The key lies in a robust low-frequency model. LogToVolume, part of the Kingdom software suite, builds high-resolution, geologically consistent models tied to well data, enabling precise seismic inversion for reservoir characterisation.
Seismic data lacks the low-frequency information needed to resolve absolute impedance, limiting inversion to relative variations. A reliable low-frequency model provides the baseline for quantitative interpretation. LogToVolume solves this by creating detailed models that honour well data and geological trends.
LogToVolume Generates High-Resolution Subsurface Models
It propagates well log velocities within a geologically consistent framework, respecting structural features and velocity trends. These models are precisely tied to well data, providing the critical low-frequency component for accurate seismic inversion.
Data required
- Sonic and density logs
- Seismic grid
- Formation tops tied to grids
- Background velocity or density model
- Seismic volume to be inverted
Key Features
- Propagates well logs following geological structures
- High-resolution models at seismic sample rate
- Supports deviated and horizontal wells
- Handles P-wave velocity (Vp), S-wave velocity (Vs), density (ρ), and more
- Suitable for conventional and ultra-high-resolution (UHR) windfarm seismic
Background Model
The background model captures large-scale geological trends and compaction and can be built from:
- Stacking (RMS) velocities converted to interval velocities
- Framework velocities from time grids and formation tops in depth
- Linear velocity trends (Vo+kZ, where Vo is the velocity at surface (z=0) and kZ accounts for depth-dependent compaction)
- Vs and ρ models derived from Vp using well log relationships
Using detailed Vp, Vs, and ρ models, we calculate acoustic impedance (AI = Vp × ρ) and shear impedance (SI = Vs × ρ). These models match well logs exactly at well locations and are guided by the background model and nearby well logs between wells. Prior to inversion, AI and SI are smoothed to retain only the low-frequency component, preparing them for integration with band-limited seismic data. In applications like offshore exploration, LogToVolume reduces uncertainty in reservoir models, aiding better decision-making.
Summary
LogToVolume delivers geologically consistent, well-tied low-frequency models, ensuring robust, quantitative inversion results for offshore, onshore, and windfarm seismic studies.
Ready to enhance your seismic workflows? Explore LogToVolume in the Kingdom suite today.
Written by:
Frank (Xin-Quan) Ma (PhD) Senior R & D Geophysicist at Equipoise Software Limited