Multi-Physical Field Imaging Method and System Based on PET-CT and DAS

A multi-physical field imaging method based on PET-CT and DAS, for studying a dynamic fluid-solid coupling effect in non-metallic material, to study hydraulic fracturing process and earthquake induced by the hydraulic fracturing process, comprising:

• Step A:
• wrapping distributed acoustic sensors on a surface of a non-metallic sample to be tested, and then placing the non-metallic sample to be tested and the distributed acoustic sensors in a pressure device;
• wherein the distributed acoustic sensors are phase-sensitive optical frequency domain reflectometers, made of silicon dioxide, the phase-sensitive optical frequency domain reflectometers are configured to have a spatial resolution of 10 cm, a strain resolution of
• 1
• n
• ε
• /
• Hz
• ,
• and a vibration sampling frequency of 300 Hz, so as to obtain internal dynamic vibration signals generated from the fluid-solid coupling effect of the non-metallic samples to be tested;
• the pressure device is made of a composite material of polyether ether ketone and carbon fiber, and the composite material is made from pure polyether ether ketone material filled with 40% by weight carbon fiber;
• Step B:
• utilizing electric metering pumps remotely controlled by a computer to load triaxial pressures on the non-metallic sample to be tested, according to requirement of a research experiment, simulating different mechanical conditions to monitor interaction process between fluid and solid and physical response under different mechanical scenarios;
• wherein experimenters set pressures of the electric metering pumps remotely through the computer outside a PET/CT equipment room, according to the requirement of the experiment, and record pressure changes in real time;
• Step C:
• preparing a tracer fluid, and diluting the tracer fluid;
• Step D:
• pumping the diluted tracer fluid into the non-metallic sample to be tested through a metering pump remotely controlled by a computer;
• Step E:
• continuously and in-situ collecting PET images and CT images of internal structure of the non-metallic sample to be tested;
• meanwhile, monitoring internal acoustic emission events of the non-metallic sample to be tested by using distributed acoustic sensors in real time;
• Step F:
• combining the continuously-obtained PET images with the continuously-obtained CT images, to obtain PET/CT images;
• Step G:
• analyzing data from monitoring of the distributed acoustic sensors, locating the acoustic emission events, and obtaining occurrence time and spatial location of internal structural perturbation of the non-metallic sample to be tested;
• and
• Step H:
• combining continuous in-situ dynamic PET/CT images with locating results of the acoustic emission events, to analyze a mechanism of fluid-solid coupling effect in the non-metallic sample to be tested under loaded stress;
• projecting spatial location information of the acoustic emission events to three-dimensional PET/CT images, to analyze a fluid-solid coupling process in the non-metallic sample to be tested.