Mechanical sealing and flushing method and device of seafloor mud lifting pump

Abstract

A mechanical sealing and flushing method and device of a seafloor mud lifting pump comprises a seawater pump, a pump outlet, a pump inlet, an impeller, an O-type ring and a seawater flushing pipe. The seawater pump is arranged in seawater and is coaxial with a motor, the pump outlet is formed in the seawater pump, the pump inlet is formed in a front end cover of the seawater pump, the impeller is arranged inside the seawater pump and is connected with a motor shaft through keys, the O-type ring is arranged between the seawater pump and the front end cover of the motor, and the seawater flushing pipe is connected with the pump outlet and a sealing and flushing opening. The seawater pump is immersed in the seawater, the pump inlet is directly communicated with the seawater, the seawater is boosted through the effect of the impeller inside the seawater pump, and seawater flowing and flushing to a sealing face are achieved. The mechanical sealing and flushing method and device of the seafloor mud lifting pump is simple in structure, sealing liquid does not need to be drawn from a sea surface to flush a circulation pipeline, the problem of sealing face flushing of the seafloor mud lifting pump of a seafloor mud lifting drilling well can be effectively solved, meanwhile, the mechanical sealing and flushing method and device of the seafloor mud lifting pump can be applied to ocean mining and other seafloor solid-liquid two-phase conveying pumps, and the demands for mechanical sealing and flushing of deep sea seafloor solid-liquid two-phase conveying pumps are met.

Description

technical field [0001] The invention relates to a mud recovery drilling technology without a riser, in particular to a method and device for flushing a mechanical seal of a seabed mud lift pump. Background technique [0002] Riserless mud recovery drilling technology is a realization of dual-gradient drilling technology. Different from other dual-gradient drilling system solutions, single-gradient mud is used in the riserless system, but the subsea wellhead pressure is controlled close to seawater hydrostatic pressure by subsea pumps. Realize dual-gradient drilling. In this system, the drilling fluid is pumped into the drill pipe from the sea surface, reaches the bottom of the well through the drill pipe, impacts and breaks the rock and carries the cuttings back up the borehole annulus, and enters the subsea lift pump through the rotary diverter device at the top of the annulus. Cuttings and drilling fluid are returned to the drilling platform through the mud return pipelin...

AI Technical Summary

Problems solved by technology

[0003] If the traditional self-circulating mechanical seal flushing method is used, it is necessary to introduce the seal flushing pipeline from the drilling platform. For deep water drilling, too long seal flushing pipeline will bring too high cost and reliability problems. At the same time, the self-circulation flushing method It will also increase the number of auxiliary components such as circulation pumps and control valves for mechanical seal flushing.

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