US2698054A

US2698054A - Method of and apparatus for lowering pipe within a well bore

Info

Publication number: US2698054A
Application number: US73812A
Authority: US
Inventors: Cicero C Brown; Ernest L Potts
Original assignee: BROWN
Current assignee: BROWN
Priority date: 1949-01-31
Filing date: 1949-01-31
Publication date: 1954-12-28
Anticipated expiration: 1971-12-28

Description

Dec. 28, 1954 c. c. BROWN ET AL 2,698,054

METHOD OF AND APPARATUS FOR LOWERING PIPE WITHIN A WELL BORE Filed Jan. 31, 1949 5 Sheets-Sheet l INVENTOBS A T TORNEYS Dec. 28, 1954 c. c. BROWN ET AL METHOD OF AND APPARATUS FOR LOWERING PIPE WITHIN A WELL BORE 5 Sheets-Sheet 2 Filed Jan. 31, 1949 INVENTORS 'fi/m E/Wcs A. Rpfffi v Clcero C Brown ATTORNEY;

Dec. 28, 1954 c. c. BROWN ET AL 2,698,054

METHOD OF AND APPARATUS FOR LOWERING PIPE WITHIN A WELL BORE Filed Jan. 31, 1949 5 Sheets-Sheet 3 f'm'esf L. P01 4 5 C/cero C. Brown [/Vl/t'NTO/PS A T TORNEYJ Dec. 28, 1954 c. 0. BROWN ET AL 2,698,054

METHOD OF AND APPARATUS FOR LOWERING PIPE WITHIN A WELL BORE F-1ed Jan 31 1949 5 Sheets-Sheet 4 'f/"f765 L. pofzfs C/cero C Brown v [/VVE/VTORS jd i Zia/aimle- A T TORA/EYJ Dec. 28, 1954 c. c. BROWN ETAL 2,698,054

METHOD OF AND APPARATUS FOR LOWERING PIPE WITHIN A WELL BORE Flled Jan. 31, 1949 5 Sheets-Sheet 5 Men .11 r z A. POzZ $7 Q0 2 30 C. Brown [NI/ENTO/ifi @12 8 fl w ium A TORNEYJ' United States Patent METHOD OF AND APPARATUS FOR LOWERING PIPE WITHIN A WELL BORE Cicero C. Brown and Ernest L. Potts, Houston, Tex.;' said Potts assignor to said Brown Application January 31, 1949, Serial No. 73,812

23 Claims. (Cl. 166-21) is lowered through said bore after which the lower end thereof is bonded ,or permanently attached to the formation by the usual cementing operation. During lowering or running of the pipe or casing, the bore is substantially filled with drilling mud or fluid and said pipe or casing must necessarily be lowered through such mud or fluid. After the pipe or casing has reached bottom the cement is pumped downwardly through the pipe and is forced outwardly and upwardly around said pipe to cement the lower portion thereof to the sub-surface formation. Because of the subsequent cementing opera tion, it is necessary that fluid may pass outwardly from the lower end of the pipe or casing and in some instances, the casing may be run in or lowered with its lower end open; however, because of the danger of a blow-out through the open casing, it has become the usual practice to mount an upwardly closing back check or cementing valve in the lower end of the casing, wherebythe casing is closed during lowering against the possibrlrty of a blow-out and yet, after reaching bottom cement may be pumped outwardly from the lower end thereof.

With an upwardly closing back check or cementing valve in the lower end of the casing, it is apparent that no fluid can enter the casing from the well bore during lowering and it therefore becomes necessary to fill the casing with fluid from the surface. Obviously, filling of the casing is essential for otherwise, it would be substantially impossible to open the check valve downwardly against the entire hydrostatic head pressure of the fluid outside said casing; also, if an empty casing were suddenly opened to the relatively great hydrostatic head pressure of the fluid exteriorly of the casing, the excessive suction efiect which would be produced may result in' damage to the oil producing formation or might cause a blowout.

The filling 0f the casing is ordinarily accomplished by pumping fluid from the mud pit into the casing, with the introduction of fluid being carried out periodically, as for example, upon the running of each two or'three stands of pipe. The filling operation requires holding the pipe stationary and considerable time is consumed in connecting and disconnecting the pump outletto the casing and in actually filling said casing. Thus, the running or lowering of relatively long strings of well casing becomes a lengthy operation which requires an excessive amount of valuable rig time.

Not only does the filling of the casing from the surface result in lost rig time and additional labor on the part of the crew, but also the fact that the casing must be stopped or held stationary at periodic relatively long intervals creates a constant threat or danger of the formation caving and sticking the entire casing string. Because of the danger of cave-in which might stick the casing at any time, it is desirable to run or lower said casing as rapidly as possible and without holding the same stationary for any lengthy periods. A further disadvantage of filling the casing from the surface is that the fluid or mud which is pumped into the casing may not be identical to the mud or fluid within the well bore so that after the casing is run and communication be- 2,698,054 Patented Dec. 28, 1954 tween the interior and exterior of the casing is had, these dissimilar fluids will admix which is not desirable.

It is, therefore, one object of this invention to provide an improved method of lowering pipe, such as well casing, into a Well bore whereby the pipe is automatically filled with fluid from the well bore during lowering to thereby obviate the necessity of filling said pipe from the surface at periodic intervals.

An important object of the invention is to provide an improved method of lowering pipe within a well bore which includes, closing or substantially closing the lower end of the pipe during lowering movement thereof, whereby either no entry of fluid or a controlled entry of said fluid into the pipe may occur, and then shutting ofi flow of fluid into the pipe when the fluid rises to a predetermined level therein, whereby the pipe is filled with fluid from the well bore during the lowering operation or during the time that the next pipe stand is being connected in the string and the loss of any additional rig time, as is the case when filling of the pipe is accomplished from the surface, is eliminated.

A further object is to provide an improved method of lowering or running well pipe within the well bore wherein the opening and closing of the lower end of the pipe during running in of said pipe is effected by the pressure conditions in the well bore and within the well casing and also by the pressure conditions which are produced by the lowering movement of the casing through the fluid within the bore, whereby the opening and closing of the lower end of the casing are accomplished in a completely automatic manner.

Still another object of the invention is to provide an improved apparatus for lowering well pipe within a well bore and including a valve mechanism in the lower portion of the pipe which valve mechanism is actuated by the pressure diiferential thereacross; said valve mechanism being so constructed that the lower end of the pipe is closed during lowering movement of said pipe through the fluid and is opened when movement is halted to allow filling of the casing, with said valve closing automatically when proper filling of said casing has been completed.

A particular object is to provide an improved appara tus of the character described, wherein the kinetic pressure developed during the lowering of the well casing through the fluid within a well bore is utilized to maintain the lower end of the casing closed while the lowering operation continues; halting of the lowering of said casing permitting the differential in static head pressures acting across the apparatus to open said casing to allow filling thereof to a desired point, after which said casing is again closed.

Still another object is to provide an improved valve mechanism which is operated by the differential in pressures acting on opposite sides thereof and which may have the areas exposed to the pressures varied in desired ratios, whereby the operation of the valve mechanism may be varied.

A further object is to provide a valve mechanism which has incorporated therein an adjustable element, such as a spring, which acts on one side of said valve mechanism, whereby control of the filling of the casing may be maintained.

Still another object is to provide an improved valve mechanism for controlling the opening and closing of the lower end of a well casing and which includes a relatively large back-pressure cementing valve for permitting the usual cementing operation after the casing has been lowered into position; the valve mechanism comprising a minimum number of parts and being preferably constructed of a drillable material, whereby after the casing has been landed and cemented in place, the mechanism may be readily drilled out and thereby removed from the bore of the casing.

Other objects will hereinafter appear.

The construction designed to carry out the invention will be hereinafter described together with other features of the invention.

The invention will be more readily understood from a reading of the following specification and by reference to the accompanying drawings, wherein an example of the invention is shown, and-wherein:

Figures 1 to 3 are diagrammatic views of a well casing being run into a well bore in accordance with the improved method, with the lower end of said casing being shown open and closed during the various steps of the method,

Figure 4 is a transverse, vertical, sectional view of the valve. mechanism which is connected to the lower end of thercasing, the valve being in the closed position which it assumes after filling of the casing is complete and with the casing stationary,

Figure 5 is a sectional detail of the valve of Figure 4,

illustrating the same in the closed position it assumes dur- "mg lowering of the casing,

Figure 6 is a view, similar to Figure 5, with the valve being shown in its open position during filling of the easing,

Figure 7 is a partial plan view of the valve, taken on the line 7-7 of Figure 4,

Figure 8 is a horizontal, cross-sectional view, taken on the line 8--8 of Figure 4,

Figure 9 is a view, similar to Figure 4, of a slightly modified form of the invention,

Figure 10 is a view, partly in section and partly in elevation of another form of the invention, the valve being closed after filling and the casing being stationary,

Figure ll is a view, similar to Figure 10, with the valve in: its closed position during lowering of the casing,

Figure 12 is a similar view, illustrating the valve open durmg filhng, and

Figure 13 1s a horizontal, cross-sectional view, taken on the-line 13l3-of Figure 10.

In the drawings, the numeral 19 designates a well bore within which the well casing or pipe 11 is to be lowered. As is well known, the bore is drilled, after which the well casing islowered therethrough to a final position, and it has been the practice to cement or otherwise bond the lower end of the casing within said bore. The well bore is filled with the drilling mud or fluid and the casing is necessarily lowered downwardly through this fluid. The

lowered through the fluid and functions to allow filling of .thepipe-by admitting fluid from the bore while preventing a blowout through the pipe. As shown in the drawings, and as described herein, the valve device operates to close .the casing against the admission of fluid while the casing is undergoing a lowering movement and when the casing string is halted to permit connection af another stand of casing to the string, the valve unit functions to permit automatic filling of the interior of the casing. When the casing fills with fluid to a desired level, the valve unit A automatically closes and thus, the lower end of the casing is closed during lowering and is opened only for a suflicient period to permit automatic filling thereof. In this manner, controlled fillina of the casing is accomplished so that the possibility of blowout during running or lowering of the casing is eliminated. The valve unit A also has incorporated therein the usual back-pressure or cementing valve, so that after the casing has reached its final position within the well bore 18, a cementing operation may be carried out through said casing.

The valve unit A is clearly shown in Figures 4S, and

includes an outer tubular housing or body 12 which is provided with an internally threaded box 13 at its upper end' to permit the same to be attached to the lowermost section of the casing string ll. The lower end of the valve body or housing has a perforated plug 14 provided With inlet openings 15 connected thereto. Intermediate .the ends of the body or housing are located a plurality of outlet ports 16 which are normally closed by an annular piston type valve 17. The valve 17 is upwardly seating against an annular seat 18 and is urged toward its seated position closing the outlets 16 by means of a coiled spring 19 which is confined between the under side of the valve 17 and the upper end of the plug 14. It will be apparent that the valve 17 comprises the usual back pressure valve which closes the lower end of the casing against upward flow, while permitting a downward flow from the casing when the internal pressure within the casing exceeds the pressure holding the valve 17 in its upper or seated position.

A tubular sleeve or cylinder 20 is disposed axially within the valve body or housing and has its lower end connected by threads to the valve member 17; however, the cylinder may, if desired, be made integral with the valve 17. The cylinder has an axial bore 21 which has its lower end reduced, as indicated at 22, and immediately above this reduced portion, an annular valve seat 23 is formed. Above the valve seat 23, the wall of the cylinder is provided with a plurality of ilow ports 24. it will be evident that the lower end of the bore of the cylinder communicates with the space below the back pressure valve 17 so that the fluid within the well bore outside or" the casing string entering the openings 15 in the plug 14 may flow upwardly into the cylinder. From the bore of the cylinder, flow may be through the radial ports 24 and into the casing to which the valve housing or body 12 is connected. Therefore, the lower portion of the bore of the cylinder 29 and the flow ports 24 establish communication between the area extcriorly of the casing string and the bore of said casing string. For controlling the flow past the annular valve seat 23 within the cylinder, a cylindrical valve element 25 is slidably mounted within the bore 20 of the cylinder. The valve member has its major portion of a diameter smaller than the bore 21 of the cylinder and is formed with an outwardly directed annular flange 26 at its upper end, which flange has a sliding fit within said bore. At its lower portion the valve element 25 is provided with an annular seating surface 27 which is adapted to engage the seat 23 to close flow through the reduced portion 22 of the bore of the cylinder and thereby shut off a flow through the ports 24. A valve stem 28 extends upwardly from the valve member 25 and is slidable within an axial opening 29 of a guide ring 30 which is threaded into the upper end of the cylinder. The ring has a plurality of vertical passages or openings 31 which are spaced radially throughout the ring. A coiled spring 32 is confined between the ring 3% and the upper surface of the valve element 25 and constantly exerts its pressure to urge the valve element to a seated position. It will be evident that since the ring 30 is threaded into the upper end of the cylinder, said ring may be adjusted within the cylinder to vary the tension upon the spring 32. The fluid pressure within the casing string may act downwardly through the passages or openings 31 against the upper end of the valve element 25, this pressure being added to the pressure of the spring 32 to urge the valve element 25 to a seated position on the valve seat 23.

A sealing head 33 is spaced from the lower end of the valve element 25' and is secured thereto by a reduced neck or shank 34, these parts being illustrated as integral with the valve element 25. It is apparent, however, that the sealing head 33 and shank 34 could be made separately and suitably connected with the valve element. The external diameter of the sealing head 33 is substantially the same as the diameter of the reduced portion 22 of the bore of the cylinder 20, and when the valve element 25 is moved upwardly, the head 33 is adapted to enter the reduced portion 22 of the cylinder bore. An annular sealing ring 35 which is mounted on the exterior of the head 33 is arranged to seal with the bore 22 to completely shut off flow therethrough when the head is within said bore, as illustrated in Figure 5. It will be obvious that since the head 33 is spaced from the valve element 25, said head is disposed outside of the bore 22 and. is located in a plane therebelow when the valve element 25 is in a seated position, as shown in Figure 4.

As the valve element moves upwardly and is disengazed from its seat 23, a flow may occur from the space below the cylinder, through the reduced portion of the cylinder. past the valve seat, and through the flow ports 24 into the interior of the casing string. This is possible because the diameter of the connecting shank 34 is considerably less than the diameter of the bore 22, and thus as long as the valve element and sealing head are in the position shown in Figure 6, a flow may occur into the casing strin from the area exteriorly of said casing. As the valve continues to move upwardly, the sealing head 33 enters the bore 22 and upon such entry closes flow into the casing string.

In the operation of the valve unit A, said unit is connected to the lower end of the casing string and'is lowered downwardly through the fluid within the well bore. When first introduced into the wel bore, the valve element 25 will be in its lowered position, as shown in Figure 4, with the seating surface 27 of said element engaging the valve seat 23. The valve is held in this position by the spring 32 and at this time, the sealing head 33 is outside of and below the bore 22. As the casing 11 is lowered through the fluid, the kinetic pressure which is built up due to the movement of the casing string downwardly through the fluid will result in an impact pressure against the sealing head 33 and the valve will be moved upwardly so that the head 33 enters the bore 22 to close said bore (Figure 5). The spring 32 is of such strength that upward movement of the valve element and head is halted with the sealing ring 35 of the head within the bore 22. Thus, so long as the casing string is being lowered and the kinetic or impact pressure is acting against the head 33, the valve element and head are in a raised position with the head sealing or closing the bore 22. At this time, the pressure of the spring 32, as well as any pressure within the casing string, are acting against the external pressure holding the valve raised and are tending to urge the valve and head downwardly.

The casing string is lowered until the next stand of casing is to be connected, and at this time, the lowering operation is halted. As soon as movement of the casing through the fluid within the well bore is stopped, the kinetic pressure decreases and the lower end of the sealing head 33 is then subiected only to the hydrostatic head pressure present in the area outside of the casing string above the valve unit A. This static pressure is insufficient to maintain the valve in a position with the sealing head 33 Within the bore, and the valve and head are moved downwardly to the position shown in Figure 6. Upon moving to this position with the reduced connecting shank 34 within the bore 32. an immediate flow of fluid from the area exteriorly of the casing string may flow upwardly through the port 22 and through the valve 25 into the casing. Tt is noted that the external pressure is acting against the lower surface of the valve member 25 and against the lower surface 26a of the flange 26 tending to maintain the valve in an open position against the pressure of the spring 32. which is, of course, tending to move the seating surface 27 downwardly through the seat. The flow of fluid into the well casing continues until the admitted fluid builds up a predetermined head pressure within said casing. This pressure internally of the casing may act through the passages or openings 31 against the upper end of the valve element 25 and thus. when a predetermined head pressure is built up within the casing strin this pressure plus the pressure of the spring 32 is sufficient to move the valve downwardly into en a ement with the seat 23 and shut off further entry of fluid into the casing string.

The parts remain in this position until the next stand of easing has b en connected and lowering of the string through the fluid again takes place. Immediately upon lowering the kinetic pressure developed by such lowering moves the sealing head 33 and valve element 25 upwardly. The instant that the valve element 25 is unseated or disen aged from its seat 23. the pressure mav immediately act not only on the head and the lower end of the valve element but also a ainst the enlarged under surface 26a of the flan e 26 whereby the valve element and head are quickly raised to the osition shown in Figure 5. The

provision of the additional surface 26a provides for a ra id upward movement of the valve element with a snap action and thus. as the valve is moved upwardly. onl a sli ht am unt of fluid may flow into the interior of the casing until the head 33 seals the bore 22. This sli ht flow or admission of fluid occurs only momentarily as thesealing head is moving into its closin osition. As explained. the head 33 seals the bore 22 and remains in sealing posit n so .lon as lowering of the casing strin continues. Whenthecasin string is stopped in order to permit connection of the next stand of p pe. the valve element 25 and sealing head 33 are actuated solely b the differential in the static head pressures interiorly and exteriorly of the tubing. Therefore. when the lowering motion of the well casing stops, fluid is admitted into the casing string to fill the casing string to a predetermined level after which the valve element 25 is lowered onto the seat 23. It will be evident that by adjusting the pressure of the string 32 which is added to the internal casing pressure'acting on the valve element 25, any desired or predetermined liquid level may be maintained.

The valve element 25 and sealing head 33 are operated automatically so that the lower end of the casing is closed while said casing is in motion during its lowering through the well bore. This closure is effected by means of the kinetic pressure acting against the lower end of the valve element during the lowering operation. When the casing is halted, the valve is operated solely by the differential in the static head pressures which are present interiorly and exteriorly of the casing and thus, the valve is opened to admit fluid into the casing string until proper filling of the casing is accomplished. The differential in pressures then closes the valve which remains in the position shown in Figure 4 until the lowering movement is again started. As explained, the lowering movement urges the sealing head 33 to its upper position to maintain the valve closed so long as lowering continues.

After the casing is landed in final position, and it is desired to perform a cementing operation, it is only necessary to pump the cement downwardly through the easing string 11 and the pumping operation will move the back pressure valve 17 downwardly to open the outlets 16 and thereby discharge the cement into the space around the lower end of the casing string. The valve element 25 and its associate parts being carried by the back pressure valve 17 do not interfere with the normal operation or function of such back pressure valve and thus, the usual cementing operation may be carried out in the ordinary manner. After the cementing is complete, the device may be drilled out in the usual manner. It is preferable that the valve elements such as the cylinder 20, valve e ement 25, sealing head 33, and the back pressure valve 17, be constructed of a plastic or other material which may be readily drilled through.

From the foregoing, it will be seen that a simple and effective method of running or lowering the well casing is provided. As the casing is lowered through the fluid, the lower end of the casing is closed so that there can be no entry of fluid into the casing string (Figure 2). Upon movement of the casing being halted. the differential in pressures across the valve element 25 results in opening the valve (Figure 3), and said valve remains open until the casing is filled to the desired level. Ordinarily, this filling operation is carried out during the time that the next stand of casing is being connected in place and thus, no additional ri time is necessary for the filling operation. Upon proper filling, the valve closes (Figure l). The advantages of the automatic opening and closing of the lower end of the casing to effect filling without any additional rig time loss are ap arent. By maintaining the lower end of the casing closed during lowering, a washin action is produced upwardly around the casing by the fluid within the bore being forced upwardly between the casing and the wall of the bore. This washing action is desirable since it maintains loose particles with n the well bore within the fluid and prevents settlin thereof. It is, of course, evident that any time that danger of b ow out might occur. the excessive pressure acting a ainst the lower end of the valve e ement and the sealing head ill urge the pa ts to the position shown in Figure 5 and thereby close he lower end of said casing.

As has been pointed out, the provision of the enlarged flange 26 at the upper end of the valve element 25 is desirable to effect a snap action or upward movement of the valve element and sealing head 33 from the position shown in Figure 4 to the position shown in Figure 5. However, it has been found that the enlarged flan e 26 is not necessary and in Figure 9, a sli htly modified form of the invention is shown. In this form, a cylinder 20a has the lower portion 22a of its bore only sli htly reduced to provide a relatively larger diameter valve seat 23a. A valve element 25a is adapted to enga e the seat and is connected through a reduced shank 34a with a sealing head 33a. The operation of this form of the invention is identical to the form shown in Figures l*8, the only difference being that no additional area is exposed to the pressure acting below the valve member upon initial unseating of the valve element 25a. Instead, the valve element 25a is operated solely by the pressure differential. acting on opposite sides thereof, with substantially the same area exposed at all times.

In Figures 10-13, another type of valve, which functions to carry out the method in an identical manner, is illustrated. This form comprises a tubular valve body 40 having a threaded box '41 at its upper end which is arranged to be attached to the well casing 11. An undercut annular shoulder 42 which forms a seating surface is formed exteriorly of the body nearer the lower end thereof and below this shoulder the body is formed with radial inlet slots 43. An annular valve seat 44 is threaded into the lower end of the body 40 and a tubular valve 45 is adapted to engage the seat 44. The tubular valve 45 has a piston section 46 formed at its upper end and this section is slidable within the bore 4% of the body A coiled spring 47 normally urges the piston valve 4:) to a seated position engaging the seat 4 and obviously, when the valve is seated, a flow from exteriorly of the valve body through the slots 43 and into the bore of the body may not occur; similarly, when the piston valve is raised, as shown in Figure 12, flow from the area outside the body 40 and into the well casing 11 may occur through the slots 43 and past the valve seat 44.

For additionally closing .the inlet slots 43, an elongate sleeve valve 48 has its upper portion surrounding the lower portion of the body 40 and is adapted to telescope said body. The sleeve has an internal shoulder 49 within its bore which is adapted to engage an outwardly directed annular flange 4.4a which is formed integral with the annular valve seat 44, whereby downward movement of the sleeve with respect to the body is limited. When the sleeve moves upwardly with respect to the body, as will be explained, and as shown in Figure 11, the upper beveled end of the sleeve engages the undercut seating surface 42 to completely close the inlet slots 43. The lower end of the sleeve valve 4-8 has a plug 50 threaded therein and said plug is formed with a plurality of fluid inlets 51. A back pressure valve 52 is mounted within the sleeve and is arranged to engage a valve seat 53, said valve being normally urged to its uppermost position by a coiled spring 54 which is confined between a nut 55 on the upper end of a valve stem. and a spider 56 which rests upon the valve seat and through which the valve stem extends. An enlarged coiled spring 57 is disposed within the sleeve 48 and has its lower end engaging the valve seat 53 with its upper end engaging beneath the flange 44a of the valve seat 44. The enlarged spring 57 constantly exerts its pressureto urge the valve sleeve 48 and its associate parts downwardly with respect to the valve seat 44-, and the valve body 410 which carries said valve seat.

In the operation of this form with the well casing at rest within the well bore and with the fluid having entered the interior of the casing to a predetermined level upon the preceding cycle of operation of the valve, the parts will be as shown in Figure 10. Upon connection of the next stand of casing and a lowering of said casing through the fluid, the kinetic pressure developed through such lowering will act upon the sleeve valve 48 and will be suificient to overcome the tension of the spring 57 plus pressure within the interior of the casing and said sleeve valve 48 will be moved to the position shown in Figure 11. In such position, the fluid inlet slots 43 are closed and no fluid can enter the casing during the lowering of said casing.

Upon the casing movement being halted, the static pressure exteriorly of the casing is insufficient to maintain the valve sleeve inits raised position and said sleeve moves downwardly as shown in Figure 12 to uncover the inlet slots 45. The external pressure then acts through the slots 43 and against the piston of the valve 45 to urge the valve upwardly. Upward movement of the valve 45 is resisted by the static head pressure within the casing and the pressure of the spring 47, and therefore, as soon as the sleeve valve 48 uncovers the slots 43, the pressure differential across the piston valve moves said valve to its raised position as shown in Figure 12. The fluid continues to be admitted into the casing until the pressure within the casing which is built up by the admitted fluid plus the pressure of spring 47 overcomes the head pressure which is present exteriorly of the casing, at which time the piston valve 4-5 is again reseated, as shown in Figure 10. The parts then remain in this position until the next lowering operation of the casing. It is noted that the form shown in Figures 10-13 functions to accomplish the same result as the other forms of the invention. However, in this form, there is a positive shut ofl or closure immediately upon the initial downward movement of the well casing, whereas in the forms shown in Figures 1-9 thereof, a slight admis- 0 sion of'fiuid into the casing occurs immediately following the lowering motion. This slight admission of fluid is 'due to the fact that the reduced connecting shank 34 must pass through the bore 22. of the cylinder 20 between the instant that the valve element 25 is unseated and the sealing head 33 moves into said bore.

The valve devices shown in Figures 1 to 13 have been described as closing the casing against the entry of fluid during the lowering operation but it is noted that by varying the ratio of the areas on opposite sides of the valve member the valve member may be held in a partially open position during the lowering movement to allow controlled filling during the lowering operation. it is apparent that the areas of the valve together with the strength of the spring 32 may be adjusted so that the kinetic pressure developed during lowering would move the valve member 23 and head 33 to the position shown in dotted lines in Figure 6 so that a restricted. entry of fluid into the casing may occur during actual lowering; however, if the pressure within the bore below the valve exceeded the kinetic pressure developed during the lowering the head would be moved into the bore 22 to close further entry of fluid which would be at a time when a blow out was threatened. Thus, the. invention contemplates controlled filling of the casing or pipe during lowering with the valve closing either when. the bore hole pressure becomes excessive or when the admitted fluid rises to a predetermined level in said pipe.

The foregoing description of the invention is explanatory thereof and various changes in the size, shape and materials, as well as in the details ofthe illustrated construction, may be made, within the scope of the appended claims, without departing from the spirit of the invention.

Having described the invention, we claim:

1. The method of lowering pipe into a well bore which ncludes, lowering the pipe string within said bore, closing the lower portion of said string against entry of fluid during lowering movement of the string, periodically halting downward. movement of the pipe string, opening the lower end of the pipe string when the same is stationary to admit fluid into said string, and controlling the level to which the admitted fluid rises within the pipe stung by closing said pipe string when said fluid. reaches a predetermined level therein.

2. The method of lowering well pipe which includes, lowering said well pipe within the fluid within a well bore, controlling the admission of fluid from the well bore into the pipe during the lowering movement, and utilizing the differential in hydrostatic head pressures interiorly and exteriorly of the pipe to close the lower end of the pipe when the fluid therein rises to a predetermined level.

3. The method of lowering well casing including, lowering said well pipe into the well bore having fluid therein by connecting successive stands together and progressively lowering the pipe into the well,v closing the lower end of the. pipe string against entry of fluid during lowering movement of the pipe, and opening the lower end of the pipe string when said lowering movement is halted to connect the next successive stand. thereto to admit fluid from thte well bore into the casing.

4. The method of lowering pipe into a well bore which comprises, lowering said pipe into the well bore by progressively connecting successive stands together and progressively lowering the pipe string within the bore, closmg the lower end of the pipe string during lowering movement of said string, opening said lower end of the pipe string to allow an inflow of fluid from the well bore into the string each time movement of the string is halted to connect the next successive stand to said string, and closing said lower end of the pipe string while said string is stationary and after a predetermined amount of fluid has entered the pipe string.

5. The method set forth in claim 3, wherein the closing of the lower end of the pipe string is accomplished by utilizing the kinetic pressure of the well fluid developed by lowering movement of the pipe string through the fluid Within the well bore.

6. The method set forth in claim 3, wherein the dos ing of the lower end of the pipe string is accomplished by utilizing the kinetic pressure of the well fluid developed by lowering movement of the pipe string through the fluid within the well bore, and also wherein the opening and closing of the lower end of the pipe string while said pipe is stationary is effected by utilizing the differential in hydrostatic head pressures interiorly and exteriorly of the tubing.

7. the method as set forth in claim 4, with the additional step of opening the lower end of the casing in a direction to permit now from the interior of the casing outwardly therefrom when the casing has been lowered to its iinal position in the well bore, whereby a cementing operation may be performed through the casing.

8. A valve device adapted to be mounted at the lower end of a well pipe including, a valve body having an inlet passage at its lower end, an annular valve seat within the inlet passage, a movable valve element having an annular seating surface adapted to engage said seat to close flow through the passage, a resilient means acting on the valve element urging the same toward said seating surface, and a sealing head secured to said valve element below said seating surface and disposed below said passage when the valve element is engaging the valve seat, said head having a seating surface engageable with the walls of said passage as said head is moved upwardly into said passage for closing said inlet passage when said valve element is moved in a direction moving its annular seating surface away from said seat.

9. A valve device as set forth in claim 8, wherein the valve element presents an area of a predetermined size to the pressure exteriorly of the device when said valve element is engaging the valve seat and presents an enlarged area to said pressure immediately upon said element being unseated, whereby a snap action in moving said valve to fully open position may be obtained.

it). A valve device adapted to be mounted at the lower portion of a well pipe and lowered therewith into a well bore having fluid therein, including a tubular body having cementing ports therein, an upwardly closing cementing valve within the body normally closing the cementing ports and movable downwardly to open said ports, and a pipe filling valve assembly carried by the body and having a passage establishing communication between the iriterioi' and exterior of the well pipe, said assembly including a valve means which has one side exposed to the pressure interiorly of the well pipe and its opposite side exposed to the pressure exteriorly of the well pipe so as to be operated to open and close the passage by the differential in said pressures.

11. A valve device as set forth in claim 10, together with a spring means acting upon that side of the filling assembly valve means which is exposed to the pressure interiorly of the tubing.

12. A valve device adapted to be mounted at the lower portion of a well pipe and lowered therewith into a well bore having fluid therein, a tubular body having cementing ports therein, an upwardly closing cementing valve within the body normally closing the cementing ports and movable downwardly to open said ports, and a filling valve assembly mounted on the cementing valve and having a passage establishing communication between the interior and exterior of the well pipe, said assembly including a valve element slidable within the passage and having one side exposed to the pressure interiorly of the well pipe and its opposite side exposed to the pressure exteriorly of the pipe so as to be actuated by the differential in such pressures to open and close the passage.

13. A valve device as set forth in claim 12, together with a spring acting upon that side of the valve element which is exposed to the pressure interiorly of the well i e. l4. A valve device as set forth in claim 12, wherein an annular seat is formed within the passage spaced from the lower end of the passage and also wherein the valve element is provided with a seating surface adapted to engage the seat upon downward movement of the valve element, said element having a sealing head which is disposed outside of the passage when the seating surface is engaging the seat and adapted to move upwardly into sealing engagement with the passage upon upward movement of the valve element.

15. A valve device adapted to be mounted at the lower end of a well pipe including, a valve body having an inlet passage therein, an annular valve seat within the inlet passage, a movable valve element having an annular seating surface adapted to engage said seat to close flow through the passage, a resilient means acting on the valve element urging the same toward said seating surface, a sealing head secured to said valve element and disposed outside of said passage when the valve element 1S engaging the valve seat, said head being adapted to move lLlLO a position closing said inlet passage when said valve element is moved in a direction moving its annular seating surface away from said seat, and an enlarged upwardly closing valve member which Will open when the pressure within the pipe exceeds the pressure exteriorly thereof, whereby a cementing operation may be carried out through said pipe.

lo. the method of lowering a well pipe having a fluid inlet in MS lower portion into a well bore having fluid therein which consists in, closing the inlet during lowering movement of the pipe, opening said inlet when lowering movement of the pipe 18 halted to admit nuid into the interior of the pipe, and closing said inlet to shut off the admission of rluid when the admitted nuid rises to a predetermined level within the pipe.

1'7. 'l'he method of lowering a well pipe having a fluid inlet in its lower portion into a well bore having fluid 'therein which consists in, closing the inlet during the lowering movement or the pipe by the KmCIlC pressure of the well nuid developed during such lowering, opening said inlet by the dirterential in pressures interiorly and exteriorly of the pipe after lowering movement of the pipe is halted, and then again closing said inlet when the pressure exteriorly or the pipe exceeds the pressure interiorly ol' the pipe by a predetermined amount.

lb. '1 he method of lowering a well pipe having a fluid inlet in its lower portion into a well bore having fluid therein which consists in, closing the inlet during lowering movement of the pipe, opening said inlet when lowering movement of the pipe is halted to admit Iluid into the interior of the pipe, closing said inlet to shut off the admission of Iiuid when the admitted iiuid rises to a predetermined level within the pipe, and performing a cementing operation through said pipe after the same has been lowered into its final position within the well bore.

19. A valve device adapted to be mounted in the lower end of a well pipe and lowered therewith within a well bore having a nuid therein, said valve including, a valve body having a cylindrical bore in the lower end communicating with the well bore, a iluid opening in said body above said bore establishing communication between said bore and the interior of said well pipe, a valve member movable with respect to the opening to open and close the same and having areas on opposite sides thereof exposed to pressures interiorly and exteriorly of the well pipe, whereby said member is actuated by the differential in such pressures, resilient means acting on that side of the valve member which is exposed to the pressure interiorly of the pipe, an upper valve seating surface in said body below said opening and above said bore, the cylindrical walls of said bore forming a lower valve seating surface, an upper valve surface on the valve member for seating on the upper valve seating surface to close said opening, a lower valve surface on said valve member for seating with said lower valve seating surface to close said opening when said upper valve surface on said valve member is above said upper valve seating surface, the valve being moved upwardly to close by the excessive pressure developed when the device and pipe are lowered through the well fluid in the bore, and its actuation being controlled when the pipe is stationary solely by the differential in static pressures interiorly and exteriorly of the pipe.

20. A well pipe valve to control the movement of fluid from a well bore into a pipe as said pipe is being lowered within said well bore, said valve including, a body adapted to be connected in the well pipe and having a fluid inlet passage establishing communication between the well bore and the interior of the pipe, a movable valve member carried by the body for controlling flow of fluid from the well bore into the pipe through said passage, said valve member being solid and having an upper valve seating surface and a lower valve seating surface, said passage having an upper valve seat for engagement by said upper valve seating surface and a lower valve seat for engagement by said lower valve seating surface, said valve member also having a recess in its external surface between the upper and lower valve seating surfaces to enable fluid to flow within said passage and to thereby establish fluid communication between the interior of the pipe and the well bore when the valve seating surfaces are unseated or open, one side of said valve member being exposed to the pressure within the pipe and the opposite .side thereof being exposed to the pressure within the well bore, a resilient means acting upon that side of the valve member which is exposed to the pressure within the pipe and exerting a force .on said valve member which is added to the pressure within the pipe, whereby the valve member is actuatedby the differential between the pressure within the well bore acting on one side thereof and the pressure within the pipe plus the resilient means acting on the opposite side thereof, said valve member being movable in one direction to a closed position and being movable in the opposite direction to an open position and upon subsequent movement in the same direction to a closed position, whereby within a predetermined pressure differential limit the valve member is open and .beyond such limit the valve is closed.

21. A well pipe valve as set forth in claim 20, wherein the resilient means is a spring and wherein the strength of said spring controls the pressure difierential limit within which the valve means is open.

22. A well pipe valve as set forth in claim 20, wherein the valve means is a single valve element mounted within the fluid inlet passage.

12 23. The method of lowering well pipe which includes, lowering said well pipe within the fluid within a well bore, controlling the admission of fluid from the well bore into the pipe during the lowering movement, utilizing the differential in hydrostatic head pressures interiorly and exteriorly of the pipe to close the lower end of the pipe when the fluid therein rises to a predetermined level, and,

opening the lower end of the well pipe in a direction to permitflow from the interior of the well pipe outwardly therefrom when the well pipe has been lowered to its final position in the well bore.

References Cited in the file of this patent UNITED STATES PATENTS