Classifications

• • E—FIXED CONSTRUCTIONS
  • E21—EARTH OR ROCK DRILLING; MINING
  • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
  • E21B7/00—Special methods or apparatus for drilling
  • E21B7/18—Drilling by liquid or gas jets, with or without entrained pellets

Definitions

• 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 in a drilling fluid flow 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.
• the invention can be regarded as a further development and improvement of structures being described in Norwegian Patent Specifications Nos. 169.088, 171.322, 171.323 and 171.325.
• Norwegian Patent 171.323 s particularly directed to a valve assembly for this type of pressure converters, which advantageously can be replaced by new and improved designs to be described in the following description. This new designs involve, inter alia, less wear of vital valve parts and besides better reliability and safety under the extreme conditions that the structures are subjected to in actual practice.
• the present invention takes its starting point in an arrangement comprising a reciprocating piston having a pressure stroke and a return stroke between opposite end positions in a cylinder, and being at one side (lov; pressure side) provided with a relatively large piston ⁇ rea which during the pressure stroke is subjected to the drilling fluid pressure in the drill pipe, a first opposite area and a second, opposite and relatively small piston area which during the pressure stroke generates an increased pressure in a smaller portion (high pressure side) of the drilling fluid flow, valve means for controlling drilling fluid flows to and from the piston, a channel for connecting a space in front of the first, opposite piston area to the annulus outside the drill pipe at least during the pressure stroke, a second channel with a check valve, connecting said high pressure side to a high pressure channel leading forward to the drill bit, and at least one additional channel j-»eing adapted to connect the low pressure side to the annulus outside the drill pipe during the return stroke.
• hydraulic motors in principle are known for use at the lower end of drill pipes for deep drilling, as for example described in US 3.112.800, European patent publication 335.543 and international patent publication WC 83/00183. In these known uses, however, the hydraulic motor has other purposes and functions than what is contemplated in connection with the present invention.
• What is novel and specific in the pressure converter according to the invention in th first place consists therein that it comprises a hydraulic rotary motor arranged beyond the end of the cylinder and adapted to be driven by the pressure difference between the drilling fluid flows in the drill pipe and the annulus, and that a transmission mechanism is adapted to convert the rotation of the hydraulic motor into intermittent re-positioning movements of the valve means between two operative positions.
• Fig. 1 in longitudinal sectional view shows an embodiment of a pressure converter according to the invention, wich the piston in a lower end position, « fig. 2 shows a cross-sectional view along lines II- II in fig. 1, fig. 3 shows a cross-sectional view similar to fig.
• fig. 4 shows a cross-section along the line IV-IV in fig. 1
• fig. 5 schematically shows a group of pressure converters based upon an upper pressure converter according to the embodiment in figs. 1-4, coupled to other pressure converters which have a simplified design. Since the present pressure converter as far as the main features thereof are concerned, except for the valve arrangement, is closely related to corresponding structures according to the above mentioned Norwegian Patent Specifications, it seems to be sufficient here just to include a short discussion of these main features and functions.
• the embodiments of fig. 1 comprises a generally cylindrical housing 1, 2 and 3 adapted to acco odate the piston 6.
• This has three active piston areys, i.e. and upper relatively large piston area 11, a first opposite piston area 13 and a second opposide and relatively small piston area 12 at the lower end of piston member 6.
• This is adapted to be freely movable axially under the influence of varying drilling fluid pressure on the respective piston areas.
• the space or volume in front of piston area 11, can be designated low pressure space, whereas the volum in front of piston area 12 correspondingly can be denoted high pressure space.
• This latter space is connected through a channel 15A with a check valve 15, to a header channel (not shown in fig.
• the channel runs through the whole longitudinal direction of the housing, i.e. the cylinder wall 1, for the purpose of intercon ecting several such pressure converter units into a group, as will be discussed below with reference to fig. 5.
• valve arrangement as shown in figs. 1-4, comprises two rotatable valve bodies 4A and 4B each provided with respective through-flow openings 4A1, 4A2 and 4B1, 4B2. These valve bodies are provided in the cylinder wall 1 and diametrically opposite to one another. Valve bodies 4A and 4B wit.n their respective valve balls preferrably are adapted to be rotated through an angle of about 90° between open and closed positions. In fig. 1 there is accordingly a free opening for flow through the valve balls 4A1 and 4B2, whereas th other two are closed.
• a novel and specific control and actuator device for bringing about the above re-positioning movements of the valve bodies 4A and 4B, will be explained more closely below. At this point, a short discussion of the main function of the pressure converter shall be given.
• piston 6 will be urged upwards. Fluid being present in front of piston area 11 ⁇ t the upper side of piston 6, thereby will flow out through channel HA with the open valve ball 4A1 to the annulus 50 between the drill string or the cylinder wall 1 and the casing (not shown) . Thus, piston 6 will be driven upwards to its top position. Accordingly this represents a return stroke of the piston.
• the pressu ⁇ e or working stroke taker place upon valve re ⁇ positioning, as will be seen without any closer explanation here.
• FIG. 1 shows the particular co ⁇ ⁇ trol and actuator apparatus according to the invention, being based on a hydraulic rotary motor 10 which has an output axle 10A.
• a first embodiment of the hydraulic mr-tor is shown somewhat more in detail in fig. 2.
• the motor is driven by the pressure difference between the drilling fluid flow in the drill pipe (indicated at 1A) and th- annulus 50, respectively. It will be realized that only a very small proportion of the total drillin ⁇ fluid flow is utilized in the hydraulic motor 10, which only serves for the movement of the valve device, as will be explained in the following description. It can be an advantage that the drilling fluid flow through the hydraulic motor, and thereby the power or rotational speed thereof, is adjustable.
• Fig. 1 shows a transmission mechanism for converting the rotation of output axle 10A into adequate valve movements in the valve device described above.
• the transmission mechanism is shown in cross-sectional view in fig. 4 and in this embodiment is based upon the Maltese cross principle.
• On the output axle 10A there is mounted a main disc 12 having recesses 12A and 12B in the circumference, for cooperation with slit wheels 14A and 14B each being rotationally connected to a valve body 4A and 4B.
• fig. 4 shows two pins 12AC and 12BC provided on the main disc 12 and centrally outside the recess portions 12A and 12B.
• the mtin disc 12 with associated pin or pins 12AC, 12BC has radial dimensions being substantially larger than the radial dimensions of the cooperating slit wheels 14A, 14B.
• the hydraulic motor 10 in this embodiment more specifically has the form of a wing motor having a number of wings or vanes 101,102,103 and so forth, being mounted for radial translation in a rotor 10B which is keyed to the output axle 10A.
• the rotor vith the wings is arranged in a cavity 10C the circumference of which has a non-circular or oval shape being so oriented in relation to inlet 1A av ⁇ outlet 50A to the annulus 50, that rotation is obtained by the pressure difference already mentioned above.
• This motor principle as such is previously known per se.
• a gear wheel motor as illustrated in fig. 3.
• This is likewise a principle known per se for a hydraulic motor, comprising two gear wheel rotors 31 and 32 for rotation in engagement with one another in a housing 30C which incorporates v .ialf-cylindrical wall portions in cooperation with the rotating tooth tops on gear wheels 31 and 32.
• the resulting hydraulic motor 30 preferrably has an output axle 3 ⁇ A carrying the gear wheel 31, located so as to coincide with the pressure converter axis AX, (as shown in fig.
• drilling fluid channel 1A which supplies drilling fluid under pressure as a portion of the total drilling fluid -flow in the drill string and the drill pipe.
• each valve body 4A and 4B has a longitudinal extension in parallel with the axis of piston 6, corresponding at least to the stroke of the piston.
• valve means or arrangement can be based on a plate-shaped, rotatable valve body as described in Norwegian patent No. 169.088.
• actuator cylinder with a linear movement as shown and described herein
• other forms of hydraulic actuators can be contemplated, being controlled by a control valve as described.
• a pressure converter according to the present invention can be incorporated ir- a ⁇ roup of pressure converters for generating a resulting, larger drilling fluid flow at the desired, increased pressure.
• Fig. 5 shows such a pressure converter group, wherein an upper pressure converter 10 is illustrated in the form of the same pressure converter embodiment as in figs. 1-4. Moreover in fig.
• valve bodies 4A and 4B in the uppermost pressure converter 10 drive the whole series of valve bodies below, such as valve bodies 64A and 64B in pressure converter 20 and valve bodies 66A and 66B in pressure converter 40.
• the ⁇ e further pressure converters, for example 20 and 3 ⁇ . therefore can be of a simplified design without any specific means for bringing about the re-setting movement of their valves.
• the pressure converters 10, 20, 40 and so forth as illustrated here are aligned along a common longitudinal axis 70, with a common, through-running high pressure header channel 16 and with the respective valve bodies axially aligned in relation to each other.
• drive axles 60A, 60B, ... 60G with associated axle couplings as shown for example at 60X between pressure converter 10 and pressure converter 20.
• valve bodies in the Dressure converters with angular orientations being alternately opposite, as will appear from the valve positions being indicated for the respective valve bodies in pressure converters 10, 20 and 40 in fig. 5.

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• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Geology (AREA)
• Mining & Mineral Resources (AREA)
• Physics & Mathematics (AREA)
• Environmental & Geological Engineering (AREA)
• Fluid Mechanics (AREA)
• General Life Sciences & Earth Sciences (AREA)
• Geochemistry & Mineralogy (AREA)
• Fluid-Pressure Circuits (AREA)
• Hydraulic Motors (AREA)
• Tone Control, Compression And Expansion, Limiting Amplitude (AREA)

Priority Applications (3)

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Publications (1)

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ID=19897496

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Cited By (1)

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Citations (4)

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• 1994
  • 1994-10-12 NO NO943857A patent/NO179879C/no not_active IP Right Cessation
• 1995
  • 1995-10-05 EP EP95934895A patent/EP0784729A1/en not_active Withdrawn
  • 1995-10-05 US US08/817,087 patent/US5924498A/en not_active Expired - Fee Related
  • 1995-10-05 WO PCT/NO1995/000179 patent/WO1996012083A1/en not_active Application Discontinuation
  • 1995-10-05 AU AU37113/95A patent/AU3711395A/en not_active Abandoned

Patent Citations (4)

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