Tool driving or impacting – Impacting devices – Hammer head constitutes piston of drive motor
Patent
1997-04-11
1999-04-06
Gerrity, Stephen F.
Tool driving or impacting
Impacting devices
Hammer head constitutes piston of drive motor
175 93, 175107, E21B 400
Patent
active
058905472
DESCRIPTION:
BRIEF SUMMARY
CROSS REFERENCE TO RELATED APPLICATIONS
This application is related to and claims priority from Patent No. WO 96/12082 filed Oct. 4, 1995, which is related to and claims priority from Patent No. NO 943858 filed Oct. 12, 1994.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an improved design of a pressure amplifier or converter for mounting above the drill bit at the lower end of a drill pipe for deep drilling, in particular for oil and gas, and for generating an increased fluid pressure by utilizing energy from the flow of drilling fluid downwards through the drill string and the drill pipe. This may be, inter alia, for the purpose of obtaining an enhanced drilling effect, preferably by means of one or more high pressure jets adapted to have a cutting effect in the surrounding rock.
2. Description of the Related Art
The invention can be regarded as a further development and improvement of structures described in Norwegian Patent Specification Nos. 169.088, 171.322, 171.323 and 171.325. Norwegian Patent 171.323 is particularly directed to a valve assembly for this type of pressure converter, which advantageously can be replaced by the new and improved designs described below. The new designs involve, inter alia, less wear of vital valve parts and better reliability and safety under the extreme conditions that the structures are subjected to in use.
SUMMARY OF THE INVENTION
As in the pressure converters described in the above Norwegian Patent Specifications, the present invention includes an arrangement comprising a reciprocating piston having a pressure stroke and a return stroke between opposite end positions in a cylinder. The pressure converter includes a cylinder having a bore with a first section and a second section, the first section having a larger diameter than the second section. A reciprocating piston is located in the cylinder, with having a first end, a second end, and an annular surface, the first end having a larger diameter than the second end, the annular surface formed at the transition between the first and second ends. The first end defines a first cavity in the first section of the bore, the second end defines a second cavity in the second section of the bore, and the annular surface defines a third cavity in the first section of the bore. A first channel connects the first cavity to the annulus outside the drill pipe during a return stroke, and a drilling fluid valve for controls the drilling fluid flow to and from the first cavity. A second channel with a check valve connects the second cavity in fluid flow communication with the drill bit. A third channel connects the third cavity to the annulus outside the drill pipe at least during a pressure stroke.
The pressure converter also includes a control valve with a control valve body, a slide member moveable between opposite ends of the control valve body, and a slide rod cooperating with the piston for moving the slide member in the control valve body, and an actuator for adjusting the drilling fluid valve to control drilling fluid flow to and from the low pressure cavity. The actuator is in fluid flow communication with the control valve and the actuator is operated by drilling fluid pressure supplied from the control valve.
BRIEF DESCRIPTION OF THE DRAWINGS
In the following description, the new structural solutions according to the invention as well as additional advantages and specific features thereof will be more closely explained with reference to the drawings, wherein:
FIG. 1 in longitudinal sectional view shows a first embodiment of a pressure converter according to the invention, with the piston in an upper end position,
FIG. 2 shows a cross-sectional view along lines II--II in FIG. 1,
FIG. 3 shows a sectional view similar to FIG. 1, but with the piston in its lower end position,
FIG. 4 shows a cross-section along the line IV--IV in FIG. 1,
FIG. 5 shows a second embodiment of the pressure converter according to the invention, in a similar sectional view as FIG. 1, and
FIG. 6 schematica
REFERENCES:
patent: 1142478 (1915-06-01), Bayles
patent: 5246080 (1993-09-01), Horvei et al.
patent: 5361857 (1994-11-01), Horvei
patent: 5375671 (1994-12-01), Horvei
patent: 5429036 (1995-07-01), Latos
Den Norske Stats Oljeselskap A.S
Gerrity Stephen F.
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