US2417181A - Oil well pressure control system - Google Patents

Description

f Mmh11, 1,947. J', c, sANmLANl-s 2,417,181

OIL WELL PRESSURE CONTROL SYSTEM Filed June "8, 1942 s sheets-sheet 1 Marl'l v11151947., l 1 Q snlQVDlLAN|35 2,417,181

OIL WELL PRESSURE 'CONTROL SYSTEM Filed June 8, 1942 3 Sheets-Sheet 2 March 11, 1947. Y L C, SANDlLANDS 2,417,181l on. WELL PRESSURE oo NTRoL sYsTEM Filed June 8, 1942 vs' sheets-sheet s" yUTI val-H731 Patented Mar. 11, 1947 UNITED; STATES Parent oFFlfc E:

OIL WELLv PRESSURE CONTROILSYSTEM;

James, Caldwell Sandilands, Toronto, O'iitarigg Canada; assign'or to'The James'Morrison Brass Mfg. Co., Limited, Toronto; Ontario," Canada,` a."-

company of `Canatlar Y Application June-8, 1942, ,SerialNo.f446,248-f Y l This invention relates Vto an oilwell pressure control system or well head"and-is particularly directedto providingiir'nprovern'entsV in the arrangement by means ,of which thewintermediate casing` is car'riedbyl the .casing head in its. xed position in the. oil well. l

Oneofthe diilcultiesintlie present oil well.

pressure control systems is thatl of :providing a firm and permanent. gripping connection' between the intermediatecasing andthe casing hea'd,`by means'of which the heavy intermediate casinglis" heldrmly` in it'slfixed position by the.

casing head and in. exact",l alignment. therewith. The intermediatecasing is .usuallysecured tothe casing head by' means of slips having serrated' teeth, the slipsibeing wedged. between the intermediate casinggand the casinghead. The outside.

diametenof. the intermediate casing is, however, subject'to considerable variation within manu.- facturing tolerances, and inlusinga conventional set of four slips, the slipsdo not conform with the outer surface ofthe intermediate casing ,with theresult that there is not sufficient gripping contact'between the outside surface oflthecasing,

5' tainingthe slipsiiexact vertical alignment with each other asth'e slips are being' loweredinto:

and theserrated'surface ofthe slips. For-exam'- 25 ple; when the"` diameter `of i thev casingiis slightly. larger than thediameter of -tlie circular serrated;

surface of the slips,only the serrated surfaces at the edges ofth'eslipsiare in'grippingl contact withth'esurface' of the casing,` Alternatively; if the diameter of theouter` surface ofthe intermediate casing,isslightlysmaller than that ofthe serrated surface ofthe slips, onlyV the central parts of the serratedsurface' ofthe slips are in grip- -ping contact withV the surface of the casing. Wherethe 'gripping contaetbetween` the serrated surface'of the s1ips"and' theV outer surface yof 'the intermediate 'casing fis insuf'cient, the casing may, be deformed or may4 tear loose .thereby y putting al1 the'load' ofi` the casing 4"on" the '.we1d or other connection; joiningu the casing; tot` the landing head2' One of ftheprincipal objects of the present invention is to increasethe number'of serratedslips employed in. supportingjthe intermediate casing from the casingheadgthereby dividing the inner surface of "th'e slips into smallersegments, making possible uniform contact between the entire serrated'surfaces ofth'esli'psand the outer surA face -ofthe intermediate casing, regardlessof Y 2 variations the diameter of the intermediate casing.-

Alfrtler'. problem ,in assembling the parts of" thetapparatus arises fi'omztliel difficulty of" main:

position. T 1

A', further .ob'jct oft "tlieginvention, therefore,` is

to provide,asimplebutlverm effective arrangement of," parts by means ofwhich the slips arebrought' into and`held"inexact vertical alignment ras the' intermediate casing is adjusted into its nal"per' marient position.

A still'l'frther "object "of "the inve-enticn is to "increasetheeiective'span of 7Athe'packing space between the upper surface of the slips andthe lower surface ofthe; casinglandingihead without increasing theheight'of'tne' casing head and without decreasing" the. height of'l the serratedk surfaces oftlieslips;

An understanding .,of'tneobjects ofthe presents invention: and ltlie "manner in' which they are attained may behad from? the following description and -accoinpanving drawings, inf which:

Figure' 1 isacrossf-sectional front elevation of an oil 'wellfpressure control systemincorporating the. present` invention Figure `2"is"a."si`d elevation "of an "outer view` of the slips; v

Figure" 3" is-` a crossesectional topA planview taken" alor1g:the line 3:--31v Figure' 1, showing the intermediate casing having" a smaller diameter tharrthatofl the slips;A

Figure "3hJ `is asimilar viewfof an intermediate casing having a, larger diameter than that of the Figure-:.6 isa planyiew` oitheaunderside of thel mount'd;" one positioned 'on top of the other, and' vfissatacrosssectionall elevation of" the l 3 are formed with an aligned centrally located chamber 22. The lower end of the tubing head I and the upper end of the casing head I2 are formed with outwardly extending flanges 25 and 26, respectively, which are secured together in fluid tight engagement by the bolts I9.

The lower end of the casing head is internally threaded, as indicated by the numeral 2U, to receive the threaded upper end of the outer casing I 4 The outer casing I4 usually extends downwardly into the well a distance of about 500 feet.

The upper Aenol of the intermediate casing I5 extendsinto chamber 22vapproximately the full height of the casing head I2 and is carried by that head in the manner described in detail hereinafter. The intermediate casing I5 is of less dlameter than the outer casing I4 and extends downwardly through that casing, usually extend.

ing into the well a distance of'about 4000 feet.

The tubing landing head II,`v provided on the upper part of the tubing head I0, is formed with a vertical slightly tapered central opening into which is wedged the tapered inner casing-or tubing hanger II which is drilled and tapped, as i11- dicated at I8, to receive the threaded upper end of the inner casing or tubing I6. The hanger I'I is held firmly in its fixed position bythe adjustable set screws I9. In ordinary practice, the in-v ner casing or tubing extends downwardly through the intermediate casing I5 to the lowermost depths of the well, for example, from 6000 to 8000 feet. v

Oil outlet ports 2| are located in the upper part of the tubing head ID and are providedwith the usual valve members (not shown)` by means of which the flow of oil from the several casings is controlled.

The manner in which the intermediate casing I5 is carried by the casing head I2 constitutes one of the principal features of the' present invention and is described in detail hereinafter.

The central chamber 22 formed by the bore of j y the heads Iii and I2 is of greater diameter than that of the intermediate casing I 5 which extends into it. The upper walls of chamber 22 are curved inwardly, as indicated by the numeral 21, above the upper end of the intermediate casing I5, to provide a passageway for the oil flowing through the chamber 22 to the outlet ports 2i. The Walls of the lower end of the chamber are tapered inwardly as indicated by the numeral 23.

The intermediate casing I5 isheld in its fixed position by the serrated inner surfaces of the slips 24 which form an'annular ring around the outer surface of the intermediate casing. Ther slips 24 are wedged into the space between the wall of the intermediate casing and the tapered wall 23 of the chamber 22, 'the outer wall of each slip being tapered to conform with the tapering of the chamber wall 23.

I have found that by increasing the number of slips, it is-possible to provide a gripping contact between all the serrated surfaces of the slips around the periphery of the outer surface of the intermediate casing, regardless of the variations in the diameter of the intermediate casing within manufacturing tolerances. This feature is shown in Figures 3 and 3a which illustrate the serrated surfaces of the slips in gripping contact with intermediate casing members, the diameter of which is larger and smaller, respectively, than standard. This complete gripping contact is effected by increasing the number of the slips and making it possible to shape the slips in smaller segments of a circle of the approximate average diameter of the intermediate casing.

The serrated surface of each slip is formed such that, in a vertical plane, the surface is in exact alignment with the intermediate casing and, in a horizontal plane, the surface is curved in a. segment of a circle, the diameter of which is approximate to that of the average diameter of the intermediate casing. I have found that six slips are the minimum number which will bring all of the serrated surfaces of the slips in gripping contact with allparts of the surface of the intermediate casing over the area which the slips extend.' This number of slips may be increased, if desired.

An aligning ring or slip ring 28 is fitted into the aligned grooves 34 cut in the outer walls of the slips. The slip ring 28 is preferably formed in three or more `segments for convenience in passing around the casing and fitting into the grooves 34. Also, when formed in this manner,

it permits freer horizontal movement of the slips.

The slip'ring 2B is drilled vertically at spaced intervals to receive the vertical retaining bolts 29. An outwardly extending flange formed on each slip may be drilled to receive the ends of the bolts 29, The holes in the slip ring and in the slips are aligned in such a manner that the slips are retained in exact alignment as they are being formed into an annular ring in their desired position around the outer surface of the intermediate casing. The'bolt holes in the slip ring and slips are preferably made sufficiently larger than the bolts Vto permit the maximum horizontal movement of the slips.

A stuffing box ring 30 is inserted above the slips 24 and between the walls of the outer casing I5 and the walls of chamber 22. Packing rings 33 are inserted above the stuffing box ring 30 and the intermediate casing hanger head I3 is inserted above packing 33. The upper surfaces of 33 and the lower surface of the hanger head I3 at an angle to the horizontal.

The upper end of the intermediate casing terminates in the hanger head I3 which is drilled to receive the packing studs 32 which pull on the packing gland 35 to adjust and to hold the packing rings in their xed position while the apparatus is being assembled.

It has been found that this arrangement of packing more effectively seals the oil in chamber 22' and prevents the oil from escaping down the outer'casing I4.

The upper end of the intermediate casing is joined to the hanger head I3, such as by welding, as indicated by the numeral 3B.

In assembling the apparatus, the outer casing I4 is joined to the base of the,` casing head I2. The intermediate casing I5 is then lowered into position and the slips, retained in their aligned position by the slip ring 28, are lowered into their position in the lower part of chamber 22 and are retained, as they are lowered, in their circular position by the vertical retaining bolts 29 which pass through the aligning or slip ring 28. The serrated surfaces of the slips grip the outer surface of the casing and the weight of the casing causes the slips to be wedged tightly in their ping contact between the serrated surfaces of the slips andthe outer surface of the intermediate casing. The' inner casing or tubing I6 is then lowered. into place and the upper end joined to the tubing landing head H as described hereinbefore.v

It has been found that by having the aligning or slip ring 28 extend horizontally, and by using vertically disposed retaining bolts, it is possible to increase the number of slips to such an extent that each slip forms only a very small segment of a circle, thereby ensuring that the entire serrated surface of each of theslips is in its proper position and all the slips form an annular ring, the entire serrated surface of which is in gripping contact with the outer surface of the intermediate casing.

It has been found, also, that the increased vertical span of packing serves to prevent more positively the possibility of any of the oil in the chamber 22 escaping from that chamber except through the outlet lines provided for that purpose.

What I claim as new and desire to protect by Letters Patent of the United States is:

1. In an oil well pressure control system, a casing head, a chamber in said casing head, the lower wall of said chamber being tapered inwardly, a casing extending into said chamber, means for anchoring said' casing in said casing head which comprises a plurality of slips tapered to t snugly into the lower part of the said chamber between the tapered wall thereof and the Wall of the casing extending thereinto, each of said slips having a serrated inner surface and being formed in a segment of a circle to comprise part of an annular, Wedge-like ring extending around and in gripping contact with the outer surface of said casing, and means for aligning the slips in their predetermined position comprising an annular ring formed of separate segments fitted into aligned grooves formed in the cuter walls of the said slips and extending horizontally therearound, the segments being positioned simultaneously in aligned grooves in adjacent slips, the combination of the slips and the aligning ring being free to adjust itself within the chamber to the diameter of the casing.

2. In an oil well pressure control system, a casing head, a chamber in said casing head, the lower wall of said chamber being tapered inwardly, a casing extending into said chamber, means for anchoring said casing in said casing head which comprises a plurality of slips tapered to fit snugly into the lower part of the said chamber between the tapered wall thereof and the wall of the casing extending thereinto, each of said slips having a serrated inner surface and being formed in a segment of a circle to comprise part of an annular, wedge-like ring extending around and in gripping contact with the outer surface of said casing, and means for aligning the slips in their predetermined position comprising an annular ring formed of separate segments fitted into aligned grooves formed inthe outer walls of the said slips. and extending horizontally therearound, the segments being positioned simultaneously in aligned grooves in adjacent slips, and vertically disposed retaining bolts passed through the said aligning ring into aligned holes in said slips, the combination of the slips and the aligning ring being free to adjust itself within the chamber'to the diameter of the casing.

3. In an oil well pressure control system, a casing head, a chamber in said casing head, the lower wall of said chamber being tapered inward- 6 ly, a casing" extending into-said chamber, means for anchoring said easing in said casing head which comprises a plurality of slips tapered to fit snugly into the lower part of the said chamber between the tapered wall thereof andthe wall of the casing extending thereinto, each of said slips having a serrated inner surface and being formed in a segment of a circle to comprise part of an annular, wedge-like ring extending around and in gripping contact with the outer surface of said casing, and means for aligning the slips in their predetermined position comprising an annular ring formed of separateA segments fitted into aligned grooves formed in the outer walls of the said slips and extending horizontally therearound, the segments being positioned simultaneously in aligned grooves in adjacent slips, the combination of the slips and the aligning ring being free to adjust itself within the chamber to the diameter of the casing, and packing rings angularly disposed to said slips and positioned between said slips and the top of the casing, and means for adjusting and holding said packing rings in their predetermined, angularly disposed position.

4. In an oil well pressure control system, a casing head, a chamber in said casing head, the lower wall of said chamber being tapered inwardly, a casing extending into said chamber, means for anchoring said casing in said casing head which comprises a plurality of slips tapered to snugly into the lower part of the said chamber between the tapered wall thereof and the wall of the casing extending thereinto, each of said slips having a serrated inner surface and being formed in a segment of a circle to comprise part of an annular, wedge-like ring extending around and in gripping contact with the outer surface of said casing, and means for aligning the slips in their predetermined position comprising an annular ring formed of separate segments fitted into aligned grooves formed in the outer walls of the said slips and extending horizontally therearound, the segments being positioned simultaneously in aligned grooves in adjacent slips, the combination of the slips and the aligning ring being free to adjust itself within the chamber to the diameter of the casing, and packing rings angularly disposed to said slips and positioned between said slips and the top of the casing, and means for adjusting and holding the packing rings in their predetermined, angularly disposed position.

5. In an oil well pressure control system, a casing head, a chamber in said casing head, the lower wall of said chamber being tapered inwardly, a casing extending into said chamber, means for anchoring said casing in said casing head which comprises a plurality of slips tapered to lt snugly into the lower part of the said chamber between the tapered wall thereof and the wall of the casing extending thereinto, each of said slips having a serrated inner surface and being formed in a segment of a circle to comprise part of an annular, wedge-like ring extending around and in gripping contact with the outer surface of said casing, and means for aligning the slips in their predetermined position comprising an annular ring formed of separate segments tted into aligned grooves formed in the outer walls of the said slips and extending horizontally therearound, the segments being positioned simultaneously in aligned grooves in adjacent slips, and vertically disposed retaining bolts passed through the said aligning ring into '7 aligned holes in Vsaid slips, the combination of the slips and the aligning ring being free to adjust itself within the chamber to the diameter of the casing, and packing rings angularly disposed to said slips and positioned between said slips and the top of the casing, and means for adjusting and holding the packing rings in their predetermined, angularly disposed position.

J. C. SANDILANDS.

REFERENCES CITED The following references are of record in the file of this patent:

Number UNITED STATES PATENTS Name Date Begg July 30, 1935 Tschappat Mar. 16, 1937 Weaver et al. Sept. 6, 1921 Rhea June 27, 1916 Smith Feb. 21, 1939 Brown July 28, 1942 Tschappat May 10, 1938 Spalding Dec. 3, 1935 Tschappat Nov. 5, 1940

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