Fiber Optic Seismic Sensors on Subsea Infrastructure
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Solution Overview
Problem
Current seismic imaging techniques struggle to effectively identify and produce hydrocarbon reservoirs with wide lateral extent, especially when field obstructions are present, as they often require costly undershooting operations or deployment of sea floor sensors, which limit coverage and result in sparse sampling.
Innovation Solution
A system and method utilizing fiber-optic sensing systems attached to existing subsea oilfield infrastructure, creating a 3D volume of sensors with high-density sampling in x, y, and z dimensions, and employing interferometric principles, imaging data from traditional geometries, and advanced processing techniques to minimize artifacts and enhance imaging quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If traditional seismic survey methods are used, then equipment deployment is simpler, but coverage is limited and sampling is sparse
Solution Approach 1:
The patent combines fiber optic sensing technology with existing subsea infrastructure (production pipes, flowlines, templates) to create a seismic sensor array. By integrating the sensing function into already-deployed infrastructure, the system achieves high sensor density without proportionally increasing system complexity, as the infrastructure serves dual purposes: production support and seismic sensing.
Solution Approach 2:
The fiber optic cables attached to subsea infrastructure serve multiple functions: they act as both production flowlines/pipes and as seismic sensors. This multi-functionality allows the system to achieve high sensor density using existing infrastructure, avoiding the need for separate dedicated sensor deployment systems.
2Area of stationary object
If field obstructions are present, then traditional survey coverage is limited, but deploying sea floor sensors increases complexity and cost
Solution Approach 1:
The patent segments the seismic survey system by attaching fiber optic sensors to multiple distributed subsea infrastructure elements (production pipes, flowlines, templates) rather than using a single centralized sensor array. This segmentation allows coverage around field obstructions by utilizing the distributed nature of existing infrastructure, achieving broad coverage without complex coordinated deployment.
Solution Approach 2:
The existing subsea infrastructure serves its own production function while simultaneously providing the mounting structure for seismic sensors. The infrastructure 'services itself' by dual-purpose utilization, eliminating the need for separate sensor deployment systems and reducing overall deployment complexity despite expanded coverage requirements.
3Measurement precision
If high-density sampling is implemented, then imaging quality improves, but data processing complexity increases
Solution Approach 1:
The patent replaces traditional mechanical sensor arrays with fiber optic sensing technology that utilizes the existing infrastructure. Fiber optic sensors provide high-density sampling capabilities with inherent advantages in data quality and signal-to-noise ratio, which simplifies certain processing challenges compared to traditional geophone or hydrophone arrays, despite the high sampling density.
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 provides improved seismic imaging by covering larger subsurface volumes, reducing sampling-related artifacts, and enabling more accurate identification and monitoring of hydrocarbon reservoirs, with enhanced imaging quality and increased efficiency compared to traditional methods.
Implementation Method 1
employing interferometric principles
Implementation Method 2
fiber optic sensing systems
Implementation Method 3
The sources generate seismic waves, which propagate into the geological medium creating pressure changes and vibrations
Implementation Method 4
Some seismic sensors are sensitive to pressure changes (e.g., hydrophones), others to particle motion (e.g., geophones)
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A system for performing seismic surveys may include devices to attach fiber-optic cables and/or sensors to existing subsea infrastructure, as well as devices for recording seismic data at the fiber-optic cables/sensors attached to or incorporated within existing infrastructure. A method for seismic imaging of a subsurface volume of interest may include recording seismic data using fiber-optic cables attached to existing subsea infrastructure, processing the seismic data to create processed seismic data, and generating seismic images/attributes of the subsurface volume of interest from the processed seismic data. Additionally, the invention includes a one-way ranging technique to determine the location of FO cables using an integrated dynamic monitoring system and FO cables/sensors. The methods may be executed by a computer system.