CSEM Data Inversion via Composite Gather Summing
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Solution Overview
Problem
Current CSEM data inversion methods are computationally intensive and inefficient, especially for large 3D surveys, due to the need for numerous forward simulations and the limitations of existing forward-modeling techniques, which hinder their application in hydrocarbon exploration.
Innovation Solution
A computer-implemented method that forms composite gathers from selected ordinary gathers, allowing for simultaneous simulation of multiple transmitter configurations in a single operation, reducing the number of forward modeling operations required and enhancing computational efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional CSEM data inversion methods are used, then inversion accuracy can be maintained, but computational time and processing efficiency deteriorate significantly
Solution Approach 1:
The patent segments the large 3D survey data into multiple smaller 2D subsets or profiles that can be inverted independently and more efficiently. By dividing the complex 3D inversion problem into multiple manageable 2D inversion problems, the computational burden is reduced while maintaining inversion accuracy through subsequent integration of the subset results.
Solution Approach 2:
The patent performs inversion on a selected subset of transmitter-receiver gathers rather than processing all possible combinations. This partial action approach processes only the most informative or critical data subsets, achieving sufficient inversion accuracy with significantly reduced computational time compared to exhaustive processing of all data.
2Manufacturing precision
If numerous forward simulations are performed for accurate inversion, then inversion quality improves, but computational complexity and resource requirements worsen
Solution Approach 1:
The patent divides the complex forward simulation process into smaller segments corresponding to individual 2D subsets. Each subset requires fewer forward simulations than the full 3D problem, reducing computational complexity while maintaining overall inversion quality through the aggregation of subset results.
Solution Approach 2:
The patent performs forward simulations only for selected transmitter-receiver subsets rather than all possible combinations. This partial simulation approach reduces computational complexity and resource requirements while still achieving sufficient inversion quality by focusing on the most informative data subsets.
3Measurement precision
If traditional forward modeling techniques are used, then modeling accuracy is maintained, but processing speed and efficiency deteriorate
Solution Approach 1:
The patent segments the large-scale forward modeling problem into multiple smaller 2D forward modeling problems. Each 2D subset can be modeled more quickly and efficiently while maintaining accuracy, and the results are integrated to produce the overall 3D subsurface model, thereby improving processing speed without sacrificing modeling accuracy.
Data Source
AI summary
Method for rapid inversion of data from a controlled-source electromagnetic survey of a subterranean region. Selected (51) common-receiver or common-source gathers of the data are reformed into composite gathers (52) by summing their data. Each composite gather is forward modeled (in the inversion process) with multiple active source locations (53). Computer time is reduced in proportion to the ratio of the total number of composite gathers to the total number of original common-receiver or common-source gathers. The data may be phase encoded to prevent data cancellation. Methods for mitigating loss of far offset information by data overlap in the summing process are disclosed.