US2846015A - Self fill differential collar - Google Patents

Description

Aug. 5, 1958 c. PITTMAN 2,846,015

SELF FILL DIFFERENTIAL COLLAR v Filed lay 10, 1957 2 Sheets-Sheet 1 FILL UP COLLAR I I, I: CASING 'f- IO E l /E'| I g 4 i/ -FLoAT COLLAR 4% I: I it; 3/ EM 5' ag DRILLING MUD ii i CASING Z IO 5 i FLOAT SHOE INVENTOR. FORREST c. PITTMAN, FIG. I. BY

ATTORNEY.

Aug. 5, 1958 F. c. PITTMAN 2,846,015 SELF FILL-DIFFERENTIAL COLLAR Filed May 10, 1957 2 Sheets-Sheet 2 FIG. 2.' FIG.4. .FIG. 5.

54 Fl G. 3. ZNVENTOR.

FORREST c. PITTMAN,

ATTOR NEY.

Unite tates ice SELF FILL DIFFERENTIAL COLLAR Forrest C. Pittman, Duncan, burton Oil Well Cementing a corporation of Delaware Application May 10, 1957, Serial No. 658,334 4 Claims. (Cl. 166-224) Okla, assignor to Halli- Company, Duncan, {)ltla,

and difliculties have been encountered in lowering such casing through the well fluids, as the depths of dn'lled wells have increased.

A common practice, still employed, is to fill the casing manually with the drilling fluids as it is being lowered into the well. To overcome the obvious difficulties of such manual filling practices, various so-called automatic devices have been developed. These devices are gen erally attached to the bottom of a string of casing and are modifications of the conventional float shoes or float collars. Such devices are of necessity complicated in design and operation, and in many instances do not operate too successfully. Such devices employ a valving means to control the flow of fluids from the bore hole into the casing, and they must also have another valving means for the discharge of fluids into the bore hole in order to place the cement around the casing. Some examples of such devices attached to the bottom of a string of easing are found in the following United States Patents: 2,713,870, 2,718,265, 2,713,914, 2,724,443, 2,717,647, 2,717,648, and 2,717,649.

The first departure from the devices of the prior art that is known to this applicant is that of Maly et al., in patent application Serial No. 546,620, filed November 14, 1955. In the Maly, et a1. application a device separate from the conventional float shoe or float collar is employed, which results in satisfactory, reliable, and controlled filling of a well casing. The filling of the casingis effected through side ports in the tool rather than through the bottom of the string of casing.

One object of this invention is to provide a novel improvement of the casing fill up device disclosed in the above Maly et al., application.

It is another object of this invention to provide a means to close the tool, if it becomes necessary to float the easing into the bore hole.

It is still another object of this invention to provide a means to establish circulation at any time during the lowering of the easing into the bore hole without aflecting subsequent operations of the tool and without losing circulation through the ports provided in the tool.

Other objects and advantages of the invention will become apparent from the following description, when taken in connection with the accompanying drawing in which:

Figure 1 is a diagrammatic view in elevation showing a casing provided with a conventional float shoe and the tool of the invention being lowered in a well bore.

Figure 2 is a longitudinal cross sectional view of the tool in the closed position.

Figure 3 is a cross sectional view taken along A-A of Figure 2.

Figure 4 is a longitudinal cross sectional view of the tool opened so that fluids will enter the casing.

Figure 5 is a longitudinal cross sectional view of the tool showing the permanent closure of the ports.

Referring to the drawings in detail, Figure 1 illustrates a string of wellcasing 10 being lowered into awell bore 12. Assembled to the lower end of thecasing 10 is aconventional float shoe 14. Placed above thefloat shoe 14, at any position desired in the string ofcasing 10, is the fill uptool 16 of the invention.

Thehousing 18 of thetool 16 is adapted at 20 and 22 to be placed between two joints of thecasing 10. If desired, thehousing 18 may be connected at 22 directly to thefloat shoe 14 by means of anadapter coupling 23 and at 20 to thecasing 10. At least twotransverse ports 24 are provided in thehousing 18.

Ahollow valve body 38 of drillable material, such as aluminum, is positioned inside thehousing 18. The hollow portions are designated by thenumeral 42. Fitted around the outside of the lower portion of thevalve body 38 is asleeve 26 with ports 24a. Horizontal fluid passageways 2412 are provided in thevalve body 38. As shown in Figure 2shear pins 28 are provided to hold thesleeve 26 and thevalve body 38 in temporary fixed relationship to the housing 13 and to hold theports 24 and 24a in communication with thefluid passageways 24b.

Thesleeve 26 is provided with agroove 30 in which is placed asnap ring 32. Thesnap ring 32 is adapted to engage agroove 34 in thehousing 18 when thesleeve 26 is in the position shown in Figure 5. Leakage of fluid between thehousing 18 and thesleeve 26 is prevented by O-rings 36.

Thesleeve 26 is shown as fitted into a recess in thevalve body 38 and is of a different material. Thesleeve 26 could be constructed as an integral part of thevalve body 38 without departing from the spirit of the invention. However, the preferred embodiment is shown in the drawing. A vertical conduit 40 is provided to connect thefluid passageway 24b with thehollow portions 42. A valve means 44 is positioned in ahollow cylinder 40a defined by thewalls 41 of thevalve body 38. At the point where thehorizontal fluid passageway 24b and the vertical conduit 41) intersect, the interior of thevalve body 38 is machined to provide aseat 46. Thetop 64 of thevalve body 38 has ashear ring 66 inserted therein.

The valve means 44 consists of several coacting elements. Apiston 48 of clrillable material has arubberlike plug 58 molded to its upper end. Arounded portion 52 of thenose 53 of the rubber likeplug 50 has a smaller diameter than thebase 54, which provides a bearing surface for the application of pressure. At thebase 49 of thepiston 48 is acoil spring 56 with ahollow spring retainer 58 positioned therein. Thespring 56 and itsretainer 58 are held in the position shown in the drawing by aretaining ring 60, which fits into agroove 62 of thevalve body 38. An O-ring 68 prevents fluid leakage between thepiston 48 and the portion ofvalve body 38 defined by theconduit 40a.

An illustration of the operation and coaction of the elements of the invention is as follows:

Thetool 16 is assembled in the string of well casing 10 at any place above theconventional float shoe 14. It a float collar is employed in addition to thefloat shoe 14, the tool is placed above such float collar. The assembly is then lowered in thebore hole 12, which contains drilling fluid. As the assembly is lowered additional joints of well casing 10 are added. The valve means 44 of thetool 16 is in the position shown in Figure 2 of the drawing, since thespring 56 exerts force on thepiston 48, whereby thenose 52 of the rubber likeplug 50 firmly engages theseat 46 of thevalve body 38. The

valve in thefloat shoe 14 remains in the closed position, and the interior of thecasing 10 remains empty until the embodiment of the invention begins to function.

The fluid in thebore hole 12 enters theports 24 as the assembly is lowered and exerts a pressure on thebase 54 of the rubber likeplug 50; such pressure at any depth is of course that of the hydrostatic head of the fluid in thebore hole 12. Thespring 56 is of such strength that it will overbalance a predetermined pressure exerted by the hydrostatic head of the fluid. By way of example in illustrating the invention, thespring 56 will maintain the valve means 44 in a closed position up to a pressure of 80 pounds per square inch (p. s. i.). When the pressure exerted by the hydrostatic head of the fluid on thebase 54 of the rubber likeplug 50 approaches 80 p. s. i., thepiston 48 moves downwardly and starts to compress thespring 56. Thenose 52 of the rubber likeplug 50 separates from theseat 46 and the fluid, then passes around and enters the vertical conduit 40. At this point the pressure of the hydrostatic head of the fluid is acting on the entire surface of the rubber likeplug 50, and such increase in pressure snaps thepiston 48 downwardly, whereby the valve means 44 assumes the open position as shown in Figure 4 of the drawing.

Fluid enters thecasing 10 through theports 24, conduit 40, and thehollow portions 42. The fluid inside thecasing 10 will exert a pressure due to its hydrostatic head. The hydrostatic head of the fluid outside thecasing 10 is greater than that of the fluid inside. Such difference is commonly termed the diflerential pressure. Depending upon the strength of thespring 56, fluid will continue to enter thecasing 10. Before thecasing 1% completely fills and overflows the system is so adjusted, so that the valve means 44 will close thepassageway 24b and thereby prevent the entry of additional fluids. Again as an illustration, thespring 56 is so designed that at about a differential pressure of 60 p. s. i., it starts pushing thepiston 48 upwardly. As the rubber-like plug 50 moves toward theseat 46, less area of the nose 5'2 is subjected to the fluid pressure from thebore hole 12, and thus the valve means 44 snaps shut and the system again assumes the position as shown in Figure 2 of the drawing. When the differential pressure reaches about 80 p. s. i., the system again opens as described above and the fluid enters thecasing 10. It is thus seen that the unique arrangement and construction provide a means for self or automatic filling of a well casing as it is lowered into a bore hole to a desired depth. It is to be noted that the valve means 44 normally has only two positions, either fully closed or fully opened. The intermediate position is barely perceptible due to the pressure exerted by the fluid and thespring 56. Such a feature is advantageous in that it prevents clogging theports 24 and 24a and thepassageway 24b.

The next step in the operation is to cement thecasing 10 in thebore hole 12, by any of the conventional methods employed in the art. After the cement is displaced it is desirable to seal ofl permanently theports 24. As is known in the cementing art, a solid top plug'(not shown) is placed on top of the cement in order to displace the cement in thecasing 10 out through thefloat shoe 14 at the bottom of thecasing 10. In the embodiment of the invention such a plug will come to rest on the top 64 of thevalve body 38. Increased pressure applied at the surface to the displacing fluid is transmitted through the top 64 to thevalve body 38 and shears pins 28 between thehousing 18 and thesleeve 26. Thesleeve 26 and thevalve body 38 move downwardly until thesnap ring 32 engages thegroove 34 in thehousing 18, and the ports 24a of thesleeve 26 are moved out of communication with theports 24 of thehousing 18.

The cement sets up around the outside of the casing to and inside thecasing 10 to the top 64 of the valve '12, and hence has a tendency to float.

4body 38. If desired the cement, thevalve body 38 and the valve means 44 are then drilled out.

The above description of the operation of the invention is that of the normal situation in which no difficulties are encountered in lowering thecasing 10 into thebore hole 12.

The present invention is adapted also to overcome some common difficulties encountered in lowering casing through fluid into a well bore.

it occasionally happens that after thecasing 10 is lowered part of the way in the well bore 12, it becomes necessary to circulate before thecasing 10 can be lowered any further, due to some obstruction in the well bore 12. By circulate" it is meant to pump the drilling fluid down through thecasing 10, out thefloat shoe 14 at the bottom, and up to the surface through the well bore 12 and outside thecasing 10. With the valve means 44 in the open position of Figure 4, circulation could not be accomplished as the fluids would tend to be forced out into the well bore 12 through thepassageway 24b and theports 24a and 24.

Before the circulation operation is commenced, thepassageway 24b would be automatically closed by the valve means 44, as is described in the operation above, since the differential pressure would not be sufficient to overcome the force exerted by thespring 56. During circulation the valve means 44 is maintained in the closed position, as shown in Figure 2. The circulating fluid passes down through thecasing 10 by means of pump pressure exerted at the surface. The fluid passes around the valve means 44 and thetubular passageway 24b through thehollow portions 42. The fluid in the conduit 4% acts on thenose 53 of the rubber likeplug 50, which would tend to move the valve means 44 downwardly and hence unseat it. However, the pressure of the fluid in thecasing 10 also acts on thebase 49 of thepiston 48. Thebase 49 is so constructed that it is of a larger cross sectional area than that of thenose 53 of the rubber likeplug 50. Therefore, the pressure acting upwardly on thebase 49 is greater than that acting downwardly on thenose 53, so the valve means 44 is aided by thespring 56 will remain firmly closed. As soon as the circulation operation is completed thetool 16 operates as has been described above.

Sometimes after thecasing 10 has been lowered to a certain depth, and fluid added as described above, it is desirable to float thecasing 10 the remainder of the distance in thebore hole 12. By floating it is understood in the art that thecasing 10, empty or partially filled with fluids, is buoyant in the fluids in the well bore In this event, it is necessary to permanently close off theports 24 in thehousing 18. This is accomplished in a similar manner as described above after the cementing operation. Instead of the top cementing plug, a ball (not shown) is dropped through thecasing 10 and lands on theshear ring 66 in thevalve body 38. Suflicient pressure is applied to the ball so that thepins 28 shear, whereby thesleeve 26 and thevalve body 38 move down and close off theports 24 as described above. In order to perform the cementing operation the ball must be removed. This is accomplished by additional pressure on the ball, which breaks theshear ring 66, allowing the ball to fall into thespace 42, where it will not obstruct flow through the bottom of the casing during the cementing operation.

From the foregoing description in connection with the various figures of the drawing, it is seen that this invention provides a novel automatic means to fill a well casing as it is lowered into a well bore and that such device provides a solution in the event certain common dithculties are encountered.

Although the invention has been described in terms of a specific embodiment, it should be understood that this was by way of illustration only and that the invention is not limited thereto. Accordingly, modifications of the vertical fluid passageways, said horizontal fluid passageway being in temporary communication with said ports in said housing, shearable means adapted to hold said valve body in temporary fixed relationship to said housing, said shearable means being adapted to hold said ports and said horizontal fluid passageways in temporary 1 communication, and valve means in said valve body adapted to permit the entry of fluid and to exclude the entry of fluid into said conduit as it is being lowered into a bell bore, said valve means being operated by the differential pressure.

2. An improved device for automatically filling with fluid a conduit lowered into a well bore, comprising, in combination, a housing connected to said conduit, said housing having ports, a hollow valve body fitted inside said housing, said valve body having connecting horizontal and vertical fluid passageways, a sleeve disposed inside said housing and disposed around said valve body, said sleeve having ports in temporary communication with the ports in said housing, said sleeve being adapted to close the ports in said housing, shearable means adapted to hold said sleeve and said valve body in temporary fixed relationship to said housing, said shearable means being adapted to hold said ports and said horizontal fluid passageways in temporary communication, and valve means in said valve body adapted to control automatically the flow of fluids through said ports and said fluid passageways, as said conduit is being lowered into a well bore, said valve means being operated automatically as the fluid pressures inside said conduit and outside said conduit vary.

3. A11 improved device for automatically filling with fluid a conduit lowered into a well bore, comprising, in combination, a housing connected to said conduit, said housing having transverse ports, a hollow valve body fitted inside said housing, said valve body having connecting horizontal and vertical fluid passageways, a sleeve having transverse ports fitted in a recess in said valve body, shearable means adapted to hold said sleeve and said valve body in temporary fixed relationship to said housing, said shearable means being adapted to hold said transverse ports and said horizontal fluid passage- Ways in temporary communication, and valve means in said valve body adapted to automatically close said horizontal and vertical fluid passageways to the flow of fluids from the well bore into the said conduit by the action of differential pressure as said conduit is being lowered into a well bore.

4. An improved device for automatically filling with fluid a conduit lowered into a well bore, comprising, in combination, a housing connected to said conduit, said housing having transverse ports, a hollow valve body fitted inside said housing, said valve body having connecting horizontal and vertical fluid passageways, a sleeve having transverse ports fitted in a recess in said valve body, shearable means adapted to hold said sleeve and said valve body in temporary fixed relationship to said housing, said shearable means being adapted to hold said transverse ports and said horizontal fluid passageways in temporary communication, and valve means in said valve body adapted to automatically open said horizontal and vertical passageways to the flow of fluids from the well bore into the said conduit by the action of diiferential pressure, as said conduit is being lowered into a well bore.

References Cited in the file of this patent UNITED STATES PATENTS

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