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

Abstract

The Kevin Dome [Formula: see text] storage project, located in northern Montana, attempted to characterize the Duperow Formation as a potential long-term storage zone for injected [Formula: see text]. A multicomponent (9C) seismic survey was acquired for the Big Sky Carbon Sequestration Partnership over a portion of the Kevin Dome using P- and S-wave sources. Prestack migrated PP, PS, SH, and SV data sets were generated. We then applied several stratigraphic inversion workflows using one or several kinds of seismic wavefield at the same time resulting in joint inversions of each data set. The aim of our study is to demonstrate the benefits of doing quadri-joint inversion of PP-, PS-, SH-, and SV-wavefields for the recovery of the elastic earth parameters, especially the S-wave impedance and density. These are crucial parameters because they can help determine lithology and porefill in the reservoir characterization workflow. Because the inversion workflow always uses the original seismic data recorded in its own time domain, it is necessary to compute registration laws between PP-PS-, PP-SH-, and PP-SV-wavefields using a time shift computation procedure (warping) based on inverted S-wave impedances from inversion of a single wavefield. This generated a significant improvement over methods that rely on attempting to match trace waveforms that may have a different phase, frequency content, and polarity. Finally, we wanted to investigate the reliability of the quadri-joint inversion results in the Bakken/Banff Formations, which have less lateral geologic variation than the underlying Duperow target. This interval shares many of the geophysical characterization challenges common to shale reservoirs in other North American basins. We computed geomechanical parameters, such as Poisson’s ratio and Young’s modulus, which are a proxy for brittleness. Comparison of these results with independent laboratory measurements in the Bakken interval demonstrates the superiority of the quadri-joint inversion method to the traditional inversion using P-wave data only.

Skin factor and potential formation damage from chemical and mechanical processes in a naturally fractured carbonate aquifer with implications to CO2 sequestration

“…Our data include the well logs that were incorporated into a prior geologic model of the site (Zaluski, 2018), water injection pressure response data from the Middle Duperow Formation (Big Sky Carbon Sequestration Partnership, 2015), and water geochemical sample analyses from the same formation (Test America and Big Sky Carbon Sequestration Partnership, 2015). This study also updates the site-scale geologic model by incorporating the latest 3D seismic data (Clochard et al, 2018) that describe spatial heterogeneity in reservoir properties near the injection well. In section 2.2, relevant characterization data for this updated site-scale model are described in more detail.…”

“…At this site, the Big Sky Carbon Sequestration Partnership (BSCSP) has carried out an extensive reservoir characterization study by gathering well, core, seismic, geological, and operational data to assess its potential for CO 2 storage (Nguyen et al, 2017c;Clochard et al, 2018;Onishi et al, 2019). Large pore volumes within these same geologic formations, which lie deeper in the dome, are not saturated with CO 2 , providing a potential reservoir for sequestering large quantities of CO that can be captured at industrial sites and transported here.…”

“…(3) 3D TVD elastic attributes (Pimpedance, S-impedance, and density). Seismic data incorporated into the new geologic model of this study were previously described (Onishi et al, 2019) with their inversion approach and interpretation reported in Clochard et al (2018).…”

“…At Kevin Dome, the Middle Duperow Formation consists of Devonian carbonates (mixed dolostone and limestone) and spans an interval of approximately 30 m. The formation fluid contains CO 2 from legacy well tests conducted near the peak of the dome and low-salinity brine on the down dip side. As part of the BSCSP characterization effort at the site, a 3D seismic survey was carried out to delineate major reservoir intervals (Clochard et al, 2018). Two wells were drilled with one gas producer completed on the gas cap of the Middle Duperow and one gas injector (Wallewein 22-1) completed on the brine leg, respectively (Fig.…”

Near‐surface three‐dimensional multicomponent source and receiver S‐wave survey in the Tannwald Basin, Germany: Acquisition and data processing

“…The latter ones face a series of problems: (1) the excitation of S-waves with horizontally oriented forces is more intricate than for conventional vertically-oriented forces (Simmons and Backus, 1999a); (2) a pure single-mode excitation of waves is not possible (Pugin and Yilmaz, 2017), since any real source excites SH-as well as SV-and P-waves in different angles and azimuths; and (3) anisotropy leads to S-wave splitting (Alford, 1986;Crampin, 1985;Simmons and Backus, 1999b), demanding an elaborate processing to properly treat the different S-wave modes. Nonetheless, 9-C seismic methods are used in the in the industry to image deeper targets (e.g., Shuck et al, 1996;Hitchings and Potters, 2000;Davis et al, 2003;Clochard et al, 2018). Pan et al (2021) used a random objective wave function approach to evaluate a shallow 3-D 9-C experiment by full-waveform inversion, but did not perform reflection imaging.…”