Sparse Ocean Bottom Nodes With Mini-Streamers for Better Subsurface Imaging
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Solution Overview
Problem
High-density ocean bottom seismic data acquisition is expensive and time-consuming, and sparse node surveys face challenges in subsurface imaging due to inadequate sampling, leading to poor resolution of shallow targets and steeply dipping structures, especially in complex geological settings.
Innovation Solution
A system combining sparse ocean bottom nodes with mini-streamers, where the mini-streamers' length is coordinated with node spacing, allowing simultaneous data acquisition and joint processing with existing datasets to enhance subsurface imaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional ocean bottom node surveys are used to improve subsurface imaging quality, then imaging precision is improved, but acquisition time and cost increase significantly
Solution Approach 1:
The patent segments the traditional ocean bottom node survey into two components: sparse ocean bottom nodes for deep subsurface imaging and mini-streamers for shallow target imaging. This segmentation allows each component to be optimized for its specific function, reducing overall acquisition time while maintaining imaging quality for both shallow and deep targets
Solution Approach 2:
The patent merges sparse ocean bottom node data with mini-streamer data into a unified imaging workflow. By combining these two data types with complementary characteristics (nodes provide deep penetration and mini-streamers provide shallow coverage), the system achieves comprehensive subsurface imaging without the full time and cost burden of traditional dense node surveys
2Ease of manufacture
If sparse ocean bottom nodes are used to reduce acquisition cost, then cost is reduced, but sampling density decreases leading to suboptimal imaging
Solution Approach 1:
The patent applies local quality by using different receiver densities in different depth zones: sparse ocean bottom nodes for deep subsurface sampling and dense mini-streamer receivers for shallow target sampling. This localized optimization ensures adequate sampling density where needed while reducing costs in areas where sparse sampling is sufficient
Solution Approach 2:
The patent creates an asymmetric sampling strategy where the receiver spacing varies by depth and target type rather than using uniform spacing. Mini-streamers provide dense sampling near the surface while ocean bottom nodes provide sparse but effective deep sampling, creating an asymmetric but optimized sampling pattern that improves cost-effectiveness
3Area of stationary object
If long streamers are used to improve subsurface coverage, then coverage area is improved, but device complexity and acquisition cost increase
Solution Approach 1:
The patent segments the receiver system into two parts: short mini-streamers that are easier to deploy and handle, and sparse ocean bottom nodes that extend the effective coverage area. This segmentation reduces the complexity of each individual component while maintaining or expanding overall subsurface coverage through coordinated operation
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 reduces acquisition costs and time while improving imaging quality by optimizing subsurface sampling, addressing issues of inadequate sampling and environmental footprint, and enhancing resolution of shallow geology and complex structures.
Implementation Method 1
Vessel 110 (or another vessel) may also tow a seismic source 120 configured to generate acoustic waves 122a. Acoustic waves 122a propagate downward and penetrate the seafloor 124.
Implementation Method 2
When encountering a layer interface 126 (different impedance in different layers), the acoustic waves are at least partially reflected.
Implementation Method 3
The reflected wave 122c passes by the detectors and is reflected back at the water surface 118 (the interface between the water and air serving as a quasi-perfect reflector to mirror acoustic waves).
Implementation Method 4
The detectors record amplitude versus time series, known as traces, which are processed to generate a reflectivity image of the underground structure 124 and, in particular, the location of reflectors 126.
Data Source
AI summary
A correlated sparse nodes and mini-streamers system for collecting seismic data includes plural nodes distributed on the ocean bottom, and a mini-streamer spread that includes plural mini-streamers. The plural nodes and the mini-streamer spread are configured to simultaneously collect seismic data from a surveyed subsurface, and wherein a length of the mini-streamers is equal to or less than three times an inline distance between adjacent nodes of the plural nodes.