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
  • E21B25/00—Apparatus for obtaining or removing undisturbed cores, e.g. core barrels or core extractors
• • 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
  • E21B21/00—Methods or apparatus for flushing boreholes, e.g. by use of exhaust air from motor
  • E21B21/10—Valve arrangements in drilling-fluid circulation systems

Definitions

• the present invention relates to a core barrel, in particular in the field of petroleum prospecting, comprising: - a coring ring, an outer tube for driving the coring ring in rotation, and an inner tube having an element of free anterior end intended to receive a core during coring, the inner and outer tubes being substantially coaxial, and a surface of revolution of the free end element, on the side of the crown, arranged to cooperate with a surface internal of the latter, or if necessary of the outer tube, so as to regulate between them a determined passage of coring fluid.
• the free end element of the inner tube has a circular lip parallel to the longitudinal axis of rotation and located in an annular housing, of the crown, which also extends parallel to the longitudinal axis of rotation.
• the adjustment of the fluid passage turns out to be delicate there, for example since the inner tube is fixed to the outer tube at a great distance from the place of this passage and given significant variations in length which can appear in a corer because of the variable and high temperatures that it can undergo during coring.
• the operator who assembles a core barrel tries to obtain a correct adjustment of this passage, taking into account the differences in length presented by the different sections of the inner and outer tubes and taking into account the temperatures assumed to be reached during coring.
• the inner tube may be made of a different material (for example fiberglass coated with a binder) than that of the outer tube which is usually made of steel, the differential expansions that these two tubes undergo are opposed to the '' and / or maintaining a desired adjustment of the fluid passage.
• a core entering the inner tube can push it a little bit up the outer tube, depending on a clearance in the ball bearings or ball bearings which connect the inner and outer tubes, and this can significantly change the above setting.
• a bad adjustment of said passage can lead for example to a too great flow of coring fluid towards the core and to a possibly deep deterioration of this one by washing, etc., or lead for example, in too great contact between said surface of revolution of the free end element and the internal surface of the crown or of the outer tube, with consequently seizing of these surfaces during the rotation of one with respect to the other, or a deformation and / or rupture of the free end element, etc.
• the object of the present invention is to remedy the aforementioned drawbacks, and others not explained above but known to those skilled in the art, and to provide a means which makes it possible to obtain, in a safe and simple manner, the correct one. adjustment, even adjustment up to zero or close to zero passage for the coring fluid between the free end element of the inner tube and the corresponding internal bearing surface, without annoying pressure from one on the other, therefore without the aforementioned risks of seizure, deformation or rupture at this location.
• the free end element is mounted in the core barrel so as to be able to slide coaxially on an end section of the inner tube, between a position in which the surface of revolution is in contact with the internal surface of the crown or respectively of the external tube and an extreme position away from this internal surface.
• the sliding free end element and the end section each have a stop cooperating with each other, when the inner tube is removed from its position. core drilling in the outside tube, so as to block the free end element on the end section in another extreme position located beyond said contact position starting from the extreme position away of the internal surface.
• Figure 1 shows schematically in axial section a section of a core barrel equipped according to the invention.
• FIG. 2 schematically represents, on another scale, in axial half-section a section of another corer equipped according to the invention.
• the core barrel 1 of FIG. 1 has a core bit 2 mounted on an outer tube 3, intended inter alia for driving the crown 2 in rotation, and an inner tube 4 intended to receive a core 5 during a coring operation.
• a split frustoconical ring 6 is provided in the inner tube 4 and is intended to block a carrot in the latter.
• the inner 4 and outer 3 tubes are each formed of various sections of tubes fixed to each other for example by screwing and are practically coaxial.
• the inner tube 4 has a free front end 7, considering the direction of advancement of the core barrel 1 during coring.
• This free end element 7 is delimited by a surface of revolution 8 arranged to cooperate with an internal surface 9 of the ring 2, or where appropriate of the outer tube 3 according to the reciprocal arrangement of these two components mounted one on or in the other, so as to adjust between the surface of revolution 8 and the internal surface 9 a determined passage of coring fluid.
• the coring fluid is brought into an annular conduit 10, delimited by the inner 4 and outer 3 tubes, so as to reach the bottom of a coring hole by means of nozzles 11 crown 2. It may be desirable that a small amount of core fluid can pass directly from the annular duct 10 to a gap 12 between a core 5 and the crown 2, so as to lubricate and cool this place of friction between these two components. The flow of fluid to this gap must however be limited to prevent this fluid from damaging the core produced.
• the free end element 7 is mounted in the core barrel 1 so as to be able to slide coaxially on an end section 13 of the inner tube 4, between a position in which the surface of revolution 8 is in contact with said internal surface 9 and an extreme position away from this internal surface 9.
• the free end element 7 ends in a groove 14 which extends parallel to the longitudinal axis of the core barrel 1 and which has in its bottom the internal surface 9 for the support of the surface of revolution 8.
• the free end element 7 abuts against an internal surface 9 of the crown 2 and the end section 13 has another free end element 15 which is fixed to it and which , in the coring position in the corer 1, can protrude relative to the free end element 7 sliding.
• the sliding assembly can be adjusted so that the pressure of the coring fluid, acting on the surfaces of the free end element 7, presses against each other the surface of revolution 8 and the internal surface 9.
• the force pressing can be considered low given the small area that presents or can present the free end element 7 at the pressure of the fluid.
• This pressing force can however be increased by known hydraulic means (pressure drop for example and / or increase in flow rate) to prevent the free end element 7 from being pushed upwards, for example by debris. carrot passing between the crown 2 and the end section 13.
• the contact between the surfaces of revolution 8 and internal 9 can be continuous and the passage of fluid from the conduit annular 10 towards the gap 12 is then practically closed. It is however possible, for example, to provide the free end element 7 with calibrated through holes (not shown) or calibrated notches (not shown) made in the surface of revolution 8 to allow a predetermined flow of fluid to pass pressure from it).
• the sliding free end element 7 can also be mounted so as to be able to rotate on the end section 13. This makes it possible for example to distribute the wear due to friction, during the rotation of the outer tube 3 relative to to the inner tube 4, between the contact point of the revolution 8 and internal 9 surfaces and the contact point of the free end element 7 and the end section 13, or else to report this wear to this last place, for example the components are removable and replaceable.
• At least said end section 13 can be arranged in a removable manner on the rest of the inner tube 4.
• the free end elements 7 and end section 13 can be made of materials different from those of the inner 4, outer 3 and crown 2 tubes and can be adapted as a function of the friction to be subjected.
• the free end element 7 and the end section 13 each comprise a stop 20, 21 cooperating with each other, when the inner tube 4 is removed from its coring position in the outer tube 3.
• the stops 20, 21 cooperate so as to block the free end element 7 on said end section 13 in another extreme position (not shown) situated opposite said position of contact between surfaces of revolution 8 and internal 9 relative to the first extreme position cited, disposed away from the internal surface 9.
• the end section 13 can comprise, as a stop 20, on the side of a well bottom in the coring position, an external cylindrical collar 22 and, between the latter and the rest of the inner tube 4, a cylindrical body 23 with an external diameter smaller than that of the external cylindrical collar 22.
• the free end element 7 then comprises, on the side of the same well bottom, a cylindrical hole 24 opening, the internal diameter of which is adapted to the external diameter of the collar external 22 for the aforementioned sliding and, on the side opposite the bottom of the well, as a stop 21, an internal cylindrical collar 25 whose internal diameter is less than that of the cylindrical hole 24 and is adapted to the external diameter of the body cylindrical 23 for said sliding.
• the removable arrangement of the end section 13 on the rest of the inner tube 4 can be constituted, for example, by an assembly with external thread on the end section 13, at its end away from the well bottom, and with internal thread on the corresponding end of the remainder of the inner tube 4.
• the external thread has a diameter at most equal to the external diameter of the cylindrical body 23 and, when the threads are cylindrical, they are advantageously threads on the left.
• a seal 30 can be mounted for example in the inner surface of the internal cylindrical collar 25 in order to cooperate with the peripheral surface external of the cylindrical body 23 and thus improve a seal against the coring fluid at this location.
• the core barrel 1 of the invention advantageously comprises a tapered frustoconical ring 6, as shown in FIG. 1 and having a V-shaped groove 33 where it is split, an internal cylindrical surface 34 made rough, in known manner, for hooking a carrot 1 and a grooved outer frustoconical surface 35.
• One or more notches 40 may be provided on one face of the free end element 7 facing the remainder of the inner tube 3. These notches 40 can be used to take off, optionally by pres ⁇ sion of the fluid, an element 7 by remaining audit report of the inner tube 3.
• Notches 41 may be provided on the end face of the unscrewable end section 13, in order to receive a tool for screwing or unscrewing this section 13.

Landscapes

• Engineering & Computer Science (AREA)
• Geology (AREA)
• Life Sciences & Earth Sciences (AREA)
• Mining & Mineral Resources (AREA)
• Environmental & Geological Engineering (AREA)
• Fluid Mechanics (AREA)
• Physics & Mathematics (AREA)
• General Life Sciences & Earth Sciences (AREA)
• Geochemistry & Mineralogy (AREA)
• Mechanical Engineering (AREA)
• Investigation Of Foundation Soil And Reinforcement Of Foundation Soil By Compacting Or Drainage (AREA)
• Earth Drilling (AREA)
• Joints Allowing Movement (AREA)
• Sampling And Sample Adjustment (AREA)

Applications Claiming Priority (3)

Publications (2)

Family

ID=3889782

Family Applications (1)

Country Status (7)

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• 1996
  • 1996-06-05 BE BE9600504A patent/BE1010325A3/fr not_active IP Right Cessation
• 1997
  • 1997-06-03 WO PCT/EP1997/002964 patent/WO1997046790A1/fr active IP Right Grant
  • 1997-06-03 DE DE69709638T patent/DE69709638T2/de not_active Expired - Lifetime
  • 1997-06-03 US US09/194,902 patent/US6145604A/en not_active Expired - Lifetime
  • 1997-06-03 EP EP97925061A patent/EP0904481B1/de not_active Expired - Lifetime
  • 1997-06-03 CA CA002257377A patent/CA2257377C/en not_active Expired - Fee Related
• 1998
  • 1998-12-03 NO NO19985641A patent/NO315530B1/no not_active IP Right Cessation

Non-Patent Citations (1)

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