US3166124A

US3166124A - Wellhead closure plug

Info

Publication number: US3166124A
Authority: US
Inventors: Glena D Johnson
Original assignee: Shell Oil Co
Current assignee: Shell USA Inc
Priority date: 1962-05-24
Filing date: 1962-05-24
Publication date: 1965-01-19
Anticipated expiration: 1982-01-19

Description

Jan. 19, 1965 e. D. JOHNSON 3,166,124

WELLHEAD CLOSURE PLUG Filed May 24, 1962 2 Sheets-Sheet 1 l Ht I53 i'%\\ ii !I H 1 H5 I I I2? I I26 I25 H FIG. I

INVENTOR:

GLENN D. JOHNSON HIS AGENT Jan. 19, 1965 G. D. JOHNSON 3,166,124

WELLHEAD CLOSURE PLUG Filed May 24, 1962 2 Sheets-Sheet 2 FIG. 3

FlG.-2 FIG 4 INVENTOR:

GLENN D. JOHNSON BY; 4.7 #W 's AGENT United States Patent 3,166,124 WELLHEAD CLOSURE PLUG Glenn D. Johnson, Downey, Calii, assignor to Shell Gil Company, New York, N.Y., a corporation of Delaware Filed May 24, 1962, Ser. No. 197,496 19 tillaims. (til. 166-66.5)

assembly positioned underwater where equipment is subject to the corrosive action of the sea water as well as to the accumulation of various types of marine growth after prolonged exposure to sea water. A copending application, Serial No. 24,558, filed April 25, 1960, now Patent No. 3,099,315, describes a method for drilling and completing wells underwater at an offshore location which drilling and completion operations are carried out from a remote operational station or vessel positioned on or above the surface of the water. After installing the Wellhead equipment'on a completed well, the top of the production wellhead assembly is closed in a suitable manner, such as by means of a lubricator and a wellhead closure device in accordance with the present invention.

It is a primary object of the present invention to provide apparatus adapted to form a fiuidtight seal at the top of a wellhead assembly or a related wellhead member.

A further object of the present invention is to provide a wellhead closure member adapted to be installed in or removed from an underwater wellhead assembly by operations carried out from a remote location such as a vessel on the surface of the water.

Another object of the present invention is to provide a wellhead closure member of rugged design and construction which is not readily injured by the rough handling encountered during the completion of a well at an oilshore location.

A further object of the present invention is to provide a wellhead closure plug adapted to seal and close the upper open ends of concentric tubular strings of pipe.

Another object of the present invention is to provide a wellhead closure plug adapted to be inserted into the open top of a fluid filled well allowing the fluid in the well to escape therefrom prior to seating the closure plug in place.

Another object of the present invention is to provide a wellhead closure plug including means for allowing fluid to bleed past or through the plug prior to removing the plug from its seated position in the top of the wellhead assembly.

These and other objects of the present invention will be understood from the following description taken with regard to the drawing, wherein:

FIGURE 1 is a schematic view of a closure plug, taken in partial longitudinal cross section, when positioned in the top or lubricator section of a wellhead assembly;

FIGURE 2 is an expanded view of the latching element of the closure plug of FIGURE 1;

FIGURE 3 is a longitudinal view, taken in partial cross section of a running tool attached to the closure plug 6? FIGURE 1; and p FIGURE 4 is a diagrammatic View taken in partial longitudinal cross section of one type of a fishing tool for removing the closure plug of FIGURE 1 from the wellhead.

In FIGURE 1 of the drawing, the apparatus illustrated is designed for use on a wellhead assembly which is seice cured to and in communication with a pair of parallel or concentric well conduits 6t) and 61 as shown and described in copending patent application, Serial No. 72,168, filed November 28, 1960,

Fixedly attached to the top of the wellhead assembly,

as to a valve spool member 35 at the top thereof, is a re-entry housing or lubricator mandrel 86 whose lower flange or plage member 87 maybe bolted to the valve spool 85, by

bolts

88 and 89. The lower end of the lubricator mandrel 86 or the upper end of the valve spool'85 is provided with a cross-over chamber 91 in communication between the top of the conduit 61 through the valve spool and a space 91a at least partially surrounding a bushing member 92 which is screw-threaded into and in communication with the flow conduit 60 in the valve spool 85.

The lubricator mandrel 86 may take a variety of forms but in general the lubricator mandrel 86 is provided with at least one upwardly extending tubular member 93 having a sealing surface, preferably grooved, as at 94, on the outer wall thereof, against which a surrounding piece of equipment, such as a landing head or a well- 'head connector, may be sealed in a fiuidtight manner.

In its most simple form the re-entry housing or lubricator mandrel is provided with the upwardly-extending tubular member 93 which has a sealing surface 95 on the inner wall thereof against which the seals 96 carried by a closure plug 97 may seal in a fluidtight manner. If it is desired to communicate with the

separate flow conduits

60 and 61 of the wellhead assembly through the lubricator mandrel 86, it would be necessary to provide a second or innertubular member99 as well as the bushing 92. An upward extension of the bushing 92 is formed by the innermost tubular member '99 which is fixedly secured to and depends from the closure plug 97, while being provided with seals 10% which seal against the inner wall 101 of the bushing 92 in a fiuidtight manner. Thus, the flow conduit 60 of valve spool member 85 is in communication, through the bore 101 of the bushing 92, with the bore 102 of the innermost tubular member 99. At the same time the flow conduit 61 in the valve spool member 85 is in communication, through the cross-over chambm 91, with the space 104 between the bushing 92 and the lower end of the intermediate tubular members 99 and 98, respectively. The tubular members 98 and 99 are in spaced relationship with each other so that fiuid can flow between them.

For this particular oil installation it is also desired to have a third flow conduit 106 within the mandrel 86 when the plug 97 is removed. Thus, the intermediate tubular member 98 is in spaced relationship within the outermost tubular member 93 of the mandrel providing a flow conduit 196 which communicates at its lower end with a pressure line 107 which in turn is in pressure communication with the valve operators (not shown) on the valves (not shown) of the wellhead assembly, so as to selectively open and close the valves. The valves are preferably arranged so that pressure from the pressure line 107 of the lubricator mandrel would open valves of the wellhead, permitting operations to be carried on through vertical conduits 6t and 61 While at the same time closing other fiow control valves. The bushing 92 may be provided with latches or grooves 108a to which a running tool could latch when the plug 97 is removed from the man- Patented Jan. 19., 1965 7 may expand.

It will be apparent that since the top of an underwater wellhead assembly is filled with fluid at the time it is desired to insert a closure plug therein, suitable flow passageways must be provided in the plug to allow the escape of fluid trapped in. the top of the wellhead through the plug before the plug has been sealed and latched in the wellhead assembly in a fluidtight manner. It is' also realized that'in order to pull a plug out of'the top of a closed wellhead assembly, it is necessary to provide open passageways through the plug across the sealing elements thereof in order to allow fluid to bleed into the top 'of wise, it would be extremely diificult to pull a plug out vided with an upper shoulder 149 which presses against 7 the bottom of the camming section 117 when the upper screw-threaded end 141 of rod section 118 is screwed in the recessed portion 142 of the upper rod section 116.

A lower shoulder 143 engages the upper end of the innermost piston or sleeve valve 120, as shown in FIGURE 1. The

latching dogs

112 and 113 are illustrated as being provided with a series of horizontally-disposed teeth or

serrations

144 and 145 on the outwardly-extending surfaces thereof. It is to be understood that these teeth may be in the form of pins or any other suitable latch- 'ing device.

In FIGURE 3, a tubular running tool 147 is shown as being secured to the lower end of'a pipe string 148 for running the closure plug 97 into place in the top of a wellhead during running or lowering the closure plug 97 into place. The running tool 147 is seated in a shoulder of a wellhead assembly since one would be pulling against a vacuum created beneath the plug when it moved upwardly. 'The operating element of the closure plug 97 of FIG- URE- 1 comprises a fishing head 114 at the'top of anoperating rod made up of sections 115 which is screwthreaded to a lower section 116to which a camming section 117 is fixedly secured by a rodsection 118 whose upper end is screw-threaded to the bottom. of rod section member 122. A stop member and closure element 123' is screw-threaded to the lower end of the cylindrical member 122 while a compression spring 124 tendsto' urge the outer sleeve or piston valve 121 upwardly away from the stop member 123. T

The upper end of the cylindrical housing member 122 of the closure plug 97 is provide'd with a chamber 125 containing a compression spring 126 which acts between an end plug 127 and the shoulder 128 of operation rod section 116 to force the operating rod normally downwardly. The lower face 130 of the actuating rod section 116 is provided with a pair of downwardly and

inwardlydirected camming elements

131 and 132 which are adapted to engage cooperating

camming surfaces

133 and 134 ment of the closure plug 97 as it enters the top of the lubricator mandrel 86.

As shown in FIGURE 2 of the drawing, the camming section 117 of the operating rod is provided with

offset camming elements

135 and 136 whose sloping faces are adapted to engage cooperating camming faces or

surfaces

137 and 138 on

latching elements

113 and 112,"respectively. The

camming elements

135 and 136 are offset from each other. with the camming element 135 being nearer the front of the camming section, as viewed and the other camming element 136 being offset to the rear *of the element 117. This allows for simultaneous actuation of both of the

latching dogs

112 and 113 by the camming section 117. As shown in FIGURE 2,. the lower portion of the operating rod, that is,-section '118 is pro- 149 on the cyiindrical housing member 122 of the closure plug 97. v The two elements are releasably secured together by means of a shear pin 150 which is shown in its shear position in FIGURE 1 as portions 150 and 159a.

At the time the closure plug 97 is secured in the running tool 147 the head 151 of'an adjustable screw 152 bears against the top of an auxiliary operating rod or a valve 'rod153 to hold it in its most downwardly position. The valve rod 153 (FIGURE 1) extends through the fish- 'in'g' head 114 and the operating rod sections 115,116,;

117 and 118 and is slidably movabletherein. The lower end of the rod 153 bears against the closed lower end 154 of theiouter sleeve valve 121 and the action of the compression spring 124 against the sleeve valve 121 tends to raise the valve rod 153 to the position shown in FIG- URE 1. At the time the closure plug 97 is shear-pinned to the running tool 147 as shown in FIGURE 3, the closed lower end 154 of the outer sleeve valve 121 is in contact with the stop member 123 closing thelower end of the housing member 122 of the closure plug 97. The shoulder 155 extending outwardly on the housing member 122 is adapted to engage the top end of tubular member 93 of r the lubricator mandrel 86. An annularseal 156 is pro- The camming surfaces 133 and 134 are j preferably at about a 45 angleso that the latching

dogs

112 and 113 may be pushed inwardly on downward move- .seal 156 and out of the lubricator mandrel.

vided just below'the shoulder to keep sea water from entering the top of the lubricator mandrel. The seal 156 is not designed to keep fiuid within the lubricator mandrel from coming out and thus, any fluid which can escape to the centrai'chamber 157 of the closure plug 97 can escape past the latching

dogs

112 and 113 and past the Seals 96, 1 119 and 100 however, are pressure seals which prevent the escape of fluid at these points.

The closure housing member 122 may be provided with one or more-fluid passageways 158 which permit the escape of fluid from flow conduits 107. through 106 and 158 into the chamber 157 and thence out of the lubricator mandrel.

At the time closure plug 97 is shear-pinned to the running tool 147 asshown in FIGURE 3, the valve rod 153 is depressed so that the outer sleeve 154 touches the stop member 123 of the housing member 122. At this time the port 160 through the wall of the housing member 122 is in communication with the port 161 and flow passage 162 of the sleeve valve 121, thus allowing any fluid trapped within tubular member 99 below the stop member 123 to fill up the annular space between the tubular member 99' and housing member 122, through port 160 and into port 161 and thence through

flow passageways

162 and 163 to' the low pressure chamber 157 from which the fluid can escape in a manner described hereinabove.

At the same time, with the outer sleeve valve 121 at its lower position, the port 164 through the housing member is in communication with flow passageway 163 and thence with chamber 157 whereby any fluid between tubular memand thence out of the lubricator mandrel. During normal operations, with the underwater wellhead closed by the closure plug, the various elements of the closure plug assume the position illustrated in FIGURE 1.

When it is desired to pull the plug out of the Wellhead,

any suitable type of fishing tool maybe employed which will engage the fishing head 114 of the plug whereby an upward pulling force can be exerted on the operating rod 115. The fishing tool (FIGURE 4) would be mounted on the lower end of a pipe string and would preferably be provided with a series of spring fingers 166 and adapted to be forced outwardly by a carnming surface 167 on the top of the fishing head 114 and subsequently engage the shoulder 168 of the fishinghead 114. Upon an upward pull of the fishing head 114, the operating

rod sections

115, 116, 117 and 118 as well as the inner sleeve valve 1213 move upwardly with it. Before the

camming elements

135 and 136 on the camming section 117 engaged cooperating camming surfaces 137 and 138 on the latching dogs 112' and 113, the upper port 170 through the inner sleeve valve 120 would be in alignment with port 171 through the wall of the outer sleeve valve 121 and also in alignment with port 172 through the Wall of the housing member 122 and in communication below pressure seal 1419 with the space between tubular members 93 and $5 thus allowing pressure to equalize as port 1769 in the inner sleeve valve 129 is in communication through flow passageways 173 with the low pressure chamber 157. At the same time the lower port 174 through the inner sleeve valve 121 is in communication with port 175 through the outer sleeve valve 121 and through port 176 through the housing member 12?. so as to permit fluid to bleed into the chamber 129 within the innermost tubular member 99. Ana these ports are opened, continued pulling on the fishing head 114 causes the

camrning elements

135 and 136 to retract the latching

dogs

112 and 113 so that the closure member 97 can be pulled out of the wellhead assembly.

I claim as my invention:

1. A wellhead closure plug connectible to an underwater wellhead for closing concentric conduit means therein having space within each of said conduit means, said plug comprising (a) a plug body having formed thereon sealing surface means engageable with said each of said conduit means of said wellhead,

(b) sealing means carried by each of said sealing surface means for forming a fluidtight seal against an adjacent Wall of said conduit means when positioned thereagainst, and

(c) latching means carried by said plug body and extendible beyond the outer surface thereof and adapted to engage one of said well conduit means for anchor ing the plug body in the wellhead against upward movement therefrom. 2-. The apparatus of claim 1 wherein said plug body has flow passageway means formed therein in communication between the space outside the plug body and the space within each of said well conduit means when the plug body is seated therein, and includes valve means, carried by said plug body normally closing the flow passageway means therein. 3. A wellhead closure plug insertable into an underwater wellhead for closing concentric conduit means therein, the ends of said conduit meansand mandrel conduit means terminating at axially-spaced intervals one from the other, said plug comprising i (a) a plug body having formed thereon axially-displaced sealing surface means insertable within said axiallyspaced ends of said conduit means,

(b) sealing means carried by each of said sealing sur face means for forming a fiuidtight'seal against the adjacent face of each of said conduit means when positioned thereagainst,

(c) said plug body having'flow passageway means formed therein in communication between the space r v e I outside the plug body and the space within each of said well conduit means when the plug body forms a closure therefor,

, (d) valve means carried by said plug body normally closing the flow passageway means therein, and

(e) latching means carried by said plug body and ex.-

tendible beyond the outer surface thereof and adapted to engage one of said well conduit means for anchor! ing the plug body in the wellhead.

4. The apparatus of claim 3 including actuating'rod means carried by said plug body and extending out the upper end thereof, said'actuating rod means being operatively connected to said valve means and said latching means. 7

5. The apparatus of claim 4 including fishing head means on the top of the said rod means for'rernoving said plug from said wellhead.

6. The apparatus of claim 5 wherein said rod means comprises bearing surface means engaging said valve means for removing said valve means to at least one operative position, and camming surface means .carried outwardly on said rod means and engageable with said latching means.

7. The apparatus of claim 6 including spring means carried in said plug body and engaging said rod means normally urging said camming means against said latching means to extend said latching means outwardly in locking position and urging said valve means to a closed position. 8. The apparatus of claim 5 wherein said rod means comprises bearing surface means engaging said valve means for selectively opening said valve means, and first and second axially-displaced and oppositely-directed camrning surface means carried outwardly on said rod means and engageable with cooperating surfaces on said latching means for selectively extending and retracting said 'latching means.

9. The apparatus of claim 8 including spring means carried in said plug body and engaging said rod means nor- .rnally urging said first camming means against said latching means to extend said latching means outwardly in locking position and urging said valve means to a closed position, said second camming surface means being axially spaced on said rod means whereby said valve means open said flow passageways in said plug body before said second camming surface means retracts said latching means.

10. Apparatus of claim 5 wherein said rod means comprises first and second concentric rods and said valve means comprises first and second concentric sleeve valves, each of said rod means having (a) bearing surface means engaging one of said valve means for selectively opening said valve means,

(b) first and second axially-displaced camming surface means engageable with cooperating surfaces on said latching means for selectively extendingand retract ing said latching means,

' (c) first spring means carried in said plug body and engaging said rod means normally urging said first camming means against said latching means to extend,

said latching means outwardly in looking position and urging said one of said valves to a closed position,

' said second camming surface means being axially.

spaced on said rod means whereby said valve means open said flow passageways in said plugbody before said second camming surface means'engages and retracts said latching means, and a (d) second spring means carried inv said plug body and engaging the other of said valves urging it to a normally closed position r References Cited by the Examiner UNITED STATES PATENTS BENJAMIN HERSH, Primary Eramz 'ner.

Claims

1. A WELLHEAD CLOSURE PLUG CONNECTIBLE TO AN UNDERWATER WELLHEAD FOR CLOSING CONCENTRIC CONDUIT MEANS THEREIN HAVING SPACE WITHIN EACH OF SAID CONDUIT MEANS, SAID PLUG COMPRISING (A) A PLUG BODY HAVING FORMED THEREON SEALING SURFACE MEANS ENGAGEABLE WITH SAID EACH OF SAID CONDUIT MEANS OF SAID WELLHEAD, (B)SEALING MEANS CARRIED BY EACH OF SAID SEALING SURFACE MEANS FOR FORMING A FLUIDTIGHT SEAL AGAINST AN ADJACENT WALL OF SAID CONDUIT MEANS WHEN POSITIONED THEREAGAINST, AND (C) LATCHING MEANS CARRIED BY SAID PLUG BODY AND EXTENDIBLE BEYOND THE OUTER SURFACE THEREOF AND ADAPTED TO ENGAGE ONE OF SAID WELL CONDUIT MEANS FOR ANCHORING THE PLUG BODY IN THE WELLHEAD AGAINST UPWARD MOVEMENT THEREFROM.