US2503896A - Pressure regulating device for pipes - Google Patents

Description

April 1950 t B. F. YpuNT 2,503,896

PRESSURE REGULATING DEVICE FOR PIPES Filed July 3, 1948 INVENTOR.

B.F. YOUNT ATTORNEY Patented Apr. 11, 1950 UNITED STATES ATENT OFFICE PRESSURE REGULATING DEVICE FOR PIPES Benjamin F. Yount, Alvin, Tex.

Application July 3, 1948, Serial No. 37,005

9 Claims. 1

This invention relates to a pressure equalizing tool and particularly to a tool adapted to equalize pressures between the interior and exterior of a pipe string in a well containing hydrostatic fluids. In the drilling of wells, particularly by a rotary method, tubular pipe strings, such as drilling pipe, casing tubing, fishing strings, and the like must be run in and out of the well. The well bore or casing conventionally forming the lining for the well bore, are of relatively restricted area and are normally filled with the drilling fluids or with fluid from the earth formations penetrated by the well. The various pipe strings which must be run in and out of such wells ordinarily have tools of various types attached to them which are generally of larger diameter than the pipe strings on which they are run but of only slightly smaller diameter than the well or casing through which they are run, leaving only a relatively narrow annular space between the tool and the surrounding casing or well bore for displacement of the fluid in the well to permit passage of the tool through the well. This frequently causes considerable difficulty in the lowering of a pipe string and its attached tools into the well, particularly when restrictions, such as back pressure valves and the like are present in the tool string. The resulting piston effect of the tools on the fluid in the well may often act as a hydraulic ram forcing large quantities of fluid back into the earth formations at the bottom of the well. Where formations are relatively permeable, as in the case of oil or gas containing formations, forcing of water or drilling muds-into them in this manner may seriously damage the production possibilities of the formations, or may cause such formations to appear to be unproductive upon subsequent flow tests. When such a string of tools is being withdrawn from a hole containing fluid, the piston effect may produce undesirable suction and consequent swabbing action may occur which may be detrimental to the well or the operations being performed in the well. Surges of fluid from the bottom of the well under formation pressures often occur which may force the tools upwardly and even blow them from the well in the absence of some method for quickly relieving the pressure to the exterior of the tool string above the restriction.

Accordingly it is a principal object of this inr vention to provide a pressure equalizing device which is designed to obviate the aforementioned dimcultie's.

An important object is the provision of a de* vice for insertion into a pipe string extending into a well containing fluid, which will serve to equalize the fluid pressures inside and outside of the string during movements of the pipe string or when the string is stationary.

Other and more specific objects and advantages of this invention will become apparent from the following detailed description when read in conjunction with the accompanying drawing in which Fig. 1 is an elevational, generally quartersectional view showing one embodiment of the pressure equalizing device in accordance with this invention inserted in a pipe string which extends into a well;

Fig. 2 is a perspective view showing details of one of the valve elements of the device:

Fig. 3 is an elevational view of one of the valve closure elements of the device;

Fig. 4 is a perspective view of the valve structure in its closed position;

Fig. 5 is a side elevation of one of the valve closure elements; and

Fig. 6 is a diagrammatic illustration of the manner in which the valve closure elements in accordance with one embodiment of this invention may be formed.

Referring to the drawings, the tool comprises a tubular body I having an axial bore 2 extending therethrough. One end of the body is reduced in diameter and externally threaded at 3. The opposite end of body I is provided with an internally threaded box 4 of somewhat larger internal diameter than bore 2 forming an annular shoulder 5 at the base of box 4. A sub 6 is provided with an externally threaded pin portion 1 adapted to be received in box 4 and having an axial passageway 8 therethrough of somewhat smaller diameter than bore 2 and in registration therewith. The lower end of pin portion 1 is reduced in external diameter forming an annular extension 9 which is adapted to extend into bore 2 when pin portion 7 is made up into box 4. The opposite end of sub 6 carries an internally threaded box portion It for connection in the usual manner to a lower end of a string of pipe H the bore of which comm-unicates with passageway 8 of the sub. The reduced threaded portion 3 of the body is adapted to be screwed into a socket l2 carried by the upper end of a tool l3 having a hollow bore l4 communicating with bore 2 of the body. Pipe string l I may be a conventional string of tubing, of drilling pipe, or of easing smaller in diameter than the well or casing in which the pipe and attached tools are to be run. Tool l3 may be any of the various types of tools which are commonly operated in wells,

such as fishing tools, drilling tools, core barrels, or

the like. Normally such tools will be considerably larger in diameter than the operating pipe string on which they are run and will usually be only slightly smaller in diameter than the well bore or well casing through which they are run. The equalizing tool in accordance with this invention will, therefore, usually be inserted, as illustrated, at the juncture of the smaller pipe string with the larger diameter tool being run thereon. Accordingly, body I and sub will ordinarily be made or the same external diameter as that of the tools while socket will ordinarily be reduced in external diameter to that of the pipe string to which the tools are attached.

Body I is provided with oppositely disposed ports I5 which extend radially through the wall of the body to provide communication between the exterior of the body and bore 2. will usually be arranged in cylindrical inserts l6 which are adapted to be threadedly inserted through the wall of body I. Ports l5 may be lined with a tapered bushing ll, constructed of synthetic or natural rubber or other resilient material, the inner ends of which project slightly from the wall of body I into bore 2. A pair of complementary generally clam shell-shaped valve closures [8 are arranged in bore 2 over the inner ends of ports l5 for opening and closing these ports, and for forming a closure across bore 2 of the tool. Closures is shaped in the form of sections of cylinders of substantially the same radius as that of bore 2, so that when closures 18 are pressed outwardly against the inner ends of ports [5, they will form tight seals over the inner ends of the ports. The sides of the closures I B which are formed as continuations of the cylindrical'surfaces, taper angularly toward the opposite ends of the'closures and intersect at a point intermediate the ends of the closures, so that in side elevation, the sides'appear as triangles, having upper sides 20 and lower sides 2!. Each of the closures has an ear 22 extending upwardly from the center of side 20 and engageable in a slot 23 cut longitudinally in the lower edge of extension 9 and are'pivotally mounted therein on hinge pins 23a for swinging movement toward and away from the inner ends of ports l5. A spring member 24 is suitably connected to each of the cars 22 and arranged in slot 23in such a manner as to normally urge the closures inwardly toward the iongitudinal axis of bore 2. I'he lower edge of extension 9 is cut or machined to form a seat 25 against which the upper edges 28 of the closures will be tightly pressed when the closures are swung inwardly to the position illustrated in Fig. 5. At the same time, when this position is assumed by the closures, the adjacent angular edges 2 I of the closures will abut and form longitudinal seals as illustrated in Fig. 5, which together with the seal formed by edges 20 with seat 25, form a closure for bore 2. At the center of the lower end of each of the closures iii a semi-circular groove 26 may beprovidedsothat when the closures are in the position illustrated in Fig. 5 for closing bore 2, an axial orifice. 21 of relatively restricted area will .be provided through the closures. Instead of providing the complementary grooves 25 to form'orifice 21, as described, orifice 21 may be merely ajsmall hole drilled in one or more of the closures to provide a restricted passage for fluid through the closures when they are in the bore-closing position.

Fig. 6 illustrates the angular relationships of Ports I 5 sides 20 with seat 25 and sides 2| with each other, by means of which closures l8 may, by the pivoted arrangement described, form closures for ports I5 when swung outwardly about pivot pins 23, and also close bore 2 when swung inwardly. Closures l8 and seat 25 may be visualized as sections of the same cylinder C, which are formed by cutting the cylinder along planes which angularly intersect the cylinder. Sides 2!] and 21 of each of the closures iii are formed by converging planes extending from the same side of the cylinder toward the axis thereof and which intersect each other to form the included angle b. Seat 25 isformed by planes which extend at equal angles from opposite sides of the cylinder and intersect at the center line L of the cylinder to form the included angle a. In order that sides 20 may form a tight circumferential seal with seat 25, while, at the same time, sides 2! will form a tight longitudinal seal, one-half of angle a. should be or less, angle b should be 90 or more andthe sum: of one-half'angle a plus angle hshouldequal Thus, seat 25 may even'be on a straight line extending at right angles to the axis of the cylinder, in which case angle b should be 80. In every case side 2!) should be approximately equal in'length to one-half of seat 25.

It should be understood that two or more ports l5 and a corresponding number of closure members I8 may be employed. Where more than two closures are used it will be understood that the geometrical forms of seat 25 and closures i 8 will be correspondingly altered, as will the angular relationships between their several cooperating surfaces.

The above-described regulating device'is employed in the following manner: As indicated previously, the: device will be inserted at the juncture of an operating pipe string, such as pipe H, and a tool 13; which normally forms an enlargement on the string, and the string'will be run into a well in the'usual manner. It'will be assumed that the well contains fluids, such as ordinary drilling mud or fluids from the earth formations. As the string is lowered in the well, closures I8 will occupy their normal bore-closing position, asillustrated in Fig; 6. As the string moves downwardly in the well, fluid will rise through the interior thereof and the major portion thereof will be rapidly discharged to the exterior of the string through ports l5, thereby relieving the pressure on the bottom of the well produced by the piston efiect of the tool. At the same time orifice 21 will admit the fluid to the interior of the string above closures 18' thereby reducing the buoyancy of the string, and permitting the string to sink rapidly of'its own weight through the fluid.

When the tools have been landed in the well, circulation of drilling or washing fluid may be conducted in the conventional manner, that is, downwardly through the interior of the string and thence upwardly outside thereof through the annular space between'the string and the well bore or casing. The pressure of fthepfluid flowing downwardly through the interior'foftlie string will overcome the force of spring members 24 and will force closures l 8 outwardly to open bore 2 while at the same time closing oiI ports iii to thereby prevent short-circuiting of the fluid flow.

It will be seen that any surges of fluid under pressures from below the regulating device will force closures l8 to close on" bore 2 and thereby permit relief of excessive pressures through ports l8 to the exterior of the string. Should the pressure in the annular space above tool l3 exceed the pressure inside the string, the resulting pressure differential across ports 15 will force closures I8 inwardly and allow fluid from the annular space to enter bore 2 below the closures to equalize the pressures.

From the foregoing, it will be evident that the tool in accordance with this invention may be employed for equalizing pressures between concentric tubular bodies which are immersed in a hydrostatic fluid.

It will be understood that various changes and alterat ons may be made in the details of the illustrative embodiment without depart ng from the scope of the appended claims but within the sp rit of this invention.

What I claim and desire to secure by Letters Patent is:

1. A pressure equalizing device, comprising, a tubular body adapted for insertion in a pipe string, a plurality of angularly spaced passageways extending through the walls of said body, a generally annular shoulder arranged in the bore of sa d body above said passageways, segmental complementary closure members swingable in said bore between said passageways and said shoulder to open said bore when said passageways are closed thereby and to close said bore when said passageways are open, and resilient means associated with sa d members to normally urge them toward their bore-closing position.

2. A pressure equalizing device, comprising, a tubular body adapted for insertion in a pipe string, a plurality of angularly spaced passageways extending through the wall of said body, a generally annular shoulder arranged in the bore of said body above said passageways, segmental complementary closure members swingable in said bore between said passageways and said shoulder, said members and said seat being cvlindrical segments having a common diameter and of such complementary shape as to form closures for said passageways in one position and a closure for said bore in another position, and resilient means associated with said members to normally urge them toward their bore-closing position.

3. A pressure equalizing device, comprising, a tubular body adapted for insertion in a pipe string, a plurality of angularly spaced passageways extending through the wall of said body, a generally annular shoulder arranged in the bore of said members mounted below said shoulder for swinging movement relative to the longitudinal axis of said bore for opening and closing said passageways, said members having complementary surfaces engageable with said shoulder and with each other to form a closure for said bore when swung inwardly toward each other, and spring means associated with said members to normally urge them toward their bore-closing position.

4.. A pressure equalizing device, comprising, a tubular body adapted for insertion in a pipe string, angularly spaced passageways extending through the wall of said body, a generally annular shoulder arranged in the bore of said body above said passageways, a plurality of segmental closure members mounted below said shoulder for swinging movement relative to the longitudinal axis of said bore, said members being formed of cylindrical segments having outer surfaces concentric with said bore for opening and closing said passageways, and having complementary inner surfaces engageable with said shoulder and with each other to form a closure for said bore when swung inwardly toward each other, and spring means associated with said members to normally urge them toward their bore-closing position.

5. A pressure equalizing device, comprising, a tubular body adapted for insertion in a pipe string, a plurality of angularly spaced passageways extending through the wall of said body, a generally annular shoulder arranged in the bore of said body above said passageways, segmental complementary closure members swingable in said bore between said pasageways and said shou1- der to open said bore when said passageways are closed thereby and to close said bore when said passageways are open, resilient meansassociated string, a hollow sub insertible in said body for connecting the body to a pipe string, the inner end of said sub forming a generally annular shoulder in the bore of said body, a plurality of angularly spaced passageways extending through the wall of said body below said shoulder, segmental closure members radially arranged in said bore below said shoulder for swinging movement relative to the longitudinal axis of said bore for opening and closing said passageways, said members having complementary surfaces engageable with said shoulder and with each other to form a closure for said bore when swung inwardly toward each other, spring means associated with said members to normally urge them toward their bore-closing position, and an orifice of relatively restricted area through said closure members when in their bore-closing position.

7. A pressure equalizing device, comprising, a tubular body adapted for insertion in a pipe string, a hollow sub insertible in said body for connecting the body to a pipe string, the inner end of said sub forming a generally annular shoulder in the bore of said body, a plurality of angularly spaced passageways extending through the wall of said body below said shoulder, segmental closure members radially arranged in said bore below said shoulder for swinging movement relative to the longitudinal axis of said bore, said members being formed of generally cylindrical segments having outer surfaces concentric with said bore for opening and closing said passageways, and having complementary inner surfaces engageable with said shoulder and with each other to form a closure for said bore when swung inwardly toward each other, spring means associated with said members to normally urge them toward their bore-closing position, and an orifice of restricted area through said closure members when in their bore-closing position.

8. A pressure equalizing device, comprising, a tubular body adapted for insertion in a pipe string, a threaded box in the upper end of said body, a sub having a hollow threaded pin for 1nsertion into said box and a socket for attachment to a pipe string, said pin having an extension rcceivable in the bore of said body to form a generally annular shoulder therein, a plurality of angularly spaced passageways extending through the wall of said body below said shoulder, a plurality of segmental closure members mounted in said bore below said shoulder for swinging movement relative to the longitudinal axisof said bore for opening and'closingisaid passageways, said members having complementary surfaces engageable with said shoulder and with each other to form a closure for said bore when swung inwardly toward each other, spring means associated with said members to normally urge them toward their bore-closing position, and an orifice of restricted area through said closure members when in their bore-closing position.

9. A pressure equalizing device, comprising, a tubular body adapted for insertion in a pipe string, a pluralityof angularly spaced passageways extending through the wall of said body, segmental complementary closure members swingable in the bore of said body relative to said passageways to open said bore when said passageways are closed thereby and to close said REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 4 Number Name Date 1,461,847 Jackson July 17, 1923 1,543,637 W011; June 23, 1925 1,793,193 Price Feb; 1'7, 1931.

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