Physical simulation experiment system for vapor-liquid multiphase seepage in underground gas storage facility in depleted gas reservoir

A physical simulation experiment system for vapor-liquid multiphase seepage in an underground gas storage (UGS) facility in a depleted gas reservoir, comprising:

• a rock sample sealing, heating, and insulation system, comprising a rock sample sealing unit for accommodating a rock sample and a heating and insulation unit for heating the rock sample, wherein the rock sample sealing unit comprises a main pressure chamber, a rock sample rubber sleeve, and loading plates;
• the main pressure chamber has a central cavity for accommodating the rock sample and providing a confining pressure environment for the rock sample;
• the rock sample rubber sleeve is fitted around an outer wall of the rock sample to seal the rock sample;
• and the loading plates are arranged around the rock sample respectively and press against the rock sample rubber sleeve on the outer wall of the rock sample;
• a triaxial stress and confining pressure loading system, comprising a triaxial stress loading unit for applying triaxial stress to the rock sample and a confining pressure loading unit for applying a confining pressure to the rock sample, wherein the triaxial stress loading unit comprises loading cylinders positioned around the rock sample, a servo loading pump that provides a power source for the loading cylinders, a servo oil source that offers pre-pressurization for axial loading, a servo valve that controls a hydraulic pressure of the loading cylinders, a directional control valve that controls a piston movement direction of the loading cylinders, a displacement sensor that controls displacement of the loading cylinders, and an air compressor that supplies a low-pressure power to reset pistons of the loading cylinders;
• loading heads of the loading cylinders press against the loading plates around the rock sample respectively;
• and the confining pressure loading unit comprises a high-precision constant flow/pressure pump connected to the main pressure chamber via a pipeline to provide a constant pressure within the main pressure chamber, thereby applying the confining pressure to the rock sample;
• an oil-gas-water injection and pore pressure supply system connected to an inlet end of the rock sample via a pipeline, comprising a vapor-phase injection unit and a liquid-phase injection unit to perform oil-gas-water three-phase injection into the rock sample;
• a vapor-liquid-solid three-phase separation and measurement system connected to an outlet end of the rock sample via a pipeline, comprising a back-pressure unit, a solid separation and measurement unit, and a vapor-liquid separation and measurement unit;
• an optical micro/nanofiber gas detection and monitoring system, configured to detect leakage of specified gases;
• a distributed fiber optic sensing system, configured to monitor and record internal deformation and fracture initiation of the rock sample during a loading process;
• and
• a gas supply and leakage alarm system, configured to provide safe and reliable centralized gas supply;
• wherein the heating and insulation unit comprises:
• heating rods embedded around an interior of the main pressure chamber to heat the main pressure chamber and transfer heat to the rock sample;
• and
• a flexible insulation jacket wrapped around an exterior of the main pressure chamber to provide thermal insulation and temperature compensation for the main pressure chamber.