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Seal potential of shale sequences through seismic anisotropy; case study from Exmouth Sub-basin, Australia

Hadi Nourollah, Milovan Urosevic and Jeffrey Keetley
Seal potential of shale sequences through seismic anisotropy; case study from Exmouth Sub-basin, Australia
Interpretation (Tulsa) (November 2015) 3 (4): T257-T267

Abstract

Sedimentary rocks with sealing potential can cap a reservoir by impeding the upward movement of hydrocarbons. An effective seal should have three qualifying factors of geometry, integrity, and capacity. Mapping seismic horizons and faults across the area of study reveals much about the geometry and integrity of the sealing unit. Capacity, however, depends on capillary pressure measurements of core and cuttings samples. Modeling capacity of seals away from and between wells has traditionally involved simple gridding techniques or association with most likely geologic or seismic facies. We have developed a different approach in using seismic data and applying it to the evaluation of sealing potential. Shales are the most common seals in petroleum systems. Seismically, well-developed shale units that have undergone compaction are likely to be anisotropic and are typical vertical transverse isotropic media. Seismic data with suitable acquisition parameters were processed to extract eta and Thomsen's parameters of weak seismic anisotropy, tied to the vertical seismic profile data at wells. The spatial distribution of epsilon has shown a good correlation with capillary measurements of well samples. Hence, 3D modeling of epsilon was used as a weight factor to guide the capillary pressure (P (sub c) ) values away from the wells. Capillary pressure values were then mapped on the fault planes to high grade the analysis of sand-shale juxtaposition. Our results helped to explain the distribution of successful wells and dry holes within the study area.


ISSN: 2324-8858
EISSN: 2324-8866
Serial Title: Interpretation (Tulsa)
Serial Volume: 3
Serial Issue: 4
Title: Seal potential of shale sequences through seismic anisotropy; case study from Exmouth Sub-basin, Australia
Affiliation: 3D-Geo, Melbourne, Victoria, Australia
Pages: T257-T267
Published: 201511
Text Language: English
Publisher: Society of Exploration Geophysicists, Tulsa, OK, United States
References: 36
Accession Number: 2016-007424
Categories: Economic geology, geology of energy sourcesApplied geophysics
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. sects., strat. col., 2 tables, sketch maps
S23°00'00" - S20°00'00", E112°00'00" - E116°00'00"
Secondary Affiliation: Curtin University, Exploration Geophysics Department, AUS, Australia
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data from GeoScienceWorld, Alexandria, VA, United States. Reference includes data supplied by Society of Exploration Geophysicists, Tulsa, OK, United States
Update Code: 201604
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