--> Abstract: Deep Cardamom Discovery Enabled by Multi-azimuth Seismic and Anisotropic Imaging, by Ben Hewett, David Garner, Jan Douma, Madhu Kohli, and Duane Johnson; #90124 (2011)

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Making the Next Giant Leap in Geosciences
April 10-13, 2011, Houston, Texas, USA

Deep Cardamom Discovery Enabled by Multi-azimuth Seismic and Anisotropic Imaging

Ben Hewett1; David Garner1; Jan Douma2; Madhu Kohli1; Duane Johnson1

(1) Upstream Americas - Deepwater, Shell E&P Co, Inc, New Orleans, LA.

(2) Upstream Americas - Exploration - Geophysics, Shell E&P Co, Inc, New Orleans, LA.

Shell’s Auger TLP near field exploration is focused on the deep potential at Cardamom. Difficult extended reach wells around the Auger salt dome are required. Seismic imaging is impaired by the prospect’s proximity to salt. Steeply dipping seismic events and velocity uncertainty makes well positioning difficult. The application of multiple azimuth seismic data and anisotropic imaging reduced targeting uncertainty and resulted in the discovery of a deep hydrocarbon reservoir at Cardamom.

Well positioning uncertainty and improvement of the seismic image is discussed through the use of modern Wide Azimuth (WAZ) streamer seismic in combination with existing Narrow Azimuth (NAZ) streamer seismic. The use of multiple seismic azimuth data for anisotropic velocity model building and pre-stack depth imaging resulted in a reduction in lateral and vertical well positioning uncertainty. To further understand positioning uncertainty and improve surface seismic calibration, drilling was executed using Logging While Drilling (LWD) measurements and Vertical Seismic Profile (VSP) data was acquired.

Implementing these geophysical methods contributed to the Deep Cardamom discovery and provided data to drill a successful up dip side track well. Additional geophysical efforts (updating velocity models, acquiring Ocean Bottom Sensor (OBS) seismic data) have been initiated with the objective of yielding higher quality seismic images to be used for the development phase of the Deep Cardamom accumulation.