US 5,348,107 A · Pressure balanced inner chamber of a drilling head

Abstract

A system for maintaining an optimum pressure balance within an inner chamber of a drilling head for improved seal life and integrity. The system maintains a pressure differential across the seals thereby preventing well fluids from contaminating the seals and improving their useful life. The drive ring of a drilling head is rotatably supported by a series of bearings disposed within a bearing chamber. The secondary chamber of the drilling head is sealed to prevent contaminants from entering the chamber and fouling the seals. The seals withstand the borehole well pressures to prevent the introduction of contaminants, by maintaining a pressure differential across the seals. The present system compensates for variations in the borehole pressure. A pressure compensator is in communication with the borehole to activate a lubricant pump for increasing lubricant pressure within the inner chamber in response to increased borehole pressures. A relief valve associated with the inner chamber relieves pressure in the seal chamber to maintain lubricant pressure at optimum levels when borehole pressure decreases for controlled operation of the seals. Additional check valves are included in the inner chamber to control the chamber pressure while preventing contamination of the lubricant.

Claims15

Dependent claims

A system for maintaining a predetermined fluid pressure differential within a chamber of a drilling head in relation to the downhole fluid pressure within a wellbore associated with said drilling head, said system comprising:

means for relieving fluid pressure from said chamber in response to an increase in said fluid pressure differential above a predetermined value;
and
means for increasing fluid pressure within said chamber in response to a decrease in said fluid pressure differential below a predetermined value, said means for increasing fluid pressure includes a fluid pump in fluid communication with said chamber to inject fluid until said fluid pressure differential increases to said predetermined value, said fluid pump having means for detecting said fluid pressure differential, said means for detecting said fluid pressure differential comprises a pressure compensator valve in fluid communication with the wellbore for detecting downhole fluid pressure and with said chamber for detecting fluid pressure within said chamber, said compensator valve opening and closing to operate said fluid pump in response to variations in said fluid pressure differential.

A system for maintaining a predetermined fluid pressure differential within an inner chamber of a drilling head in relation to the downhole fluid pressure within a wellbore associated with said drilling head, said system comprising:

means for relieving fluid pressure from said chamber in response to an increase in fluid pressure differential above a predetermined first value, said fluid pressure being relieved into said wellbore:
and
a pressure compensator valve operatively connected to a fluid pump for increasing fluid pressure within said chamber in response to a decrease in said fluid pressure differential below a predetermined second value, said fluid pump is in fluid communication with said chamber to inject fluid until said fluid pressure differential exceeds said second value and said pressure compensator valve for detecting said fluid pressure within said chamber, said pressure compensator valve in fluid communication with the wellbore for detecting downhole fluid pressure, said compensator valve opening and closing to operate said fluid pump in response to variations in said fluid pressure differential, said compensator valve includes a valuing member reciprocatingly movable in response to variations in said pressure differential, movement in said valuing member in a first direction within said compensator valve opening a fluid path for operation of said fluid pump and movement of said valuing member in a second direction within said compensator valve closing said fluid path to shut down said fluid pump, said pressure compensator valve detecting said fluid pressure differential and selectively operating said fluid pump to maintain said fluid pressure differential.

Dependencies are inferred from the claim text.

Pressure balanced inner chamber of a drilling head

Life of this patent

Pressure balanced inner chamber of a drilling head

Life of this patent

Abstract

Claims15