Well drilling tool with lubricant level indicator

• US 4,114,702 A
• Filed: 11/09/1977
• Issued: 09/19/1978
• Est. Priority Date: 11/09/1977
• Status: Expired due to Term

• Current Assignee: Maurer Engineering GmbH
• Original Assignee: Maurer Engineering GmbH
• Inventors: Maurer, William C., Ward, Charles E., McDonald, William J. Jr.
• Primary Examiner(s): Purser, Ernest R.
• Assistant Examiner(s): Favreau, Richard E.
• Application Number:
  US05/849,976
• Time in Patent Office: 314 Days
• Field of Search: 175/227, 175/228, 175/229, 175/39, 175/40, 175/107, 175/57, 175/237, 184/1 C, 308/76, 308/78, 308/1 A, 308/DIG. 13, 415/501, 415/502, 415/DIG. 11, 415/110, 415/111, 415/112, 415/113
• US Class Current: 175/107
• CPC Class Codes: E21B 21/10 Valve arrangements in drilling-fluid circulation systems
• CPC Class Codes: E21B 4/003 Bearing, sealing, lubricating details for roller bits E21B10/22
• CPC Class Codes: E21B 4/02 Fluid rotary type drives
• CPC Class Codes: F16C 2352/00 Apparatus for drilling in general E21
• CPC Class Codes: F16C 33/108 with a plurality of elements forming the bearing surfaces, e.g. bearing pads
• CPC Class Codes: F16N 19/003 Indicating oil level measuring liquid level in general G01F

Abstract

A turbo drill which is connected to a string of drill pipe as a rotating shaft for driving a drill bit which may be a rotary bit or a high speed solid head diamond bit. The turbine section has rotor and stator blades which are cresent shaped in cross section with each blade having an exit angle of 14° - 23° for maximum turbine efficiency. The bearing shaft is provided with chevron rotary seals positioned below the rotary bearings carrying both radial and vertical thrust. Fluid lubricant fills the space from the rotary seals to a predetermine level above the bearings. A piston seals the lubricant chamber and is pressurized by drilling fluid (i.e. mud) flowing through the tool. A layer of lubricant fluid overlies the first piston and has a second piston covering said fluid and transmitting pressure from the drilling fluid to the lubricant fluid surrounding the bearings. A plug member in the bearing shaft is positioned to be dislodged at the low lubricant position of the first piston to provide a temporary obstruction to the flow of drilling fluid to give an indication, at the well surface, of loss of lubricant in the turbo drill. An optional feature provides for increasing the pressure drop of drilling fluid in the turbo drill to cause the vertical thrust to be carried on the bottom vertical thrust bearings, after the top vertical thrust bearings are worn, and thus extend the drilling life substantially. A further optional feature is a locking ring arrangement which prevents separation of threaded connections in the drill housing during use.

Claims

1. A down hole well drilling tool adapted for connection at one end to the lower end of a drill string and at the other end to a drill bit to be driven thereby, said drilling tool comprising tubular housing means and rotary shaft means supported therein and extending therefrom and adapted to support a drill bit, motor means in said housing means actuated by flow of drilling fluid therethrough and operable to rotate said shaft means, bearing means in said housing means supporting said rotary shaft means, lubricant fluid filling the space between said housing means and said shaft means around said bearing means and for a predetermined distance above said bearing means, piston means sealing the space between said shaft means and said housing means above said lubricant fluid and moveable longitudinally of said housing means, said piston means being operable by pressure of drilling fluid to maintain said lubricant fluid under pressure to lubricate said bearing means, and means actuated by predetermined downward movement of said piston means to effect a change in pressure or flow rate of drilling fluid to indicate at the well surface the loss of lubricant from said tool.

2. A down hole well drilling tool according to claim 1 in which rotary seal means is positioned between said shaft means and said housing means below said bearing means to restrict the loss of lubricant fluid therefrom.

3. A down hole well drilling tool adapted for connection at one end of a drill string and at the other end to a drill bit to be driven thereby, said drilling tool comprising tubular housing means and rotary shaft means supported therein and extending therefrom and adapted to support a drill bit, motor means in said housing means actuated by flow of drilling fluid therethrough and operable to rotate said shaft means, bearing means in said housing means supporting said rotary shaft means, lubricant fluid filling the space between said housing means and said shaft means around said bearing means and for a predetermined distance above said bearing means, piston means sealing the space between said shaft means and said housing means above said lubricat fluid and moveable longitudinally of said housing means, said piston means being operable by pressure of drilling fluid to maintain said lubricant fluid under pressure to lubricate said bearing means, and means actuated by predetermined downward movement of said piston means to indicate at the well surface the loss of lubricant from said tool, said piston-actuated indicated means including means operable to obstruct the flow of drilling fluid whereby a sudden change in pressure or flow rate of drilling fluid indicates loss of lubricant from said tool.

4. A down hole well drilling tool according to claim 3 in which said piston-actuated indicating means includes means operable to obstruct the flow of drilling fluid for a short time whereby a sudden change in pressure or flow rate of drilling fluid for a short time indicates loss of lubricant from said tool.

5. A down hole well drilling tool according to claim 4 in which said drilling fluid obstructing means comprises a friable plug member engageable by said piston means for movement to a position obstructing flow of drilling fluid and operable to be disintegrated by flow of drilling fluid past said plug member when in said obstructing position.

6. A down hole well drilling tool according to claim 5 in which said shaft means has a longitudinal passageway for flow of drilling fluid therethrough, said plug member is positioned on said shaft means adjacent said passageway, and said piston means is engageable with said plug member to dislodge the same into said passageway to obstruct flow of drilling fluid therethrough.

7. A down hole well drilling tool according to claim 3 in which said drilling fluid obstructing means comprises a plug member engageable by said piston means for movement to a position obstructing flow of drilling fluid.

8. A down hole well drilling tool according to claim 7 in which said shaft means has a longitudinal passageway for flow of drilling fluid therethrough, said plug member is positioned on said shaft means adjacent said passageway, and said piston means is engageable with said plug member to dislodge the same into said passageway to obstruct flow of drilling fluid therethrough.

9. A turbo drill adapted for connection at one end to the lower end of a drill string and at the other end to a drill bit to be driven thereby, said turbo drill comprises a tubular housing having an upper stator portion and a lower bearing portion, a stator comprising a plurality of fixed turbine blades in said stator portion, a rotor shaft extending through said stator portion and rotatably supported therein, a plurality of rotor blades fixed on said rotor shaft and cooperable with said stator blades to direct flow of drilling fluid though said turbo drill to rotate said rotor shaft, a bearing shaft operatively connected to said rotor shaft at its upper end adapted to support a drill bit at its lower end, a plurality of bearings supported in said housing bearing portion and on said bearing shaft supporting said bearing shaft for rotation and providing support for thrust in both vertical and radial directions, a rotary seal positioned below said bearing shaft and housing to retain lubricant on said bearings, lubricant fluid in the annular space around said bearing shaft extending from said rotary seal to a predetermined level above said bearings, a piston positioned at the upper level of lubricant providing a rotary seal between said bearing shaft and housing and operable by pressure of drilling fluid flowing through said turbo drill to apply pressure to said lubricant, said piston being moveable longitudinally of said housing with changes in lubricant level, said bearing shaft having a longitudinal passage for conducting drilling fluid passing from said stator and rotor blades, said bearing shaft having an aperture opening into said passageway at a level just above said bearings, a plug member positioned in said aperture and having a portion engageable with said piston, and said piston being operable upon movement to the level of said plug member to engage and dislodge the same into said bearing shaft passageway to provide an obstruction to the flow of drilling fluid which indicates by a change in drilling fluid flow rate or pressure the loss of lubricant from the turbo drill.

10. A turbo drill in accordance with claim 9 in which said plug member is of a friable material which in an obstructing position is eroded by said drilling fluid and thus provides only a temporary obstruction to the flow of drilling fluid.

11. A bearing pack for a down hole well drilling tool comprising a bearing housing adapted to be connected to the housing of a well-drilling-fluid actuated down hole motor, a rotary bearing shaft positioned in said bearing housing having one end adapted to support a drill bit and another end adapted to be driven by the rotary shaft of a well-drilling-fluid actuated down hole motor when assembled thereon, bearing means in said bearing housing supporting said bearing shaft, rotary seal means positioned below said bearing means in said bearing housing, lubricant fluid filling the space around said bearing shaft from the level of said rotary seal means to a predetermined level above said bearing means, piston means sealing the space between said bearing housing and shaft at the upper surfave of said lubricant fluid and adapted to be actuated by drilling fluid pressure to maintain said lubricant fluid under pressure to lubricate said bearning means, and means actuated by downward movement of said piston means to effect a change in pressure or flow rate of drilling fluid to indicate loss of lubricant from said bearing pack.