some locations. In contrast, no significant burial dissolution occurred in limestone reservoirs and non-TSR dolostone reservoirs. The deeply buried sour dolostone reservoirs may therefore be potential exploration targets in Tarim Basin or elsewhere in the world. 相似文献
15.
Mohamed S. Abu El Ghar 《Marine and Petroleum Geology》2012,29(1):276-292
The Middle Eocene deposits in the Fayoum Ranges are composed of complex alternative clastic (claystone and sandstone) and carbonate (limestone and dolostone) facies and dominated carbonate (limestone) facies. Facies are arranged mainly in regression and shallowing upward (emergence) cycles and sequences. Field stratigraphic and microfacies analysis of the study area permits recognition of four major sequences, reflecting 3rd-order cycles. Depositional sequences and cycles are bounded by subaerial erosive surfaces or caliche deposits, ferruginous crust, and by their correlative conformities. Sequence-1 consists of two shallowing-upward cycles (dominate carbonate facies), each of which starts with nummulitic wackestone, capped with nummulitic packstone including Globigerinatheka subconglobata subconglobata biozone. These cycles were deposited under tropical to subtropical conditions as evidenced by the carbonate nature of the rocks and the abundance of nummulites, which need warm conditions for their flourishing. Sequence-2 consists of four emergence cycles based with claystone and capped with wackestone including Morozovella lehneri biozone. The duration (Ma) of sequence-2 (Morozovella lehneri zone) is 3.05 Ma (44.25 Ma for the upper of TA3 3.3 to 41.2 Ma for the lower of TA3 3.5). Sequence-3 includes three rock units (includes Trucorotaloides rohri biozone). The lower unit involves lowstand systems tract, the middle unit contains transgressive systems tract and the upper rock unit includes highstand systems tract. The lowstand systems tract consists of emergence cycles of mixed clastic- carbonate facies, clays at the base and capped with wackestone and packstone facies. The transgressive systems tract consists of dominant carbonate facies, wackestone at the base and capped with packstone facies. Sequence 4 involves transgressive systems tract. The duration of both sequence-3 and sequence 4 has been estimated as 1.8 Ma. 相似文献
16.
Tight grainstones, although widespread throughout the Lower Triassic Feixianguan Formation in the Sichuan Basin, have received little attention, in part, due to their lower porosity and greater heterogeneity relative to their dolostone counterparts. Based on data from cores and thin sections, as well as petrophysical properties, the Feixianguan grainstones, representing a major gas reservoir in the Jiannan gas field were systemically analysed to better understand porosity evolution in tight carbonates that have experienced original oil accumulation and subsequent thermal cracking during progressive burial. The grainstones were divided into two types according to whether pyrobitumen was present, and their porosity evolutions were quantitatively reconstructed. Taking 40% as the original porosity, the grainstones without pyrobitumen, which were ineffective palaeo-oil reservoirs, lost 21.94% and 3.13% of their porosities through marine and burial calcite cementation, respectively, and 13.34% by compaction, and have a current porosity of 1.59%, thus allowing them to serve as major present-day gas reservoirs. Comparatively, pyrobitumen-bearing grainstones, which were once palaeo-oil reservoirs, lost 23.96% and 2.36% of their porosities through marine and burial calcite cementation, respectively; 11.4% by compaction, and 1.44% by pyrobitumen and have a current porosity of 0.84%, thus making them ineffective gas reservoirs. This study provides a quantitative understanding of the close association between porosity evolution and reservoir effectiveness for the palaeo-oil charge and present-day gas accumulation with respect to diagenetic history, which is useful for the future exploration in tight gas limestone reservoirs. 相似文献
17.
Origin,physical, and mineralogical nature of red clays: The Pacific Ocean Basin as a model 总被引：2，自引：0，他引：2
Extensive examination of North Pacific Basin red clays by scanning and transmission electron microscopy reveals that the mean constituent of the red clays are illite-rich argillaceous or shale clasts, quartz and authigenic smectite. The main source of the shale clasts and quartz are aeolian in nature and are derived mainly from African and Asian shales. Illite-rich argillaceous or shale clasts are identifiable by their morphology (high degree of roundness), selected area diffraction, and their unique fracture characteristics created by an ultra thin-sectioning process. This allows for the identification and differentiation of illite-rich shale clasts from other clays, including detrital illite, kaolinite, and smectite. Geotechnical examination of the red clays indicate that they are overconsolidated: the preconsolidation stress is in all cases larger than the vertical effective stress. The overconsolidation is attributed to the strong bonding of argillaceous or shale clasts, quartz and other particulate matter by x-ray amorphous and well developed crystalline sheets of authigenic smectite characterized by high surface activity. 相似文献
18.
The Daxing conglomerate reservoir has become an important exploration target in the Langgu Depression of the Bohai Bay Basin. In this paper, gravel composition, void space, poroperm characteristics and hydrocarbon productivity of the Daxing conglomerate in the third member of the Oligocene Shahejie Formation (Es3) are studied in detail to understand the impact of gravel type on reservoir quality based on cores, petrographic thin-sections, scanning electron microscope (SEM) photos, porosity, permeability and well test data. The Daxing conglomerate is composed of limestone and dolomite gravels. The void space of the Daxing conglomerate includes intragravel and intergravel pores as well as fissures. Intragravel pores are dominated by gravel type. They develop as intergranular pores, intergranular dissolved pores, intragranular dissolved pores and few intercrystalline pores in limestone gravels, whereas in dolomite gravels they develop as intercrystalline pores, intercrystalline dissolved pores, dissolved pores and cavities, few intergranular pores and intergranular dissolved pores. The analysis shows that dolomite conglomerates provide better reservoir quality than limestone conglomerates. Microscopically, areal porosity in dolomite gravels is higher than that in limestone gravels. Macroscopically, porosity and permeability of conglomerates that are dominated by dolomite gravels (dolomite conglomerates) are better than those of conglomerates dominated by limestone gravels (limestone conglomerates). The dolomite conglomerates are superior to the limestone conglomerate with regard to hydrocarbon productivity at the level of parent rock and gravel properties. Poroperm characteristics and hydrocarbon productivity of dolomite reservoirs in the middle Proterozoic Changcheng and Jixian Systems (parent rocks of dolomite gravels) are better than those of the limestone reservoirs in the lower Paleozoic, Cambrian and Ordovician (parent rocks of limestone gravels). Gravel properties, including grain structure, physical nature and dissolution velocity cause the dolomite conglomerates to have more intercrystalline pores, fissures and secondary dissolved pores than limestone conglomerates. 相似文献
19.
在详细调研国内外页岩气储层非均质性研究的基础上,以四川盆地下寒武统筇竹寺组为例,通过平面、层内和微观3个方面分析了泥页岩非均质性特征。平面非均质性主要受区域沉积特征和泥页岩有机地球化学特征控制,盆地中西部主要发育泥质砂岩和砂质泥岩,总有机碳含量TOC和有机质成熟度相对较低;东北部泥质灰岩发育,TOC和有机质成熟度较高;南部以碳质泥页岩为主,TOC和有机质成熟度最高(镜质体反射率Ro可达4.0%)。连井剖面和单井泥岩层矿物特征分析表明,层内非均质性较强,主要表现为横向上地层总厚度、泥页岩单层厚度、泥页岩发育层数、夹层特征和顶—底板岩性沿剖面变化快,纵向上矿物成分和岩石脆性度差异明显。微观非均质性主要受孔隙类型和基质微裂缝影响,黏土层间孔隙和有机质孔隙发育,基质微裂缝对沟通孔隙起主要作用。综合分析认为,四川盆地下寒武统筇竹寺组页岩气储层非均质性特征明显,对页岩气井产能和页岩气采收率有重要影响。 相似文献
20.
珊瑚礁灰岩是孔隙结构复杂、密度变化较大的一类岩石, 但过去对珊瑚礁灰岩纵波波速与孔隙结构的关系及其影响因素研究不够深入。本文测定和分析了南沙海区某岛礁钻孔中珊瑚礁灰岩的纵波波速、孔隙度以及密度特征, 结果显示礁灰岩的纵波波速变化范围为5104~5958m·s-1, 孔隙度变化范围为1.47%~17.7%, 密度变化范围为2.07~ 2.72g·cm-3。这些特征表明, 埋藏后的压实作用和重结晶作用, 对珊瑚礁灰岩的孔隙度和密度产生影响。珊瑚礁灰岩弹性波速主要受孔隙度和孔隙结构类型的影响, 礁灰岩横、纵波速比值能有效地确定岩体的结构和稳定性, 因此礁灰岩的声学特性研究成果可为珊瑚岛礁工程建设的稳定性评估提供可靠的数据支撑。 相似文献