scholarly journals Sequence stratigraphy of Oxfordian and Kimmeridgian shelf carbonate reservoirs, offshore Abu Dhabi

GeoArabia ◽  
2002 ◽  
Vol 7 (1) ◽  
pp. 31-44 ◽  
Author(s):  
Ahmed S. Al-Suwaidi ◽  
Sabah K. Aziz
Keyword(s):  
Carbonate Platform ◽  
Carbonate Reservoirs ◽  
Abu Dhabi ◽  
Depositional Sequence ◽  
Offshore Area ◽  
Depositional Sequences ◽  
Eastern Flank ◽  
Stratigraphic Model ◽  
Intrashelf Basin ◽  
System Tracts

ABSTRACT Carbonate reservoirs on the eastern flank of the Oxfordian-Kimmeridgian intrashelf basin in offshore Abu Dhabi had received little attention until commercial oil accumulations in structural traps were discovered in the late 1980s and early 1990s. In order to clarify the geometric and chronostratigraphic relationships of the Oxfordian-Kimmeridgian reservoirs, a multidisciplinary study (seismic, lithobiofacies, geochemistry, strontium isotope dating, and well-log data) was used to develop a sequence stratigraphic model. After deposition of the Callovian upper Araej Formation, a differentiated carbonate platform was established in the early Oxfordian in offshore and western onshore Abu Dhabi. Tectonic subsidence coupled with sea-level fluctuations controlled the geometry, deposition, and distribution of the lithofacies. These ranged from organic-rich, limy mudstones in the basinal area, to porous and permeable bioclastic packstones, grainstones, and dolomites in shallow waters on the eastern flank of the intrashelf basin. The upper Kimmeridgian Arab-D Member of the Arab Formation overlies the basinal deposits. Three third-order Depositional Sequences were identified in the offshore area. They are named according to their contained Maximum Flooding Surface; a fourth sequence is an intermediate unnamed Depositional Wedge. Depositional Sequence Jurassic 50 is of Oxfordian age and was deposited during transgressive and highstand periods. The lower Kimmeridgian Depositional Sequence Jurassic 60 is a well-defined lowstand system tract overlain by short-lived transgressive and highstand system tracts. Overlying Depositional Sequence Jurassic 60 is the Depositional Wedge. Finally, Depositional Sequence Jurassic 70 consists of transgressive and highstand system tracts developed on an undifferentiated platform that had localized depressions in the west. The best reservoir developments are in highstand bioclastic packstones and grainstones below the type-1 sequence boundaries that cap Depositional Sequences Jurassic 50 and Jurassic 60. The reservoir units have porosities greater than 20 percent and permeabilities of more than 1,000 milliDarcies. The basinal facies of Depositional Sequence Jurassic 50 have the best source-rock potential in the intrashelf basin.

scholarly journals High-resolution Sequence Stratigraphic Architecture of Barremian/Aptian Carbonate Systems in Northern Oman and the United Arab Emirates (Kharaib and Shu’aiba Formations)

GeoArabia ◽  
2002 ◽  
Vol 7 (3) ◽  
pp. 461-500 ◽  
Author(s):  
Frans S.P. van Buchem ◽  
Bernard Pittet ◽  
Heiko Hillgärtner ◽  
Jürgen Grötsch ◽  
Abdullah I. Al Mansouri ◽  
...  
Keyword(s):  
High Resolution ◽  
Sea Level ◽  
United Arab Emirates ◽  
High Energy ◽  
Abu Dhabi ◽  
Third Order ◽  
Depositional Sequences ◽  
Sequence Stratigraphic ◽  
Stratigraphic Model ◽  
Intrashelf Basin

ABSTRACT A regional sequence stratigraphic model for the Kharaib and Shu’aiba formations (Barremian, Aptian) is proposed based on outcrop and subsurface transects in Oman and the United Arab Emirates. The model shows distinct variations in depositional facies and geometrical patterns in relation to third-order sequences. The sedimentary systems evolved from a low-angle carbonate ramp (Kharaib Formation), to an organic-rich intrashelf basin surrounded by carbonate platforms (Hawar Member and Lower Shu’aiba), to a clay-dominated sedimentation restricted to the intrashelf basin (Upper Shu’aiba). Eustatic sea-level changes and, to a lesser extent, local tectonic controls influenced the development of the systems. This high-resolution sequence stratigraphic model has implications for both exploration and production strategies. This study presents a revised sedimentological facies interpretation based on detailed outcrop observations with geological constraints provided by a regional well-log correlation from Oman and the United Arab Emirates. Time control was provided by biostratigraphy (including new nannofossil data), and carbon isotope stratigraphy. Four third-order depositional sequences bounded by regional exposure surfaces were defined that are composed of at least two higher-order sequences (fourth- and fifth-order). Depositional sequences I and II have a flat ramp setting. The typical ecological succession was orbitolinid and/or miliolid wackestone-packstone deposited in a low-energy, inner ramp environment during early transgression; a mixed-fauna mudstone-wackestone in an open lagoon during maximum flooding and early highstand; and a rudist/miliolid wackestone-packstone-grainstone-framestone of the succeeding late highstand in a high-energy, inner- to mid-ramp environment. The doubling in thickness of the sequences from Oman to Abu Dhabi is attributed to differential subsidence. The Sequence III succession was somewhat similar, but differences were caused by the creation of the intrashelf Bab Basin, and by well-developed microbial boundstones. The basin morphology was primarily due to differential accumulation rates and tectonism was of only minor importance. Rapidly aggrading and backstepping microbial boundstones formed the platform, whereas condensed sedimentation and the accumulation of carbonate source rocks occurred in the basin. Highstand deposits were primarily grainy, high-energy rudist-dominated facies. The sequence ended with a forced regressive wedge along the basin margins. Sequence IV was restricted to the Bab Basin and sedimentation consisted of a clay-rich infill phase. At that time, the Oman and Abu Dhabi platforms were exposed on both sides of the basin. Nannofossils dated this major relative fall in sea level to the early-late Aptian.

scholarly journals Revisiting the Cupidito unit (Cupido Formation) along peritidal carbonates from northeastern Mexico

2020 ◽  
Vol 37 (1) ◽  
pp. 9-25 ◽  
Author(s):  
Felipe de Jesús Torres de la Cruz ◽  
Elizabeth Chacón-Baca ◽  
Gabriel Chávez-Cabello ◽  
María Isabel Hernández-Ocaña
Keyword(s):  
Carbonate Platform ◽  
Sedimentary Facies ◽  
Equilibrium Conditions ◽  
Diagnostic Features ◽  
Depositional Sequence ◽  
Short Pulses ◽  
Upper Limit ◽  
Stratigraphic Model ◽  
Northeastern Mexico ◽  
Organic Productivity

Depositional episodes are readily identified along representative localities of the Lower Cretaceous Cupido platform in northeastern Mexico. The basal part of the Cupido Formation exhibits a progradational reef platform that, at the upper limit, is truncated by a sequence boundary defined by a breccia. This breccia marks the development of a peculiar sedimentary facies informally known as the Cupidito unit, a distinctive stratigraphical unit in northeastern Mexico that remained uninterpreted for decades. Through the analysis of facies, microfacies and stable isotope comparisons from representative localities (Potrero Chico, Potrero de García, La Huasteca, La Muralla and Puerto Mexico) and from other previously reported outcrops, this work describes six diagnostic features for Cupidito and an improved stratigraphic model is proposed. The depositional sequence suggests a broad flat-topped platform with a general low organic productivity and restricted conditions followed by recurrent inundations of lagoon waters. Before drowning, this carbonate platform remained under equilibrium conditions interrupted by short pulses of relative higher-temperatures (48.3 °C and 39.2 °C). Coral-rudist-stromatoporoid patch-reefs with inferred inter-tropical temperatures between 31.5 °C and 32.2 °C originated as a progradational response to the instauration of a new Sequence Boundary at the base of Cupidito.

Chapter 4 Depositional geometry at selected locations around the basin

10.1144/m53.4 ◽  
2020 ◽  
Vol 53 (1) ◽  
pp. 95-111 ◽  
Author(s):  
A. O. Wilson
Keyword(s):  
Saudi Arabia ◽  
Source Rock ◽  
Cross Sections ◽  
Abu Dhabi ◽  
Well Log ◽  
Depositional Sequences ◽  
The Cross ◽  
Intrashelf Basin

AbstractThis chapter includes 11 cross-sections and one well log profile to show the depositional geometry and setting in specific areas around the basin: the Saudi Arabia outcrop belt; the Rimthan Arch; and the eastern and central areas of the intrashelf basin in Saudi Arabia, Bahrain, Qatar, Abu Dhabi and Oman. These cross-sections are used to demonstrate the similarity and degree of continuity of the upper Dhruma Formation, the Tuwaiq Mountain Formation, the source rock, the Hanifa, Jubaila–Arab and Arab–Hith formations and depositional sequences in these different locations in the basin. They show the manner in which the underlying platform formed, the rim developed, the source rock was deposited and the basin progressively filled. The blanket deposition of the Arab-D anhydrite was followed by the Arab-C to Arab-A and Hith carbonate and evaporite sequences. The cross-sections provide the framework used in subsequent chapters to make a series of facies maps and other interpretative diagrams and cross-sections that summarize and, for some intervals, revise the interpretation of the settings and geological events that formed the Arabian Intrashelf Basin.

scholarly journals Seismic forward model of a Natih Formation outcrop: the Adam Foothills Transect (northern Oman)

GeoArabia ◽  
2005 ◽  
Vol 10 (1) ◽  
pp. 17-44 ◽  
Author(s):  
M.Schwab Anne ◽  
W.Homewood Peter ◽  
S.P.van Buchem Frans ◽  
Razin Philippe
Keyword(s):  
Carbonate Platform ◽  
Depositional Environments ◽  
Frequency Resolution ◽  
Seismic Line ◽  
Impedance Model ◽  
Stratigraphic Model ◽  
Platform Margin ◽  
Seismic Characteristics ◽  
Seismic Sections ◽  
Intrashelf Basin

ABSTRACT The platform carbonates of the Natih Formation (Albian-Turonian) are hydrocarbon reservoirs throughout the Middle East. This study uses a high-resolution sequence stratigraphic model built from the Natih outcrops of the Adam Foothills Transect, in northern Oman, as the basis for the construction of synthetic seismic sections along the Natih outcrops. The model covers the seaward progression from a proximal carbonate platform to a distal intrashelf basin. Three third-order depositional sequences had been identified and correlated across the outcrops, and facies were mini-core plugged for petrophysical data measurement, which were then used to construct an impedance model from the stratigraphic model. This impedance model was used to construct synthetic seismic sections with a zero phase Ricker wavelet at varying peak frequencies (80 Hz, 60 Hz and 40 Hz). The high-frequency synthetic seismic identified seismic characteristics of specific depositional environments, notably the organic-rich intrashelf basin, the platform margin and the platform interior. These seismic characteristics were very subtle on the lower frequency data, but could nonetheless be identified. A seismic line passing through a nearly analogous setting in the subsurface Natih was used to try and identify the characteristics observed on the synthetic seismic data. Many of the synthetically-produced characteristics were found on the industry seismic, which shows that this method is a good way of using the detail of the outcrop to help with predictions on the lower frequency/resolution seismic.

Technology Focus: Extended-Reach and Complex Wells (May 2021)

2021 ◽  
Vol 73 (05) ◽  
pp. 58-58
Author(s):  
Chris Carpenter
Keyword(s):  
Western Australia ◽  
Fibrous Material ◽  
Collaborative Work ◽  
Middle Eastern ◽  
Carbonate Reservoirs ◽  
Friction Reduction ◽  
Work Flow ◽  
Abu Dhabi ◽  
Hole Cleaning ◽  
Extended Reach Drilling

In selecting papers for this feature, reviewer Stéphane Menand of Helmerich and Payne has identified a trio of papers that investigates new approaches toward familiar issues encountered when drilling complex well types. Whether considering the customization of drilling approaches in Middle Eastern carbonate reservoirs, implementing a collaborative work flow in tackling high-tortuosity wells offshore Western Australia, or researching the ability of a fibrous material to effect hole cleaning as opposed to polymeric sweeps, the authors of these papers understand that technical expertise may not be completely realized if it is not applied to problems in original ways. In carbonate reservoirs, the goal of drilling extended-reach wells is set against the geological makeup of such formations, the complexity of which adds significant uncertainty to geosteering and well placement. The authors of paper SPE 203335 develop a work flow that makes possible the customization of drilling scenarios through an emphasis on mechanical specific energy, as well as the use of an optimized borehole-assembly design. The work flow helped deliver what the authors write is the longest well in the Middle East offshore Abu Dhabi. In a similar vein, the authors of paper SPE 202251 describe a challenging scenario involving an ultraextended-reach well in a mature field offshore Western Australia. The project overcame shallow water depth and a high tortuosity requirement by implementing an integrated plan that used a reservoir-mapping-while-drilling service. The authors stress that this technology, coupled with active collaboration between specialists, town, and rig site, allowed the project to achieve the desired oil-column thickness with zero collision incidents. Highly deviated wells often face problems resulting from ineffective hole cleaning. Paper SPE 203147 studies the properties of a fibrous material when compared with the hole-cleaning performance of common polymeric pills. The authors write that the fibrous material proved effective, in part because of a unique characteristic in which a spiderweb-like network of fibers is created that does not allow cuttings to settle easily in complex wells. In addition, the material is environmentally friendly. All three papers approach well- established problems in the critical industry sector of extended-reach drilling with innovation and confidence. Enjoy the papers and be sure to search SPE’s OnePetro online library for more fresh approaches to the technical challenges posed by these well types. Recommended additional reading at OnePetro: www.onepetro.org. SPE 196410 - Analysis of Friction-Reduction System During Drilling Operation at a High-Inclination Well on Field X by Rizqiana Mudhoffar, Tanri Abeng University, et al. SPE 197257 - Successful Management of Collision Risk in an Extended-Reach Well by Manchukarn Naknaka, Mubadala Petroleum, et al. SPE 202730 - Challenges in Drilling and Completion of Extended-Reach-Drilling Wells With Landing Point Departure of More Than 10,000 ft in Light/Slim Casing Design by Nitheesh Kumar Unnikrishnan, Abu Dhabi National Oil Company, et al.

Significance in the Integration of Facies Analysis, Stable Isotopes and Diagenetical Results for the High-Resolution Sequence Stratigraphy Characterization in the Shallow Platform of Shuaiba Formation, Lower Cretaceous, Abu Dhabi Onshore, UAE

2021 ◽  
Author(s):  
Kevin Michael Torres ◽  
Noura Al Madani ◽  
Rodrigo Rafael Gutierrez
Keyword(s):  
High Resolution ◽  
Direct Evidence ◽  
Facies Analysis ◽  
Carbonate Platform ◽  
Nutrient Supply ◽  
Abu Dhabi ◽  
Small Scale ◽  
Facies Association ◽  
Accommodation Space ◽  
Shallow Platform

Abstract The study presents the sequence stratigraphy of the carbonate platform focused in lower part of Shuaiba Formation, as well as the organization of the arrangement formed by the cyclical sedimentological evolution at high-resolution scale, through the facies analysis, diagenetical imprints and finally, significance of stable carbonate isotope results in the building up of carbonate platform in southeast Abu Dhabi. Interpreted stratigraphic surfaces from integration of depositional facies reviewed in all available cored data within studied area and stable carbon isotope results allowed that four small-scale regression-transgression depositional cycles can be discriminated which are stacked into a medium-scale sequence, that may record a 600 kyr Milankovitch signal. The small-scale sequences were correlated within the studied area using both conventional well logs and stable isotope records. Transgression hemicycles represent the increasing of accommodation space and can be identified in direct evidence, such as 25-40 ft. thickness of lithocodium/bacinella floatstones and skeletal peloidal packstones facies, association of facies interpreted within upper slope sub-environment. Likewise, in δ13C profiles, the rise/fall turnarounds of small-scale sequences are marked by negative δ13C peaks and associated with characteristics patterns: (1) proportion decrease of shallower sub-environments facies is interpreted as an rising relative sea-level and (2) decreasing δ13C trends interpreted to be related to decreasing nutrient supply. The medium/big pores of floatstones poorly connected in packstone matrix are expressed in the medium/high porosity with low permeabilities. In contrast, regressive hemicycles represent the reduction in accommodation space and can be characterized in direct evidence, such as the growing up of persistent 10-20 ft. thickness with thousands of meters of correlation of stromatoporoids and rudist facies, association of facies interpreted within shelf-margin complex sub-environment. In addition, the fall/rise turnarounds are marked by positive δ13C peaks, associated with the stromatoporoids/rudists mounds with characteristic patterns: (1) proportion increase of shallower sub-environments facies is interpreted as falling relative sea-level and increase in proximity and (2) increasing δ13C values interpreted to reflect increasing nutrient supply. Unusually very high permeability is attributed to the present of fractures and dissolution events that is enhanced where proportion of stromatoporoids facies are more pronounced. The described characterization resulted in the identification of genetic cycles that reproduce the sedimentological evolution, which are presented in small-scale sequences. In addition, the δ13C values enabled to understand the internal organization and the development of the carbonate building up in the Shuaiba shallow platform evolution. This study provides update and understanding on sedimentary facies, depositional pattern, and expands on previous published works, using new approach from semi-regional to local scales. Finally, results help to understand the laterally extensive water break-through thin intervals, which are directly related to the regressive hemicycles described previously.

scholarly journals Sequence Stratigraphy of Well DX, Gongola Sub-Basin, Upper Benue Trough, Nigeria

2019 ◽  
Vol 23 (10) ◽  
pp. 1855-1860
Author(s):  
F.O. Amiewalan ◽  
E.O. Bamigboye
Keyword(s):  
Gamma Ray ◽  
Third Order ◽  
Depositional Sequence ◽  
Benue Trough ◽  
Sequence Stratigraphic ◽  
Surface System ◽  
Sequence Boundaries ◽  
System Tracts ◽  
Maximum Flooding Surface ◽  
Gamma Ray Log

: Biostratigraphic study of Well DX has yielded Cretaceous miospores and dinoflagellates cysts which heightened the recognition of sequence boundaries (SB), Maximum Flooding Surfaces (MFS) and associated Systems Tracts. Five maximum flooding surfaces between 95.6 Ma and 89.0 Ma, four sequence boundaries between 96.4 Ma and 93.0 Ma and threedepositional sequences were identified with varying average thicknesses of sediments interpreted from the gamma ray log and biostratigraphic data. The threedepositional sequences interpreted are -depositional sequence I (96.4 Ma - 95.4 Ma) (8240 ft. - 8120 ft.), depositional sequence II (95.4 Ma - 94.0 Ma) (8120 ft. - 7850 ft.) and depositionalsequence III (94.0 Ma - 93.0 Ma) (7850 ft. - 7550 ft.). All the depositional sequences fall within the third order cycle. The age of the well was attempted based on the presence of some selected marker fossils - Ephedripites spp., Classopollis spp., Spiniferites spp., Cyclonephelium distinctum, Cyclonephelium vannophorum, Subtilisphaera spp., Eucomiidites spp., Triorites africaensis, Odontochitina costata and Droseridites senonicus recovered from the studied intervals and was dated Albian - Santonian. The Sequence stratigraphic interpretations are useful in further deepening the knowledge of thesubsurface geology of the studiedwell in Gongola Sub Basin, Upper Benue Trough of Nigeria.Keywords: Sequence Boundary, Maximum Flooding Surface, System tracts, Depositional sequence

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