CA1036929A - Blowout ram preventer - Google Patents
Blowout ram preventerInfo
- Publication number
- CA1036929A CA1036929A CA230,486A CA230486A CA1036929A CA 1036929 A CA1036929 A CA 1036929A CA 230486 A CA230486 A CA 230486A CA 1036929 A CA1036929 A CA 1036929A
- Authority
- CA
- Canada
- Prior art keywords
- ram
- bore
- preventer
- housing
- members
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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Abstract
BLO?CUT RA? ?REVE?TER ABSTRACT
OF THE DISCLOSURE
A preventer comprises a housing with a through bore.
Rams are arranged in the cavity of the housing to recipro-cate therein relative to the bore. The distance between the guides which are in the plane parallel to the plane of the axis of the through bore reduces uniformly in the direction from the housing ?eriphery to said bore, the ram packer being reinforced from the bore side with radial metal members while the body of the ram is comprised of a plurality of members adapted to move relative to one another during move-ment of the ram.
OF THE DISCLOSURE
A preventer comprises a housing with a through bore.
Rams are arranged in the cavity of the housing to recipro-cate therein relative to the bore. The distance between the guides which are in the plane parallel to the plane of the axis of the through bore reduces uniformly in the direction from the housing ?eriphery to said bore, the ram packer being reinforced from the bore side with radial metal members while the body of the ram is comprised of a plurality of members adapted to move relative to one another during move-ment of the ram.
Description
03~9Z'~
The present invention rela~es to the oil ~nd gas industrg equip~ent and more particularly to preventers intended for sealing the mouths of oil and gas wells~
As to the design and ouerational performance thé known preventers are divided i~to the ram a~d universal ones.
~ ram preventer usually comprises a housing ~ith covers, rams arranged in its plane and hYdraulic cylinders secured on the housing covers. ~he hydraulic cylinders accommodate pis-tons with rod~ intended for moving the ram~.
~ he preventer housing is made in the form of a massive steel casting or forging of a bo~ or oval section ~th a central through bore for pa~sing the tool. ~he inner wall~ of the housing serve as guides for the rams.
~ he lo~er surface of the ;nner cavity of the housing is made, as a rule,with-longitudinal ribs which form a passage for the fluid (oil, drilling mud) and gasffrom the well.
- ~he inner cavity of the housing intended to receive rams i~ closed at both ends thereof with covers ~hich are a~tack-ed to the housing with the aid of bolts or studs. ~he covers ~re adapted for rotation on the axles secured at the ends of the housing ~nd have, as a rule, passages for admitting fluid to the h~draulic cylinder.
~ he surfaces of covers adjoining the housing are provided ~ith grooves to accommodate sealing elemen~s for sealing the hou~i~g-to-cover joint.
~'~.
The present invention rela~es to the oil ~nd gas industrg equip~ent and more particularly to preventers intended for sealing the mouths of oil and gas wells~
As to the design and ouerational performance thé known preventers are divided i~to the ram a~d universal ones.
~ ram preventer usually comprises a housing ~ith covers, rams arranged in its plane and hYdraulic cylinders secured on the housing covers. ~he hydraulic cylinders accommodate pis-tons with rod~ intended for moving the ram~.
~ he preventer housing is made in the form of a massive steel casting or forging of a bo~ or oval section ~th a central through bore for pa~sing the tool. ~he inner wall~ of the housing serve as guides for the rams.
~ he lo~er surface of the ;nner cavity of the housing is made, as a rule,with-longitudinal ribs which form a passage for the fluid (oil, drilling mud) and gasffrom the well.
- ~he inner cavity of the housing intended to receive rams i~ closed at both ends thereof with covers ~hich are a~tack-ed to the housing with the aid of bolts or studs. ~he covers ~re adapted for rotation on the axles secured at the ends of the housing ~nd have, as a rule, passages for admitting fluid to the h~draulic cylinder.
~ he surfaces of covers adjoining the housing are provided ~ith grooves to accommodate sealing elemen~s for sealing the hou~i~g-to-cover joint.
~'~.
- 2 -~0369Z,9 ~ he rams are made of a reCtc~gular shape, semi-round in the for~ o~ a flat semi-discs or oval. Constructionally the ra~s are integral metal bloc~s with a sealant potted or inserted t~erein; or composed of a housing a~d an insert ~ith ~aid sealant potted or inserted therein.
Each ram is linked ~ith the hydraulic cylinder rod at a d de opposite to the through bore in the housing.
~ o seal the well head with the tool being in the well, u9e i8 made of casing rams ~hose butt end facing the vertical bore is provided with a cutout whose radius corresponds to the radius of the tool being sealed off (drill pipe).
~ o seal off a well head without the tool in the ~ell, use is made of rams ~ihose butt ends facing the vertical bore have no cutouts, i~e. are made flat.
~ s a rule, the ram portion facing the bore has guide projections ~hich are arranged at both sides of the drill plpe cutout. ~hese projections serve to align the string of drill pipes.
~ he ram preventer operates as follo~s. ~o close the preventer, a pressure is applied to the hydraulic cylinder locking cavi~y through the pipelines arranged on the housing or through the ch~nnels made directly in the housing. ~he pressure makes the piston ~7ith rod move towards the through.
bore. ~he movement, i.e. the stroke, of the piston with rod hence the movement of each ram generally corresponds to a ^ ~0369Z9 h~lf-diameter of the t~ough bore in the hou~ing. ~he rod moves the ra~ to~;ards the tnrough bore in the preventer housing. ~he ram projections disnlace the pipe to the center of the through bore and the cutout rams ~eal about the pipe.
~he ~ell pressure presses the ram to the upper wall of the housing cavity and, through the passage between the longitu-~inal ribs of the housing cavity lower wall, presses the rams oto the drill pipe and to one another, thus sealing off the preventer.
-When opening the preventer, the piston moves to the ini-~ial positio~. ~he piston rod pulls the rams and opens the preventer.
~ he ram preventers are compact, simple to control and operate but have a number of disadvantages, the main one con-sisting in that the rams are capable of sealing off only one pa~ticular diameter of the pipe, thus necessitating employ-ment of sets of rams or replaceable inserts with packing elements to fit pipes of different diameter as well as of special rams or inseIts with packing elements for sealing off the ~ell head having no tool in it~
Besisdes, the ram preventers cannot be used for sealing square - or hexagonal-section drill pipes.
~ o eliminate these di~advantages use is made of univer-sal preventers.
Th,e uniYersal preventer housing is made in the form of ~, , ~ ` :
~ 369Z9 a thick-wall bush of a large di~meter whose lo~er portion ter3inate~ u~ually ~n a flan"e for mounting the universal preventer on the ram preventer and co~necting it to the la-tter.
A cover with a vertical through bore surrounded by a sealing groove is attached to the housing. An a~nular packing element and a plunger are arranged in~ide the housing. ~he inner cavity of the cylindrical plunger is made conical, expanding upwa~d. The outer ~urface of the plunger has a cir~ular projectio~ which accommodates sealing elements and divides the inner cavity of the housing into two chambers com-municated ~ith a hydraulic drive.
Installed insdie the inner cone cavity of the plunger is a~ annular cone-shaped packing element which is made of a defo~mable resilient material reinforced with metal elements.
Provided in the c~ter of the packer is a vertical through hole ~hich corresponds to the vertical bore made in the housing cover.
~ he pre~enter operates a~ follows. A pressure fed to the locking chamber inside the housing forces the plunger to move upward along the outer cone surface o~ the pac~ing eleme~-c.
~he pa~ker with reinforcing members displaces towards the center of the vertical hole to clo~e it.
After closing the vertic~l bore and sealing off the well the well pressure acts on the packer thus improving sealing.
~ 5 ~
~369Z9 ~ he universal preventer seals tool~ of any diameter and shape a~d provides for sealing o~f the ~7ell ~thout or ~ith the tool as well as for performing round trips ~Jith the mouth sealed off.
However, the universal preventer features a number of significant disadvantages. Inasmuch as sealing is effected by a considerable displace~ent o~ the elastic packing,materi~
this results in premature destruction of the latter.
~ he reinforcing elements are arran~ed on the packer outside diameter and with the packer shifted through the m~mum travel thereof said members form the in~ide diameter which cannot be smaller than the m~x;mum diameter of the pipe ~rom the pipe string sealed off by a given preventer. There-fore, ~hen sealing drill pipes, and especially so if the mouth ~ithout pipes is sealed off, the major area of the resilient packer material is not protected with the reinfor-cing elements and is therefore exposed to the well pressure which may reach considerable values. ~his dictates increasing the packer height. ~ large height of the packer and conside-rable bulk thereof which are necessary for closing the through bore result in such an increase of the overall dimensions of the universal preventer that its height exceeds by several times the height of the ram preventers. Besides, to replace the annular packer it is necessary to remove the preventer cover which is difficult ~hen the tool is in the well and re-.
- i ~o369Z9 quire~ additional height under the deck of the rig base for accomplish~ent of this operation.
Development ~ork i9 con~tantLy carried out at pre~ent to provide compact, reliable a~d llniversal preventers.
In the art there is kno~m a universal preve~ter ~ith compound rams ~hich encompa~s a tubular resilie~t member at sealing. Such preventers, though universal to some extent, ha~e not found wide application becauYe of lo~ reliability thereof. ~he packer of said preventer is made of a deiormable resilien~ material, is not reinforced, he~ce fails to ensure reliable sealing, especially at high pressures in the well, because of its premature de~truction. ~his preventer does ~ot offer a noticeable advantage in the ~imensions either.
In the art there is kno~n another ram preventer with a unive~al ram, comprising a set of small rams made in the form of a plurality of plane-parallel members covered with a resi-lient material. Each ram is actuated by an individual hydrau-lic drive. ~aking the ram as a plurality of small ram segments ensures a multi-purpose use of the preventer but rules out centering of the string of drill pipe~ in the well. Intri-cate design of ram of a pluarlity of small ram segments and especially of the individual hydraulic drives, insufficient reliability have dictated a restricted use of this preventer.
~ nother kno~l ram preventer has a ram made of a resilient material in the form of a rectangualr block rei~forced from -- 7 ~
- .. ,,, - ~., -- 103~9Z9 the housing ver~cal bore side by parallelmetal members. ~he disadvantage of said ram resides in that a plusalitg of reinforcing m~mb~rs ma~es the ram too rigid thus requiring the application of considerable forces for sealing off the pipe. Besides, such a ram cannot be used for centering of pipes, e~pecially small dia&eter pipes, and the well he4d cannot be properly sealed off.
In connection with the above the afore-diPclosed preventer has not found wide applicauion either.
In the art is also knov~ a preventer whose packer moves along a spherical surface during the sealing of the pipe.
T~is preventer offers some advantages over the u~iversal preventer described above but it has large dimensions a~d is rather complicated to manufacture.
Another known universal preventer has a packer madc In the form of a split ring re;nforced with members which move during the sealing one on another to approach the center of the vertical bore. ~e packer is moved by eight radial h~dra-ulic cglinders. O~ing to complicated technology and insigni~i-ca~t bene~it from smaller overall ~;mensions, this preventer is used in dri'ling to a li~ited degree.
~ uiversal preventers cannot prevent the sealed string from the driving pressure in the well and are used only in combination with ram preventers.
~ hus, a modern preventer system comprises a universal and ~everal (2 to 4) ram prever~er~ that results in a high metal consu~tion ~d hi~h co~t thereof.. Besides, such a preventer Sy9tem i9 very high a~d requires con~iderable space under the deck of the rig base. A higher base o~ the drill rig requires more metal for construction, increase~ the cost and complica-te~ the operation.
~ n object of the present invention i~ to pro~ide a pre-venter which would improve the reliability of the well sealin~
~ nother object of the present in~ention is to provide a preventer which will seal off tools of an~ diameter and shape.
Still another object of the present invention is to pro-vide a simple-design preventer whose overall ~;men~ions will not exceed the overall dimensions of the ram preventers in use.
Yet another object of the present invention i9 to pro-vide a preventer ~hose design would permit decreasing the height of the preventer unit.
~ nother object o~ the present invention i~ to provide a preventer ~hose de~ign ~ould permit replacement of the packer irrespective of the tool being in the ~ell.
A~d the last objcct of the present in~ention is to pro-vide a simple preventer ccnvenient in operation.
~ he above and other objects o~ the invention are achi-eved by providing a ram preventer comprising a housing with a central through bore for a tool to be sealed o~f and guide~
_ 9 _ ~03f~9Z9 in~he ~aid hou~in~ vJhereon are reciprocatedl~ arra~ged rams made of an elastic packing material r~ith reinforcing members thereof envelopped by the ram bod~, according to the inven-tion, the distance bet~Jeen the guides located in the plane parallel to the ~lane of the axis of said bore i9 unifor~ly reduced in the direction from the housin~ periphery to said bore, the distance between the ends of said guides in the vici - nity of said peri~hery being equal to or exceeding the diame~
ter of said bore, and the packer reinforcing members are arra~
ged radially in the direction of through bore, while the ram bo~y i9 comprised of at least two coupled me~bers conver-. ging during reciprocation of the ram.
~ he claimed preventer pro~.ides for reliable sealing of a tool oi any diameter and shape and 3eals off thewell with the tool removed therefrom.
- ~hi5 rules out the necessity-for providing the preven-ter with replaceable ra~s for sealing pipes of different di-ameters. - ~
-- ~he design of the preventer ensures round trip and tur-~ing the pipe under well pressure ~ithout distrubing the seal-ing.
Besides, there is no need for.preventer assemblies ~ith a great number of preventers, hence the height and ~eight of the pre~e~ter set is reduced, thus reducing the heig~t of the drill rig platform.
, ~036929 In case o~ failure of the^packer in the clai~ed pre-venter, it may be replaced irres~ective of the tool being in the well.
The preventer is simple and con~enie~t to operate.
It is preferable that eac~ member of the ram body be I,shaped in cross section.
Due to the ~-shaped members the ram body covers the packer resilient materizl from the side opposite to the reinforci~g members and directs said material towards the bore to the tool being ~ealed.
Besides, such a shape ensures covering of the lower part of the pac~er thus preventing the forcing aut of the resilient material down~ards.
~ he ram body may be made of three members: a central one I;nked with the drive and t~o l,shaped side ones coupled movably to each other and to said central member. ~he side members are rigidly secured to the packer. Such a design of the-ram body of~ers ~r~e movemer,t of the members relative to each other during displacement of the ram and prevents wed-giDg of the latter in the guides.
~ Besides, such a design of the ram body is ~imple from the production vie~oint.
It is preferable that each re;n~orci~g member be made in the form of two plates rigidly interconnected and nar-rowing uniforml~ to~ards ths through bore, and the face of the-plate directed to~ard~ said bore be made with an angle ensuring maximwm approach of t~e reinforci~g me~ber to the tool bein~, sealed.
Such a design of the reinforcing members provides a ram of a small height but strong enough to ~ithstand high well pressures. The major part of the bore i~ over}apped b~ strong rein~orcing members and reliably protects the pac~er resili-ent material.
~ his ensures the min;mum di~tance between the re;nfor-cing members and the tool that reduces the area of the resi-lient material unprotected part and provides for round trip and turning the pi~e with the tool in the well without disturbing the sealing.
~ ccording to one embodi~e~t o~ the invention the pre-~enter may have guides located in the plane parallel to the plane of the through bore axis, formed by two in~erts made in the form of a rectangualr prism having an equilateral triangle as its base, and fabrica*ed of a resilie~t material reinforced b7 metal member~.
~ his provides for using a series ram preventer for manfuacturing the preventer according to the present i~ven-tio~. ~o thi3 end, the inserts are arranged in the preventer housing cavit~ and cone ram~ are positioned in between. ~he design of the ram ensures sealing along the housing and the ram without additional sealing members.
Other objects and advantages of the present invention , ~ill be more re~dil~ a~arent from the follo~ing detailed descri?tion 3f t;ne preferred embod~;ents thereof ~ith refe-rence to the accom~anying drawings, wherein:
Fig. 1 is a plan ~ie~ of a preventer, according to the invention;
Fig. 2 is a longitu ;nal plan section of a preventer;
shown in Fig. 1.
Fig. 3 i8 a section o$ a preventer housing;
Figs 4 a~d 5 are a ram and parts of the body thereof.
Fig. 6 packing Fig. 7 is Section VII-VII of Fig. 4;
Figs 8 i~ a ram packing reinfbrcing member;
Fig. 9 is an embodiment of ram body;
Fig.10 is an embodiment of a-preve~ter housing with detachable inserts.
~ he preventer according to the present invention (Figs 1, 2, 3) comprises: a housing 1 of a box shape with a central bore 2 for the tool being sealed of~ (not sh~n).
~hreaded holes 38 and g~ooves 39 are provided on the external sides of horizontal walls of housing 1, serYing ~or joining~
the preve~ter with other elements when mounting the latter on the well mouth. ~he inner walls of the housing 1 serve as guides ~ for rams 4 arranged in the cavity of the housing 1.
The distance between the ~uide~ located in the plane parallel to the ?l~ne of the bore 2 axis is u~iforml~
decreased in the direction from the periphery of the housi~g 1 to the bore 2. T~e distan~e betlk~en the ends 5 of the guides 3 in the vicinity of the bore 2 is equal or exceeds the diameter of the latter. Several longitudinal ribs 6 ~here-alo~g the ram 4 mo~es are arranged on the lower surface of the i~ner cavity of the housing 1. Gaps betwee~ the ram 4 and the housing 1 per~its using the v~ell pressure for improving the seali~g of the ~orking tool.
~ he rams 4 (Figs 4, 5, 6) are made of a resilient packin~
7 and are reinforced from the bore 2 side by radially arran-ged members 8 (~igs 7, 8, 9, 10? made as horizo~tal plates 9 which are narrowing in the direction of the bore 2 and have a vertical connectio~ member 10, a side 11 of the plate 9 iacing the bore 2 is bevelled to e~sure maximum approach of the reinforcing members 8 to the tool being sealed. A side 12 of the connection member 10 facing the bore 2 is made with a radial recess and ha~4 a hole 13 is provided in the center of ~aid con~ecting member 10 to ensure better adhesio~ of the rein~orci~g member 8 to the resilient material of the packer ~he body 14 of the ram 4 (~igs. 1, 2, 5) is made of three coupled members: central member 15 whose vertical ~all has through grooves 16 and ~-shaped groove 17 for coupling to the rod 18 of the hydraulic c~linder, and l,shaped side members 19, 20. The members 19, 20 of the body 14 have a vert-ical 21 and horizontal 22 walI~ with threaded hole~ 23 for coupling to '~he central memb~r 15 ~lith balts ~8 a~d hole~ 24 to ensure rigid connection to the packer 7. Stepped grooves 25 are provided in tne horizontal ~all 22 for travelling joint of the members 19, 20. The body 14 of the ram 4 may also be compri~ed of two coupled members 19, 20 (Fig. 11) moving with re~pect to each other during displace~ent of the ram 4.
~he packer 7 is reinforced by a member 26 which ensures rigid connection of the packer 7 with the side members 19, 20 oi ~he body 14.
~ olted to the housing 1 (~igs 1, 2) oi the preventer by bolts 27 are covers 28 which mou~t hydraulic cylinder~
29 with pistons 30 and rods 18. ~he cover side adjoining the housing 1 is provided YJith grooves to accomodate scaling element 40 for sealing cover 28-to-housing 1 -joint. ~he cover 28 has cha~nel 41 ~or permitting pressure to be appli-ed ior o~eni~g the piston 30, and a chPnnel ~ith sealing element 42 ior sealing the hydraulic cylinder. Sealing ele-ment~ 43 disposed in the cover serve ~or sealing off the rod 18. Each hydraulic cylinder 29 is closed ~ith a cover 31 coupled to the cover 28 b~ studs 32. The cover 31 has a screw 33; the ram 4 is fi~ed in the closed position by driving in said screw. ~he cover 31 has a sealing element 44 for sealing the cover to h~draulic joint and sealing elements 45, which seal the screw 33. A channel 46 is provided in the cover 31 , 10369;Z9 for pre.~.sure to be a?plied to c~ose the pisto~ 30.
~he guides 3 o the housing 1 oE the ~reY~nter may be made i~ the form of two lnserts ~ L~.~2) of a re~ilie~
~ erial 35 (such as rubber) rein:Eorced by metal members 36.
Each m sert 34 is ~de in the for~ of aright triacgular prism which has an equilateral tr~gle as its base. ~he insert~ 34 are arra~ged s~metrically to the bore 2 of the housing 1 and are rigidly ~ecured to ~ppo~ite walls of t~e housing 1 by ~cre~s 37.
~he preve~ter operate3 as follo~.
Pressure of the fluid fed înto the h~draulic c~li~der 29 (~ig. 2) moYes the piston 30 to~ards the bore 2. ~he rod 18 of the piston 30 pushes the central member 15 of the body 14 o~ the ram 4 (~igs 1, 2, 5). ~he ce~tral member 15 of the body 14 o~ the ram 4 presses against the side members 19, 20, whose vertical ~.~all~ 21 slide along the ce~tral member 15, while the horizontal walls 22 move alo~g the guides 3 and ribs 5 o~ the inner cavity of the preventer housing l.
~ he ram 4 moves to the narrowing horizontal cavit~ of the preventer housing 1, the process the ~idth of the resi-lient packer 7 is reduced, while the length thereof increases thus pus~ing the reinforcing members 8. ~he larger is the piston 30 stroke, the larger area of the bore 2 is re~tricted b~ the rams 4. ~he reinforcing members 8 o~ the packer 7 i~-tersect the vertical bore 2 of the housing 1, the plates 9 of said members converging in the radial direction, thus 10369Zs~
. ~
protecting th~ resilie~t packer 7. Inas~uch as the reinfor-cing me~bers 8 always ~ove in front of the ~acker 7, they lag but slightly behind a small portion of the resilient packer 7 displaced into the bore 2. Since the ram 4 keeps on mo~ing, 3aid ~ortion of the resilient packer 7 which i~ so-mewhat ahead with respect 'o the reinforcing members 8 comes mto contact ~ith a similar portion of the resilient material of the second ram 4, thus fully closing off the vertical bore 2. ~he major part of the bore ~ cross-~ection is closed by the reinforcing members 2 and onl~ a narro~ section of the pac~er 7 located on the lateral axis of the pre~enter remains unprotected. Si~ce the ram 4 length changes in the course of movement thereof, the stroke of the piston 30 intended to close the claimed preventer i~ shorter than that of the prior art preventers. If the working tool is in the well, the reinforcing members 8 converge on the tool and embrace ~he latter irres~ective of its shape. ~he resilient ma~erial of the packer 7 pressed by the members 15, 19, 20 of the housing 14 of the ram 4 fills the space bet~een the guide~ 3 and when abutting the resilient packer 7 of the other ram 4 seals off the well complete with the tool located there~n. ~hus the well mouth is sealed off together with the tool by a minimum volume of the forced-out resilient material of the packer 7,-the shape of the tool being of no consequence.
1~369Z5 ~ he clPired preventer will-ali~n the ~tri~g of drill pipes in the well. Since the rein~orcing members 8 are arra~-ged in the packer 7 close to the through bore circle, the~e are abutted ~it~ the reinfGrcing ~embers 8 of the ~eco~d ram successi~el~ from the periphe~J to the center. ~he side reinforcing members 8 converge first, the~, the intermediate o~es, and, finally, the central members. Said member~ 8 coming abutt, they constantly press the drill pipes cowards the centre of the bore 2, that is ali~ning said pipes.
Since the reinforcing members 8 come up almost to the tool a~d seal it by a minimum amount of the resilie~t materi-al forced out of the packer 7, round trips may be readilg performed with the well mouth being sealed off, resulting in an insignificant ~Jear of the packer material, the wear bei~g compensated for by a continuous pressure on the ram 4 effected by the piston 30 due to a flov~-over of the resilient material of t~e packer 7 bet~een the rein~orcing members 8.
~ he preventer is opened in the reverse order. ~he pressure is applied to the hydraulic cylinder 29 to ef~ect the open~ing. ~he pisto~ 30 starts moving away ~rom the bore 2 and pulls by rods 18 the central members 15 of the body 14 of the rams 4 coupled to the side members 19, 20 which, i~
turn are coupled ~it~ the packer~ 7. ~he packers 7 release the grip, the members 19, 20 come apart and the rams 4 retreat thus ope~i~g the bore 2 of the preventer.
., ~0369Z~
- ~he rams are replaced as fol:Lows. The bolts 27 all unscre~ed. T~ e co~er 28 i9 tur~ed arou~d the a~is and the seal mg element 7 (Fig. 4) of part~ 15, lg, 2G (Fig. 5) is connected to the rod 13. ~ new packer 7 i~ installed on to-shaped side elements 19, 20 in such a manner that projections 49 of reinforcing elements 26 e~ter the holes 24.
~hen the cover 28 i9 replaced and clamped to the housing 1 with bolts 27.
." ~. ..
Each ram is linked ~ith the hydraulic cylinder rod at a d de opposite to the through bore in the housing.
~ o seal the well head with the tool being in the well, u9e i8 made of casing rams ~hose butt end facing the vertical bore is provided with a cutout whose radius corresponds to the radius of the tool being sealed off (drill pipe).
~ o seal off a well head without the tool in the ~ell, use is made of rams ~ihose butt ends facing the vertical bore have no cutouts, i~e. are made flat.
~ s a rule, the ram portion facing the bore has guide projections ~hich are arranged at both sides of the drill plpe cutout. ~hese projections serve to align the string of drill pipes.
~ he ram preventer operates as follo~s. ~o close the preventer, a pressure is applied to the hydraulic cylinder locking cavi~y through the pipelines arranged on the housing or through the ch~nnels made directly in the housing. ~he pressure makes the piston ~7ith rod move towards the through.
bore. ~he movement, i.e. the stroke, of the piston with rod hence the movement of each ram generally corresponds to a ^ ~0369Z9 h~lf-diameter of the t~ough bore in the hou~ing. ~he rod moves the ra~ to~;ards the tnrough bore in the preventer housing. ~he ram projections disnlace the pipe to the center of the through bore and the cutout rams ~eal about the pipe.
~he ~ell pressure presses the ram to the upper wall of the housing cavity and, through the passage between the longitu-~inal ribs of the housing cavity lower wall, presses the rams oto the drill pipe and to one another, thus sealing off the preventer.
-When opening the preventer, the piston moves to the ini-~ial positio~. ~he piston rod pulls the rams and opens the preventer.
~ he ram preventers are compact, simple to control and operate but have a number of disadvantages, the main one con-sisting in that the rams are capable of sealing off only one pa~ticular diameter of the pipe, thus necessitating employ-ment of sets of rams or replaceable inserts with packing elements to fit pipes of different diameter as well as of special rams or inseIts with packing elements for sealing off the ~ell head having no tool in it~
Besisdes, the ram preventers cannot be used for sealing square - or hexagonal-section drill pipes.
~ o eliminate these di~advantages use is made of univer-sal preventers.
Th,e uniYersal preventer housing is made in the form of ~, , ~ ` :
~ 369Z9 a thick-wall bush of a large di~meter whose lo~er portion ter3inate~ u~ually ~n a flan"e for mounting the universal preventer on the ram preventer and co~necting it to the la-tter.
A cover with a vertical through bore surrounded by a sealing groove is attached to the housing. An a~nular packing element and a plunger are arranged in~ide the housing. ~he inner cavity of the cylindrical plunger is made conical, expanding upwa~d. The outer ~urface of the plunger has a cir~ular projectio~ which accommodates sealing elements and divides the inner cavity of the housing into two chambers com-municated ~ith a hydraulic drive.
Installed insdie the inner cone cavity of the plunger is a~ annular cone-shaped packing element which is made of a defo~mable resilient material reinforced with metal elements.
Provided in the c~ter of the packer is a vertical through hole ~hich corresponds to the vertical bore made in the housing cover.
~ he pre~enter operates a~ follows. A pressure fed to the locking chamber inside the housing forces the plunger to move upward along the outer cone surface o~ the pac~ing eleme~-c.
~he pa~ker with reinforcing members displaces towards the center of the vertical hole to clo~e it.
After closing the vertic~l bore and sealing off the well the well pressure acts on the packer thus improving sealing.
~ 5 ~
~369Z9 ~ he universal preventer seals tool~ of any diameter and shape a~d provides for sealing o~f the ~7ell ~thout or ~ith the tool as well as for performing round trips ~Jith the mouth sealed off.
However, the universal preventer features a number of significant disadvantages. Inasmuch as sealing is effected by a considerable displace~ent o~ the elastic packing,materi~
this results in premature destruction of the latter.
~ he reinforcing elements are arran~ed on the packer outside diameter and with the packer shifted through the m~mum travel thereof said members form the in~ide diameter which cannot be smaller than the m~x;mum diameter of the pipe ~rom the pipe string sealed off by a given preventer. There-fore, ~hen sealing drill pipes, and especially so if the mouth ~ithout pipes is sealed off, the major area of the resilient packer material is not protected with the reinfor-cing elements and is therefore exposed to the well pressure which may reach considerable values. ~his dictates increasing the packer height. ~ large height of the packer and conside-rable bulk thereof which are necessary for closing the through bore result in such an increase of the overall dimensions of the universal preventer that its height exceeds by several times the height of the ram preventers. Besides, to replace the annular packer it is necessary to remove the preventer cover which is difficult ~hen the tool is in the well and re-.
- i ~o369Z9 quire~ additional height under the deck of the rig base for accomplish~ent of this operation.
Development ~ork i9 con~tantLy carried out at pre~ent to provide compact, reliable a~d llniversal preventers.
In the art there is kno~m a universal preve~ter ~ith compound rams ~hich encompa~s a tubular resilie~t member at sealing. Such preventers, though universal to some extent, ha~e not found wide application becauYe of lo~ reliability thereof. ~he packer of said preventer is made of a deiormable resilien~ material, is not reinforced, he~ce fails to ensure reliable sealing, especially at high pressures in the well, because of its premature de~truction. ~his preventer does ~ot offer a noticeable advantage in the ~imensions either.
In the art there is kno~n another ram preventer with a unive~al ram, comprising a set of small rams made in the form of a plurality of plane-parallel members covered with a resi-lient material. Each ram is actuated by an individual hydrau-lic drive. ~aking the ram as a plurality of small ram segments ensures a multi-purpose use of the preventer but rules out centering of the string of drill pipe~ in the well. Intri-cate design of ram of a pluarlity of small ram segments and especially of the individual hydraulic drives, insufficient reliability have dictated a restricted use of this preventer.
~ nother kno~l ram preventer has a ram made of a resilient material in the form of a rectangualr block rei~forced from -- 7 ~
- .. ,,, - ~., -- 103~9Z9 the housing ver~cal bore side by parallelmetal members. ~he disadvantage of said ram resides in that a plusalitg of reinforcing m~mb~rs ma~es the ram too rigid thus requiring the application of considerable forces for sealing off the pipe. Besides, such a ram cannot be used for centering of pipes, e~pecially small dia&eter pipes, and the well he4d cannot be properly sealed off.
In connection with the above the afore-diPclosed preventer has not found wide applicauion either.
In the art is also knov~ a preventer whose packer moves along a spherical surface during the sealing of the pipe.
T~is preventer offers some advantages over the u~iversal preventer described above but it has large dimensions a~d is rather complicated to manufacture.
Another known universal preventer has a packer madc In the form of a split ring re;nforced with members which move during the sealing one on another to approach the center of the vertical bore. ~e packer is moved by eight radial h~dra-ulic cglinders. O~ing to complicated technology and insigni~i-ca~t bene~it from smaller overall ~;mensions, this preventer is used in dri'ling to a li~ited degree.
~ uiversal preventers cannot prevent the sealed string from the driving pressure in the well and are used only in combination with ram preventers.
~ hus, a modern preventer system comprises a universal and ~everal (2 to 4) ram prever~er~ that results in a high metal consu~tion ~d hi~h co~t thereof.. Besides, such a preventer Sy9tem i9 very high a~d requires con~iderable space under the deck of the rig base. A higher base o~ the drill rig requires more metal for construction, increase~ the cost and complica-te~ the operation.
~ n object of the present invention i~ to pro~ide a pre-venter which would improve the reliability of the well sealin~
~ nother object of the present in~ention is to provide a preventer which will seal off tools of an~ diameter and shape.
Still another object of the present invention is to pro-vide a simple-design preventer whose overall ~;men~ions will not exceed the overall dimensions of the ram preventers in use.
Yet another object of the present invention i9 to pro-vide a preventer ~hose design would permit decreasing the height of the preventer unit.
~ nother object o~ the present invention i~ to provide a preventer ~hose de~ign ~ould permit replacement of the packer irrespective of the tool being in the ~ell.
A~d the last objcct of the present in~ention is to pro-vide a simple preventer ccnvenient in operation.
~ he above and other objects o~ the invention are achi-eved by providing a ram preventer comprising a housing with a central through bore for a tool to be sealed o~f and guide~
_ 9 _ ~03f~9Z9 in~he ~aid hou~in~ vJhereon are reciprocatedl~ arra~ged rams made of an elastic packing material r~ith reinforcing members thereof envelopped by the ram bod~, according to the inven-tion, the distance bet~Jeen the guides located in the plane parallel to the ~lane of the axis of said bore i9 unifor~ly reduced in the direction from the housin~ periphery to said bore, the distance between the ends of said guides in the vici - nity of said peri~hery being equal to or exceeding the diame~
ter of said bore, and the packer reinforcing members are arra~
ged radially in the direction of through bore, while the ram bo~y i9 comprised of at least two coupled me~bers conver-. ging during reciprocation of the ram.
~ he claimed preventer pro~.ides for reliable sealing of a tool oi any diameter and shape and 3eals off thewell with the tool removed therefrom.
- ~hi5 rules out the necessity-for providing the preven-ter with replaceable ra~s for sealing pipes of different di-ameters. - ~
-- ~he design of the preventer ensures round trip and tur-~ing the pipe under well pressure ~ithout distrubing the seal-ing.
Besides, there is no need for.preventer assemblies ~ith a great number of preventers, hence the height and ~eight of the pre~e~ter set is reduced, thus reducing the heig~t of the drill rig platform.
, ~036929 In case o~ failure of the^packer in the clai~ed pre-venter, it may be replaced irres~ective of the tool being in the well.
The preventer is simple and con~enie~t to operate.
It is preferable that eac~ member of the ram body be I,shaped in cross section.
Due to the ~-shaped members the ram body covers the packer resilient materizl from the side opposite to the reinforci~g members and directs said material towards the bore to the tool being ~ealed.
Besides, such a shape ensures covering of the lower part of the pac~er thus preventing the forcing aut of the resilient material down~ards.
~ he ram body may be made of three members: a central one I;nked with the drive and t~o l,shaped side ones coupled movably to each other and to said central member. ~he side members are rigidly secured to the packer. Such a design of the-ram body of~ers ~r~e movemer,t of the members relative to each other during displacement of the ram and prevents wed-giDg of the latter in the guides.
~ Besides, such a design of the ram body is ~imple from the production vie~oint.
It is preferable that each re;n~orci~g member be made in the form of two plates rigidly interconnected and nar-rowing uniforml~ to~ards ths through bore, and the face of the-plate directed to~ard~ said bore be made with an angle ensuring maximwm approach of t~e reinforci~g me~ber to the tool bein~, sealed.
Such a design of the reinforcing members provides a ram of a small height but strong enough to ~ithstand high well pressures. The major part of the bore i~ over}apped b~ strong rein~orcing members and reliably protects the pac~er resili-ent material.
~ his ensures the min;mum di~tance between the re;nfor-cing members and the tool that reduces the area of the resi-lient material unprotected part and provides for round trip and turning the pi~e with the tool in the well without disturbing the sealing.
~ ccording to one embodi~e~t o~ the invention the pre-~enter may have guides located in the plane parallel to the plane of the through bore axis, formed by two in~erts made in the form of a rectangualr prism having an equilateral triangle as its base, and fabrica*ed of a resilie~t material reinforced b7 metal member~.
~ his provides for using a series ram preventer for manfuacturing the preventer according to the present i~ven-tio~. ~o thi3 end, the inserts are arranged in the preventer housing cavit~ and cone ram~ are positioned in between. ~he design of the ram ensures sealing along the housing and the ram without additional sealing members.
Other objects and advantages of the present invention , ~ill be more re~dil~ a~arent from the follo~ing detailed descri?tion 3f t;ne preferred embod~;ents thereof ~ith refe-rence to the accom~anying drawings, wherein:
Fig. 1 is a plan ~ie~ of a preventer, according to the invention;
Fig. 2 is a longitu ;nal plan section of a preventer;
shown in Fig. 1.
Fig. 3 i8 a section o$ a preventer housing;
Figs 4 a~d 5 are a ram and parts of the body thereof.
Fig. 6 packing Fig. 7 is Section VII-VII of Fig. 4;
Figs 8 i~ a ram packing reinfbrcing member;
Fig. 9 is an embodiment of ram body;
Fig.10 is an embodiment of a-preve~ter housing with detachable inserts.
~ he preventer according to the present invention (Figs 1, 2, 3) comprises: a housing 1 of a box shape with a central bore 2 for the tool being sealed of~ (not sh~n).
~hreaded holes 38 and g~ooves 39 are provided on the external sides of horizontal walls of housing 1, serYing ~or joining~
the preve~ter with other elements when mounting the latter on the well mouth. ~he inner walls of the housing 1 serve as guides ~ for rams 4 arranged in the cavity of the housing 1.
The distance between the ~uide~ located in the plane parallel to the ?l~ne of the bore 2 axis is u~iforml~
decreased in the direction from the periphery of the housi~g 1 to the bore 2. T~e distan~e betlk~en the ends 5 of the guides 3 in the vicinity of the bore 2 is equal or exceeds the diameter of the latter. Several longitudinal ribs 6 ~here-alo~g the ram 4 mo~es are arranged on the lower surface of the i~ner cavity of the housing 1. Gaps betwee~ the ram 4 and the housing 1 per~its using the v~ell pressure for improving the seali~g of the ~orking tool.
~ he rams 4 (Figs 4, 5, 6) are made of a resilient packin~
7 and are reinforced from the bore 2 side by radially arran-ged members 8 (~igs 7, 8, 9, 10? made as horizo~tal plates 9 which are narrowing in the direction of the bore 2 and have a vertical connectio~ member 10, a side 11 of the plate 9 iacing the bore 2 is bevelled to e~sure maximum approach of the reinforcing members 8 to the tool being sealed. A side 12 of the connection member 10 facing the bore 2 is made with a radial recess and ha~4 a hole 13 is provided in the center of ~aid con~ecting member 10 to ensure better adhesio~ of the rein~orci~g member 8 to the resilient material of the packer ~he body 14 of the ram 4 (~igs. 1, 2, 5) is made of three coupled members: central member 15 whose vertical ~all has through grooves 16 and ~-shaped groove 17 for coupling to the rod 18 of the hydraulic c~linder, and l,shaped side members 19, 20. The members 19, 20 of the body 14 have a vert-ical 21 and horizontal 22 walI~ with threaded hole~ 23 for coupling to '~he central memb~r 15 ~lith balts ~8 a~d hole~ 24 to ensure rigid connection to the packer 7. Stepped grooves 25 are provided in tne horizontal ~all 22 for travelling joint of the members 19, 20. The body 14 of the ram 4 may also be compri~ed of two coupled members 19, 20 (Fig. 11) moving with re~pect to each other during displace~ent of the ram 4.
~he packer 7 is reinforced by a member 26 which ensures rigid connection of the packer 7 with the side members 19, 20 oi ~he body 14.
~ olted to the housing 1 (~igs 1, 2) oi the preventer by bolts 27 are covers 28 which mou~t hydraulic cylinder~
29 with pistons 30 and rods 18. ~he cover side adjoining the housing 1 is provided YJith grooves to accomodate scaling element 40 for sealing cover 28-to-housing 1 -joint. ~he cover 28 has cha~nel 41 ~or permitting pressure to be appli-ed ior o~eni~g the piston 30, and a chPnnel ~ith sealing element 42 ior sealing the hydraulic cylinder. Sealing ele-ment~ 43 disposed in the cover serve ~or sealing off the rod 18. Each hydraulic cylinder 29 is closed ~ith a cover 31 coupled to the cover 28 b~ studs 32. The cover 31 has a screw 33; the ram 4 is fi~ed in the closed position by driving in said screw. ~he cover 31 has a sealing element 44 for sealing the cover to h~draulic joint and sealing elements 45, which seal the screw 33. A channel 46 is provided in the cover 31 , 10369;Z9 for pre.~.sure to be a?plied to c~ose the pisto~ 30.
~he guides 3 o the housing 1 oE the ~reY~nter may be made i~ the form of two lnserts ~ L~.~2) of a re~ilie~
~ erial 35 (such as rubber) rein:Eorced by metal members 36.
Each m sert 34 is ~de in the for~ of aright triacgular prism which has an equilateral tr~gle as its base. ~he insert~ 34 are arra~ged s~metrically to the bore 2 of the housing 1 and are rigidly ~ecured to ~ppo~ite walls of t~e housing 1 by ~cre~s 37.
~he preve~ter operate3 as follo~.
Pressure of the fluid fed înto the h~draulic c~li~der 29 (~ig. 2) moYes the piston 30 to~ards the bore 2. ~he rod 18 of the piston 30 pushes the central member 15 of the body 14 o~ the ram 4 (~igs 1, 2, 5). ~he ce~tral member 15 of the body 14 o~ the ram 4 presses against the side members 19, 20, whose vertical ~.~all~ 21 slide along the ce~tral member 15, while the horizontal walls 22 move alo~g the guides 3 and ribs 5 o~ the inner cavity of the preventer housing l.
~ he ram 4 moves to the narrowing horizontal cavit~ of the preventer housing 1, the process the ~idth of the resi-lient packer 7 is reduced, while the length thereof increases thus pus~ing the reinforcing members 8. ~he larger is the piston 30 stroke, the larger area of the bore 2 is re~tricted b~ the rams 4. ~he reinforcing members 8 o~ the packer 7 i~-tersect the vertical bore 2 of the housing 1, the plates 9 of said members converging in the radial direction, thus 10369Zs~
. ~
protecting th~ resilie~t packer 7. Inas~uch as the reinfor-cing me~bers 8 always ~ove in front of the ~acker 7, they lag but slightly behind a small portion of the resilient packer 7 displaced into the bore 2. Since the ram 4 keeps on mo~ing, 3aid ~ortion of the resilient packer 7 which i~ so-mewhat ahead with respect 'o the reinforcing members 8 comes mto contact ~ith a similar portion of the resilient material of the second ram 4, thus fully closing off the vertical bore 2. ~he major part of the bore ~ cross-~ection is closed by the reinforcing members 2 and onl~ a narro~ section of the pac~er 7 located on the lateral axis of the pre~enter remains unprotected. Si~ce the ram 4 length changes in the course of movement thereof, the stroke of the piston 30 intended to close the claimed preventer i~ shorter than that of the prior art preventers. If the working tool is in the well, the reinforcing members 8 converge on the tool and embrace ~he latter irres~ective of its shape. ~he resilient ma~erial of the packer 7 pressed by the members 15, 19, 20 of the housing 14 of the ram 4 fills the space bet~een the guide~ 3 and when abutting the resilient packer 7 of the other ram 4 seals off the well complete with the tool located there~n. ~hus the well mouth is sealed off together with the tool by a minimum volume of the forced-out resilient material of the packer 7,-the shape of the tool being of no consequence.
1~369Z5 ~ he clPired preventer will-ali~n the ~tri~g of drill pipes in the well. Since the rein~orcing members 8 are arra~-ged in the packer 7 close to the through bore circle, the~e are abutted ~it~ the reinfGrcing ~embers 8 of the ~eco~d ram successi~el~ from the periphe~J to the center. ~he side reinforcing members 8 converge first, the~, the intermediate o~es, and, finally, the central members. Said member~ 8 coming abutt, they constantly press the drill pipes cowards the centre of the bore 2, that is ali~ning said pipes.
Since the reinforcing members 8 come up almost to the tool a~d seal it by a minimum amount of the resilie~t materi-al forced out of the packer 7, round trips may be readilg performed with the well mouth being sealed off, resulting in an insignificant ~Jear of the packer material, the wear bei~g compensated for by a continuous pressure on the ram 4 effected by the piston 30 due to a flov~-over of the resilient material of t~e packer 7 bet~een the rein~orcing members 8.
~ he preventer is opened in the reverse order. ~he pressure is applied to the hydraulic cylinder 29 to ef~ect the open~ing. ~he pisto~ 30 starts moving away ~rom the bore 2 and pulls by rods 18 the central members 15 of the body 14 of the rams 4 coupled to the side members 19, 20 which, i~
turn are coupled ~it~ the packer~ 7. ~he packers 7 release the grip, the members 19, 20 come apart and the rams 4 retreat thus ope~i~g the bore 2 of the preventer.
., ~0369Z~
- ~he rams are replaced as fol:Lows. The bolts 27 all unscre~ed. T~ e co~er 28 i9 tur~ed arou~d the a~is and the seal mg element 7 (Fig. 4) of part~ 15, lg, 2G (Fig. 5) is connected to the rod 13. ~ new packer 7 i~ installed on to-shaped side elements 19, 20 in such a manner that projections 49 of reinforcing elements 26 e~ter the holes 24.
~hen the cover 28 i9 replaced and clamped to the housing 1 with bolts 27.
." ~. ..
Claims (6)
1. A blowout ram preventer, comprising: a housing with a central through bore; guides arranged in the cavity of said housing , the distance between said guides located in a plane parallel to the plane of the axis of said through bore decre-asing uniformly in the direction from the periphery of said housing to said bore, adjacent of which the distance between the ends of said guides being equal or exceeding the diameter of said bore; rams arranged in the plane of said housing and adapted to reciprocate relative to said bore, each of said ram being made of a resilient material packer whose body is provided with reinforcing members at the side thereof facing the bore, while the opposite side of said packer is enveloped by the ram body made of at least two coupled members adapted to move relative to each other at the reciprocation of said ram.
2. A blowout ram preventer as claimed in Claim 1, where-in each member of the ram body is L-shaped in cross section.
3. A blowout ram preventer as claimed in Claim 1, where-in the body of the ram is comprised of three members: a cen-tral member linked with a hydraulic drive and two side mem-hers L-shaped in cross section and movably coupled to each other and to said central member.
4. A blowout ram preventer as claimed in Claim 3, where-in the side members of the ram body are rigidly connected to the packer by fasteners.
5. A blowout ram preventer as claimed in claim 1, wherein each reinforcing member is made in the form of two plates rigidly interconnected and uniformly narrowing in the direction to the vertical bore, the side of the plate facing said bore being bevelled to ensure maximum approach of the reinforcing member to the tool being sealed off.
6. A blowout ram preventer as claimed in claim 1, wherein the guides lying in the plane parallel to the plane of the through bore axis are formed by two inserts having a shape of a right prism with an isosceles triangle as its base and made of a resilient material reinforced with metal members.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA230,486A CA1036929A (en) | 1975-06-30 | 1975-06-30 | Blowout ram preventer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA230,486A CA1036929A (en) | 1975-06-30 | 1975-06-30 | Blowout ram preventer |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1036929A true CA1036929A (en) | 1978-08-22 |
Family
ID=4103481
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA230,486A Expired CA1036929A (en) | 1975-06-30 | 1975-06-30 | Blowout ram preventer |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1036929A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111441737A (en) * | 2020-04-15 | 2020-07-24 | 青岛理工大学 | Double-rotary-barrel double-plunger sliding key type shaft-plug core three-in-one blowout preventer |
| CN114599855A (en) * | 2019-08-27 | 2022-06-07 | 贝克休斯油田运营有限责任公司 | Blowout preventer systems and methods |
-
1975
- 1975-06-30 CA CA230,486A patent/CA1036929A/en not_active Expired
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114599855A (en) * | 2019-08-27 | 2022-06-07 | 贝克休斯油田运营有限责任公司 | Blowout preventer systems and methods |
| CN111441737A (en) * | 2020-04-15 | 2020-07-24 | 青岛理工大学 | Double-rotary-barrel double-plunger sliding key type shaft-plug core three-in-one blowout preventer |
| CN111441737B (en) * | 2020-04-15 | 2022-02-01 | 青岛理工大学 | Double-rotary-barrel double-plunger sliding key type shaft-plug core three-in-one blowout preventer |
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