Helically Wrapped Seismic Source for Shear Wave Generation
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Solution Overview
Problem
Conventional seismic energy sources primarily generate radial explosive energy, resulting in insufficient shear wave energy, which limits the accuracy of fracture distribution and orientation mapping in subterranean formations during seismic surveys.
Innovation Solution
A seismic energy source comprising an elongate rod with a detonator and bull plug, featuring an explosive helically wrapped around the rod at a predetermined pitch angle, allowing controlled axial detonation to maximize shear wave energy generation, and potentially using time-delayed, asymmetric explosive configurations to direct energy along the wellbore axis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional explosive sources are used, then radial energy coverage is achieved, but shear wave energy generation is insufficient
Solution Approach 1:
The patent applies asymmetry by configuring explosives in a non-radial, asymmetric pattern around the borehole axis. Specifically, the explosives are positioned at different radial distances and angular positions to create a preferred direction for shear wave generation, breaking the symmetric radial energy distribution of conventional sources. This asymmetric configuration enables enhanced s-wave energy in specific directions while maintaining operational simplicity.
Solution Approach 2:
The patent transitions from conventional radial (2D circular) explosive distribution to a three-dimensional asymmetric configuration. By positioning explosives at varying radial distances (r1, r2, r3) and angular positions around the borehole axis, the energy distribution extends into the third dimension, creating directional shear wave generation capability while maintaining radial p-wave coverage.
2Measurement precision
If radial explosive energy is used, then p-wave generation is sufficient, but s-wave energy for fracture mapping is inadequate
Solution Approach 1:
The patent applies local quality by assigning different energy generation characteristics to different spatial locations around the borehole. Specific explosive positions (at different radii and angles) are optimized to generate shear waves in directions where fracture mapping is most needed. This localized energy optimization enhances s-wave generation in critical zones while maintaining overall p-wave coverage for comprehensive formation characterization.
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 enhances the generation of shear wave energy, improving the accuracy of fracture mapping by increasing s-wave energy while minimizing radial energy, allowing for more precise determination of subterranean formation properties.
Implementation Method 1
detonating an explosive that is helically-wrapped about the elongate rod from the first end to the second end
Data Source
AI summary
The present disclosure provides embodiments seismic energy sources configured to generate enhanced shear wave energy in order to more accurately determine the distribution and orientation of fractures in subterranean formations. At least one seismic energy source includes an elongate rod having a first end and a second end, a detonator coupled to the first end, and a bull plug coupled to the second end. An explosive is helically-wrapped about the elongate rod continuously from the first end to the second end and configured to detonate such that a time-delayed detonation is achieved which induces increased shear wave energy in the surrounding formations.