Seismic Source Signature Extraction via Inactive Array Contamination Modeling
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Solution Overview
Problem
Existing seismic data processing methods struggle to accurately remove water bottom and geology contamination from near-field sensor recordings, which contaminates the source signature and far-field data, especially in shallow water conditions where the water bottom reflection time is less than the required far-field signature length.
Innovation Solution
A method involving the use of two source arrays where one array is active and the other is inactive, allowing for the recording of contamination signals from the inactive array to create a contamination model, which is then subtracted from the active array's recordings to produce cleaned data for calculating the source signature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If near-field sensors are used to record source signature data, then the recording time can be shorter than the far-field signature length, but water bottom and geology contamination occurs when water depth is shallow
Solution Approach 1:
The patent creates a contamination model by copying the contamination signals recorded by the inactive source array's sensors. This model is then subtracted from the active array's recordings to remove the harmful water bottom and geology reflections, enabling accurate source signature extraction from near-field data without requiring extended recording times.
Solution Approach 2:
The patent introduces an intermediary contamination model derived from the inactive array's recordings. This model serves as a mediator that represents the water bottom and geology reflections, allowing these contaminants to be identified and removed from the active array's near-field recordings through subtraction.
2Measurement precision
If two source arrays are used to create a contamination model, then water bottom and geology contamination can be removed, but device complexity increases
Solution Approach 1:
The patent makes the inactive source array serve a dual function: it acts as a regular seismic source array for data acquisition while simultaneously functioning as a reference array for contamination modeling. This multi-functionality allows the system to remove water bottom and geology contaminants without requiring a completely separate reference array, thereby reducing overall device complexity.
Solution Approach 2:
The system uses its own inactive array to generate the contamination model needed for cleaning the active array's data. Rather than requiring external reference data or separate measurement systems, the seismic survey system self-services by utilizing its redundant inactive array resources to eliminate contamination from the recorded data.
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 ocean bottom and geology-related contamination from seismic data, enabling the derivation of accurate source signatures and far-field signatures, improving seismic data processing and subsurface imaging.
Implementation Method 1
The air gun instantaneously releases large peak acoustic pressure and energy. The released air forms a bubble (which may be considered spherical), with air pressure inside the bubble initially greatly exceeding the hydrostatic pressure in the surrounding water. The bubble expands, displacing the water and causing a pressure disturbance that travels through the water.
Implementation Method 2
The acoustic waves from the air gun propagate in all directions.
Implementation Method 3
Sensors or receivers 106 used to record the reflected energy include hydrophones, geophones and/or accelerometers. The pressure variation generated in the water by a single air gun (which can be measured using a hydrophone or geophone located near the air gun) as a function of time is called the near-field signature.
Implementation Method 4
part of the energy is partially reflected back from the ocean bottom 113 and from rock formation interfaces 112 (rock layer that has a change in acoustic impedance)
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
A method for removing ocean bottom and/or geology related contamination. The method includes receiving (1000) first measurements corresponding to first seismic sensors mounted on a first source array; receiving (1002) second measurements corresponding to second seismic sensors mounted away from the first source array; processing (1004) the second measurements to determine a contamination model (560) related to the ocean bottom and geology; removing (1006) the contamination model from the first measurements to obtain cleaned data; and calculating (1008) a source signature of the first source array based on the cleaned data.