Deghosting Variable Depth Seismic Streamer Data
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Solution Overview
Problem
Current methods for deghosting seismic data collected with streamers of varying depths, particularly in three-dimensional configurations, are inadequate as they cannot effectively generalize from one-dimensional and two-dimensional processing, leading to inaccuracies in imaging underwater geological structures.
Innovation Solution
A method involving the generation of migration and mirror migration data, derivation of ghost-free models using linear operators, and adaptive subtraction to produce a deghosted dataset, which improves image resolution by accounting for ghost lag models in both time and depth domains.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional deghosting methods are used for three-dimensional seismic data, then processing can be performed using existing one-dimensional and two-dimensional procedures, but imaging accuracy of underwater geological structures deteriorates due to inability to generalize from lower dimensions
Solution Approach 1:
The patent transitions from one-dimensional and two-dimensional deghosting methods to a three-dimensional deghosting approach by incorporating depth domain processing and three-dimensional migration techniques. This allows the system to handle the additional spatial dimension in 3D seismic surveys, properly accounting for variable streamer depths and three-dimensional ghost interference patterns that cannot be resolved by lower-dimensional methods.
2Area of stationary object
If streamers are deployed with curved or slanted profiles to improve data collection, then coverage area increases, but ghost interference worsens due to varying receiver depths
Solution Approach 1:
The patent applies local quality by processing different segments of the streamer cable with depth-specific deghosting parameters. Each receiver element's ghost removal is customized based on its actual depth and orientation, allowing the system to handle curved and slanted streamer profiles effectively. This localized processing approach maintains the benefits of flexible streamer deployment while correcting for the varying ghost interference characteristics at different positions along the cable.
3Manufacturing precision
If adaptive subtraction with ghost lag models is applied to remove ghost interference, then image resolution improves, but processing complexity increases due to multiple domain transformations
Solution Approach 1:
The patent performs preliminary deghosting operations in the depth domain before final migration and imaging. By removing ghost interference early in the processing workflow using depth-domain ghost lag models, the system simplifies subsequent processing steps. This preliminary action prevents ghost artifacts from propagating through later processing stages, reducing the overall complexity despite the advanced techniques employed.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances the accuracy and clarity of subsurface images by effectively removing ghost interference, improving the resolution of seismic data collected with streamers having curved or slanted profiles, particularly in three-dimensional scenarios.
Implementation Method 1
a sound source 20 configured to generate an acoustic wave 22a. The acoustic wave 22a propagates downward and penetrates the seafloor 24, eventually being reflected by a reflecting structure 26
Implementation Method 2
The reflected acoustic wave 22b propagates upward and is detected by detector 12
Implementation Method 3
Parts of the reflected acoustic wave 22c pass the detectors 12 and arrive at the water surface 18. Since the interface between the water and air is well approximated as a quasi perfect reflector, the reflected wave 22c is reflected back toward the detector 12 as shown by wave 22d
Data Source
AI summary
Computing device, computer instructions and method for deghosting seismic data related to a subsurface of a body of water. The method may include receiving input seismic data recorded by seismic receivers that located at different depths (zr), generating migration data (du) and mirror migration data (dd) from the input seismic data, deriving a ghost free model (m) based on simultaneously using the migration data (du) and mirror migration data (dd), generating primary (p) and ghost (g) datasets based on the ghost free model (m), simultaneously adaptively subtracting the primary (p) and ghost (g) datasets from the migration data (du) to provide adapted primary (p′1 and p′2) and adapted residual (r′1 and r′2) datasets and generating a final image (f) of the subsurface based on the adapted primary (p′1 and p′2) and the adapted residual (r′1 and r′2) datasets.