Seismic Deblending for Attenuating Source Signatures and Free-Surface Effects
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional seismic data processing techniques fail to accurately generate high-resolution images of subterranean formations in rough water conditions due to time-varying free surface waves causing perturbations in arrival times of source ghosts and multiples, leading to inaccurate representation of structural features and hydrocarbon deposits.
Innovation Solution
The use of simultaneous source acquisition (SSA) and deblending processes to attenuate source signatures and free-surface effects in seismic data, allowing for the generation of deblended seismic data with reduced noise, which can then be processed to produce high-resolution images of subterranean formations regardless of water conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional seismic data processing techniques are used, then the processing method is simple, but the image resolution and accuracy deteriorate in rough water conditions
Solution Approach 1:
The patent divides the seismic data processing into distinct segments: first separating primary wavefields from multiple wavefields, then independently processing each component. The deblending process separates simultaneous source data into individual source contributions, while the multiple attenuation process specifically targets free-surface multiples. This segmentation allows complex rough water conditions to be handled through systematic, modular processing steps rather than attempting to solve all problems simultaneously.
Solution Approach 2:
The patent applies preliminary deblending operations before multiple attenuation to remove source signatures and separate overlapping source contributions. By performing this separation in advance, the subsequent multiple attenuation process operates on cleaner, more isolated wavefield data, improving its effectiveness. The preliminary removal of source ghosts and signatures prepares the data for more accurate multiple identification and elimination.
2Productivity
If simultaneous source acquisition is used, then the productivity increases, but the data complexity and processing difficulty increase
Solution Approach 1:
The patent extracts individual source contributions from the blended simultaneous source data through deblending processes. By separating the overlapping wavefields from multiple sources activated at different times, the system recovers clean primary wavefields from each source. This extraction approach allows simultaneous source acquisition to maintain its productivity advantage while delivering data quality comparable to conventional single-source methods after processing.
Solution Approach 2:
The patent introduces intermediate processing stages including wavefield separation, deblending, and multiple attenuation as mediator steps between data acquisition and final imaging. These intermediary processes systematically reduce the complexity of simultaneous source data by progressively eliminating interference and artifacts, transforming the raw blended data into clean primary wavefields suitable for high-resolution imaging.
3Reliability
If free-surface effects are not attenuated, then the processing time is reduced, but the image accuracy and reliability deteriorate
Solution Approach 1:
The patent converts the harmful free-surface multiple effects into beneficial information by using the predicted multiple wavefields as a template for subtraction. The multiple attenuation process predicts what the multiples should look like based on the separated primary wavefields and known free-surface properties, then removes these predictions from the data. This approach transforms the problematic multiple energy into a useful reference for eliminating it, improving image reliability while maintaining reasonable processing efficiency.
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 effectively removes source signatures and free-surface effects from seismic data, enabling the creation of accurate, high-resolution images of subterranean formations even in rough water conditions, improving the identification of structural features and hydrocarbon deposits.
Implementation Method 1
The acoustic energy generated by a seismic source spreads out in all directions. A portion of the acoustic energy travels down through the water and into a subterranean formation to propagate as sound waves within the subterranean formation.
Implementation Method 2
At each interface between different types of liquid, rock and sediment, a portion of the sound wave is refracted, a portion is transmitted, and another portion is reflected into the body of water to propagate as a reflected wavefield toward the water surface.
Implementation Method 3
Processes and systems are disclosed for deblending blended seismic data recorded using simultaneous source acquisition (SSA), and for attenuating source signatures and free-surface effects in the deblended seismic data.
Data Source
AI summary
Processes and systems for deblending blended seismic data with attenuated source signatures and free-surface effects are described. The blended seismic data may have been recorded in a marine survey in which multiple sources are activated in the body of water above a subterranean formation. Receivers record overlapping pressure and vertical velocity wavefield responses from the subterranean formation as corresponding blended pressure wavefield and blended vertical velocity wavefield. Processes and systems compute an upgoing pressure wavefield and a downgoing vertical velocity wavefield based on the blended pressure wavefield and blended vertical velocity wavefield. Deblended primary pressure wavefields are computed based on the upgoing pressure and downgoing vertical velocity. The deblended primary pressure wavefields may be used to generate images of the subterranean formation that are substantially free of source signatures and free-surface effects.