Seismic Beam Steering Coherent Stacking Resolution
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Solution Overview
Problem
Conventional seismic surveying techniques have limited vertical and lateral resolution due to the Earth's subsurface acting as a low-pass filter, restricting the use of high-frequency seismic energy, which hinders precise monitoring of fluid distribution changes in subsurface rock formations.
Innovation Solution
A method involving the deployment of seismic sensors in a selected pattern with a seismic energy source that uses higher frequency seismic energy and coherent stacking from multiple actuations to enhance resolution, combined with beam steering to focus responses and improve signal-to-noise ratios, allowing for more precise imaging of subsurface structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high-frequency seismic energy is used, then vertical and lateral resolution is improved, but signal attenuation increases and signal quality deteriorates
Solution Approach 1:
The seismic energy source is repeatedly actuated at the same location with periodic timing, allowing multiple recordings of the same subsurface reflections. These periodic measurements are then coherently stacked to reinforce the desired high-frequency signal while suppressing random noise and attenuation effects, enabling resolution improvement without proportionally increasing energy loss.
Solution Approach 2:
Multiple seismic recordings from repeated source actuations are merged through coherent stacking. The signals from different actuations are combined with proper time alignment, causing constructive interference for coherent reflections and destructive interference for incoherent noise, thereby improving signal quality and reducing the effective attenuation impact.
2Measurement precision
If sensor array aperture and sensor spacing are increased, then lateral resolution is improved, but data processing time and cost increase
Solution Approach 1:
The sensor array configuration is made dynamic through beam steering capability. Instead of requiring a physically large fixed array, the system electronically steers the beam direction and focuses energy on different subsurface points by adjusting phase and amplitude weights on a more compact array, achieving high lateral resolution with reduced physical aperture and faster processing.
Solution Approach 2:
The system changes the processing parameters (phase shifts, time delays, amplitude weights) to achieve different beam steering angles and focal points. By modifying these parameters rather than physically reconfiguring a large array, the system achieves high lateral resolution imaging of different subsurface locations with consistent, manageable data processing requirements.
3Reliability
If beam steering and coherent stacking are applied, then signal-to-noise ratio is improved, but processing complexity increases
Solution Approach 1:
The system replaces complex physical signal filtering mechanisms with computational beam steering and coherent stacking algorithms. Instead of using complex hardware filters to improve signal-to-noise ratio, the invention uses software-based processing that applies phase and amplitude corrections to achieve coherent summation of desired signals and suppression of noise, managing complexity through algorithmic rather than mechanical means.
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 higher vertical and lateral resolution seismic imaging, enabling better monitoring of subsurface reservoirs and earlier detection of fluid changes, such as 'coning' or permeability anisotropy, by mitigating attenuation and improving signal quality.
Implementation Method 1
The seismic signals typically include events caused by seismic energy reflecting from acoustic impedance boundaries in the subsurface
Implementation Method 2
seismic energy reflecting from acoustic impedance boundaries
Implementation Method 3
beam steering a response of the seismic sensors such that the at least one point is equivalent to a focal point of a response of the plurality of sensors
Implementation Method 4
stacking recordings from each sensor for a plurality of actuations of the source
Data Source
AI summary
A method for seismic surveying includes disposing a plurality of seismic sensors in a selected pattern above an area of the Earth's subsurface to be evaluated. A seismic energy source is repeatedly actuated proximate the seismic sensors. Signals generated by the seismic sensors, indexed in time with respect to each actuation of the seismic energy source are recorded. The recorded signals are processed to generate an image corresponding to at least one point in the subsurface. The processing includes stacking recordings from each sensor for a plurality of actuations of the source and beam steering a response of the seismic sensors such that the at least one point is equivalent to a focal point of a response of the plurality of sensors.