Advanced suspended-core fiber sensor for seismic physical modeling.

Area of Science:

• Fiber optics sensing
• Seismic exploration technology
• Acoustic wave detection

Background:

• Traditional seismic exploration relies on accurate acoustic wave detection.
• Existing sensors often face limitations in sensitivity and stability for weak signal analysis.
• Advanced fiber optic technologies offer potential for enhanced sensing capabilities.

Purpose of the Study:

• To propose and demonstrate a micro ultrasonic sensor based on advanced suspended-core fiber.
• To improve sensor response and stability for seismic physical modeling.
• To validate the sensor's performance in practical seismic exploration scenarios.

Main Methods:

• Fabrication of a suspended-core fiber sensor using acid corrosion.
• Imprinting two cascaded uniform fiber Bragg gratings (FBGs) onto the fiber.
• Constructing an in-fiber interferometer with dual-FBG reflectors.
• Experimental analysis of reflection spectra and ultrasonic response.
• Comparative measurements against conventional weak-reflection sensors.

Main Results:

• The dual-FBG configuration significantly improved sensor response and stability.
• Experimental validation confirmed the sensor's superior performance compared to weak-reflection sensors.
• Successful modeling of crosswell and surface seismic surveys using reservoir and fault models.
• Accurate measurement of reservoir velocities and reconstruction of fault features.

Conclusions:

• The developed micro ultrasonic sensor demonstrates enhanced performance for seismic physical modeling.
• The suspended-core fiber with dual FBGs is highly effective for weak acoustic detection.
• This approach significantly advances the application of fiber optics in seismic exploration.