FIELD: oil and gas industry.
SUBSTANCE: group of inventions relates to oil and gas industry, in particular to regulation of pressure of drilling fluid in annular space of the well. System and method include drilling fluid pumping through the drill string lowered into borehole extending under the bottom of the water body, outlet of bottom-hole assembly and in annular space of the well shaft. Solution is discharged from annular space into the riser and discharge pipe. Riser is placed above the top of the well shaft and is extended to water surface. Exhaust pipe is connected with raiser and includes a controlled hydraulic nozzle. Solution return line is connected to outlet nozzle and contacts with water surface. Gas under pressure is pumped to return line at the selected depth below the water surface. Operation of adjustable hydraulic nozzle can be controlled to maintain the specified level of drilling mud in riser pipe, the specified level of solution is selected on the distance below the water surface.
EFFECT: higher speed and accuracy of pressure control, compact arrangement of installation, provides a higher level of safety.
20 cl, 5 dwg
