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High-Resolution Sequence Stratigraphic Interpretation of the Upper Jurassic Arab Formation from New Field Development, Offshore Abu Dhabi*
By
Christoph T. Lehmann1, Khalil Ibrahim1, Hani Bu-Hindi1, Reyad Al-Kassawneh1, David Cobb1, and Ahmed Al-Hendi1

Search and Discovery Article #50112 (2008)
Posted August 25, 2008

*Adapted from oral presentation at AAPG Annual Convention, San Antonio, Texas, April 20-23, 2008

1FDD (UDS), ADMA-OPCO, Abu Dhabi, United Arab Emirates ([email protected])

Abstract

The Upper Jurassic carbonates of the Arab Formation form some of the most important hydrocarbon reservoirs for future development in offshore Abu Dhabi. A detailed sequence stratigraphic interpretation for one of the fields was established in order to understand the internal architecture and Previous HitreservoirNext Hit Previous HitqualityNext Hit.

Carbonates and evaporites of the Arab Formation exhibit a long-term shallowing-upward trend to the overlying Hith Formation and are interpreted as part of the highstand systems tract (HST) of the Upper Jurassic (Oxfordian to Tithonian) 2nd order sequences. The lower part of the Arab D is characterized by bioturbated lime mudstones which grade into outer ramp storm deposits and a series of shoaling-upward cycles and sequences of the upper part of the Arab D. Previous HitReservoirNext Hit Previous HitqualityNext Hit is related to interparticle porosity of the grainstone part of the cycles and sequences and vuggy porosity related to stromatoporoid layers. The Arab D is overlain by a series of thin peritidal cyles which are interpreted to be correlative to evaporites in other parts of the basin. The Arab D and the overlying peritidal cycles are interpreted as a 3rd order sequence.

The style and the make up of the cycle and sequences above the Arab D change dramatically. Smaller-scale sequence and cycles are composed of dolomitized packstones and grainstones shallowing-upward to evaporites. Previous HitReservoirNext Hit Previous HitqualityNext Hit is closely related to dolomitization and small-scale facies changes within the succession. Two other third-order sequences can be identified: The Arab C / Arab B third-order sequence and the Arab A / Hith third-order sequence.

Establishing a detailed sequence stratigraphic framework is essential in order to understand the Arab Previous HitreservoirNext Hit architecture and Previous HitqualityNext Hit. This work will be key in building a reliable Previous HitreservoirNext Hit model for the next fields to be developed in offshore Abu Dhabi.

 

 

 

¨  Abstract

¨  Figures

¨  Objectives

¨  Conclusions
¨  References

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

¨  Abstract

¨  Figures

¨  Objectives

¨  Conclusions
¨  References

Selected Figures

 

Paleographic map, Late Jurassic as Previous HitlocationNext Hit map (modified from Ziegler, 2001).

 

Previous HitLocationNext Hit map of offshore Abu Dhabi fields and “Field A”

 

Structure map, “Field A”

 

Stratigraphic cartoon outlining the distribution of major rock types

 

Depositional model for Arab.

Third- and fourth-order sequnce boundaries within Arab-D Previous HitreservoirNext Hit.

 

Third- and fourth-order sequence boundaries within Arab-A, B, and C reservoirs.

Depositional / stratigraphic model of the Arab.

Objectives

•The sequence stratigraphic interpretation is part of an ongoing Previous HitreservoirNext Hit characterization study for a new field to be developed in offshore Abu Dhabi.
•Basis of the layering scheme.
•Previous HitPredictingNext Hit the distribution of Previous HitreservoirTop facies (rock types, major baffles and high K zones).
•Translate the sequence stratigraphic framework over the area offshore Abu Dhabi.

Conclusions

•The third order and fourth order sequence stratigraphic framework has been established.
•Assigning SB in Arab A-C succession hinges on interpretation of evaporites.
•It is important in the Arab D to understand the distribution of the stromatoporoids and the development of the shoals.
•Next step is assigning RT within the sequence stratigraphic framework.

Reference

Ziegler, M.A., 2001, Late Permian to Holocene paleofacies evolution of the Arabian Plate and its hydrocarbon occurrences: GeoArabia (Manama), v. 6/3, p. 445-504.

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