US2647728A

US2647728A - Inside blowout preventer

Info

Publication number: US2647728A
Authority: US
Inventors: Alonzo L Smith
Original assignee: Individual
Current assignee: Individual
Priority date: 1947-11-03
Filing date: 1947-11-03
Publication date: 1953-08-04
Anticipated expiration: 1970-08-04

Description

Aug. 4, 1953 2 Sheets-Sheet 1 Filed NOV. 3. 1947 Aug. 4, 1953 A. L. SMITH Filed NOV. 3. 1947 I I I I ."///////////////////I////. ""1

INSIDE BLOWOUT PREVENTER 2 Sheets-Sheet 2 INVENTOR. A. L.S Ml TH TTORNE YS perform many other Patented Aug. 4, I953 UNI-TED" PA 24647328 m smnl remove BREVENTER' Amntoii: seen; nbiis'tnjn ek. Applicatiiim-Novem'lier 3, 1947, Serial nadsarw a o1. zttzsi.

The invention relates to? a blowoutpreventer ibe'disposed inside 01f the drill stem-: r'operatlngi pipe-used in the rotary method on drilling. wells-i; Whena well is being; drilled; by; the'rotary method the drill bit is connected: to the-lower? endofapiece of pipe and uponrotation the weight of thebit and the: pipe causes the bil'zgtO cut intOthe-earth formation; Additional lengths; of pipe are added as the drilling progresses; ,In order to carry the cuttingsaway from thelbit andtomaint-ain-thedrill hole andi to prevent caving of the walls: of the drill hole and in addition to functions the practice hasbeendevelopedof: circulating a drilling mud; or liquid: downwardly through the drill stem todis-- charge from the bit and to'flow upwardly in the well bore: around the outside-of. the pipe; 4 'I-hepresent day drilling mudsare compounded from various ingredients and chemicals with, a view of accomplishing variousresults; one; of which is to maintain a; predominant pressure" upon the earth formations'whichare; being cut and which have been penetrated by the drillv bit. Various finely ground powdered materials are addedito the mud toincrease the specific gravity thereof andobtain more suitable drilling mud. Inmanyinstances and. quite frequently due to various causes-the pressures in the earthformationsmay exerta predominant pressure against the column of drilling mud-in-the-well bore. For instanceii vgas enters the Wellbore and dilutes the mud naturally the pressure againstfihe formation due to the column of mudisrreduced-b- In some instances as such predominant pressure from the formation moves upwardly inthe well bore: or inside of the drill pipe it mayexpet the mudfrom the well ZI'IdlthG-PiDBfiSWBJ-l;

Various types of drill valves-and: outside blowa out preventers have been devised-to grip and, seal; the outer periphery of the drill pipe so asto confine the mud in the well outside of the-drill pipe;- It is much more difficult however to provide a closure or blowout preventerfor the-inside of the; drill pipe due to the fact that the. abrasive-and solids-laden drilling mud is being pump'eddown wardly through the insideof'such drill pipe antd any valves,.such as back pressure valvesorlother; control members will of necessitybe subjected to,- wear and abrasion which soon; decreasesitheefiiciency and satisfactory operationthereof. With the foregoing difficulties mind the pros ent' invention contemplates an ins-ide blowout prevent'er which will automatically close the-in side offthe drill stemgor other pipfijwhich it is positioned when flow of 'fiuidin the drill'pipe.

thera ist a reverse or upward It-is therefore one of. the objects of the invention to provide an automatically operable flexible insid eblowout preventer.

Another: object of the invention is to provide an inside blowout preventer which may be deposited within the drillpipe and permit a downfiow'; of liquids through the pipe while auto' matioally sealing; itself and; the pipeagainst any return orupwardflow of fluid or pressure.

Another close the passage? through the: pipe when there is a predominant pressure exerted thereagainst from'beneath;

A-still furtherobject of the invention is to provideraihollow tubeoir sleeve-like blowout preventer adapted: to be positioned in the drill pipe, possibly-adjacent the drill bit, so that any pres suraexerted thereon from below will tend to collapse thesleeve and closethe passage through the drillpipeg Another object of the invention is toprovide a: fl'exiblehollow sleeve-like inside blowout prevent-er havingananchor flange adjacent one end thereof: with the other endof such sleeve being. constructed of relatively thin flexible material-so that. the sleeve will" collapse automatically upon pressure being exerted against the outer surface of the sleeve.

A still-further object of the invention is to provide a method of automatically closing a drill pipe upon the exertion of an upwardfiow or force dueto fluidwithin the pipe; 7

Qtherr and further objects of the invention will be: readily apparent when the following description is: considered in connection with the accompanying drawings, wherein Fig; l is; aside elevation of a well drill assembly inwhicn the-means-and method of the invention haveibeen{illustrated Fig; 2% is: a-pvertical sectional View of a. length of preventer;-

Fig; 3:: isqaavertical sectional? view through one half of the flexible blowout preventer sleeve n'an enlargedxscaleil Fig; 4': is a-aside elevation of the blowout preventer-sleeve in collapsedposition.

In Fig. 1 the well bore 2 has been drilled by the rotation of, thefbi't 3 duetortheturn-ing of the drillrpipe lvby means of -therotary table 5. i

The casing in the well may be closed by one or more outside blowout preventers 6 which are shown diagrammatically and are arranged to close about the drill pipe 4.

The pumps 9 pick up the drilling mud from the slush pit In and force it through the rotary hose II, the upper end of which is not shown but which hose is connected to the upper end of the drill pipe 4.

The drilling mud moving upwardly in the annular space I2 in the well bore around the outside of the pipe 4 will discharge as at Hi from the return pipe 15.

In order to obtain as straight a well bore as possible it is usual to place a considerable length of heavy pipe or drill collar it above the bit 3 and to which the lower end of the drill pipe 4 will be connected, as best seen in Fig. 1. 7

Both the pipe 4 and the collars is are made up of lengths of pipe which are usually provided with a threaded pin !9 on the lower end and a threaded box on the upper end as illustrated in the length of pipe or sub 2| seen in Fig. 2;.

The sub 2! as well as the rest of the pipe and the drill collars are hollow so as to provide a passage such as 22 through which the drilling mud is forced downwardly by the pumps. As an illustration it is not uncommon to circulate four or five hundred gallons of drilling mud per minute downwardly through the pipe at pressures which may exceed a thousand or fifteen hundred pounds per square inch. It will thus be appreciated that a tremendous abrasive problem is present. It is impractical to close the passage 22 to any substantial extent because any restrictions in such passage tend to quired to circulate the drilling mud downwardly on the one hand and also interfere with the vol-' ume which can be pumped on the other hand. Flat or butterfly valves supported upon cross shafts spanning the passage 22 have been found to be impractical because of the corrosive and abrasive action of the flowing stream of mud.

It is desirable that, in event of emergency or reversal of pressure in the lower end of thedrill pipe, the passage 22 be instantly and automatically closed. Speed in closing is of the essence because if a high pressure gas or other formation is encountered such pressure immediately enters the drill bit and reverses the direction of flow of the fluid in the drill pipe. Of course the resistance to upward flow of mud inside of the drill pipe is primarily due to the pressure of the pumps and also to the weight of the column of liquid in the pipe. If the predominant pressure in the bottom of the well begins to lift the column of mud in the pipe the resisting pressure or load of mud is materially reduced as the mud is expelled from the drill pipe. Oftentimes the rotary hose H may be disconnected during procedural operations and the drilling mud may begin to flow out of the top of the drill pipe which is open. Due to the lessening of the weight of the mud in the pipe the rate of discharge increases geometrically to such an extent that in a few seconds or minutes at most the well may blow out causing tremendous damage and injury so that it is imperative that the inside of the drill stem be closed off instantly and as automatically as possible.

The present invention directs itself to a sleevelike blowout preventer member 30, seen in position in Fig. 2, in half section in Fig. 3, and in side elevation in Fig. 4.

This blowout preventer is made up of an annular body 3| which is a composite member increase the power remade up of resilient material such as natural or artificial rubber or a similar composition 33 which may have the fabric or reinforced material 34 arranged therein as seen in Fig. 3 so as to provide a rounded internal tapering surface 35 which extends laterally to provide a more or less rigid flange 36 which may have a rigid reinforcing member 31 therein which is in the form of a hollow annular disc, or plate.

The body 3! as seen in Fig. 3 tapers gradually at 38 with a diminishing amount of reinforcing material 34 therein so that the body becomes more and more flexible as it terminates in a downwardly extending skirt 4!] which may have little or no reinforcing material therein so that the opposite sides 4| and 42 thereof, as seen in Fig. 4 may be collapsed by a very small pressure differential or flow of liquid upwardly thereagainst. The collapsing action automatically closes the passage 45 through the blowout preventer as seen in Fig. 4 and once the lower end of the passage 45 is closed an increase of pressure against the outer periphery t? will tend to hold the blowout preventer closed and shut off any further upflow of fluid through the passage 45 of the preventer.

With a view to preventing the blowout preventer from turning inside out the body 3| has been gradually thickened and reinforced so as to insure that even relatively high pressure will be shut 01f by the preventer.

As seen in Fig. 2 the passage 45 of the preventer is of such size that a core barrel or other pipe 50 such as surveying, sampling, or testing tools may be passed downwardly through the drill pipe to enter and extend through the blowout preventer.

It is possible that this blowout preventer sleeve 3!) may be disposed in any joint of the drill pipe or drill collar but in order to suitably support the blowout preventer, and insure that there is sufficient space available for its normal position and to also permit any upward pressure to exert itself about the outer periphery 41, a special drill pipe sub has been shown in Fig. 2 wherein the shoulder 5| receives the flange 36 and such flange will be clamped in position on the shoulder 51 by the pin member of the next section of pipe or drill collar which will be threaded into the box member 20. With this arrangement a chamber 52 is provided and any pressure moving upwardly therein will instantly collapse the flexible skirt portion 49 of the preventer regardless of whether there may or may not be a pipe or instrument 50 extending through the preventer.

It is preferable that the sub 2| be located proximate the bit 3 so that the instrument 5% will not pass entirely through the preventer when operations are carried out thereby, and also that the entire static head within the well bore may be utilized in effecting normal actuation of the preventer. It is understood of course that a retractable sleeve may be positioned in the preventer to prevent collapse thereof when lowering the drill pipe 4 into the well bore 2.

Broadly, the invention contemplates a means and method of automatically closing a drill or other pipe in a well bore by collapsing a flexible member upon the occurrence of an upward flow or pressure in the pipe.

What is claimed is:

1. An inside drill pipe automatic blowout preventer for insertion in the drill pipe employed in the rotary method of well drilling to close the lower end of the pipe and prevent an up-flow of fluid during the drilling operation comprising, a sub section of pipe forming a part of said drill pipe with pin and box threads thereon, a longitudinal passage extending throughout said sub section and including a portion between said pin and box threads, whose inside wall is spaced from a flexible lip type resilient sleeve valve portion of said preventer, a shoulder at the upper end of said passage portion adjacent said box threads, said sleeve valve having a reinforced radially extending flange thereon to engage and seat on said shoulder and to be held thereon by the pin end of the adjacent drill pipe section and having a reinforced skirt portion extending downwardly into said passage to create a pressure area in the passage and around the outside of said skirt below said shoulder, said skirt portion comprising a gradually thinning wall section terminating at its lower end in a relatively thin flexible lip end, said end normally remaining open for the movement therethrough of drilling fluids or instruments employed in the drilling and investigation of the ing of such flexibility as to close upon any upflow of fluid in said sub section into the pressure area around the exterior of the sleeve to automatically prevent such up-flow and blowout.

2. An inside drill pipe automatic blowout preventer for insertion in the drill pipe employed in the rotary method of well drilling to close the lower end of the pipe and prevent an up-flow of fluid during the drilling operation comprising, a sub section of pipe forming a part of said drill pipe with pin and box threads thereon, a longitudinal passage extending throughout said sub section and includin a portion between said pin and box threads, whose inside wall is spaced from a flexible lip type resilient sleeve valve portion of said preventer, a shoulder at the upper end of said passage portion adjacent said box threads, said sleeve valve having a reinforced radially extendin flange thereon to engage and seat on said shoulder and to be held thereon-by the pin end of the adjacent drill pipe section and having a reinforced skirt portion extending downwardly into said passage to create a pressure area in the passage and around the outside of said skirt below said shoulder, said skirt portion comprising a gradually thinning wall well, said lip end bed section terminating at its lower end in a relatively thin flexible lip end, said end normally remaining open for the movement therethrough of drilling fluids or instruments employed in the drilling and investigation of the well, said lip end being of such flexibility as to close upon any up-fiow of fluid in said sub section into the pressure area around the exterior of the sleeve to automatically prevent such up-flow and blowout, said sleeve valve being reinforced throughout substantially its entire body portion but to an increasingly greater extent in the body portion adjacent the upper end thereof to resist fluid pressure inversion thereof.

3. A blowout preventer for insertion within a drill pipe comprising a resilient hollow sleeve, means comprising a laterally extending rigid flange thereon to clamp said sleeve between two adjacent drill pipes, drill collar, or pipe sections which may be threaded together, an annular flexible skirt on said sleeve which tapers downwardly in wall thickness to a relatively thin lower lip end which normally flattens so that any upward movement of fluid in the pipe passes upwardly around such skirt until the pressure thereof on the exterior of the skirt will collapse said skirt to prevent further up-flow through such skirt, said skirt being of a size to fit within the pipe and permit the passage of instruments both upwardly and downwardly therethrough, and to provide a lip type seal therearound.

ALONZO L. SMITH.

References Cited in the file of this patent UNITED STATES PATENTS