Note: Descriptions are shown in the official language in which they were submitted.
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.
~'~.
- 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
-- 3 --
^ ~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-
.
---6-- -
- 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
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- .. ,,, - ~., -
- 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
- 8
1036929
~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.
-- 10 --
,
~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
10369Z9
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
- 12 -
,
10369Z9
~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.
13 -
10369Z9
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-
- 14 -
1036929
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
- 16 -
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.
-17 -
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.
.,
- 18 -
~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.
." ~. ..
