US2082413A - Wellhead equipment - Google Patents

Description

June 1937- R. A. MUELLER ET AL 2,082,413

WELLHEAD EQUI PMENT Filed June 15, 1955 2 Sheets-Sheet 1 Z5 a ZZ l 2 H H 20 3 l 2 4. v 5 l 4- un 7 nu i 2 a Rober'AgmeHer Qwucm/DOO Job 11 Ryance 5 June 1, 1937. R. A. MUELLER El AL 2,032,413

WELLHEAD EQUIPMENT Filed June 15, 1935 2 Sheets-Sheet 2 Robert Mueller g m do hn RM an say f r atented .Fune 1, E937 2,082,413, warmrnap ntwrrrlrre er' Robert A. Mueller and JohngRZlYancey, Hons V 'iiex, assignors to Gray {Ecol Company, Eons ton, Tern, a corporation n: Application June l; i935; Serial No. 26,710

a ciarmaf (orfres i ff Our invention relates to apparatus for andrnethods of completing and equipping wells.

, In the drilling of deepwells for oil, gas, sulphur and the like it is necessary to perform such operations as setting casing, screen, packers,

tubing, and the like, or to run tools into the well for different purposes.

well equipment are now employed.

present equipment, it is necessary when the changes in equipment are made, to either kill the well with mud to prevent possible blowout or to. employ master valves, blowout preventers and the like, which, when once used, must be left in position on the well and are of no more value.

They cannot be removed from the well without danger and are lost for use thereafter. For example, when one string of casing is being set within another string, previously set, the new casing is introduced through a blowout preventer and a master valve into proper position and properly supported and sealed at its upper end, but when this job has been completed the master valve cannot be salvaged to be used as an ac.

cessory in subsequent operations, but must be left on the casing head equipment.

Further, in all wellhead equipment work it is fundamental or of first importance where the well is under pressure to consider the areas on the equipment against which the well pressure exerts itself. Obviously, it is of material advantage to be able to perform operations with 5 accessories of reduced diameters. It is not uncommon to encounter pressures of several thousand pounds per square inch, and thus each additlonal inch of exposed surface becomes important. The accomplishment efiected in reducing the areas exposed to well pressure on accessory equipment required during the performance of drilling in, running tubing under pressure, etc. is entitled to first consideration, because it makes possible the holding of pressures which could not otherwise be restrained. It is a fact that numerous patents and sales catalogues disclose cases of pyramidlng acces-- sories above the casing or tubing head, and providing the ability to hang through and remove these accessories from the well after they have performed their operation. 0n the other hand, it is apparent, without question, that, while these methods were well known, because of the attendant danger in their use, they have not been practiced by the trade, notwithstanding that This has frequently to .be done when gas pressure in the well has been encountered and danger of blowout is presents 10 To perform these operations, various types of But, with the ability to use equ'ipmen an'd 'i turn 'movief dre'ds o'f thousands" of 'dolla-rs operators have 'contiriiied'in th practic' these ex ensive s reamed dividual assembly at n o v without question-matte dangers coincident t" the 1158 of enlarged pressure eh'a'nrrbersf -l acce's'sories'cr'eate dangers wmce are-the practical rerthe performanceo this work.

' rai s tin-abject of the inventiont provide a structure or: casing supporrwmth i pass through 'such' devices' as blb moved are saved gfor subseduerit bperations; eyed name we obtainfseveral beneficial suits by being Y permitted to jre'niovef'these struc-f 20 tures nsm'abtve- =the easmg head we are errabled -to use the devices repeatedlythereafter. Further; the amount of casing *hald equipnientf necessary uponftheWell bing; thus d 'a'sed',' t-h V depth of are; cellar 'below t-he derric atfo e can "be materially lessened, and 'the' expense "for providing space" iol' the fequipirient ordinarily} necessary need not be'so great, 3 we al' sddesire-to siniplify the perations eee' sary in making changesfrolifo f of merittdaribt-her under 'Drsf'su' It is anotherb ject' or the' 'in 'ntion topro vide a superior type" ofsealing means tortheupper' endpfjastri It is'a further object of-"the inventibn to pro vide a shorter and more sturdy equipment ior the wellhead so warm variousbonnections will Fig. 4 is a side view partly in elevation and 55 partly in central longitudinal section showing one step in the equipment of the wellhead.

Fig. is a similar side elevation partly in section illustrating the assembly of parts which 5 may be employed in equipping the well; and

Fig. 6 is, a sectional detail of the upper end of a wellhead showing the manner in which the tubing may be supported in the casing head without other attachments.

This application is a continuation in part of our prior application Serial No. 756,654, filed December 8, 1934.

With reference particularly to Figs. 2 and 4, it is customary when a well has been drilled downwardly for a distance of several hundred feet to set a string of surface casing which may be indicated at l in the drawings.- At the upper end of this casing is a casing head {having one or more ports 3 therein through which fluid may be delivered to or from the well. The upper end of the casing head is provided with a lateral flange 4 whereby a sealing connection may be made with the adiacenmflange 5 of another'piece of equipment. The interior of the casing head is preferably provided with a tapered seat indicated at 6 in Fig. 4 to receive a tapered bushing or hanger I upon the next inner string of pipe 8.

The drilling operation will then proceed downwardly through the casing head 2 until it becomes 5 desirable to set another string of easing. Some-' times this may be several thousand feet and during this period gas under considerable pressure may be encountered. When therefore, due to caving formation or otherwise, it becomes neces- 5 sary to set the next inner string of easing 8. the

casing head must have been equipped with the usual master valve and blowout preventer.

In Fig. 2 the master valve 9 is shown as supported upon the casing head and secured thereto by a flanged connection. Above'the master valve 9 and secured thereto by the flanged connection i0 is a blowout preventer II and it may be understood that this blowout preventer is of the conventional form with opposite rams thereon adapted to engage the drill stem in drilling. The flanged connection is a preferred form of connection, or means of attachment, of one piece of equipment with another, for it enables the operator to maintain the same size of inner package throughout the assembly. In same size connections we mean that the flanged or threaded connections are not larger than are generally used by the trade with the size pipe upon which they are employed, according to accepted standards. Above the master valve is a flared nipple I! to 55 protect the blowout preventer when the bit is inserted downwardly through the blowoutpreventer and master valve into the well for drilling purposes. The blowout preventer is ordinarily equipped with two lateral outlets l3 below the rams.

When therefore the next inner string 8 is to be set the drill stem and drill bit are drawn upwardly out of the well until the drill bit has passed the master valve 9. The blowout pre- 65 venter still maintaining a seal around the drill stem, no blowout may occur. The master valve 9 is then closed after which the blowout preventer may be opened to allow the bit to be drawn upwardly out of the way.

70 The next step-is to insert the next string of easing. To accommodate the casing, which is larger than the drill stem, the rams in the blowout preventer must be changed to flt the casing. As will be noted from Fig. 4, this string oi casing 75 a is equipped at its upper end with a hanger 1.

Said hanger is threaded interiorly at its upper and lower ends and its lower end is provided with an outer thickened wall which is tapereddownwardly to fit theseat 6 of the casing head. There are preferably sealing rings of rubber, or the like, ll in the outer surface of the hanger so that when the hanger is in position a seal will be provided between the casing string 8 and the casing head 2. When this casing is inserted it is to be understood that the lower end is equipped in the usual manner with a float shoe or back pressure valve which prevents the gas from the well from escaping upwardly through the same llfhe hanger 'I'is sufliciently small so that it may pass through the blowout preventer and master valve and .seat within the casing head. When thus seated the casing string will hang supported in the casing head with the lower end thereof closely adjacent the bottom of the well so that it may be cemented at the lower end. This will permit the string to hang taut while the cementing operation is performed which seals about the lower end of the casing string.

An important feature of our invention may now be noted. With the string of casing thus supported in the well through the master valve and blowout preventer as described, the hanging of the inner string '8 in the casing head seals the space between the outer string I and the inner string 8, so that no'gas can escape about the inner string. The valve in the inner string prevents blowout through the same and the well is sealed against escape of pressure.

It is then possible to remove the upper equipment including the master valve 9 and the blowout preventer H, or equivalent control accessories, so that the upper end of the well will appear approximately as shown in Fig. 6. sealed against escape of pressure. This is an important feature as it permits the repeated use of the control accessories, such as the master valve and the blowout preventer. In the equipment of wells as previously carried out. it has been necessary to leave the master valve 9 upon the well for the reason that the next inner string had to be supported above the masteri valve, making it impossible thereafter to remove the same, and the control accessories then became a permanent part of the outer string of casing and was of no further use to the operator.

The next step in the finishing of the well is to attach above'the casing head 4 a second casing head IS, the lower'flange 5 of which will be secured to the casing head as previously noted. A seal is made between the casing head Iii and the hanger 1 by means of a metal gasket shown at It. It will be noted that the weight of the second casing head is clamped against the hanger so that it is thereafter fixed firmly in position. The second casing head l5 has a slightly smaller seat 6' therein to accommodate the next string of casing and it will be noted that the openlng through the second casing head I! is of the same interior diameter as the casing string 8 previously set.

Where the opening through the casing head, blowout preventer, or the like. is the full diameter of the casing through which further drilling or other operations must proceed, we call it a "full opening" casing head or a full opening" gate valve or the like. There is no constriction presented which would hinder the introduction of tools the full size of the interior of the casing string. The connections between casing heads. blowout preventers, valves and other fittings at the wellhead are the same size. that is, the flanged or threaded connections are not larger than would generally be used with a given size pipe for a given pressure in maniiolding and pipe connection work according to accepted practice. We also employ an adapter II between the casing head l and the lower end of the master valve of the blowout preventer being changed to ac- 9. which is mounted above the casing headin the same manner as shown in Fig. 2. When the master valve and blowout preventer shown in Fig. 2 are then assembled in place, the drilling may proceed.

The drill and drill stem are inserted downwardly through the blowout preventer and valve 9 and when the bit has passed the blowout preventer the rams may close about the drill stem to seal therewith during the drilling operation, the rams commodate the diameter of the drill stem. The float valve will be drilled out and the well may be extended further downwardly as desired. It will be obvious that as many strings of casing may be set as desired, and in each case the use of a hanger similar to the hanger 1 previously noted, on the string of easing which is set, will not only serve to form a seal when in position but will enable the driller to hang the inner string and set the same so that the equipment above the hanger may be thereafter removed and other pieces of equipment attached to the well head withou danger oi blowout.

Thus, in Fig. l, the upper end of the casing head is eouipped with a reduced nipple I! to which a valve I 8 and flow line l9 are connected. It will thus be possible to provide above the flow line iii any form oi Christmas tree or other equipment desired. I have shown a branch line 20 with other lines connected by means of a cross 2| thereto. The upper end oi the flow line is shown as being closed by a bull plug 22 having a vent 23 thereon.

In Fig. 5, I have shown another form of equipment in which the hanger. the upper end of which is shown at 7, is clamped in position by a plate 24, the outer margin of which is bolted to the flange I of the casing head. The upperthreaded end of the bushing .I has a pipe 25 connected therein to which is secured a tubing head 28. The upper end of the tubing 21, which is supported in the tubing head, has a tapered bushing or hanger 20 thereon with lateral arms 29 for engagement by an elevating means.

In Fig. 3 a difierent form of hanger is shown which enables theoperator to obtain a close seal at both ends of the hanger without the necessity of a packing gasket between the flanges of the parts. Thus it will be seen that the second string of easing 8 has a hanger I thereon, the lower end of which is formed in the same manner as the hanger 1. However, the upper end is extended somewhat and is provided with an upper tapered end 30 which is adapted to fit within an inner tapered seat 3| in the casing head l5. It will be obvious that when the casing head i5 is bolted and clamped downwardly against the upper end of the casing head 2 the hanger will form a seal with both casing heads, thus preventing leakage along either of the ends thereof. A similar bushing 1" may be employed at the upper end of the next inner string of casing. In this way each string of casing may be supported in the casing head structure and provide a full opening downwardly therethrough so that a drill bit or other tools may be lowered directly downwardly therethrough during the drilling operation. When the at the upper end of the tubing 34.

The advantages of the hanger I lie in a packing gasket such' as is ordinarily used and which is more liable to'leak.-

The advantages of this invention will Bi l 7,

from the description already given. By thejuse ,9! the type of hanger which has been described each succeeding string of pipe'may be suspended and supported in the casing head at a point'be low the point of attachment of 'the'master valve j andblowout' preventer without the use oimud to hold back the gas pressure. The hanger. automatically maintains a seal betweenthe 'samej and the casing head so that thereis'no danger of a blowout during thechanging 01 12 9. structure above the hanger. This enables us to remove the master valve and blowout preventer, or such other structure as may be connected above. sothat a'n- Furthermore, the hanger is. of comparatively small outer diameter. This is of advantage in that it may be lowered under heavy gas pressure with the string 01' pipe attached thereto through the usual blowout preventer and master valve and dropped into the seat below these parts and act to form a seal below said master valve so that said master valve may be removed. This is a feature of great importance and enables the driller to not only save equipment for further use but to economize largely in space which is required to house the devices which are connected at the upper end of the casing. The resulting well head equipment is short and compact and may be contained within a cellar at the upper end of the well which is comparatively shallowniurtheradvantages will be obvious to those skilled in the art.

What is claimed as new is:

1. In combination, a well casing,a lower casing head thereon, a second casing head supported above said lower casing head, a bushing threaded internally at its ends and tapered downwardly on its lower end to engage a tapered seat in said lower casing head, and having a tapered upper end to engage an upwardly tapered seat in said second casing head.

2. In combination, a well casing, a lower casing head thereon, a second casing head supported above said lower casing head, a bushing, a second string of casing supported by said bushing, said bushing being tapered at its lower end to engage a tapered seat in said lower casing head, and having a tapered upper end to engage an upwardly tapered seat in said second casing head.

3. In combination, a well casing, a full opening casing head thereon, an inner hanger seat on said casing head, control accessories mounted on said casing head, said accessories having the same size connections as said casing, a hanger to support a second string of casing in said seat, adapted to be inserted through said accessories, interior threads at the upper end oi. said hanger, and means on the exterior of said hanger to seal with an upp r casing head.

4. In combination, a well casing, a full opening well has been completed the upper section 32 will act as a support ior'the hanger 22 he tra t that we are enabled to obtain a seal which will not leak in use and-which is notdependent' upon Cal ' casing head thereon having an inner diameter as large as said casing, an inner hanger seat in said casing head, control accessories connected above said casing head, the internal diameter of said accessories being no larger than the exterior diameter of said casing, an inner pipe string, a hanger therefor having an outer diameter adapted to pass through said accessories and seat in said casing head seat, interior casing threads at the upper end of said hanger, and means onthe exterior of said hanger to seal with an upper casing head. -I

5. A casing-hanger for wells including a body adapted to be lowered through a drilling control to engage a casing head, a tapered lower end on said body to engage'said casing head and support the casing, packing rings mounted in the outer surface of said tapered end, means to thread a pipe to the upper 'end of said "hanger, and

means on the outer peripheryof said upper-end to H support a second casing head on said hanger and make a fluid seal therewith below the upper extremity of said hanger.

6. A pipe hanger for wells including a bushing internally threaded at its lower end, a tapered outer face on said bushing adapted to engage and seal upon a lower casing head and support a pipe threaded to said bushing, an upwardly tapered extension of reduced outer diameter upon said bushing adapted to support an upper casing head having a downwardly flaring seat and form a seal therewith.

7. A casing hanger for wells including a body adapted to be lowered through a drilling control, said hanger having casing threads formed at each end thereof, a seating surface tapered downwardly at the lower end of said body to engage and seal on a supporting casing head, said hanger L ing engagement with said lower casing head, said hanger being reduced in external diameter above said downwardly tapered portion to form an upwardly presented shoulder, an internally threaded upper extension above said shoulder,,rneans on the outer surface of said extension to support and seal with said second casing head, and means to secure said hanger in'said'lower casing head.

9. In combination, a casing head having a hanger seat therein, a pipe hanger adapted to be lowered through a drilling control and the lower end of which is tapered downwardly to fit said seat, sealing means secured upon the tapered portion of said hanger, an externally reduced and internally threaded upper extension on said hanger, said extension being formed on its outer periphery to support and seal with an upper casing head, and means to secure said hanger in position between said two casing heads.v

ROBERT A. MUELLER. JOHN R. YANCEY.

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