Depositional Sequence Volume Generation for Seismic Data Interpretation

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Solution Overview

Problem

Geological constraints such as faults and unconformities in subsurface regions complicate the interpretation of seismic data, leading to inaccurate modeling of hydrocarbon reservoirs due to discontinuities in geological horizons.

Innovation Solution

A computer system generates a depositional sequence volume by solving partial differential equations, applying boundary conditions to grid points, and categorizing them as continuous, unconformity, or faulting grid points to accurately represent chronological formation orders of geological horizons, thereby addressing the complexities introduced by geological constraints.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional seismic interpretation methods are used to model geological horizons, then the process is simpler and faster, but the accuracy deteriorates due to discontinuities caused by geological constraints like faults and unconformities

Engineering Contradiction:
Improveaccuracy of geological horizon extractionVSAvoidcomplexity of processing method
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the subsurface model into discrete grid points and categorizes them into different types (continuous horizon grid points, faulting grid points, unconformity grid points) based on their geological characteristics. This segmentation allows the application of appropriate boundary conditions to each category, enabling accurate handling of discontinuities while maintaining systematic processing efficiency.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transforms the geological interpretation problem into a mathematical optimization problem by defining a depositional sequence function and establishing boundary conditions for different grid point types. This parameter transformation allows the use of numerical optimization methods to solve for the depositional sequence values, achieving high accuracy in complex geological settings.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If geological constraints are not dealt with appropriately, then the processing method remains simple, but the reliability of modeling results deteriorates significantly

Engineering Contradiction:
Improvequality of modeling resultsVSAvoidcomplexity of boundary condition application
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies different boundary conditions to different types of grid points based on their local geological characteristics. Continuous horizon grid points receive one type of boundary condition, while faulting and unconformity grid points receive specialized boundary conditions that account for their discontinuous nature. This local differentiation ensures high reliability of results in complex geological settings.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent introduces a depositional sequence function as an intermediary mathematical construct that bridges the seismic data and the geological horizon modeling. This function serves as a mediator that incorporates geological constraints through boundary conditions while maintaining computational tractability and producing reliable modeling results.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If a detailed depositional sequence volume is generated to handle geological constraints, then the interpretation accuracy improves, but the computational time and resources increase

Engineering Contradiction:
Improveaccuracy of geological structure interpretationVSAvoidcomputational processing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

By segmenting the subsurface into grid points and categorizing them by type, the patent enables parallel processing and efficient numerical solution methods. This segmentation strategy allows the detailed depositional sequence volume to be computed systematically, reducing computational time while maintaining high interpretation accuracy.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The transformation of the geological problem into a parameterized optimization problem with defined boundary conditions enables the use of efficient numerical solvers. This parameterization approach reduces the computational complexity of generating detailed depositional sequence volumes while preserving interpretation accuracy.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3245541B1System and method for generating a depositional sequence volume from seismic data
Publication Date: 2022.08.10 CHEVRON USA INC
  • EP3245541B1 patent drawingFigure 1
  • EP3245541B1 patent drawingFigure 2A~2B
  • EP3245541B1 patent drawingFigure 2C

AI summary

A method of generating a depositional sequence volume from seismic data (100) is performed at a computer system having one or more processors and memory storing programs to be executed by the one or more processors. The method includes the following steps: receiving a seismic dataset (212), wherein the seismic dataset (212) includes image values at a plurality of grid points (301) of a 3-D subsurface model; identifying reflections (104) at a first subset of the plurality of grid points (301) and geological constraints (102), such as fault planes, at a second subset of the plurality of grid points (301) of the 3-D subsurface model from processing the image values of the seismic dataset (212); and generating a depositional sequence volume (216) for the 3-D subsurface model from the reflections (104) at the first subset of grid points (301) and the geological constraints (102) at the second subset of grid points. Dirichlet or Neumann boundary conditions are applied around faults or discontinuities found on the geological horizons (302).