Struggling with Pre-stack Forward Modeling? Here’s the One-Click Fix

With a single click, ColchisFM runs pre-stack acoustic and elastic wave equation forward modeling based on reservoir parameters, then automatically performs pre-stack migration, gather processing, and stacking—all in one seamless workflow. This reduces the complexity of pre-stack forward modeling, allowing users to focus on the relationship between reservoir parameters and seismic reflection characteristics.

What is Pre-stack Elastic Wave Forward Modeling?

Seismic forward modeling can be classified into post-stack forward modeling and pre-stack wave equation forward modeling. Pre-stack forward modeling includes acoustic forward modeling and elastic forward modeling:

• Acoustic forward modeling uses the acoustic wave equation and considers only longitudinal (P-wave) propagation.

• Elastic forward modeling is based on the elastic wave equation, simulating both P- and S-wave propagation, which more accurately reflects the elastic properties of real geological media.

Acoustic forward modeling uses P-wave velocity (Vp) and density (often assumed constant), while elastic forward modeling also incorporates S-wave velocity (Vs), which calls for more detailed rock physics models and greater parameter accuracy.

 

Two-dimensional constant-density acoustic wave equation (left) and two-dimensional first-order stress–velocity elastic wave equation (right)

Applications of Pre-stack Elastic Forward Modeling

In real seismic surveys, acquisition, processing, and migration followed by stacking yield a stacked seismic section. Connolly (1999) introduced the concept of elastic impedance. In effect, a stacked seismic section still carries elastic information.

Because pre-stack elastic forward modeling depends on more parameters, it can better simulate the seismic responses of different lithologies, physical properties, and hydrocarbon-bearing conditions. This guides the selection of parameters for reservoir prediction and validates the effectiveness of inversion methods.

Challenges in Performing Pre-stack Elastic Forward Modeling with Conventional Tools

1. Unreliable parameter combinations – Parameters (Vp, Vs, density) are affected by well log resolution, interpretation results, borehole conditions, and human factors, making it difficult to achieve consistency. This can lead to false AVO effects and poor correlation with actual reservoir parameters.

2. Lengthy, highly specialized workflow – The workflow is lengthy and highly specialized, involving geology, well logging, and geophysics. This high technical threshold makes it harder to apply, promote, and iterate on research workflows.

3. High computational cost – Using higher-order finite difference schemes with smaller grid spacing and shorter time steps greatly increases the computational load. Multi-core CPU parallel computing is often insufficient.

ColchisFM’s Solution: One-Click “Pre-stack Wave Equation + Pre-stack Time Migration” Automated Workflow

1. ColchisRP Rock Physics Forward Modeling for Parameter Input – Just enter key reservoir parameters—sandstone content, shale content, porosity, and water saturation—and the software instantly calculates Vp, Vs, and density. This improves parameter accuracy, ensures reasonable values, and reduces operational complexity.

Reservoir parameter input main interface

2. 1D AVO Forward Modeling and 2D Wave Equation Pre-stack Elastic Forward Modeling – The 1D AVO module uses elastic impedance (EI), delivering fast forward modeling and intuitive results. It can be used alongside 2D wave equation pre-stack elastic forward modeling to optimize model building and parameter selection. 

 

Small fault model, pre-stack wave equation full-stack section, migrated section

3. One-click Automated Wave Equation Forward Modeling + Pre-stack Time Migration – Perform pre-stack acoustic and elastic wave equation forward modeling based on reservoir parameters, then automatically carry out pre-stack migration, gather processing, and stacking in one integrated workflow.

Automated wave equation forward modeling + pre-stack time migration main interface

4. Support for Fine Grid Pre-stack Forward Modeling and GPU Acceleration – For small geological bodies, conventional 25 m grid spacing is insufficient for accurate characterization. ColchisFM uses fine grid spacing in pre-stack forward modeling to balance accuracy and efficiency. Because pre-stack forward modeling iterates through many time steps, it is computationally intensive. ColchisFM supports GPU-based pre-stack wave equation forward modeling, delivering a 15–20× speedup compared to conventional CPU processing.

Pre-stack wave equation forward modeling of a typical cave-type carbonate reservoir in the Tarim Basin

5. Integrated Gather Processing Module and AVO Analysis – ColchisFM includes a complete gather processing module with filtering, muting, denoising, Radon transform, partial-offset stacking, and PG section extraction—so all processing can be done entirely within ColchisFM, with no third-party tools required.

 

ColchisFM gather processing main interface

 

ColchisFM is the first integrated reservoir geophysics forward modeling software in the geoscience industry, featuring patented intelligent formation recognition technology. It uniquely combines rock physics forward modeling with seismic forward modeling to address the challenges of building reservoir models for complex lithologies and diverse pore types, in both post-stack and pre-stack seismic modeling.