Introduction to this special section: Rock physics

2021 ◽  
Vol 40 (9) ◽  
pp. 644-644
Author(s):  
Agnibha Das ◽  
Madhumita Sengupta
Keyword(s):  
Risk Mitigation ◽  
Special Section ◽  
Rock Physics ◽  
Time Lapse ◽  
Reservoir Properties ◽  
Amplitude Variation With Offset ◽  
Digital Rock Physics ◽  
Exploration Risk ◽  
Distributed Acoustic Sensing ◽  
And Inversion

In simple terms, rock physics provides the much-needed link between measurable elastic properties of rocks and their intrinsic properties. This enables us to connect seismic data, well logs, and laboratory measurements to minerology, porosity, permeability, fluid saturations, and stress. Rock-physics relationships/models are used to understand seismic signatures in terms of reservoir properties that help in exploration risk mitigation. Traditionally, rock physics has played an irreplaceable role in amplitude variation with offset (AVO) modeling and inversion, 3D/4D close-the-loop studies, and seismic time-lapse analysis and interpretation. Today, rock-physics research and application have influenced a much wider space that spans digital rock physics, microseismic, and distributed acoustic sensing (DAS) data analysis. In this special section, we have included papers that cover much of these advanced methods, providing us with a better understanding of subsurface elastic and transport properties, thereby reducing bias and uncertainties in quantitative interpretation.

Introduction to this special section: Basin exploration

2021 ◽  
Vol 40 (3) ◽  
pp. 170-170
Author(s):  
Carole Decalf ◽  
German Molina
Keyword(s):  
Special Section ◽  
Rock Physics ◽  
Rock Properties ◽  
Reservoir Properties ◽  
Petroleum Potential ◽  
Knowledge Based ◽  
Basin Scale ◽  
Exploration Risk ◽  
Data Gap ◽  
Seismic Volumes

Originally, explorers relied on hydrocarbon seeps and 2D seismic lines to define a basin's petroleum potential and to identify its best part. Due to dramatic improvements in seismic technology, today's explorers have access to a vast seismic tool kit, from basin-scale regional 3D seismic surveys to neural network techniques that directly derive reservoir properties from seismic volumes. However, in frontier or mature exploration, geoscientists are often limited by the amount of well data and rock properties information available, and they may deal with poor(er) seismic that makes seismic calibration difficult. Successful explorers will require a lot of knowledge-based creativity to derive meaningful geologic and reservoir properties models to reduce exploration risk. By embracing uncertainties, explorers develop “outside-the-box” thinking to help them chase the hydrocarbon molecules and unlock the prize. With their knowledge in rock physics, subsurface deformation, and wave propagation, geoscientists are deploying new methodologies and tools to fill the data gap and produce an improved description of the subsurface.

Introduction to this special section: Rock physics

2019 ◽  
Vol 38 (5) ◽  
pp. 332-332
Author(s):  
Yongyi Li ◽  
Lev Vernik ◽  
Mark Chapman ◽  
Joel Sarout
Keyword(s):  
Reservoir Characterization ◽  
Model Building ◽  
Seismic Analysis ◽  
Focal Point ◽  
Special Section ◽  
Rock Physics ◽  
Seismic Inversion ◽  
Reservoir Properties ◽  
Model Studies ◽  
Experimental Rock

Rock physics links the physical properties of rocks to geophysical and petrophysical observations and, in the process, serves as a focal point in many exploration and reservoir characterization studies. Today, the field of rock physics and seismic petrophysics embraces new directions with diverse applications in estimating static and dynamic reservoir properties through time-variant mechanical, thermal, chemical, and geologic processes. Integration with new digital and computing technologies is gradually gaining traction. The use of rock physics in seismic imaging, prestack seismic analysis, seismic inversion, and geomechanical model building also contributes to the increase in rock-physics influence. This special section highlights current rock-physics research and practices in several key areas, namely experimental rock physics, rock-physics theory and model studies, and the use of rock physics in reservoir characterizations.

Shale Reservoir Properties from Digital Rock Physics

2012 ◽  
Author(s):  
Joel D. Walls ◽  
Elizabeth Diaz ◽  
Timothy Cavanaugh
Keyword(s):  
Rock Physics ◽  
Reservoir Properties ◽  
Digital Rock Physics ◽  
Digital Rock ◽  
Shale Reservoir

scholarly journals Reservoir characterization based upon the onset of time-lapse amplitude changes

Geophysics ◽  
2015 ◽  
Vol 80 (1) ◽  
pp. M1-M14 ◽  
Author(s):  
Donald W. Vasco ◽  
Andrey Bakulin ◽  
Hyoungsu Baek ◽  
Lane R. Johnson
Keyword(s):  
Large Scale ◽  
Reservoir Characterization ◽  
Reference Model ◽  
Rock Physics ◽  
Time Lapse ◽  
Seismic Velocities ◽  
Reservoir Properties ◽  
Fluid Saturation ◽  
Seismic Amplitudes ◽  
Physics Model

Time-lapse geophysical monitoring has potential as a tool for reservoir characterization, that is, for determining reservoir properties such as permeability. Onset times, the calendar times at which geophysical observations begin to deviate from their initial or background values, provide a useful basis for such characterization. We found that, in contrast to time-lapse amplitude changes, onset times were not sensitive to the exact method used to related changes in fluid saturation to changes in seismic velocities. As a consequence of this, we found that an inversion for effective permeability based upon onset times was robust with respect to variations in the rock-physics model. In particular, inversions of synthetic onset times calculated using Voigt and Reuss averaging techniques, but inverted using sensitivities from Hill’s averaging method, resulted in almost identical misfit reductions and similar permeability models. All solutions based on onset times recovered the large-scale, resolvable features of the reference model. Synthetic tests indicated that reliable onset times can be obtained from noisy seismic amplitudes. Testing also indicated that large-scale permeability variations can be recovered even if we used onset times from seismic surveys that were spaced as much as 300 days apart.

Compaction-induced anisotropy and time-lapse AVO analysis

2015 ◽  
Vol 3 (2) ◽  
pp. SP21-SP33 ◽  
Author(s):  
Nayyer Islam ◽  
Wayne D. Pennington
Keyword(s):  
Elastic Moduli ◽  
Rock Physics ◽  
Time Lapse ◽  
Pressure Effects ◽  
Reservoir Pressure ◽  
Pressure Sensitivity ◽  
Induced Anisotropy ◽  
Amplitude Variation ◽  
Amplitude Variation With Offset ◽  
Sandstone Reservoir

Hydrocarbon reservoirs are often monitored using repeated seismic observations to track fluid movement and other changes. Here, we present a study of compaction-induced anisotropy in an unconsolidated overpressured sandstone reservoir from Teal South field in the Gulf of Mexico. Previous work at Teal South had demonstrated that the time-lapse observations could not be satisfied through models of fluid changes without strong pressure effects acting on the formation rock framework. However, those studies are not highly quantitative, and some minor inconsistencies appear on closer examination. We have examined the effect of the pressure-sensitivity of elastic moduli in the formation and carefully examined the offset-dependence of amplitudes in light of several rock-physics models, empirical and theoretical. The amplitude-variation-with-offset behavior for the interface between overlying shale and the hydrocarbon sand is best modeled under the assumption that this overpressured reservoir becomes anisotropic because it undergoes compaction during production, which reduces the reservoir pressure from highly overpressured to nearly normal for this depth. Although the results obtained here are only weakly constrained due to the limited offset ranges and low fold, this strongly suggests that anisotropic effects in poorly consolidated overpressured reservoirs undergoing primary depletion may in fact dominate over fluid effects after the bubble point has been reached.

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