Quadri-joint inversion: Method and application to the Big Sky 9C 3D data set in northern Montana

Vincent Clochard (1) , Bryan Devault (2) , David Bowen (2) , Nicolas Delépine (1) , Kanokkarn Wangkawong (1)

1 IFPEN - IFP Energies nouvelles
2 Vecta Oil and Gas

Kanokkarn Wangkawong (IFP Energies nouvelles, currently PTTEP). Abstract The Big Sky Carbon Sequestration Partnership is a US CO 2 storage project in the Duperow formation from the Kevin Dome structure located in Montana. The goal is to characterize the Duperow interval as a potential long-term storage zone for injected CO 2. During the years 2013-2015, a North American company, Vecta Oil & Gas operated a multi-component (9C) seismic survey on behalf of the Partnership over the Kevin Dome, using P-and S-wave sources. After processing of 9C 3D seismic data, pre-stack PP, PS, SH and SV datasets were generated and migrated in their corresponding time domains. We evaluate from the real case study the benefits of inverting jointly PP, PS, SH and SV pre-stack seismic data. We compute different registration laws like PP-PS, PP-SH and PP-SV using a warping (time shift computation) procedure based on inverted shear-wave impedances from sequential inversions. This parameter choice represents a significant improvement over methods which rely on attempting to match trace waveforms which may have different phase, frequency content, and polarity. The presence of Bakken formation just above the Duperow formation allow us to evaluate also the benefits of inverting jointly PP, PS, SH and SV pre-stack seismic data in recovering the elastic rock properties, like the inverted density parameter. As a matter of fact, the exploitation of unconventional hydrocarbons requires innovative skills to allow better characterization of brittle reservoir zone. The Young's modulus is a measure of their brittleness and requires an accurate determination of the rock density which is well known only at the well locations. This real case study of multi-component (9C) pre-stack stratigraphic inversion is an elegant way of employing all modes of a multi-component acquisition to generate an optimal estimate of P-and S-wave impedances and density to determine lithology and fluid contents further used by quantitative reservoir characterization. 2

Domaines: Sciences de la Terre

Vincent Clochard, Bryan Devault, David Bowen, Nicolas Delépine, Kanokkarn Wangkawong. Quadri-joint inversion: Method and application to the Big Sky 9C 3D data set in northern Montana. Interpretation, 2018, 6 (4), pp.SN101-SN118. ⟨10.1190/INT-2018-0035.1⟩. ⟨hal-02014426⟩