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Applying 3-D Previous HitSeismicNext Hit Multi-Previous HitAttributeNext Hit Analysis and Unsupervised Previous HitSeismicNext Hit Facies Classification Techniques in Jurassic Carbonate Depositional Sequences, Onshore Saudi Arabia

Wharton, Stanley R.1; Lawrence, Paul 1; Gregory, Arthur 1; Bakhiet, Abdelfattah 1
(1)Saudi Aramco, Dhahran, Saudi Arabia.

Jurassic carbonates represent some of the most productive reservoirs in Saudi Arabia. The main challenge associated with prospecting for these carbonate reservoirs is reservoir heterogeneity. This heterogeneity is caused by depositional history with tectonic, stratigraphic and diagenetic influences. To assess the heterogeneity of these reservoirs, a 3D Previous HitseismicNext Hit multi-Previous HitattributeNext Hit analysis and a neural network Previous HitseismicNext Hit facies classification analysis, were applied to an area near a large intra-shelf basin.

Previous HitSeismicNext Hit Previous HitattributeNext Hit volumes generated from input data from a 2D chronostratigraphy model, were combined to generate Previous HitseismicNext Hit facies 3D block volumes, to analyze the Previous HitseismicNext Hit stratigraphy and stratal associations, of the depositional sequences at the Oxfordian stage. Previous HitSeismicNext Hit facies 3D block volumes were visualized and sliced to define the geometry of prograding clinoforms within a highstand system tract. Waveform classification analysis of a key horizon revealed distinct lateral facies changes between carbonate shoal and distal basinal areas. A proportional slicing technique applied at the top of the sequence, revealed a strike-dominated depositional setting for the shoal facies, and a dip-oriented depositional setting for the basinal deposits. Electrofacies from well log data corroborated the Previous HitseismicNext Hit facies distribution with sporadic grainstone deposits located in a shoal belt, and poorer facies in the intra-shelf basin.

Application of multi-Previous HitattributeNext Hit analysis and unsupervised Previous HitseismicNext Hit facies classification, to assess the Previous HitseismicNext Hit stratigraphy and the Previous HitseismicNext Hit facies variations, proved beneficial in defining favorable broad carbonate facies belts. Use of a chronostratigraphy model, selected Previous HitseismicTop attributes and associated data-conditioning procedures, helped in analyzing heterogeneity of the carbonate sequences.

 

AAPG Search and Discovery Article #90135©2011 AAPG International Conference and Exhibition, Milan, Italy, 23-26 October 2011.