Control method and device for washing and bailing sand by adopting double-wall drill pipe

The invention provides a control method and device for sand washing and bailing through a double-wall drill pipe. The method comprises steps that according to density of a water phase in an oil and gas well, the pressure and temperature of a production layer, the inner diameter and the outer diameter of a production sleeve, the depth of a static liquid level, the depth of the oil and gas well, the inner diameter, the outer diameter and the length of an outer pipe of the double-wall drill pipe, the inner diameter, the outer diameter and the length of an inner pipe, the position of the gas injection valve, and the inner diameter and the outer diameter of a single wall drill pipe, establishing a model for washing and bailing an oil and gas well by adopting the double-wall drill rod according to the position of a gas injection valve and the inner diameter and the outer diameter of the single-wall drill rod, and performing simulated gas injection on an inner pipe of the double-wall drill rod in the model by adopti