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1.
Stable‐isotope and trace‐element analyses from five surface and subsurface sections of the mid‐Cretaceous Sarvak Formation in southern and offshore Iran confirm the presence of the regional‐scale Turonian unconformity and of a more local Cenomanian–Turonian unconformity. The geochemical results indicate the presence of previously unrecognized and/or undifferentiated subaerial exposure surfaces. Sarvak Formation carbonates at or near palaeo‐exposure surfaces show varying degrees of diagenetic modification, and more extensive alteration is associated with longer periods of exposure. The subaerial exposure and associated diagenetic processes greatly influenced reservoir quality and amplified karstification and evolution of porosity in the Upper Sarvak Formation. The palaeo‐exposure surfaces are identified by their negative δ13C values (as low as – 6.4%) and negative δ18O values (as low as –9.4%), together with low Sr concentrations and relatively high 87Sr/86Sr ratios. These geochemical characteristics are interpreted to be the result of the interaction of the Sarvak Formation carbonates with meteoric waters charged with atmospheric CO2. The meteoric waters also caused karstification and soil formation which in some places extends a few metres below the exposure surfaces. Depleted carbon values were not recorded in areas where palaeosols are not well developed or where the uppermost layers of the Sarvak Formation have been removed by erosion. 相似文献
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H. Rahimpour‐Bonab H. Mehrabi A. Navidtalab M. Omidvar A. H. Enayati‐Bidgoli R. Sonei F. Sajjadi H. Amiri‐Bakhtyar N. Arzani E. Izadi‐Mazidi 《Journal of Petroleum Geology》2013,36(4):335-362
Cretaceous carbonates host major hydrocarbon reserves in SW Iran and elsewhere in the Arabian Plate. Tectonic activity combined with eustatic sea‐level changes resulted in periodic exposure of these carbonates which were subsequently modified by meteoric diagenesis under a warm and humid climate. Long‐term exposure led to the formation of several disconformity surfaces within the middle Cretaceous succession which had important effects on the interval's reservoir characteristics. These disconformity surfaces in the Dezful Embayment were investigated using microfacies, diagenetic and geochemical studies at five subsurface sections. Facies differences across these boundaries, together with features such as karstification, palaeosol development and collapse‐dissolution breccias, were used to identify emergent surfaces. Stable oxygen and carbon isotope ratios and trace element profiles indicate intense meteoric diagenesis. Disconformities were dated using biostratigraphic studies. The results indicate the presence of two major erosional disconformities: one is located at the Cenomanian – Turonian boundary separating the middle Sarvak Formation from its upper part; and the other is in the mid‐Turonian at the boundary between the Sarvak and Ilam Formations. The latter disconformity is correlatable throughout the Arabian Plate. 相似文献
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H. Rahimpour‐Bonab H. Mehrabi A. Navidtalab E. Izadi‐Mazidi 《Journal of Petroleum Geology》2012,35(3):213-236
Carbonate sediments within the Mid‐Cretaceous Sarvak Formation form an important reservoir at the Abteymour oilfield in the western Dezful Embayment, SW Iran. The poroperm characteristics of this reservoir were controlled by factors including deposition under tropical climatic conditions and early diagenesis, repeated phases of subaerial exposure due to local, regional and global‐scale tectonism, and diagenetic modification during burial. From microfacies analysis, the Sarvak Formation carbonates in the Abteymour field were interpreted in a previous study as having been deposited on a homoclinal ramp‐type platform. Three third‐order sequences were recognized in the middle Cenomanian to middle Turonian part of the formation. The reservoir quality of the carbonates was enhanced both by dissolution (comprising separate phases of eogenetic and telogenetic meteoric dissolution) and dolomitization (especially stylolite‐related dolomitization). In this paper, a rock/pore type approach was used in order to integrate petrophysical data with facies and diagenetic models within a sequence stratigraphic framework. Two different rock‐typing methods for the determination of flow units were considered. Hydraulic flow units (HFUs) were identified firstly using flow zone indicators and secondly using a stratigraphic modified Lorenz plot. The flow units resulting from these two methods are compared, and their close correspondence within the sequence stratigraphic framework is discussed. In addition, the previously‐used large‐scale reservoir zonation scheme for the Abteymour field is correlated with the defined flow units, and four new Integrated Reservoir Zones are introduced. By integrating geological information with petrophysical parameters (including porosity, permeability and saturation) within a sequence stratigraphic framework, field‐scale variations and controls on reservoir quality are described. 相似文献
5.
The South Pars gasfield (offshore southern Iran) has been investigated in detail in recent studies in terms of depositional, diagenetic and reservoir properties of the Permian‐Triassic carbonate succession. In the present paper, a variety of flow unit approaches were applied to identify reservoir (flow) and non‐reservoir (baffle or barrier) units within the Permian‐Triassic carbonates. The zonation scheme was based on three approaches; (i) flow units were identified using the stratigraphic modified Lorenz plot (SMLP) method; (ii) hydraulic flow units were identified using a parameter known as the flow zone indicator (FZI); and (iii) petrophysical flow units (PFUs) were determined using the pore throat radius (R35) and water saturation (Sw) parameters. Studies of flow units at both macro‐ and micro‐scales showed that flow properties were controlled by both depositional and diagenetic features. In order to construct a reservoir flow model, the flow units and PFUs were correlated between the four wells studied within a sequence stratigraphic framework. SMLP‐derived flow units appeared to be distributed homogenously within the reservoir succession resulting in a layer‐cake architecture. By contrast, the FZI‐derived hydraulic flow units drew attention to the presence of small‐scale heterogeneities within the reservoir. A comparison between these methods showed that the flow model derived from PFUs included greater vertical and horizontal heterogeneities, especially in the Upper Dalan Member (upper K4 reservoir unit). This was due to depositional/diagenetic heterogeneities in both lateral and vertical directions, and the parameters applied in the PFU method. The PFU‐derived flow model showed a closer relationship to the actual reservoir performance than the flow units derived by the other methods and can therefore be used as the basis for future dynamic flow simulation. 相似文献
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Hamid Heydari Gholanlo Siavash Sajedi Yeganeh Vahed Goudarzi Dehrizi 《Egyptian Journal of Petroleum》2018,27(2):241-247
Well logging analysis has been recognized as the best way to characterize reservoir properties, especially water saturation. Archie equation is known as the best method to estimate water saturation from well logging data. Determination of Archie parameters is an incessant challenge in advanced reservoir engineering because of its complex intrinsic. Measurement of Archie parameters in core laboratory has a high sensitive, expensive and time consuming procedure, that causes the excluding of core analysis to be impossible for the entire depth of reservoir zone. Although some empirical and mathematical models have been introduced to measure cementation factor, without the need of coring, there is not exist a reliable method to estimate saturation exponent in similar way.Genetic algorithm is excelled than other meta-heuristic global search methods, which could be used in solving engineering problems. In this study, a genetic algorithm based strategy has been developed to develop a model to estimate saturation exponent from a core of drilled well in Sarvak Formation at Marun Oil Field in Iran. This model has been validated with laboratory measurements of saturation exponent with the accuracy (R2) of 0.91 and the miscalculation (MSE) of 0.23. 相似文献
8.
The authors present the hydrocarbon source rock potential and reservoir properties of the Eocene Formations in the Central Anatolian Kozakl? Basin. Potential source and reservoir rocks in the Kozakl? basin include transgressive-regressive bank carbonates, fore-bank, deep-marine shales and sandstones, and coal and bituminous facies. The organic geochemical data of the Middle Eocene shales (Sar?lar Formation) show that inadequate to marginal source rock qualities, and marginally mature to overmature characteristics, resulting from heat flow regime of the studied area. Alemli Member of the ?ncik Formation is good to excellent according to TOC wt% and immature to mature source rock from Tmax values. Sedimentological features and age data indicate that the Uzunlu Formation was deposited under the control of antecedent topography. Reservoir properties of the Uzunlu Formation and Keklicek member indicate that the carbonate unit is not adequate for reservoir rock. However, siliciclastics of the Sar?lar Formation could be reservoir potential due to its high porosity and permeability values. 相似文献
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This study presents a 3D numerical model of a study area in the NW part of the Persian Gulf, offshore SW Iran. The purpose is to investigate the burial and thermal history of the region from the Cretaceous to the present day, and to investigate the location of hydrocarbon generating kitchens and the relative timing of hydrocarbon generation/migration versus trap formation. The study area covers about 20,000 km2 and incorporates part of the intra‐shelf Garau‐Gotnia Basin and the adjacent Surmeh‐Hith carbonate platform. A conceptual model was developed based on the interpretation of 2700 km of 2D seismic lines, and depth and thickness maps were created tied to data from 20 wells. The thermal model was calibrated using bottom‐hole temperature and vitrinite reflectance data from ten wells, taking into account the main phases of erosion/non‐deposition and the variable temporal and spatial heat flow histories. Estimates of eroded thicknesses and the determination of heat‐flow values were performed by burial and thermal history reconstruction at various well and pseudo‐well locations. Burial, temperature and maturation histories are presented for four of these locations. Detailed modelling results for Neocomian and Albian source rock successions are provided for six locations in the intra‐shelf basin and the adjacent carbonate platform. Changes in sediment supply and depocentre migration through time were analyzed based on isopach maps representing four stratigraphic intervals between the Tithonian and the Recent. Backstripping at various locations indicates variable tectonic subsidence and emergence at different time periods. The modelling results suggest that the convergence between the Eurasian and Arabian Plates which resulted in the Zagros orogeny has significantly influenced the burial and thermal evolution of the region. Burial depths are greatest in the study area in the Binak Trough and Northern Depression. These depocentres host the main kitchen areas for hydrocarbon generation, and the organic‐rich Neocomian and Albian source rock successions have been buried sufficiently deeply to be thermally mature. Early oil window maturities for these successions were reached between the Late Cretaceous (90 Ma) and the early Miocene (18 Ma) at different locations, and hydrocarbon generation may continue at the present‐day. 相似文献
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In this paper, we discuss the relationship between the organic matter, sulphur and phosphate contents of Upper Cretaceous marine carbonates (Karabogaz Formation) in the Adiyaman Petroleum Province of SE Turkey. The results of organic geochemical analyses of core samples obtained from the Karabogaz Formation suggest that phosphate deposition occurred in settings where the water column was oxic to sub-oxic. However, the preservation of organic matter was favoured in anoxic environments. Moreover, the presence of sulphur (especially sulphur incorporated into kerogen) in organic matter-rich layers led to early oil generation. The results of stepwise py-gc analyses are consistent with a model in which, with increasing maturity, S-S and C-S bonds are the first to be eliminated from the macromolecular kerogen structure. Study of the maturity evolution of S-rich kerogen by laboratory pyrolysis implies that marginally mature and/or mature kerogen in the Karabogaz Formation, which may be classified as classic “Type II” kerogen, was most probably Type II/S at lower maturity stages. This enabled oil generation to occur at relatively shallow burial depths and relatively early stages of maturation. It is reasonable to conclude that Type II/S kerogen, overlooked in previous studies, was abundant in TOC-rich intervals in the Karabogaz Formation. Early generation (and expulsion) from Type II/S kerogen may have sourced the sulphur-rich oils in the Adiyaman area oilfields. 相似文献
11.
The evolution of the central part of the Lurestan region in the Zagros fold-and-thrust belt has been studied using newly generated isopach maps for different time intervals between the Late Cretaceous and the Miocene. The study was based on existing geological maps, gravity data, measured stratigraphic surface sections, original field work and well data. Understanding the processes which have influenced facies and thickness variations in the study area will have a significant impact on future hydrocarbon exploration.
Cenomanian carbonates assigned to the Sarvak Formation, the main reservoir unit in the study area, are composed of both pelagic and neritic facies. These facies occur along the roughly north-south trending \"Anaran lineament\", interpreted to represent a palaeohigh, which influenced patterns of sedimentation in the Cretaceous-Tertiary. The palaeohigh formed as a result of the reactivation of a basement lineament in the Late Cretaceous. The continuing influence of this lineament on patterns of sedimentation during Oligocene — early Miocene time is indicated by a range of evidence including the presence of clinoform geometries.
Analysis of sedimentary thicknesses in the Zagros foreland basin between the Late Cretaceous and the early Miocene indicates progressive SWward migration of the depocentre. Late Cretaceous ophiolite obduction and plate margin convergence exerted a major influence on stratigraphic architecture, and controlled depocentre migration and foreland basin evolution. 相似文献
Cenomanian carbonates assigned to the Sarvak Formation, the main reservoir unit in the study area, are composed of both pelagic and neritic facies. These facies occur along the roughly north-south trending \"Anaran lineament\", interpreted to represent a palaeohigh, which influenced patterns of sedimentation in the Cretaceous-Tertiary. The palaeohigh formed as a result of the reactivation of a basement lineament in the Late Cretaceous. The continuing influence of this lineament on patterns of sedimentation during Oligocene — early Miocene time is indicated by a range of evidence including the presence of clinoform geometries.
Analysis of sedimentary thicknesses in the Zagros foreland basin between the Late Cretaceous and the early Miocene indicates progressive SWward migration of the depocentre. Late Cretaceous ophiolite obduction and plate margin convergence exerted a major influence on stratigraphic architecture, and controlled depocentre migration and foreland basin evolution. 相似文献
12.
Petrographic and stable isotope investigations of Oligocene‐Miocene carbonates in the Asmari Formation from the Gachsaran oilfield and surrounding area in SW Iran indicate that the carbonates have been subjected to extensive diagenesis including calcite cementation and dolomitization. Diagenetic modification occurred in different diagenetic realms ranging from marine, meteoric and finally burial. Asmari carbonates were in general deposited in a ramp setting and are represented by intertidal to subtidal deposits together with lagoonal, shoal and low‐energy deposits formed below normal wave base. Lithofacies include bioclastic grainstones, ooidal and bioclastic, foraminiferal and intraclastic packstones, and mudstones. Multiple episodes of calcite cementation, dolomitization and fracturing have affected these rocks to varying degrees and control porosity. Four types of dolomites have been identified: microcrystalline matrix replacement dolomite (D1); fine to medium crystalline matrix replacement dolomite (D2); coarse crystalline saddle‐like dolomite cement (D3); and coarse crystalline zoned dolomite cement (D4). Microcrystalline dolomites (D1) (6–12 μm) replacing micrite, allochems and calcite cements in the mud‐supported facies prior to early compaction show δ18O and δ13C values of ?4.01 to +1.02‰ VPDB and ?0.30 to +4.08‰ VPDB, respectively. These values are slightly depleted with respect to postulated Oligocene‐Miocene marine carbonate values, suggesting their precipitation from seawater, partly altered by later fluids. The association of this type of dolomite with primary anhydrite in intertidal facies supports dolomitization by evaporative brines. Fine to medium crystalline matrix dolomites (D2) (20–60μm) occur mostly in grainstone facies and have relatively high porosities. These dolomites formed during early burial and could be considered as recrystallized forms of D1 dolomite. Their isotopic values overlap those of D1 dolomites, implying precipitation from similar early fluids, possibly altered by meteoric fluids. Coarse crystalline saddle‐like dolomites (D3) (200–300 μm) partially or completely occlude fractures and vugs. The vugs developed through the dissolution of carbonate components and rarely matrix carbonates, while fractures developed during Zagros folding in late Oligocene to early Miocene times. A final diagenetic episode is represented by the precipitation of coarse crystalline planar e‐s zoned dolomite (D4) (80–250 μm) that occurs in fractures and vugs and also replaces earlier dolomite and post‐dates stylolitization. Fluids responsible for the formation of D3 and D4 dolomites are affected by brine enrichment and increasing temperatures due to increasing burial. Reservoir porosity is dominated by microcrystalline pore spaces in muddy, dolomitized matrix and mouldic and vuggy porosity in grainstone. Porosity was significantly enhanced by the formation of multiple fracture systems. 相似文献
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Carbonate sequence of upper cretaceous (Cenomanian) of Sarvak Formation is a part of Bangestan Group with the thickness of 760 m in Ahvaz oil field (well no. 63). This formation is overlain by the Kazhdumi Formation and is uncomfortably underlain by the Ilam Formation. In this study major and minor elements and carbon and oxygen isotope values and bivariate plot of them indicate that aragonite was the original carbonate mineralogy of the Sarvak Formation. Variations of Sr/Ca and δ18O values versus Mn also illustrate that they were affected by nonmarine diagenesis in a nearly closed system. Recognition of the exact boundary between the Sarvak and Ilam Formations is difficult, due to similar lithologies. So in this study, elemental and oxygen and carbon isotope analysis were used to determine the exact boundary between these Formations. Geochemical data clearly indicate a sub aerial exposure surface, below which meteoric diagenesis effected the sediments. 相似文献
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为了揭示扶余油田扶杨油层砂体分布和流体渗流规律,采用层次分析方法,将扶余油层划分成复合河道、单河道、河道内加积体等构型要素,将杨大城子油层划分成河道、点坝、点坝内侧积体等构型要素,并归纳总结了不同构型界面同渗流屏障关系。在此基础上,综合孔隙度、渗透率、流动分层指标(FZI)、剩余油饱和度、水驱指数等参数,采用聚类方法,将扶杨油层划分成4类流动单元,并得到各自的判别标准。结合储层构型,识别出5种流动单元成因类型。油田动态数据和划分流动单元关系表明,流动单元能够有效预测产能、指示剩余油分布和砂体动用效果。 相似文献
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M.A. Kavoosi Y. Lasemi S. Sherkati R. Moussavi-Harami 《Journal of Petroleum Geology》2009,32(3):235-259
Upper Jurassic carbonates of the Mozduran Formation constitute the principal reservoir intervals at the giant Khangiran and Gonbadli gasfields in the Kopet Dagh Basin, NE Iran. These carbonates were investigated using detailed field studies and petrographic and wireline log analyses in order to clarify their depositional facies and sequence stratigraphy. Facies were interpreted to reflect deep basin, fore-shoal, shelf margin, lagoon, tidal flat and coastal plain depositional systems.
The Mozduran Formation is composed of six depositional sequences. Thickness variations were controlled by differential subsidence. Aggradation on the platform margin and reduced carbonate production in the deep basin together with differential subsidence resulted in the creation of a narrow seaway during the late Oxfordian. Petrographic studies suggest that Mozduran Formation carbonates had a low-Mg calcite mineralogy during the Oxfordian, and an aragonite to high-Mg calcite mineralogy during the Kimmeridgian. Reservoir pay zones are located in highstand systems tracts within the lower and middle Kimmeridgian depositional sequences. The rapid lateral thickness variations of these sequences were controlled by tectonic factors, leading to compartmentalization of the Mozduran Formation reservoir with the possible creation of stratigraphic traps, especially at the Khangiran field. 相似文献
The Mozduran Formation is composed of six depositional sequences. Thickness variations were controlled by differential subsidence. Aggradation on the platform margin and reduced carbonate production in the deep basin together with differential subsidence resulted in the creation of a narrow seaway during the late Oxfordian. Petrographic studies suggest that Mozduran Formation carbonates had a low-Mg calcite mineralogy during the Oxfordian, and an aragonite to high-Mg calcite mineralogy during the Kimmeridgian. Reservoir pay zones are located in highstand systems tracts within the lower and middle Kimmeridgian depositional sequences. The rapid lateral thickness variations of these sequences were controlled by tectonic factors, leading to compartmentalization of the Mozduran Formation reservoir with the possible creation of stratigraphic traps, especially at the Khangiran field. 相似文献
16.
Reservoir rocks at Gomba oilfield, located in the Hungarian Paleogene Basin, include fractured and karstified Triassic carbonates with significant fluid storage potential. However little information is available about the fracture network in these carbonates which has led to production problems at Gomba. The purpose of this study is to investigate the relationship between the spatial distribution of high porosity zones in the carbonates and the microfracture system. For this evaluation, individual fractures were studied and used in a discrete fracture network (DFN) modelling exercise at two wells, Gomba‐1 and Gomba‐3. The investigation took place at two different scales. Fracture length and aperture distributions were derived at the micro‐scale (mm to cm), whereas fracture density and fracture orientation data were investigated at the reservoir scale. The results of both investigations were taken into consideration in the modelling. The results of the fracture network models were compared to reservoir lithologies which ranged from fractured carbonates to collapse breccias. Based on the results, it appears that the porosity associated with a significant proportion of the fractures was increased as a result of dissolution. Fracture distribution was not uniform along the studied well paths, and fracture orientation was chaotic at particular depth intervals. On the basis of the DFN models, three different fractured zones are predicted to occur in the reservoir, but only two of the zones have significant fracture porosity. Comparing these results with petrographic observations, an epigene karst phase is proposed which is older than (or the same age as) the time of hydrocarbon migration; karst‐related voids were therefore important pathways for fluid migration. The void system and karst caverns partly collapsed during subsequent burial, resulting in karst‐related traps. By analogy with modern cave systems, the karst cavern zones at Gomba probably extend horizontally rather than vertically, and are oriented NE‐SW parallel to major structural lineaments. 相似文献
17.
东海平湖油气田八角亭构造H4b油藏具有储层薄、非均质性强的特点,且采用多分支水平井开发模式,加大了储层描述和油藏建模难度。以钻井和三维地震资料为基础,通过直井精细地层对比和叠前反演技术来预测储层展布特征,充分应用水平井钻进轨迹调整储层描述结果,将目标油藏作为单砂体—流动单元复合体进行地质建模,并利用水平井在砂体内钻进轨迹长、物性参数横向覆盖面广的优势,结合地震属性约束方法,最终建立了符合地质动、静态现状的精确模型。 相似文献
18.
The middle Cenomanian – early Turonian Mishrif Formation, a major carbonate reservoir unit in southern Iraq, was studied using cuttings and core samples and wireline logs (gamma‐ray, density and sonic) from 66 wells at 15 oilfields. Depositional facies ranging from deep marine to tidal flat were recorded. Microfacies interpretations together with wireline log interpretations show that the formation is composed of transgressive and regressive hemicycles. The regressive hemicycles are interpreted to indicate the progradation of rudist lithosomes (highstand systems tract deposits) towards distal basinal locations such as the Kumait, Luhais and Abu Amood oilfield areas. Transgressive hemicycles (transgressive systems tract deposits) represent flooding of the shallow carbonate platform and are recorded in oilfields such as Amara, Halfaya and Zubair. A sequence stratigraphic framework has been constructed for the Mishrif Formation based on correlation of the transgressive and regressive hemicycles which are separated by maximum flooding surfaces. Three third‐order sequences are identified which show lateral and vertical facies variations depending on relative sea‐level changes. Sequence boundaries are characterized by karstic, exposure and drowning features. Middle Cenomanian – Turonian eustatic sea‐level changes together with regional‐scale tectonic deformation of the Arabian Plate controlled the availability of accommodation space and therefore the depositional profile during development of each sequence. Both of these factors controlled the maximum flooding surfaces and sequence boundaries which have been identified. The sequence stratigraphic key surfaces presented in this study represent typical candidate horizons or datum surfaces for future seismic or resevoir modelling studies. Also, lateral facies variations in each transgressive‐regressive sequence and associated carbonate bodies (i.e. prograding shelf margin, forced regressive wedge) may form important stratigraphic traps in the Mesopotamian Basin. 相似文献
19.
伊朗Zagros盆地西南部白垩系Sarvak组碳酸盐岩储层特征 总被引：5，自引：0，他引：5
为了阐明伊朗Zagros盆地西南部白垩系Sarvak组碳酸盐岩储层特征,利用岩心、薄片、录井、试油及测井资料,通过储层岩性类型、储集空间、物性、电性特征及孔隙发育的影响因素分析,指出Zagros盆地西南部白垩系Sarvak组碳酸盐岩储层岩性类型有白垩质灰岩、云质灰岩、颗粒灰岩,储集空间类型多,主要为次生溶孔、铸模孔,其中颗粒灰岩的物性最好,白垩质灰岩中白垩质主要为浮游有孔虫,孔隙较发育,一般随物性增加,含油性级别升高。成岩作用对储层物性影响也较大,起建设性的成岩作用有溶蚀作用、白云化作用、生物扰动及压溶产生缝合线、缝合面。泥粒灰岩、粒泥灰岩在这些成岩作用的影响下,物性有较大改善。储层孔隙发育微观上主要受控于岩相、成岩作用,平面上还和构造位置及沉积环境有关,位于构造高部位的台地浅滩微相往往物性较好。利用垂向上测井响应及平面上小层物性分布特征,明确了物性较好、含油丰度较高的层段,为寻找高产有利储层提供了依据。 相似文献
20.
G. Frébourg E. Davaud J. Gaillot A. Virgone M. Kamali 《Journal of Petroleum Geology》2010,33(2):141-153
A laterally continuous, 3m thick oolitic grainstone has been studied in cores from two wells from the South Pars field (offshore Iran). This high porosity but low permeability interval occurs at the top of the gas-bearing succession in the Permian Upper Dalan Member, and is equivalent to the informally-defined K4 unit of the Khuff Formation. This interval can easily be traced between the wells and overlies high-energy marine deposits. It is composed of oomouldic, fine-grained azooic grainstones with cm-thick coarser-grained layers. Horizontal to oblique lamination or steep foresets were observed together with pinstripe lamination. Petrographic observations indicate a clean oomouldic grainstone with very thin chitonic rims associated with pedogenetic imprints as first-generation cements. Later cements include early vadose meniscus and pendant cements in coarser-grained layers and pseudophreatic cements in the finer-grained material with a tighter pore network, prior to ooid dissolution. Rhizoliths were observed in cores and thin-sections. The pedogenic imprints and the early vadose cementation, both related to emergence, as well as the presence of pinstripe lamination, suggest an aeolian depositional setting. This interval is the first aeolianite recorded within the Khuff Formation or equivalent units, and the first hydrocarbon-bearing carbonate aeolianite described in a hydrocarbon-producing unit. The discovery of aeolianites has important implications for regional sequence-stratigraphic interpretations and reservoir volume calculations. These deposits do not conform to classic subaqueous sequence stratigraphy and do not record eustatic variations in the associated marine basin. Their recognition is crucial for well-to-well correlations. 相似文献