Online Journal for E&P Geoscientists

Al-Deen, Khalid M. Shams ¹; El-Emam, Adel¹, Zahran, Wael A.¹
(1) Exploration, Kuwait Oil Company, Ahmadi, Kuwait.

Multiples contamination both surface and interbed related is a problem in almost all Middle East basins. The high acoustic impedance of carbonates and anhydrites layered with clastics is the major generator of these interbed multiples. These types of multiples are known to hinder the interpretation, fracture characterization, and inversion studies; they significantly complicate both the structural and stratigraphic interpretation within the zone of interest at the Cretaceous level as well as at the frontier Jurassic and Permian sections.

Previous work has demonstrated marginal success in attenuating the main interbed multiples using the 1D multiple modeling technique post-migration thorough the analysis and identification of the major multiple generators using well.

This paper presents a case study describing the application of several data-driven multiple attenuation techniques using more advanced true-azimuth algorithms prior to pre-stack migration. The algorithms applied in this study are general surface multiple prediction, extended interbed multiple prediction and deterministic interbed demultiple. Multiple modeling and subtraction were performed on a high-resolution full-azimuth dataset acquired in northwest Raudhatain oil field, onshore Kuwait.

This case study demonstrates the use of the latest industry multiple attenuation techniques that utilize 3D true-azimuth data-driven algorithms with no need for regularization or interpolation and produce superior results. In addition, all multiple attenuation algorithms are applied pre-stack and pre-migration; consequently, the subsequent velocity model building, subsurface imaging, and pre-stack inversion are deemed to be more robust in the absence of the multiples.

The results have been verified through various QC tools including well ties and seismic inversion; it is clearly shown that those multiples have not only been successfully attenuated in the reservoir level, but also in the overburden.