Abstract: The invention discloses a circulating system and a method for continuous downhole cooling of high-temperature drilling fluid. The circulating system includes a cooling water tank, a cooling water injection pump, a plurality of U-shaped pipes, a liquid nitrogen cooling tank, a spiral pipe, a cooling water return pump and a return pipeline. The U-shaped pipe is fixed in an unsealed bond cement gap between outer and inner casings, and two ends are respectively connected with output end of the cooling water injection pump and the spiral pipe. The spiral pipe is disposed in the liquid nitrogen cooling tank; input and output ends of the cooling water return pump are respectively connected with the spiral pipe and the return pipeline; one end of the return pipeline is disposed in the cooling water tank; input end of the cooling water injection pump is connected with the cooling water tank by a pipe.

Abstract: The invention discloses a dynamic simulation method of circulating temperature variation in RMR subsea pump mud-lift drilling system, including steps: obtaining operating parameters, environmental parameters, well structure parameters and thermal parameters of target well; establishing temperature control equation of drill string in seawater section, temperature control equation of drill string in formation section, temperature control equation of annulus in formation section, and temperature control equation of return pipe in seawater section; re-determining initial and boundary conditions; discretizing spatial structure of the whole system with inner node method; discretizing control equations on corresponding nodes; substituting corresponding parameters into discrete expressions to obtain circulating temperature in drill string of seawater section, circulating temperature in drill string of formation section, circulating temperature in annulus of formation section, and circulating temperature in return pip

Abstract: The invention discloses a dynamic simulation method of circulating temperature variation in RMR subsea pump mud-lift drilling system, including steps: obtaining operating parameters, environmental parameters, well structure parameters and thermal parameters of target well; establishing temperature control equation of drill string in seawater section, temperature control equation of drill string in formation section, temperature control equation of annulus in formation section, and temperature control equation of return pipe in seawater section; re-determining initial and boundary conditions; discretizing spatial structure of the whole system with inner node method; discretizing control equations on corresponding nodes; substituting corresponding parameters into discrete expressions to obtain circulating temperature in drill string of seawater section, circulating temperature in drill string of formation section, circulating temperature in annulus of formation section, and circulating temperature in return pip

Abstract: The invention discloses a circulating system and a method for continuous downhole cooling of high-temperature drilling fluid. The circulating system includes a cooling water tank, a cooling water injection pump, a plurality of U-shaped pipes, a liquid nitrogen cooling tank, a spiral pipe, a cooling water return pump and a return pipeline. The U-shaped pipe is fixed in an unsealed bond cement gap between outer and inner casings, and two ends are respectively connected with output end of the cooling water injection pump and the spiral pipe. The spiral pipe is disposed in the liquid nitrogen cooling tank; input and output ends of the cooling water return pump are respectively connected with the spiral pipe and the return pipeline; one end of the return pipeline is disposed in the cooling water tank; input end of the cooling water injection pump is connected with the cooling water tank by a pipe.