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Fourth EAGE Workshop on Arabian Plate Geology
- Conference date: 09 Dec 2012 - 12 Dec 2012
- Location: Abu Dhabi, United Arab Emirates
- ISBN: 978-94-6282-059-3
- Published: 09 December 2012
21 - 38 of 38 results
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Distribution of the Reservoir Properties in the Minagish and Rawati Formations (Kuwait): A Complex Interplay of Sedimentation, Depositional Architecture and Diagenesis
Authors H.R. Al-Muraikhi, D. Dutta, S.N. Al-Anezi, B. Vincent, J. Garland and P. GitteridgeMiddle Minagish (Tithonian-Berriasian) and Ratawi (Valanginian) Formations, are oil bearing carbonate reservoirs in the Umm Gudair field of Kuwait. Reservoir property varies widely between these two, due to significant variation in the interplay of sedimentation, depositional architecture, and diagenesis. In order to constrain reservoir properties and predicting their distribution, this study integrates data pertaining to sedimentology, sequence stratigraphy, high resolution petrography, of 3 cored wells (900ft of cores) from the Minagish, and 2 cored wells (350ft of cores) from the Ratawi Formations.
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Integrated Core and Log-based Approach to Enhancing the Understanding of Reservoir Distribution within the Arab Formation, Abu Dhabi: Constraining the Future Reservoir Model Build
Authors K. Garrick, G. Al-Jefri, H. Al-Menhali and I. Al-TamimiCorrelation and prediction of reservoir quality variability/heterogeneity within shallow carbonate ramp deposits of the Arab Formation in an Abu Dhabi offshore field has previously proved challenging. This study, commissioned by ADMA-OPCO, presents the results of integrated sedimentology and reservoir quality assessment of the A to D members of the Arab Formation.
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Characterizing the Relationship between Petrophysical Trends and Diagenetic Cementation Patterns: A Case Study from a Carbonate Arab Reservoir in the Dukhan Field, State of Qatar
Authors H. Al-Ansi, M. Al-Wehaibi and R. StanleyThe Upper Jurassic Arab-C Reservoir in the Dukhan Field is the product of a stable epicontinental shelf subjected to continuous relative sea-level variations, with the preserved sediments representing a complex of syndepositional carbonate lithologies and textures deposited in subtidal, intertidal and sabkha environments. Though the depositional units are spatially correlated within a sequencestratigraphic context, petrophysical observations do not conform to the primary depositional fabric, and a cross-cutting relationship is observed.
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Pre-Buwaib and Late Valanginian Unconformities in Outcrop: Inherited Concepts, Facts, and Stratigraphic Consistency
Authors A.M.S. Memesh, Y.M. Le Nindre, S.M. Dini and D. VasletIn Saudi Arabia, a pre-Buwaib unconformity was mentioned by Powers et al., (1966) on bases of angular discordance and of biostratigraphic changes. According to the Hauterivian and Valanginian ages assumed for Buwaib and underlying Yamama formations respectively by Powers, this unconformity should be equivalent to the late Valanginian unconformity. In fact, both arguments given by Powers for this unconformity were since subject to objection. Therefore, based on previous geological mapping by BRGM-DMMR and on two recent maps by SGS, we discuss the pre-Buwaib unconformity in outcrop and the age of the hiatuses from lat. 26°N to lat. 21°N. This formation is associated to the cycle GSS K30 and the Late Valanginian unconformity is thus identified as the pre-Biyadh unconformity and not as the pre-Buwaib unconformity.
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Burial Dolomitization, Late Leaching and Thermochemical Sulphate-reduction Diagenesis in Arab C and D Reservoirs (Kingdom of Saudi Arabia): Impact on Reservoir Properties
Authors C. Taberner, G. Sosa, A. van den Kerkhof, J. Sneep and A. BellDiverse diagenetic processes have been proposed to explain the reservoir properties of the Arab C and D reservoirs in the Middle East: from early diagenesis (e.g. early cementation, dissolution and/or dolomitization) to burial and late burial diagenesis (e.g. compaction, cementation, burial dolomitization, leaching, hydrothermal/fault-related dolomitization). This contribution examines the Arab C and D reservoirs from an onshore field in Saudi Arabia with specific focus on: (1) late diagenetic evolution; (2) timing of burial diagenesis with respect to charge; and (3) their impact on reservoir rock and fluid properties.
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Evidence of Glacio-eustacy during the Late Berriasian to Late Valanginian: Record in the Lekhwair/Habshan/Salil Prograding Geometries, Rayda Basin, Sultanate of Oman
Authors E. Dujoncquoy, P. Razin, C. Grélaud, P. Imbert and G. DupontThe Lekhwair/Habshan/Salil (or LHS) system is a carbonate succession that prograded by 300 km toward the northeast across the eastern part of the Arabian Plate (Rayda Basin) from Berriasian to Early Barremian. The system is organized as a series of large prograding clinoforms with amplitudes ranging from 200 to 350 m.
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A 3D Seismic Chronostratigraphy and Attribute Assessment of Late Jurassic Evaporite Sequences at the Gothnia Basin Margin, Saudi Arabia
Authors S. Wharton, A.M. Bakhiet and P. LawrenceThe Jurassic sequences on the Arabian Platform contain widespread carbonate reservoirs, source rocks and seals, which contribute to a world class petroleum system. Since the Triassic period, the Platform was subjected to alternating periods of transgression and regression and differentiation with intrashelf basins. One key variation in sediment deposition was the formation of evaporite seal beds associated with these intrashelf basins. To elucidate the basin depositional history near the flank of the Gothnia Basin margin, a 3D seismic chronostratigraphy technique and attribute assessment were adopted to assess the evaporite distribution during the Late Jurassic. Seismic chronostratigraphy cubes and Wheeler transform models were generated and interactively assessed for structural controls to deposition and assessment of transgression and regression, unconformity and hiatus events at the basin margin. The seismic chronostratigraphy model, which represents dense semi-automatically generated horizons chronostratigraphic order, was derived from mapping samples in the seismic trace. This allowed the interactive assessment of the Jurassic basin margin depositional history in both time and space, and use of horizon sets for attribute and geobody assessment. The techniques applied in this study area proved beneficial in accurately defining the limits of the evaporite salt beds and basin depositional history during the Late Jurassic
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Subsurface Jurassic-Cretaceous Dolomitization Front Mapping and Characterization, Onshore-Offshore Northeastern Saudi Arabia
Authors W. Tan, D. Tang, K. Shokair, P. Lawrence and A.F. BakhietMassive dolomite had long been documented in the Upper Jurassic and Lower Cretaceous carbonates in the northern regions (onshore and offshore) of Saudi Arabia. These dolomite bodies are characterized by their stratigraphically discordant geometries. Recently more geologic and seismic data have been acquired. Accordingly, a study with the following aims have been undertaken; 1) re-map the dolomite bodies and refine their spatial-temporal geometries, 2) document diagenesis and reservoir qualities within dolomite bodies and across dolomitization front, 3) define a dolomitization system that helps understand the mechanisms of dolomitization and associated diagenetic processes, and 4) predict reservoir qualities within the dolomitization system. This study benefited from integration of variety of data such as core/cutting sedimentology, thin-section petrography, drilling attributes, well logs and seismic attributes. This integrated approach helped not only identify the geometries of dolomite bodies but also depict their fractured natures. Preliminary results revealed that the dolomitization system contains 1) massive dolomite bodies with a spectrum of dolomite textures, varying from very fine to macro-crystalline; 2) a wide range of associated diagenetic processes, including precipitations of ferroan-nonferroan calcite, anhydrite, gypsum, fluorite, kaolinite, silicification (quartz/chert); dedolomitization, emplacement of pyrobitumen-hydrocarbon, and fracturing-leaching; 3) dolomite bodies which show chaotic seismic reflection characters, and exhibit “tornado” geometries when capped with anhydrite seals; and 4) variations in reservoir qualities within dolomite bodies and across dolomitization fronts, which results in reservoir heterogeneities and the potential diagenetic-stratigraphic traps. Two mechanisms have been proposed for onshore and offshore massive dolomitization in terms of their depositional and structural characteristics. This paper offers our current understanding of the Upper Jurassic-Lower Cretaceous regional dolomitization system and diagenetic processes, and provides great insights for reservoir prediction and potential stratigraphic trap exploration opportunities.
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The Influence of Relative Sea Level Variation on Depositional Settings of the Late Jurassic Arab Formation in a Giant Gas Field, United Arab Emirates
Authors D. Green, D.A. Lawrence and M. Al MansouriDetailed core description of multiple wells within a giant UAE gas field has enhanced understanding of the depositional make-up and possible controls on depositional style for the Arab Formation. In this field, the Arab Formation differs from other areas such as Qatar in that anhydrite and dolomite are scarce in the lower Arab Formation units and recognition of any sequence stratigraphic boundaries is limited. In summary the limestone-dominated reservoir units combine to reflect a large-scale shallowing-upwards trend from basinal/outer, mid-ramp to inner ramp depositional settings, based on core-derived facies association analysis. The facies associations are defined according to sedimentological and faunal characteristics and form genetically related, larger-scale units reflecting a low-energy, mid to outer ramp depositional setting, which grades sharply into an inner ramp shoal and shoal complex depositional setting. Within the low-energy units of the lowest Arab Formation reservoir, mudstones are interbedded with bioclast-rich accumulations of variable thickness and an uncertain origin. The vertical spacing of these units may be a function of random/non-random cyclicity (?Milankovitch) and reflect variation in depositional slope angle and hence slump/debrite deposits or deeper water faunal communities. The transition from the distal depositional setting to the proximal depositional setting occurs over a relatively narrow zone into oolitic grainstones as the system progrades. The grainstones form a thick sequence of bedded units reflecting both shoal and intershoal areas within an inner ramp depositional setting, but cyclicity is not apparent in this interval. The small-scale cyclicity present in the lower Arab Formation units may potentially be equal to those that are defined by dolomite-anhydrite cycles in Qatar, but in this area of Abu Dhabi, the overall distal setting has negated the development of these mixed evaporite-carbonate cycles. The implications of this include a lack of intraformational seals and a uniformity of lithofacies (i.e. limited variation), which is also expressed in the more proximal inner ramp deposits and provides for good reservoir potential.
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Termination of the Gotnia Salt and its Effects on the Petroleum System of the Partitioned Zone, Saudi Arabia and Kuwait
Authors R.A. Corley, M. Ye and S. KumarThe Partitioned Zone is an area located along the southern border of the State of Kuwait and the northeastern portion of the Kingdom of Saudi Arabia. The Gotnia Formation of Late Kimmeridgian to Early Tithonian age lies unconformable below Sulaiy/Makhul formations and conformable above the Jubaila Formation, within the Partitioned Zone. Gotnia age-equivalent formations, on the Arabian Platform, include the Arab-Hith formations of Saudi Arabia, Qatar and United Arab Emirates. The Gotnia Formation extends from southern Iraq through Kuwait reaching a maximum thickness of approximately 1,500 feet in southern Kuwait. The termination of the Gotnia Formation is approximately 50 km south of its recorded maximum thickness. Terminus of the Gotnia Formation is mappable and extends in an east-west direction through the Partitioned Zone. Extensive 3-D and 2-D seismic coverage allows detailed identification of the southern pinch-out of the Gotnia Formation. Subsurface control is also aided by several deep wells on either side of the Gotnia pinch-out. This effort will demonstrate and define the structural and stratigraphic nature of the Gotnia Formation’s southern terminus and its effect on the petroleum system within the Partitioned Zone. No full paper available.
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Regional Settings and Characteristics of an Oxfordian Hot Shale
Authors M.C. Poppelreiter, W. Kolkmann, H. Hordijk and M. StevanovichDevelopment of predictive geological rules is vital for successful exploration and development. The “sweet spotting” concept is widely used to predict areas with better-than-average porosity and permeability. However the definition of sweet spots in unconventional plays is still an emerging concept. Empirical observations from a decade of unconventional development in North America suggest better-than-average production is governed by a combination of favorable matrix permeability, presence of natural fractures and source-rock richness and maturity.
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Sequence Stratigraphy and Sedimentology of the Upper Jurassic Arab and Hith Formations, Abu Dhabi, United Arab Emirates
Authors A. Al-Mansoori and C. J. StrohmengerThe Kimmeridgian–Tithonian Arab and Hith formations are part of the highstand sequence set of a second-order supersequence, built by five third-order composite sequences: (1) J70 Sequence, Jubaila/ Arab-D; (2) J80 Sequence, Arab-C; (3) J90 Sequence, Arab-B; (4) J100 Sequence, Arab-A/Lower Asab Oolite; and (5) J105 Sequence, Upper Asab Oolite/Hith), bounded on top by sequence boundary J110_ SB. The J70 to J105 sequences belong to the highstand sequence set of the Upper Jurassic second-order supersequence and show progradation of the facies belts towards the east. Through time, the lagoon behind the barrier bar complex became increasingly evaporitic being dominated by salina-type deposits during Hith deposition (J105 Sequence).
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Use of Surface Analogue for 3-D Geological Modelling of the Arab D Reservoirs - Example from Jabaloyas Outcrops (Eastern Spain)
Authors B.P.R Caline, C. Pabian-Goyheneche, J.P. Rolando, G. San Miguel, M. Aurell, B. Badenas, N. Grasseau and V. MartinezThe poster illustrates how an Upper Kimmeridgian analogue exposed in NE Spain has been used to characterise the internal heterogeneities of a low-angle carbonate ramp that includes the development of reef build-ups formed by colonial forms (corals, stromatoporoids), and microbial crusts with associated encrusting organisms. Results from this outcrop analogue have been applied for improving oil recovery from the Arab D reservoirs of a mature field in UAE. The well-exposed outcrops around the Jabaloyas village (Eastern Spain) have been used for detailed facies and sequence stratigraphic reconstructions within a 16–22 m thick series. These outcrops show strike and non-strike sections across a 12 km2 area (i.e. 4 x 3 km). Seventeen stratigraphic profiles were carried out to control vertical and lateral facies distribution. The facies follows an overall retrogradational-progradational trend with the development of low-energy peloidal-skeletal wackestone-packstone in the middle part of the sequence. Different types of grain-supported facies (ooidal, peloidal, intraclastic, skeletal) are found both in high-energy mid-ramp domains and inner ramp areas. The studied series is bounded by discontinuities that are traceable across a total of 17.5 km linear distance and encompasses coral-microbial build-ups 5 to 15 m high developed in mid-ramp setting during the stages of maximum accommodation gain. A total of 274 reefs have been mapped across the different reconstructed 2D transects. Most of them have pinnacle or conical geometry. Well-cemented discontinuity surfaces were used to identify four stages of sedimentary evolution, two of them including individual episode of reef growth. Some trends on the spatial density and on the fabric within each stage have been recorded. The overall distribution of the main facies were included in a full-field model (20 x 20 m grid increment) while the geometry, size and distribution of the reefs were better adjusted in sector models (1 x 1 m). These models assess the distribution of reservoir bodies and their connectivity. They are now used as a template for diagenesis modelling and constitute the geological input for simulation models.
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Hydrocarbon Prospectivity of the Late Jurassic – Early Cretaceous Makhul Formation in North and Northwestern Kuwait
Authors R.T. Arasu, S.K. Singh, T.F. Al-Adwani, B.Z. Khan, J. Macadan and A.F.N. Abu-GhaneejThe Makhul Formation is the lowermost sequence of Tammama Group in Kuwait sub-basin, deposited during late Tithonian to early Beriasian age. The formation is dominantly argillaceous mudstone with packstone and rare wackestone. In the northern parts of Kuwait the lower Makhul is depicted in the 2D/3D seismic as prograding reflection package, downlaping onto the Hith Formation top. The upper Makhul section has parallel to sub-parallel reflection pattern in the area. The acoustic impedance of the lower Makhul is very low, comparable to shale impedance and grading to relatively higher impedance towards top. That the tight reservoirs of the Makhul Formation have hydrocarbon potential is proven. Fractures are present in the Makhul rocks as seen in the available core data and image logs. They may play vital role for the sustainable production from these unconventional reservoirs. 3D Seismic based high resolution edge mapping has brought out near evenly spaced sub-vertical discontinuities. The wells that have intersected discontinuities gave high gas readings in the mud log. Low frequency anomalies could be indicators of hydrocarbon/fractures. The challenge is to understand the trapping mechanism and geomechanical properties and to identify ‘sweet spots’ for commercial success.
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3-D Carbonate Seismic Stratigraphy of the Berriasian–Valanginian Minagish Field Region, Kuwait
Authors M. Al-Baghli and J.D. PigottMuch previous exploration in the Minagish Field of Kuwait has concentrated upon prospectivity of the principle structures facilitated by 3-D seismic with much less attention directed toward stratigraphic studies. Therefore, questions concerning the seismic imagery of carbonate reservoir quality and seal potential owing to facies changes accompanying allocyclic (global tectono-eustatic) and autocyclic (depositional) processes with a paragenetic overprint (diagenetic-fracture history) have been only modestly studied. The focus of this investigation is upon the carbonate seismic facies placed within a sequence-stratigraphic framework.
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Reconstruction of Late Jurassic Oolite Shoal Paleoenvironments in a Giant Gas Field, Onshore United Arab Emirates
Authors D.A. Lawrence, F. Al Darmaki, D. Green, Y. Bouzida and G. PopaThe Late Jurassic Arab Formation is being developed in a major gas accumulation located onshore southern UAE. The reservoir intervals form a large scale shallowing-upward cycle capped by the widespread Hith anhydrite topseal. The lower Arab Formation consists of wackestones to mudstones of mid ramp to basinal setting (Arab D Member) overlain by foreshoal and oolitic grainstone shoal deposit of the Arab C Member. The succeeding Upper Arab (A & B Members) comprises alternations of dolomitic limestone and anhydrite of restricted lagoon to backshoal and sabkha / salina origin.
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Re-evaluation of the Late Jurassic to Early Cretaceous Stratigraphy of Abu Dhabi
Authors V. Vahrenkamp, P. Van Laer, K. Leyrer, D. Popa, F. Al Katheeri, P. Razin and C. GrelaudThe Late Jurassic to Early Cretaceous sequences of the Arabian Platform form a key petroleum province with super-giant carbonate reservoirs. Despite this economic importance and an excellent database the stratigraphy still contains ambiguities with possible alternative interpretations of far-reaching implications.
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From Geochemistry to Stratigraphy: Unraveling the History of Three Oil Machines in Kuwait
Authors R. Andriany, A. Al-Khamiss and G. Al-SahlanThe application of biological markers (biomarkers) as geochemical fossils for exploration, development, and production purposes is growing rapidly. Their ability to retain the chemical structures during geological processes has been utilized to differentiate among three main source-rock intervals from Late Jurassic to Early Cretaceous. Two source-rock intervals, the Oxfordian Najmah and Berriasian Makhul formations, have been recognized as two giant oil machines. The presence of a fine-grained interval in the Hith Formation opens a new target for exploration.
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