--> Abstract: Comparative Sequence Development of Arab-D Reservoir from Three Fields, Saudi Arabia, by Saad Al-Awwad, Khalaf AlTemimi, Langhorne Smith, Geraint Wyn Hughes, and James F. Read; #90078 (2008)

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Comparative Sequence Development of Arab-D Reservoir from Three Fields, Saudi Arabia

Saad Al-Awwad1, Khalaf AlTemimi1, Langhorne Smith2, Geraint Wyn Hughes3, and James F. Read1
1Geosciences, Virginia Tech, Blacksburg, VA
2Reservoir Characterization Group, New York State Museum, Albany, NY
3Geological Technical Services Division, Aramco, Dhahran, Saudi Arabia

Cores (up to 80 m long) from the Late Jurassic Arab reservoir from three fields, Saudi Arabia, were used to define a preliminary high resolution sequence framework. Above the lower carbonate mud-dominated interval of the Jubaila Formation, carbonates of the Arab-D Formation display small, meter-scale units of lime mudstone (with grainy burrow fills), capped by hardgrounds, up into intraclastic and (oncoidal) floatstone and rudstone; these are bundled into 5 to 10 m upward deepening to upward shallowing units. These are overlain by 3 to 5 m thick units composed of fine muddy skeletal pellet wackestone up into stromatoporoid-peloid wackestone, packstone and floatstone, some of which are capped by Cladocoropsis peloid packstone and floatstone; these are intercalated with Thaumatoporella-Clypeina wackestone/packstone. This is overlain by 2 to 5 m units dominated by Cladocoropsis peloid packstone and floatstone and Thaumatoporella-Clypeina wackestone/packstone. The successions are capped by thin units of ooid grainstone and pellet packstone, with microbial laminites and evaporites at the top. Parasequences in the Arab-D are bundled into 10 to 15 m high frequency sequences, which show progressively shallower water facies upward in the Arab-D. The transition from the shallow ramp into the intrashelf basin is penetrated by a few cores. Shallow margin facies are dominated by high energy carbonates that pass downdip into parsequences of deeper water units with conspicuous oncoidal beds. The Arab-D reflects long-term shallowing of a composite sequence, punctuated by 2 high frequency sequences and at least 8 to 11 minor sequences or parasequence sets, on which are superimposed parasequence-scale cycles. Initially high but decreasing accommodation resulted in a general scarcity of subaerial surfaces throughout the bulk of the unit, except beneath the capping evaporite.

 

AAPG Search and Discovery Article #90078©2008 AAPG Annual Convention, San Antonio, Texas