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Characterizing and modeling the Upper Jurassic Arab-D reservoir using outcrop data from Central Saudi Arabia 利用沙特阿拉伯中部的露头数据对上侏罗统Arab-D储层进行表征和建模
Pub Date : 2014-04-01 DOI: 10.2113/geoarabia190253
H. Eltom, O. Abdullatif, M. Makkawi, A. Abdulraziq
Outcrop analogs are used to improve the characterization of reservoir stratigraphy, to understand subsurface facies architecture and heterogeneity, and to overcome the limitations associated with large inter-well spacing within individual oil fields. This study characterized and modeled outcropping strata equivalent to the Upper Jurassic Arab-D carbonate reservoir in Central Saudi Arabia. The study presents qualitative and quantitative sedimentological and petrographic descriptions of lithofacies associations and interprets them within a high-order stratigraphic framework using geostatistical modeling, spectral gamma-ray, geochemistry, petrography and micropaleontology. The sedimentological studies revealed three lithofacies associations, which are interpreted as a gentle slope platform depositional environment comprising nine high-frequency sequences. The biocomponents of the study area show a lower degree of diversity than the subsurface Arab-D reservoir; however, some key biofacies are present and provide indications of the nature of the paleoenvironments. The geochemical results show a strong correlation between the major and trace elements and the reservoir facies, and suggest that the concentrations of elements and their corresponding spectral gamma-ray logs follow the same general upward-shoaling pattern. The 3-D geocellular model captures small-scale reservoir variability, which is reflected in the petrophysical data distribution in the model. This investigation increases the understanding of the stratigraphy of the Arab-D reservoir and provides a general framework for zonation, layering, and lateral stratigraphic correlations.
露头类似物用于改善储层地层学特征,了解地下相结构和非均质性,并克服单个油田大井间距的局限性。本研究对沙特阿拉伯中部上侏罗统arabd碳酸盐岩储层的露头地层进行了表征和模拟。该研究对岩相组合进行了定性和定量的沉积学和岩石学描述,并利用地质统计模型、光谱伽玛射线、地球化学、岩石学和微古生物学在高阶地层格架内进行了解释。沉积学研究发现了3组岩相组合,说明该区为由9个高频层序组成的缓坡台地沉积环境。研究区生物组分多样性低于地下Arab-D储层;然而,一些关键的生物相存在,并提供了古环境性质的指示。地球化学结果表明,主微量元素与储层相具有较强的相关性,元素浓度及其对应的伽马能谱测井具有普遍的向上浅滩化规律。三维地胞模型捕获了小尺度储层的变异性,这反映在模型中的岩石物理数据分布中。这项研究增加了对阿拉伯- d油藏地层学的理解,并为分带、分层和横向地层对比提供了一个总体框架。
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引用次数: 13
Origin of gypsiferous intrusions in the Hawasina Window, Oman Mountains: Implications from structural and gravity investigations 阿曼山脉Hawasina窗中石膏质侵入岩的成因:来自构造和重力研究的启示
Pub Date : 2014-04-01 DOI: 10.2113/geoarabia1902107
Mohammed Y. Ali, D. Cooper, M. Searle, A. Al-Lazki
Gypsiferous intrusions are exposed in road-cuts in the south-central Hawasina Window in the central Oman Mountains. They are located at lower structural levels in the allochthonous Hawasina Complex and lie along faults that cut Upper Cretaceous structures related to the obduction of the Semail Ophiolite and Hawasina Complex deep-water sediments onto the Arabian Plate. The intrusions form gypsiferous pods that are up to 200 m long, in which the gypsum occurs as a dark, fine-grained matrix that contains a pervasive network of anastomosing veins of gypsum and anhydrite. The intrusions contain abundant sub-angular to sub-rounded litharenites, and less common fragments of chert and fine-grained limestone. Although these clast types are undated, their petrographic characteristics suggest they originate from the local Hawasina (Hamrat Duru Group) country rock. Very well-rounded pebbles and cobbles of feldspathic litharenites, some of which show a well-developed cleavage, and rarer cobbles of well-rounded vein quartz appear to have come from the basement. Gravity investigations indicate salt diapirs are not present beneath the Hawasina Window. Instead, the gypsiferous intrusions are interpreted as having been brought up from depth during compression to form disconnected pods along deep-rooted faults, bringing with them small amounts of the basement country rock. Strontium isotope analysis and regional considerations, in particular the distribution, age and nature of other evaporite units on the eastern Arabian Plate, suggest the gypsum may have its origins in the Neoproterozoic (Ediacaran) to lower Cambrian Ara Group evaporites, perhaps from a previously unknown extension of the Fahud Salt Basin beneath the Hawasina thrust sheets.
在阿曼山脉中部Hawasina窗口中南部的道路切割处暴露出石膏质侵入物。它们位于异域Hawasina杂岩的较低构造水平上,并沿断裂切割了与Semail蛇绿岩和Hawasina杂岩深水沉积物逆冲到阿拉伯板块有关的上白垩世构造。这些侵入物形成长达200米的石膏豆荚,其中的石膏以一种黑色的、细粒的基质形式存在,其中含有石膏和硬石膏的网状结构。侵入体中含有丰富的亚角状至亚圆形的岩屑岩,以及少见的燧石和细粒灰岩碎片。虽然这些碎屑类型没有确定年代,但它们的岩石学特征表明它们起源于当地的Hawasina (Hamrat Duru Group)乡村岩石。较圆润的长石岩屑砾石和长石岩屑砾石,部分具有较发达的解理,较少见的圆润脉石英砾石来自基底。重力调查表明,在哈瓦西纳窗下不存在盐底辟。相反,石膏质侵入物被解释为在压缩过程中从深处被带上来,沿着深根断层形成了不相连的荚果,并带来了少量的基底岩石。锶同位素分析和区域考虑,特别是阿拉伯板块东部其他蒸发岩单元的分布、年龄和性质,表明石膏可能起源于新元古代(埃迪卡拉纪)至下寒武统阿拉群蒸发岩,可能来自哈瓦西纳逆冲板下的法胡德盐盆地的一个以前未知的延伸。
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引用次数: 21
Eocene oil shales from Jordan - their petrography, carbon and oxygen stable isotopes 约旦始新世油页岩的岩石学特征及碳氧稳定同位素
Pub Date : 2014-04-01 DOI: 10.2113/geoarabia1903139
M. Hussein, Mohammad Alqudah, S. V. D. Boorn, S. Kolonic, O. Podlaha, J. Mutterlose
Sediment petrographic studies combined with carbon and oxygen stable-isotope analyses are considered to be powerful tools in deciphering the depositional and diagenetic history of carbonate rocks. These studies have been found valuable for understanding the environmental controls and global changes of climate and oceanography. Two cores of Eocene bituminous marls (OS-22 and OS-23) from central Jordan with thicknesses of 222.4 m and 256.3 m, respectively, were logged. A total of 103 thin sections were analyzed for sediment petrographic investigations. Another 295 bulk rock samples from Core OS-23 were selected for stable-isotope analysis (δ13C, δ18O). The two cores show similar lithologic variations that correspond to third-order sea-level changes. The sediment petrographic study reveals the presence of six major microfacies that range from mudstones to grainstones. The distribution of these six types of microfacies in the two cores indicates an overall shallow-marine environment in an interior carbonate-platform setting. Within this environment, conditions fluctuated between open and restricted marine. The stratigraphic variability of the carbon-isotope data of Core OS-23 reflects a highly dynamic depositional system that exhibits a variable rate of organic matter accumulation in the sediments, which can be directly linked to the interaction between primary organic-matter burial and oxidative weathering of reworked organic matter. Within the overall diagenetically controlled δ18Ocarb profile an excursion is observed for a specifically enriched organic matter interval. This excursion is believed to coincide with the Middle Eocene Climatic Optimum (MECO), suggesting that next to seawater, porewaters were influenced by this event and making it the first record of this event in the region.
沉积岩相学研究与碳氧稳定同位素分析相结合,被认为是破解碳酸盐岩沉积成岩史的有力工具。这些研究已被发现对了解环境控制和全球气候和海洋学变化有价值。对约旦中部始新世沥青泥灰岩(OS-22和OS-23)岩心进行了测井,岩心厚度分别为222.4 m和256.3 m。共分析了103个薄片,用于沉积物岩相学研究。选取OS-23岩心295块岩石进行稳定同位素(δ13C、δ18O)分析。两个岩心显示出相似的岩性变化,对应于三级海平面变化。沉积岩相研究表明,该区存在泥岩-颗粒岩六大微相。这6种微相在两个岩心的分布表明,整体上为内碳酸盐岩台地环境下的浅海环境。在这种环境下,条件在开放和受限的海洋之间波动。OS-23岩心碳同位素资料的地层变异性反映了一个高度动态的沉积体系,沉积物中有机质聚集速率变化,这与原生有机质埋藏与改造有机质氧化风化的相互作用直接相关。在整个成岩控制的δ18Ocarb剖面中,观察到一个特定富集有机质层段的偏移。这次远足被认为与中始新世气候最佳期(MECO)相吻合,这表明除了海水之外,孔隙水也受到了这一事件的影响,这是该地区第一次记录这一事件。
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引用次数: 11
Carbonate reservoir characteristics and porosity distribution in Souedih Oilfield, northeast Syria 叙利亚东北部Souedih油田碳酸盐岩储层特征及孔隙度分布
Pub Date : 2014-04-01 DOI: 10.2113/geoarabia1902177
A. Ghabra, D. Tatum, A. Gardiner, D. Stow
The Souedih (also spelled Suwaidiyah) Oilfield is located in the extreme northeast of Syria in part of the Mesopotamian Basin. The principal reservoir of most fields in this region is the Upper Cretaceous, carbonate-rich Massive Formation. Using data from 25 wells and 36 samples/thin sections, this study focuses on the nature and distribution of porosity in the main Souedih reservoir. The Massive A reservoir is 100Ð120 m thick and represented by uniform, bioturbated bioclastic packstone and bioclastic packstone-grainstone, deposited in a well-oxygenated, moderate to high-energy, shallow-marine environment. It is generally well cemented by microsparite and micrite, and more rarely by sparite. Porosity is highly variable, ranging from < 1% to 20%. Mouldic porosity is the most common type, with rare channel and fracture porosity. Average porosity values tend to decrease eastward across the reservoir, which can also be divided vertically into five zones. The uppermost of these shows the highest average porosity > 15%. The dominance of mouldic porosity throughout the study area indicates that secondary dissolution was the primary cause and that pre-existing bioclasts were the principal targets for this dissolution. The source of these diagenetic fluids is still unclear, although our data do lend some support to the karstification theory. These characteristics are important for understanding and managing reservoir production, not only for Souedih but for the region in general.
Souedih油田位于叙利亚东北部的美索不达米亚盆地的一部分。该地区大部分油田的主要储层为上白垩统富含碳酸盐的块状组。利用25口井和36个样品/薄片的数据,研究了Souedih主要储层的孔隙度性质和分布。块状A储层厚度为100Ð120 m,为均匀的生物扰动生物碎屑岩和生物碎屑岩-颗粒岩,沉积于富氧、中-高能的浅海环境中。通常由微晶岩和泥晶胶结,很少由晶岩胶结。孔隙度变化很大,从< 1%到20%不等。模态孔隙是最常见的孔隙类型,少见通道孔隙和裂缝孔隙。平均孔隙度呈向东递减的趋势,纵向上也可划分为5个带。其中最上面的孔隙度最高,平均孔隙度约为15%。整个研究区以模塑孔隙为主,表明次生溶蚀作用是主要原因,而原生生物碎屑是次生溶蚀作用的主要对象。这些成岩流体的来源仍不清楚,尽管我们的数据确实为岩溶作用理论提供了一些支持。这些特征对于了解和管理储层生产非常重要,不仅对Souedih,而且对整个地区都是如此。
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引用次数: 1
Tectonics of the Musandam Peninsula and northern Oman Mountains: From ophiolite obduction to continental collision 穆桑达姆半岛和阿曼山脉北部的构造:从蛇绿岩逆冲到大陆碰撞
Pub Date : 2014-04-01 DOI: 10.2113/geoarabia1902137
M. Searle, Alan G. Cherry, Mohammed Y. Ali, D. Cooper
The tectonics of the Musandam Peninsula in northern Oman shows a transition between the Late Cretaceous ophiolite emplacement related tectonics recorded along the Oman Mountains and Dibba Zone to the SE and the Late Cenozoic continent-continent collision tectonics along the Zagros Mountains in Iran to the northwest. Three stages in the continental collision process have been recognized. Stage one involves the emplacement of the Semail Ophiolite from NE to SW onto the Mid-Permian–Mesozoic passive continental margin of Arabia. The Semail Ophiolite shows a lower ocean ridge axis suite of gabbros, tonalites, trondhjemites and lavas (Geotimes V1 unit) dated by U-Pb zircon between 96.4–95.4 Ma overlain by a post-ridge suite including island-arc related volcanics including boninites formed between 95.4–94.7 Ma (Lasail, V2 unit). The ophiolite obduction process began at 96 Ma with subduction of Triassic–Jurassic oceanic crust to depths of > 40 km to form the amphibolite/granulite facies metamorphic sole along an ENE-dipping subduction zone. U-Pb ages of partial melts in the sole amphibolites (95.6– 94.5 Ma) overlap precisely in age with the ophiolite crustal sequence, implying that subduction was occurring at the same time as the ophiolite was forming. The ophiolite, together with the underlying Haybi and Hawasina thrust sheets, were thrust southwest on top of the Permian–Mesozoic shelf carbonate sequence during the Late Cenomanian–Campanian. Subduction ended as unsubductable cherts and limestones (Oman Exotics) jammed at depths of 25–30 km. The Bani Hamid quartzites and calc-silicates associated with amphibolites derived from alkali basalt show high-temperature granulite facies mineral assemblages and represent lower crust material exhumed by late-stage out-of-sequence thrusting. Ophiolite obduction ended at ca. 70 Ma (Maastrichtian) with deposition of shallow-marine limestones transgressing all underlying thrust sheets. Stable shallow-marine conditions followed for at least 30 million years (from 65–35 Ma) along the WSW and ENE flanks of the mountain belt. Stage two occurred during the Late Oligocene–Early Miocene when a second phase of compression occurred in Musandam as the Arabian Plate began to collide with the Iran-western Makran continental margin. The Middle Permian to Cenomanian shelf carbonates, up to 4 km thick, together with pre-Permian basement rocks were thrust westwards along the Hagab Thrust for a minimum of 15 km. Early Miocene out-of-sequence thrusts cut through the shelf carbonates and overlying Pabdeh foreland basin in the subsurface offshore Ras al Khaimah and Musandam. This phase of crustal compression followed deposition of the Eocene Dammam and Oligocene Asmari formations in the United Arab Emirates (UAE), but ended by the mid-Miocene as thrust tip lines are all truncated along a regional unconformity at the base of the Upper Miocene Mishan Formation. The Oligocene–Early Miocene culmination of Musandam and late Cenozoic folding
阿曼北部Musandam半岛的构造经历了晚白垩世沿阿曼山脉和Dibba带的蛇绿岩侵位构造和晚新生代沿伊朗Zagros山脉的大陆-大陆碰撞构造的过渡。人们已经认识到大陆碰撞过程的三个阶段。第一阶段是由东北向西南向阿拉伯中二叠世-中生代被动大陆边缘的塞梅尔蛇绿岩侵位。Semail蛇绿岩显示一个由辉长岩、闪长岩、闪长岩和熔岩组成的下洋脊轴线套(地球时代V1单元),由U-Pb锆石定年于96.4-95.4 Ma之间,上覆由95.4-94.7 Ma之间的岛弧相关火山岩(Lasail, V2单元)组成的后洋脊套。蛇绿岩的逆冲过程始于96 Ma,三叠系—侏罗系洋壳俯冲至bbb40 km深处,沿ene -倾俯冲带形成角闪岩/麻粒岩相变质底。唯一角闪岩部分熔体(95.6 ~ 94.5 Ma)的U-Pb年龄与蛇绿岩的地壳序列完全重合,表明蛇绿岩形成的同时发生了俯冲。蛇绿岩连同下伏的Haybi和Hawasina冲断片,在晚Cenomanian-Campanian期间被冲断在二叠纪-中生代陆架碳酸盐岩层序之上。俯冲以不可俯冲的燧石和石灰石(阿曼外来岩)堵塞在25-30公里深处而结束。巴尼哈米德石英岩和角闪岩伴生的钙硅酸盐显示出高温麻粒岩相矿物组合,代表了晚期逆冲作用下地壳物质的挖掘。蛇绿岩的逆冲作用结束于约70 Ma(马斯特里赫特时期),浅海相灰岩的沉积超越了所有下伏逆冲层。在山带的WSW和ENE两侧,稳定的浅海环境持续了至少3000万年(65-35 Ma)。第二阶段发生在渐新世晚期至中新世早期,当阿拉伯板块开始与伊朗-西部马克兰大陆边缘碰撞时,在穆桑达姆发生了第二阶段的挤压。厚达4公里的中二叠世至塞诺曼尼亚陆架碳酸盐岩,连同前二叠世基底岩,沿哈格布逆冲构造向西推覆了至少15公里。早中新世序外逆冲断断了拉斯哈伊马和穆桑达姆近海陆架碳酸盐岩和上覆的Pabdeh前陆盆地。这一阶段的地壳挤压发生在阿联酋始新世达曼组和渐新世阿斯马里组沉积之后,但在中新世中期结束,因为冲断尖端线在中新世上米山组底部沿区域不整合面全部截断。渐新世-早中新世Musandam的高潮和阿联酋前陆的晚新生代褶皱标志着霍尔木兹海峡地区阿拉伯与伊朗中部碰撞的开始。第三阶段是上新世阿拉伯板块与伊朗中部板块的碰撞,在扎格罗斯褶皱带上,NE-SW缩短了约50公里。穆桑达姆半岛的相关变形主要局限于半岛的北部和东部倾斜,形成了一个深凹的淹没山谷(rias)海岸线。
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引用次数: 73
Sequence stratigraphy of the Late Cretaceous–Paleocene Gurpi Formation in southwest Iran 伊朗西南部晚白垩世-古新世古尔皮组层序地层学
Pub Date : 2014-04-01 DOI: 10.2113/geoarabia190289
B. Beiranvand, E. Ghasemi-Nejad, M. Kamali, A. Ahmadi
Facies associations, microplanktonic diversity, palynofacies variations, geochemical data, and natural gamma-ray logs were analyzed from the Danial and Gurpi sections of the Campanian–Selandian Gurpi Formation in the Zagros Mountains, southwest Iran. The biostratigraphic data indicate that deposition across the Cretaceous/Paleogene boundary was continuous in the Danial Section. In contrast, a minor stratigraphic break seems to be present in the Gurpi Section, where several planktonic foraminiferal subzones are not identified. Nine depositional sequences were interpreted and correlated between the two sections. They are apparently of great lateral extent because they closely correlate to the global sea-level cycles. The Maastrichtian maximum flooding surface MFS K180 (68 Ma) of the Arabian Plate was also identified. Detailed palynofacies analysis, integrated with standard tropical/subtropical planktonic foraminifera, indicate warm Neo-Tethyan upper-bathyal to middle-shelf depositional environments for the Gurpi Formation.
分析了伊朗西南部扎格罗斯山脉坎帕尼亚-塞兰迪亚Gurpi组Danial和Gurpi剖面的相组合、微浮游生物多样性、孢粉相变化、地球化学数据和天然伽马测井曲线。生物地层资料表明,丹尼尔剖面的沉积是连续的,跨越了白垩系和古近系的界线。相比之下,Gurpi剖面似乎存在一个较小的地层断裂,在那里没有发现几个浮游有孔虫亚带。在两个剖面之间进行了9个沉积层序的解释和对比。它们显然具有很大的横向范围,因为它们与全球海平面循环密切相关。确定了阿拉伯板块马斯特里赫特最大洪水面MFS K180 (68 Ma)。结合标准的热带/亚热带浮游有孔虫,详细的孢粉相分析表明,Gurpi组形成于温暖的新特提斯上深海至中陆架沉积环境。
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引用次数: 14
A refined foraminiferal biostratigraphy for the Late Campanian–Early Maastrichtian succession of northeast Iraq 伊拉克东北部坎帕尼亚晚期-马斯特里赫特早期演替的精细有孔虫生物地层
Pub Date : 2014-01-01 DOI: 10.2113/geoarabia1901161
R. Jaff, M. Williams, I. Wilkinson, F. Lawa, Sarah Lee, J. Zalasiewicz
Species of the benthonic foraminiferal genus Bolivinoides provide a refined biostratigraphic biozonation for the Late Campanian to Early Maastrichtian (Late Cretaceous) Shiranish Formation in NE Iraq. Three biozones and two subzones are identified: the Bolivinoides decoratus Biozone (Late Campanian) subdivided into a lower B. decoratus Subzone and upper B. laevigatus Subzone; the B. miliaris Biozone (Earliest Maastrichtian); and the B. draco Biozone (late Early Maastrichtian). These zones can be related to the biostratigraphical interval of the Globotruncana aegyptiaca (Late Campanian), Gansserina gansseri (latest Campanian–Early Maastrichtian) and Contusotruncana contusa (late Early Maastrichtian) planktonic foraminiferal biozones. Combined, the benthonic and planktonic foraminiferal biostratigraphy enables the informal recognition of lower and upper intervals within both the Globotruncana aegyptiaca and Gansserina gansseri biozones that may be important for more refined inter-regional correlation in the Middle East and North Africa. The new Bolivinoides biozonation precisely locates the Campanian–Maastrichtian boundary in NE Iraq. The foraminiferal assemblages also constrain the timing of a shallowing marine trend in the Shiranish Formation beginning from the latest Campanian that is consistent with shallowing facies noted globally at this time.
底栖有孔虫属Bolivinoides为伊拉克东北部晚坎帕世至早马斯垂纪Shiranish组(晚白垩世)提供了精细的生物地层生物分带。鉴定出3个生物带和2个亚带:晚坎帕世的decoratus Bolivinoides生物带分为decoratus下层亚带和laevigatus上层亚带;马斯特里赫特最早的B. miliaris Biozone;B. drago生物带(马斯特里赫特早期晚期)。这些带可能与Globotruncana aegyptiaca(晚坎帕世)、Gansserina gansseri(晚坎帕世-早马斯垂世)和Contusotruncana contusa(晚马斯垂世)浮游有孔虫生物带的生物地层间隔有关。结合底栖和浮游有孔虫生物地层学,可以在Globotruncana aegyptiaca和Gansserina gansseri生物带中非正式地识别下部和上部间隔,这可能对中东和北非更精确的区域间对比很重要。在伊拉克东北部的坎帕尼亚-马斯特里赫特边界精确定位了新的玻利维亚属生物带。有孔虫组合也限制了Shiranish组从最新坎帕纪开始的浅海趋势的时间,这与当时全球范围内的浅海相一致。
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引用次数: 25
Gravity anomalies of the United Arab Emirates: Implications for basement structures and infra-Cambrian salt distribution 阿拉伯联合酋长国重力异常:对基底构造和下寒武纪盐分布的影响
Pub Date : 2014-01-01 DOI: 10.2113/geoarabia1901143
Mohammed Y. Ali, A. Watts, A. Farid
Gravity measurements onshore and offshore of the United Arab Emirates (UAE) have been used to construct a new Bouguer gravity anomaly map of the region. The gravity data, which has been gridded at 2,700 m × 2,700 m interval, has been used to constrain the tectonic elements, major lineation trends and structures of the Neoproterozoic basement of the Arabian Plate and the distribution of infra-Cambrian salt basins. Advanced transformation techniques (including first vertical derivative, total horizontal derivative, tilt derivative and Euler deconvolution) were applied to identify gravity source edges as an aid to structural interpretation and geological modelling of the study area. Three major structural provinces (fold-and-thrust belt, foreland and salt tectonic provinces) were identified based on the residual Bouguer gravity anomaly field. The eastern fold-and-thrust belt province is associated with short-wavelength positive gravity anomalies, which are attributed to the allochthonous series of the Semail Ophiolite and its related thrust sheets. The central foreland basin province is characterised by NNW-oriented negative gravity anomalies associated with deepening of the basement and thickening of Aruma and Pabdeh sediments in the foredeep basins and flexure of the top and base of the crust by the load of the Semail Ophiolite. The western salt tectonic province displays well-defined local gravity lows superimposed on a regional gravity high, which probably reflects the swelling of infra-Cambrian salt above a shallowing of the basement and thinning of the foredeep sediments. In addition, gravity modelling constrained by seismic and well data indicates the presence of substantial infra-Cambrian salt bodies in all basins of the UAE both onshore and offshore including the southern area of the Rub’ Al-Khali Basin. An extensive array of previously unmapped N-S, NW- and SW-trending lineaments affecting the basement and possibly overlying sediments are mapped in the UAE. The N-S Arabian trending lineament represents the effect of a major structure, along which many important oilfields are located (e.g. Bu Hasa). The SW trend has regular spacing and is dominant in the southern and central part of Abu Dhabi, east of the Falaha syncline. The NW-SE lineament is the most striking and includes two well-defined trends that cross Abu Dhabi Emirate, which in this paper are named as the Abu Dhabi Lineaments. These lineaments are associated with a linear gravity high extending from the southwestern border with Oman to the offshore close to Zakum oilfield. They are probably related to the Najd Fault System.
利用阿拉伯联合酋长国(UAE)陆上和海上的重力测量数据,构建了该地区新的布格重力异常图。利用2700 m × 2700 m格网的重力资料,对阿拉伯板块新元古代基底的构造要素、主要线理走向和构造以及下寒武统盐盆地的分布进行了约束。利用一次垂直导数、总水平导数、倾斜导数和欧拉反褶积等先进变换技术识别重力源边缘,辅助研究区构造解释和地质建模。根据残余布格重力异常,确定了褶皱冲断带、前陆构造和盐构造3个主要构造省。东部褶皱冲断带省与短波长正重力异常有关,其成因是塞梅尔蛇绿岩及其相关逆冲片的异质系列。中部前陆盆地省以nnw向负重力异常为特征,与前深盆地基底加深、Aruma和Pabdeh沉积物增厚以及塞梅尔蛇绿岩负荷下地壳顶底弯曲有关。西部盐构造省显示出明显的局部重力低叠加在区域重力高上,这可能反映了下寒武统盐在基底上的膨胀和前深沉积的减薄。此外,受地震和井数据约束的重力模型表明,阿联酋所有盆地(包括Rub ' Al-Khali盆地南部)的陆上和海上都存在大量的下寒武纪盐体。在阿联酋绘制了一系列以前未绘制的N-S、NW和sw走向的线条,这些线条影响着基底和可能的上覆沉积物。北-南阿拉伯向线代表了一个主要构造的影响,沿着这个构造有许多重要的油田(如布哈萨)。西南走向间距规整,主要分布在阿布扎比南部和中部,法拉哈向斜以东。西北-东南线是最引人注目的,包括两个明确的趋势,穿过阿布扎比酋长国,在本文中被命名为阿布扎比线。这些特征与从阿曼西南边界延伸到Zakum油田附近的线性重力高压有关。它们可能与Najd断裂系统有关。
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引用次数: 48
Modeling of the Dammam outcrop fractures: Case study for fracture development in salt-cored structures 达曼露头裂缝建模:盐芯构造裂缝发育的案例研究
Pub Date : 2014-01-01 DOI: 10.2113/geoarabia190149
M. Al-Fahmi, M. Cooke, J. C. Cole
The exposed Cenozoic carbonates of the Dammam Dome are studied to: (1) characterize fractures and associated structures; (2) interpret the fracture mechanism; and (3) gain insights into fracture development within dome-like structures in the subsurface of the Arabian Gulf region. The fieldwork is integrated with structural analysis of the near-surface horizons mapped from interpretations of 3-D reflection seismic and borehole logs. Fractures are mapped from the outcrops of the middle limestone unit of the Eocene Rus Formation. The outcrops are concentrated in the central, northern and western areas of the Dammam Dome. The fractures are interpreted as opening-mode, bed-bounded joints that form orthogonal sets in most areas. The primary (older) joint set (J1) developed in long lineaments, some of which can be traced for over 300 m across entire exposures. The J1 set is found to be broadly consistent in its trend over the dome, indicating that formation of J1 fractures was systematic and not influenced by local structural anomalies (including karst collapse) formed during the Miocene to Recent. The trend of the J1 set does not correlate with the NE-SW compressional orientation of regional stresses associated with the Zagros Orogeny. Field data interpretation, allied with analysis of dome’s growth and curvature, suggest that the overall joint pattern reflects the growth of the strata as a dome. In addition, the joint density is controlled by structural position on the dome and mechanical stratigraphy. The study results provide a first-order conceptual fracture model for the subsurface reservoirs to guide future development.
对达曼穹窿新生代出露碳酸盐岩进行了研究,目的是:(1)对裂缝及相关构造进行表征;(2)解释断裂机理;(3)深入了解阿拉伯海湾地区地下穹状构造中的裂缝发育情况。现场工作与三维反射地震和井眼测井解释绘制的近地表层的结构分析相结合。裂缝是从始新统罗斯组中灰岩单元的露头绘制的。露头集中在达曼圆顶的中部、北部和西部地区。裂缝被解释为开放模式,在大多数地区形成正交集的床界节理。原始的(较老的)关节组(J1)发育在长长的线条中,其中一些可以在整个暴露中追踪超过300米。J1组在穹顶上的走向大致一致,表明J1组裂缝的形成是系统性的,不受中新世至新近形成的局部构造异常(包括岩溶塌陷)的影响。J1组的走向与与扎格罗斯造山运动有关的区域应力的NE-SW挤压取向不相关。现场资料解释,结合对穹窿生长和曲率的分析,表明整体节理模式反映了地层作为穹窿的生长。此外,节理密度受丘上构造位置和机械地层控制。研究结果为地下储层提供了一级概念性裂缝模型,指导今后的开发。
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引用次数: 12
Ichnofabrics of Eocene oil shales from central Jordan and their use for paleoenvironmental reconstructions 约旦中部始新世油页岩技术组构及其在古环境重建中的应用
Pub Date : 2014-01-01 DOI: 10.2113/geoarabia190185
M. Hussein, Mohammad Alqudah, O. Podlaha, S. V. D. Boorn, S. Kolonic, Jörg Mutterlose
The study of trace fossils is widely used in facies interpretation. It provides a crucial tool for reconstructing depositional paleoenvironments when used in combination with other sedimentological and paleontological proxies. Here we present the first detailed study of Eocene trace fossils from Jordan. Two sections of Early to Middle Eocene age, with a total thickness of 478.7 m, from central Jordan were cored and investigated. The results of individually occurring (isolated) or co-occurring (combined) ichnofabrics and bioturbation levels, in combination with results from biostratigraphic and geochemical studies, were used for stratigraphic and paleoenvironmental reconstructions. The bioturbation index (BI) was used to classify the burrowing density versus the preservation of the original sedimentary structures. The two cores show highly variable grades of bioturbation with BI ranging from 0 to 6. Four ichnogenera were identified: Thalassinoides, Chondrites, Teichichnus and Zoophycos. Both the ichnofabrics and the variations of the BI suggest a shallow, highly dynamic depositional system with rapid changes of water depth and degree of bottom-water oxygenation.
微量化石的研究在相解释中有着广泛的应用。它与其他沉积学和古生物学指标相结合,为重建沉积古环境提供了重要的工具。在这里,我们提出了约旦始新世痕迹化石的第一个详细研究。对约旦中部早始新世至中始新世两段总厚度为478.7 m的岩心进行了研究。单独发生的(孤立的)或共同发生的(联合的)技术结构和生物扰动水平的结果,结合生物地层学和地球化学研究的结果,用于地层和古环境重建。利用生物扰动指数(BI)对挖掘密度与原始沉积结构的保存情况进行分类。两个岩心显示出高度可变的生物扰动等级,BI在0到6之间。鉴定出4个鱼属:Thalassinoides、Chondrites、Teichichnus和Zoophycos。无论是地层结构还是BI的变化,都表明该沉积体系是一个浅层、高度动态的沉积体系,其水深和底水氧合程度变化迅速。
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引用次数: 23
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Geoarabia
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