Underground gas-liquid-solid three-phase flow ultrasonic gas cut monitoring system and implementation method

The invention relates to an underground gas-liquid-solid three-phase flow ultrasonic gas cut monitoring system and an implementation method, and belongs to the technical field of oil and gas drilling. The monitoring system comprises a dispersed phase volume fraction monitoring module and a dispersed phase speed monitoring module, wherein the dispersed phase volume fraction monitoring module is used for monitoring the volume fraction of a dispersed phase in annulus drilling fluid; and the dispersed phase speed monitoring module is used for monitoring the upward movement speed of the dispersed phase in the annulus drilling fluid. By monitoring the volume fraction of the dispersed phase in a horizontal section and monitoring the speed of the dispersed phase in an annulus, whether underground gas cut occurs or not can be accurately judged, the volume fraction of gas in a gas-liquid-solid three-phase flow can be accurately calculated, the gas and a solid do not need to be separated, the problem that the resolution