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
  • E21B33/00—Sealing or packing boreholes or wells
  • E21B33/10—Sealing or packing boreholes or wells in the borehole
  • E21B33/12—Packers; Plugs
  • E21B33/127—Packers; Plugs with inflatable sleeve
• • 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
• • 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
  • E21B34/00—Valve arrangements for boreholes or wells
  • E21B34/06—Valve arrangements for boreholes or wells in wells
  • E21B34/08—Valve arrangements for boreholes or wells in wells responsive to flow or pressure of the fluid obtained

Definitions

• the present invention relates to a blowout preventer, particularly for use when drilling so-called top hole sections, i.e. bore hole sections near the seabed, and which is adapted to prevent blowout of shallow gas in the bore hole.
• the blowout preventer according to the invention is of the kind defined in the preamble of the appended claim 1.
• the blowout preventer according to the invention is primarily intended for use in preventing accidents that could occur when drilling through pockets containing shallow gas and thereby eliminate the risks associated with conducting a downhole gas inflow to the surface through the riser, the principle object of a blowout pre ⁇ venter according to the invention being to stop a gas inflow at the source.
• blowout preventers It is previously known a number of various embodi ⁇ ments of blowout preventers. These all share the disad ⁇ vantage that they have a relatively time consuming and complicated activating mechanism not providing the equip ⁇ ment with the necessary degree of reliability and safety.
• blowout preventer designed for use when drilling deep holes the releasing mechanism functions in accordance with the pressure differential principle ' . How ⁇ ever, this known blowout preventer may not be used in so- called top hole sections because sufficient pressure differences across the blowout preventer cannot be obtained for activating its release mechanism.
• This prior art blowout preventer comprises an annular, elastically expansible and contractible packing element which in the active condition is intended to rest sealingly against the bore hole wall in order to prevent uncontrolled blowout of gas in the bore hole.
• the purpose of the present invention is primarily to provide a blowout preventer of the kind defined in the introduction, which is well suited for use in so-called top hole sections. Besides, in accordance with the in ⁇ vention one has emphasized simple operation of the equip ⁇ ment and optimum reliability and safety during operation. This object is achieved by designing the blowout preventer according to the invention in accordance with the features appearing from the characterizing part of claim 1.
• blowout preventer in the drill string may be chosen quite freely along the entire length of the drill string below the drilling jar. Examples of suitable locations for such a blowout preventer could be just below or just above the lower stabilizer of the drill string.
• Fig. 1 shows in side elevation/longitudinal section a general view of the entire blowout preventer in inactive standby position (initial position);
• Fig. 2 shows on a larger scale a side elevation/ longitudinal section of "the upper portion of the blowout preventer according to Fig. 1 in inactive standby position ;
• Figs. 3 - 13 show, on the same scale as Fig. 2, longitudinal sections through the right half of different longitudinal portions of the blowout preventer according to Fig. 1, the various movable parts of the blowout pre- venter being shown in mutually different positions for starting different operations to be described below with particular reference to the different figures.
• the blowout preventer shown in the drawings com ⁇ prises (starting from above in the vertical position of use) an inner telescopic sleeve 1 and a concentric and co ⁇ operating outer telescopic sleeve 2.
• the two co-operating telescopic sleeves 1 and 2 have two extreme relative positions, viz. an extended telescopic position, see Figs. 1 and 2, and a contracted telescopic position, see Fig. 3, where a bottom stop face 1 ' on the inner telescopic sleeve 1 rests against the upper end face 2' of the outer telescopic sleeve 2.
• the co-operating faces 1' and 2' limit the movement of the inner telescopic sleeve 1 relative to the outer telescopic sleeve 2, which is rigidly connected to the cylindrical outer housing 8 of the blowout preventer, e.g. by screw threads.
• a stop ring 4 which has an axial pressure equalizing duct 5 and is screwed to the inner telescopic sleeve 1
• a spacer ring 6 which also has a through- going duct 7 and interengages with the cylindrical outer housing 8 of the blowout preventer such that the spacer ring 6 cannot move downwards with respect to the outer housing 8
• a cup spring 9 is placed in compression in a space 10 between the inner telescopic sleeve 1 and the outer housing 8.
• the space is filled with grease, which, upon compression of the spring 9, may escape through the duct 7 in the spacer ring 6 to an annular space 11 below.
• the inner telescopic sleeve 1 carries a rigidly connected, radially external transition. sleeve 12, which in turn is fixedly connected to an acti ⁇ vating sleeve 13 extending downwards from the transition sleeve 12.
• the transition sleeve 12 carries a transverse shear pin 14 for a locking arm 15, which is pivotably supported at its opposite end by means of a hinge pin 16 carried by the transition sleeve 12.
• the locking arm 15 serves as temporary supporting means for a ball 17, to be described later in more detail together with the mechanism 14 - 16.
• Reference numeral 18 designates a pressure equal ⁇ izing duct, while 19 designates an upper annular space delimited between the activating sleeve 13 and the outer housing 8 of the blowout preventer.
• a spring loaded 20 holding pin 21 in the outer housing 8 is intended for releasable engagement with a sleeve-like valve slide 22, which in addition to the groove with which the holding pin 21 is engaged, as shown in Fig. 1, has a further locking groove 23 for engagement with the locking pin 21 during one of the operations of the blowout preventer, as will be described more closely later.
• Reference numeral 26 designates an upper filling port in the outer housing 8
• 27 designates a slide port in the valve slide 22
• 28 designates a filling port in the activating sleeve 13.
• 29 is a lower filling port in the outer housing 8
• 30 is an axial filling duct therein .
• 30 is intended for conducting drilling mud to the packing element or elements of the blowout preventer for inflating the elements in case of a gas blowout in the bore hole.
• 31 is a filling port in the valve slide 22.
• a seat sleeve 32 for the ball 17 is held releasably to the activating sleeve 13 by means of a spring loaded 20' holding pin 21' in a manner corresponding to the connection between the valve slide 22 and the outer housing 8 at (20,21), the seat sleeve 32 likewise being provided with a further locking groove 33 for later engagement with the holding pin 21' of the activating sleeve 13.
• the seat sleeve 32 has an upper seat 34 for the ball 17 and is furthermore provided with an outer annular space 35, axial circulation ports 36 and outlet ports 37 connecting the annular space 35 with the inner bore of the seat sleeve 32.
• the lower end of the seat sleeve 32 is provided with circulation ports 38.
• the activating sleeve 13 is in engagement with the valve slide 22 by means of a spring loaded locking pin 39, which is supported in the activating sleeve 13 and engages in a holding groove 40 in the valve slide 22.
• Reference numeral 41 designates a lower annular space defined between the activating sleeve 13 and the outer housing 8 of the blowout preventer.
• the lower end of the activating sleeve 13 is pro ⁇ vided with a guide nut 42 screwed thereon.
• the seat sleeve 32, the activating sleeve 13 and the guide nut 42 have aligned downwardly facing conical abutment faces, the abutment face of the activating sleeve 13 being designating 44.
• these conical abutment faces 44 are arranged to co-operate with a corresponding upwards facing conical abutment face 45 on a valve stopper 46, which is fixed to the outer housing 8 by means of holding means 47 ascertaining liquid flow centrally through the blowout preventer in the area of the valve stopper 46 when the abutment faces 44 and 45 are located spaced apart in accordance with Fig. 1.
• reference numeral 48 desig- nates the flow duct (inner cavity) through the blowout preventer past the valve stopper 46.
• a filling channel 49 leads at an angle downwards through a force transmitting sleeve 50, which is fixedly connected to the outer housing 8.
• 51 - 51"' designate outer protecting ribs.
• An axial annular duct 52 defined between the force transmitting sleeve 50 and a radially inner sleeve 58 leads from the angled duct 49.
• 53 is a connecting screw for a locking ring 54 for locking the force transmitting sleeve 50, to an upper steel sleeve 55.
• 56 is a shear pin connecting the force trans ⁇ mitting sleeve 50 and the upper steel sleeve 55, but which may be sheared off during an operation to be described latelinger
• 57 is a non-return valve in the force transmitting sleeve 50.
• Reference numeral 68 designates the annular space radially inside an annular packing element 59 known per se, which is arranged with its active part in a space between the upper steel sleeve 55 and a lower steel sleeve 69.
• the packing element 59 is elastically deformable in a known manner and may expand and contract flexibly and lies in its expanded condition against the wall of the annular space of the bore hole surrounding the blowout preventer (not shown ) for the purpose of preventing blowout of gas in the bore hole. In the contracted position, as shown in Fig.
• the radially outer delimiting surface of the packing element 59 lies radially inside the radially outer limit for the upper part of the blowout preventer, and the passage through said annular space of the bore hole is therefore open.
• the packing element 59 has an attachment flange 60' , 70' for peripheral attachment to the steel sleeves 55, 69.
• 61 is a locking screw for locking a spacer sleeve 62 lying axially below the packing element 59. Below this spacer sleeve 62 follows a packing element 59' coupled in series to the packing element 59. Parts belonging to or connected to the packing device where the second packing element 59' is included and corresponding to structurally and functionally identical parts of the first packing device are designated with the same reference numerals plus an index, i.e. 53' , 54' , 56' , 57' , 60' , 6.8' , 69' and 70' . N
• the duct 52 opens into a pressure limiting* uct 63 in a lower sleeve body 64 attached to the force transmitting sleeve 50. Furthermore, the sleeve body 64 has a leakage bleed duct 65 and a non-return valve 66 provided with a port 67, which both communicate with the annular duct 52.
• the blowout preventer shown and described functions in the following manner:
• the blowout preventer is included in the drill string as mentioned in the introduction.
• the drill bit is weight loaded by e.g. 5 tons.
• the mutually telescopingly movable parts for instance the inner telescopic sleeve 1 and the activating sleeve 12, 13 on the one side and for instance the outer telescopic sleeve 2 and the outer housing 8 on the other side, will be held in the inactive standby position/ initial position.
• the position of the blowout preventer during drilling is therefore said extended telescopic position where the inner telescopic sleeve 1, the activating sleeve 12, 13 fixedly attached to the former, and the guide nut 42 fixed to the activating sleeve, are in their upper position.
• the activating sleeve is formed as two separate sleeves screwed together, one of which being called transition sleeve 12, while the acti ⁇ vating sleeve 12, 13 in Figs. 3 - 13 are shown formed in one piece. If the technical assembling conditions permit, there is in principle nothing to prevent forming the acti ⁇ vating sleeve 12, 13 in one piece with the inner tele ⁇ scopic sleeve 1.
• drilling mud is pumped down through the inner space (represented by the flow duct 48 in the figures) of the blowout preventer and out through the drill bit.
• the seat sleeve 32 is held in locked position to the activating sleeve 12, 13 by means of the spring loaded 20' pin 21' .
• the valve slide 22 is lcoked to the outer housing 8 by means of the spring loaded 20 pin 21.
• the spring loaded pins 20, 21 and 20' , 21' and also 39 are arranged in one of two co-operating adjacent parts and are arranged to releasably engage in a correspondingly formed groove in the other part in such a manner that a spring loaded pin may be brought out of engagement with its corresponding groove when a relative translation force of a certain magnitude occurs between the parts .
• said relative translation force falls below said value, the parts are held together such that the valve slide 22 is held to the outer housing 8 and the seat sleeve 32 moves together with the activating sleeve 12, 13.
• the engagement point of the pin 39 on the valve slide 22 has been moved to below the slide, Fig. 5, the upward translation movement of the activating sleeve 12, 13 will overcome the action of the pin 21.
• valve slide 22 in addition to the groove where ⁇ in the pin 21 engages, has an extra locking groove 23, while the seat sleeve 32, in addition to the groove where- in the pin 21' engages, has an extra locking groove 33.
• valve slide 22 is lifted by means of the spring loaded locking pin 39 relative to the outer housing 8 if the locking pin 21 comes out of engagement with the upper groove 71 of the slide during the translatory movement of the slide 22 until it comes to engagement with the lower locking groove 23 of the slide.
• the passage through the cavity 48 of the blowout preventer is now open and one can read the pressure at the drill bit. The situation is stable .
• the blowout preventer When the blowout has been stopped, the blowout preventer should be withdrawn.
• the shear pins 56, 56' are sheared and their outer part is pressed out by the hydraulic pressure prevailing radially inside the packing elements 59, 59' , which then go back to their in ⁇ active, contracted condition, Fig. 1.
• the drill string with the blowout preventer may now be pulled up to the surface .
• the ball 17 is dropped from the drill floor through the drill string until it is stopped by the locking arm 15, Fig. 8.
• This locking arm 15 is supported in the acti ⁇ vating sleeve 12, 13; at one end by means of a hinge pin 16 and at the other end by means of a shear pin 14.
• Drilling mud is then pumped down through the drill string and blowout preventer past the ball 17.
• the drilling mud pressure above the ball 17 is increased until the shear pin 14 breaks and the locking arm 15 swings downwards.
• Fig. 9 The ball 17 falls down to the conical seat 34 of the seat sleeve 32 and through its weight pushes the seat sleeve 32 downwards against the valve stopper 46 so that the flow through the ports 36, 35 and 37 is stopped, Fig. 10.
• the drill string is lifted as previously, Fig. 12.
• the upward flow can lift the ball 17 from the seat 34 or the flow can take place through the ports 37, 35 and 36 of the seat sleeve 32 for measuring pressure.
• weight is placed on the telescope as before, Fig. 13.
• the drill string is rotated for releasing as before.

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• Engineering & Computer Science (AREA)
• Life Sciences & Earth Sciences (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)
• Mechanical Engineering (AREA)
• Earth Drilling (AREA)
• Pipe Accessories (AREA)

Priority Applications (4)

Applications Claiming Priority (2)

Publications (1)

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ID=19889932

Family Applications (1)

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Cited By (1)

Citations (8)

• 1987
  • 1987-05-14 NO NO871995A patent/NO871995D0/no unknown
• 1988
  • 1988-05-13 BR BR888807053A patent/BR8807053A/pt not_active IP Right Cessation
  • 1988-05-13 WO PCT/NO1988/000043 patent/WO1988008917A1/en active IP Right Grant
  • 1988-05-13 EP EP88904675A patent/EP0417084B1/en not_active Expired - Lifetime
  • 1988-05-13 DE DE88904675T patent/DE3885909T2/de not_active Expired - Fee Related
  • 1988-12-06 US US07/282,128 patent/US4905958A/en not_active Expired - Fee Related
  • 1988-12-29 DK DK728488A patent/DK170260B1/da not_active IP Right Cessation

Patent Citations (8)

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