Multiples Wavefield Angle Gathers for Seismic Imaging
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Solution Overview
Problem
Conventional seismic imaging methods produce limited quality and accuracy in subsurface images due to the removal of multiples wavefields, which reduces angular illumination, especially in the crossline direction, leading to poor resolution and sparseness in three-dimensional acquisitions.
Innovation Solution
The technique utilizes multiples wavefields to improve the quality and accuracy of seismic images by generating angle-domain image gathers, effectively increasing illumination angles and using the down-going wavefield as a secondary 'aerial' source, thereby enhancing shot density and image clarity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiples wavefields are removed from seismic data processing, then primary wavefield quality is improved, but angular illumination and shot density deteriorate
Solution Approach 1:
The patent converts the previously harmful multiples wavefield into a beneficial secondary source. By treating multiples as useful signals rather than noise to be removed, the method reconstructs them to provide additional angular illumination and enhance shot density, directly resolving the contradiction between maintaining primary wavefield quality and improving angular coverage
Solution Approach 2:
The patent makes the seismic data processing system multi-functional by simultaneously utilizing both primary wavefields for high-quality imaging and multiples wavefields for enhancing angular illumination. The reconstructed multiples serve dual purposes: maintaining signal integrity while providing additional illumination angles that would otherwise be unavailable
2Ease of manufacture
If conventional seismic imaging methods are used, then processing simplicity is maintained, but image resolution and accuracy deteriorate
Solution Approach 1:
The patent segments the seismic wavefield into distinct components (primary and multiples) and processes them separately through different computational pathways. This segmentation allows each component to be optimized independently - primary wavefields for quality and multiples for angular illumination - before combining results to achieve high resolution while maintaining manageable processing complexity
Solution Approach 2:
The patent introduces an intermediary reconstruction step that bridges the gap between simple conventional processing and complex high-resolution imaging. The multiples reconstruction acts as an intermediary process that adds necessary computational complexity only where needed to improve angular illumination, rather than complicating the entire processing workflow
3Measurement precision
If shot density is increased to improve crossline direction imaging, then acquisition complexity increases, but with multiples reconstruction, effective shot density improves without additional acquisition complexity
Solution Approach 1:
The patent creates a virtual copy of the seismic source through multiples reconstruction. Instead of physically deploying additional sources to increase shot density, the method synthesizes virtual sources from the recorded multiples wavefield, effectively doubling the utility of each physical source without increasing acquisition complexity or equipment requirements
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 results in more finely sampled and accurate seismic images, particularly in the crossline direction, allowing for better identification of subsurface structures and hydrocarbon exploration.
Implementation Method 1
seismic energy source, such as an air gun, marine vibrator, or arrays of airguns and/or marine vibrators, is typically used to impart the acoustic energy into the formations below the bottom of the water
Implementation Method 2
detecting acoustic energy that is reflected from boundaries between different layers of a subsurface rock formation. Acoustic energy is reflected when there is a difference in acoustic impedance between adjacent layers to a boundary
Implementation Method 3
Hydrophones are seismic sensors that generate an optical or electrical signal corresponding to the pressure of the water or the time gradient of pressure in the water
Data Source
AI summary
One embodiment relates to a technological process for identifying a potential subsurface structure below a body of water. Three-dimensional seismic sensor data that includes at least two measured components is obtained. Up-going and down-going wavefields comprising multiples wavefields are constructed from the three-dimensional seismic sensor data by applying wavefield separation. The up-going and down-going wavefields are extrapolated to a reflector surface below a water bottom. An imaging condition is applied at the reflector surface to generate images that include information from the multiples wavefields. Angle gathers are constructed, where each angle gather is constructed by gathering the images generated using the multiples wavefields for a range of illumination angles. Other embodiments, aspects and features are also disclosed.