US2880807A

US2880807A - Apparatus for performing well operations

Info

Publication number: US2880807A
Application number: US365840A
Authority: US
Inventors: Ernest L Potts
Original assignee: Individual
Current assignee: Individual
Priority date: 1953-07-03
Filing date: 1953-07-03
Publication date: 1959-04-07
Anticipated expiration: 1976-04-07

Description

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April 7, 1959 E. 1.. POTTS 7 2,839,807

APPARATUS FOR PERFORMING WELL OPERATIONS Filed my a, 1953 e Sheets-Shee 2 A TTORNE Y6 April 7, 1959 I E. L.. POTTS APPARATUS FOR PERFORMING WE'LL OPERATIONS Filed July 3. 1953 6 Sheets-Sheet 3 [/"nesf Z. Pol fa INVENTOR. BY W Wail; ya 5- M ATTORA/[YJ April 7, 1-959 E. L; POTTS APPARATUS FOR PERFORMING WELL OPERATIONS Fixed July 5. 1955 6 Sheets-Sheet 4 IN VEN TOR. flmwna z E. L.POTTS April 7 1959 APPARATUS FoR PERFORMING WELL OPERATIONS Filed July 3, 1953 6 Sheets-Sheet 5 INVENTOR.

9 BY VMWMQ flaw A TTORNE V6 April 7, 1959 E. L. POTTS 2,880,807

I APPARATUS FOR PERFORMING WELL OPERATIONS Filed July 5, 1955 e Sheets-Sheet 6 ffrhes I L Po 2 f3 INVENTOR.

5M KKM A TTOR/VE KS willbe hereinafter described together United States PatentO APPARATUS FOR PERFORMING WELL OPERATIONS Ernest L. Potts, Houston, Tex., assignor to Cicero C. Brown, Houston, Tex.

Application July 3, 1953, Serial No. 365,840 7 Claims. (Cl. 166-146) This invention relates to new and useful improvements in apparatus for performing well operations.

An object of this invention is to provide an improved apparatus for sealing off a well formation in a well bore in order to conduct various well operations such as removal of drilling mud from the bore, acidizing, cementing, and producing the formation without the necessity for pulling the apparatus from the well bore while performing a sequence of such operations.

An important object of this invention is to provide an improved well packer apparatus having an upper packing assembly and a lower packing assembly longitudinally spaced from each other, each of said assemblies including a pair of oppositely directed sealing cups facing each other with one of the cups in each assembly being adapted to tightly engage the wall of the well bore when a differential in pressure exists across the assembly, said apparatus and particularly said packing assemblies being so constructed that the fluid pressure above the upper assembly and below each assembly as well as the pressure between the sealing cups of each assembly are equalized during the lowering of the apparatus into the well bore so that no diiferential in pressure exists across the assemblies during such lowering and therefore no force is applied to the sealing cups to urge them into tight sealing engagement with the wall of the well bore during such lowering, whereby wear on the sealing cups is eliminated or reduced to a minimum.

Another object of this invention is to provide an improved packing assembly in a well apparatus wherein the packer includes a packing assembly having a pair of adjacent annular sealing elements with the outer sealing ends thereof facing toward each other whereby sealing with the wall of the well bore can be effected without creating a reduced pressure between the elements.

Still another object of this invention is to provide an improved well apparatus in which a well formation in a well bore is cleaned of drilling mud by fluid circulation and thereafter, without removing the apparatus from the well bore, the well formation is acidized and oil or other product is conducted through the apparatus to the surface of the well.

A further object of this invention is to provide an improved well apparatus wherein a plurality of well formations in a well bore are successively treated without removing the apparatus from the well bore.

A still further object of this invention is to provide a well packer apparatus having a pair of axially spaced packing assemblies for sealing olf above and below a well formation in a well bore, and means for conducting fluid to such well formation, and means for controlling the return of fluid from such formation whereby operations such as fluid circulation to remove drilling mud in the vicinity of the formation can be effected or acid or cement squeeze operations can be performed as desired.

The construction designed to carry out the invention with other features thereof.

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

Figure 1 is a longitudinal view illustrating diagrammatically one form of the well packer of this invention positioned Within a well casing or bore.

Figure 2 is a view similar to Figure l, but illustrating a modified form of the packer illustrated in Figure 1.

Figure 3 is a view similar to Figure l, but illustrating another modification of the packer of Figure l.

Figures 4, 4A and 4B are longitudinal views, partly in elevation and partly in section, which together illustrate the details of the form of the well packer illustrated diagrammatically in Figure 1.

Figure 5 is a horizontal sectional view taken on line 5--5 of Figure 4.

Figure 6 is a horizontal sectional view taken on line 6-6 of Figure 4A.

Figure 7 is a view, partly in section and partly in elevation, of a portion of the packer illustrated in Figures 4, 4A and 4B wherein the control means has been modified.

Figure 7A is a view, partly in section and partly in elevation, illustrating a portion of the device illustrated in Figure 7, and particularly illustrating the friction spring construction on the upper end of the control means after same has been released and expanded into gripping engagement with the well casing.

Figure 8 is a sectional view illustrating in detail the locking structure for the control means of Figure 7 prior to the release of the friction springs from the retracted position.

Figures 9, 9A, 9B, 9C, 9D, and 9B are longitudinal views, partly in section and partly in elevation, which together illustrate the details of the form of the well packer diagrammatically illustrated in Figure 2.

Figure 10 is a longitudinal view, partly in elevation and partly in section, illustrating the details ofthe central portion of the modified well packer diagrammatically illustrated in Figure 3.

In the drawings, the numeral 10 designates the tubular support of the well packer apparatus of this invention, which is connected in a tubing string (not shown) which extends to the surface of the well for the positioning of the packer apparatus within the well casing or bore C. An upper packing assembly P is mounted on the exterior of the tubular support 10 near the upper end thereof for sealing off the annular space 11 between the tubular support 10 and the casing C and above a well formation F A lower packer assembly P is mounted on the exterior of the tubular support 10 a sufiicient distance below .the upper packing assembly P to seal off the annular space 11 between the tubular support 10 and-the casing C belowthe formation F. The well formation F is thus sealed ofl thereabove and therebelow by the packing assemblies P and P respectively. A control means K is associated with the tubular support 10 and is adapted to control the fluid during the various well operations which are conducted in the casing or well bore when using the well packer apparatus of this invention. As will be explained, this control means K may take several forms such as a valve or a control plug. By the manipualti-on of the control means K, fluid flow within the tubular support 10 can be controlled to perform various well operations in the well bore such as fluid circulation to remove or clean the drilling mud from the annular area 11'ad'- jacent the well formation F, acid and cement squeezing operations, and production of oil or gas from the well formation.

In the form of the invention diagrammatically illus- 3 fiate'd in Figure 1 and illustrated in detail in Figures 4, 4A and 4B, the upper packing assembly P includes a downwardly directed sealing element or cup 12 attached to the tubular support and a lower upwardly directed annular sealing'element or cup 14 attached to the tubular support 10 and spaced longitudinally below the upper cup '12. Thus, when the packer apparatus of this invention is disposed in a well casing 'or bore C as illustrated in Figure 1, a portion 11a of the annular area 11 is con- "fined between the opposed ends of the sealing elements or

trips

12 and 14.

The upper sealing element or cup 12, as shown in the drawings, has a plurality of books 16 attached to its upper end for pivotal connection to a hook ring 17 mounted thereabove, such ring 17 being threaded to a collar 18 which is confined on the tubular support 10 against longitudinal movement relative thereto by an annular inwardly directed radial shoulder 19 thereon which fits within a groove or recess 20 in the external surface of the tubular support 10. The lower end of the sealing cup 12 has a pair offlared sealing lips '21 with an annular recess 22 formed therebetween, whereby the lower end of the upper sealing cup 12 is unattached to the tubular support 10. The sealing element 12 is formed of rubber or otherelastic material so that when a fluid pressure below the element 12 is greater than a fluid pressure thereabove, the annular sealing element or cup 12 is distorted or expanded radially outwardly so that the-outer sealing lip 21 is forced tightly against the wall of the well bore or casing C and the inner sealing lip 21 is forced tightly against the external surface of the support 10. When the pressure above and below the sealing-element 12 is substantially the same, the outer lip 21 will lightly contact the casing C, but will not be tightly pressed thereagainst; obviously, the extent of such contact can be controlled by the construction of the sealing'element 12.

The lower sealing element 14 is a duplicate of the upper "sealing element 12 and is mounted in the same manner except that it is reversed or inverted, to have its lower end connected by means of hook segments 25 to an annular hook ring 26 which is threaded to a collar 27which is secured to the tubular support 10. The lips 28 at the upper end of the lower sealing cup 14 are identical with the lips 21 of the element 12 and are expanded or distorted radially into a tight sealing engageinent with the tubular support and the casing by a differential in fluid pressure. The lower sealing element or cup 14 will normally lightly touch the casing C when the pressure is the same above as below said cup 14, but will be expanded or distorted when the pressure thereabove is greater than the pressure therebelow. With this particular arrangement of the sealing cups 12'and 14, only one or the other of the sealing elements or

cups

12 and 14 will be in tight sealing engagement with the well casing at any particular time when there is a fluid'pressure differential across the packing assembly P. Thus, assuming that the fluid pressure in the casing is ,greaterfabove the packing'assembly than therebelow, the fluid 'will force its way past and below the upper sealing element 12 and will act on'the lower sealing elemeat 14 to urge it radially outwardly into a distorted tight sealing engagement with the casing. The fluid pressure in the portion 11a of the annular space 11 is therefore filled with the fluid under the greater fluid pressure. This eliminates a void area between the packing elements 12 and '14 which is present in the conventional packing assemblies and thereby eliminates collapse or failure of the casing in that portion adjacent the annular areas between the packing elements as often occurs in conventional packing assemblies.

The lower packing assembly P is identical with the upper packing assembly P andas pointed out above, is spaced longitudinally below the upper'packing assembly 1. .Ihe upper sealing element-or cup .12, is downwardly directed and is formed of rubber or other elastic material. The book segments 16', ho'okring 17' and collar 18' and the rest of the structure for attaching the upper sealing element 12' to the tubular support 10 is identical with the structure for attaching the upper sealing element 12 of the upper packing assembly P to the support 10. Likewise, the lower sealing element or cup 14', hook segments 25', hook ring 26' and collar 27 are identical with the corresponding numbered parts of the lower sealing cup 14 of the upper packing assembly P. The upper sealing "cup 12 and the lower sealing cup 14' of the lower packing assembly P confine an annular area portion 11b therebetween and fluid pressure difierentials act upon the cups of the lower packing assembly P in the same manner as above described in connection with the upper packing assembly P.

The control means K of the form of the invention illustrated in Figures 4, 4A and 4B is clearly shown in Figure 4A. This control means K includes a valve sleeve or cylinder 30 which is longitudinally slidable upon the external surface of the tubular support, with seal rings 31 being provided at the upper and lower ends on the internal surface thereof. Friction springs 32 are mounted on the exterior of the valve cylinder 30 and are retained in place thereon by retaining

rings

33 and 34 disposed at the upper and lower ends of the cylinder 30 respectively. Such friction springs 32 are bowed for engagement with the well casing and during the lowering of the well packer apparatus into the well casing C, the upper shoulder 33a is in abutment with a radial flange or shoulder 35 on the tubular support 10 because the friction springs 32 hold the cylinder 30 against downward movement relative to the tubular support 1 0. When the cylinder 30 is in such raised position, (as shown in solid lines in Figure 1), the lower collar 34 of the control means K is above the radial ports or openings 36 in the wall of the tubular support 10, whereby fluid flowing to or from the interior or bore of the tubular support 10 can pass through such openings 36, the purpose of which will be hereinafter explained. Also, as will be explained, the valve cylinder 30 is adapted to be movedlongitudinally relative to the tubular housing 10 by a longitudinal raising of the tubular support 10 whereby the friction springs 32 hold the cylinder 30 in a fixed position relative to the casing C to move the cylinder 30 to the position shown in Figure 4A to thereby close ofl the openings 36 from flow into or out of the interior of the tubular support 10.

For directing well fluid through the tubular support 10 to or from the well formation F when the well packer apparatus is positioned in the well with the packing assemblies P and P above and below such formation F, an inner tube or fluid conductor 40 is mounted concentrically within the support 10. The upper end of the tube or conductor 40 extends within the tubular support 10 above the upper packing assembly P and is threadedly connected to the support 10 by

annular members

41 and 42, which are threaded to each other, with the annular member 41 being welded at 43 to the interior of the tubular support 10 and the annular member 42 being welded to the exterior of the tube 40 at 44. A seal ring 45 is disposed between the exterior surface of the tube'40 and the internal surface of the member 41 to prevent fluid from passing between the pipe or tube 40 and the tubular support 10 at the upper'end of the tube 40. The lower end of the tube 40 is threaded into an adapter sub 47 mounted between sections of the tubular support 10 and between the packing assemblies P and P. The adapter sub 47 has a transversely downwardly extending flow port 48 in its wall which establishes fluid communication with' the exterior of the tubular support and the bore 47a'of thesub 47 which in turn is in communication with the bore 40a'of'the tube 40. The lower end of the adapter sub 47 "below the'bore'47a is closed at 49 but longitudinal passagesSt) are provided through the sub 47 so that fluid may flow through the tubular support above and below the sub 47 without mixing with the fluid flowing from the tube 45 through the port 48. Since the port 48 is between the packing assemblies P and P, fluid communication is established between the well formation F and the interior or bore 40a of the tube 40, so that fluid may be pumped to or from the well formation from the surface of the well through the tubular support 10. Thus, fluid which is pumped from the surface of the well will be conducted through the subular support and by reason of the seal 45 such fluid will pass into the bore 40a of the tube 40 and will be directed outwardly into the formation F through the port- 48. When the ports 36 are open, that is, when the control means K is in its upper position, the fluid which emerges from the port 48 can pass through the ports 36 and return to the inside of the tubular support 10 and then pass upwardly through the longitudinal passages 50 into the annular space 52, between the tube 40 and the tubular support 10. As the fluid flow continues upwardly through such annular space 52, it will be prevented from passing above the upper end of the tubing 40 by reason of the seal 45, but such fluid can pass into the annular space 11 above the upper packing assembly P through radial ports 53 in the tubular support 10 above the upper packing assembly P.

In using the apparatus of this invention, when employing the apparatus illustrated in Figures 1 and Figures 4, 4A and 4B, the well packer apparatus is lowered into the, well casing C to the position desired so that the packing assemblies P and P are above and below the well formation F, respectively. During such lowering the control means K is held in its upper position (solid lines in Figure l) by reason of the drag of the friction springs 32 on the well casing C. This holds the valve cylinder 30 above the radial ports 36 and maintains such ports open during the lowering of the apparatus into the casing. Since the

passages

36, 53, and 48 and the lower end of the tubular support 10 are open during the lowering of the packer apparatus into the well bore, the fluid pressure of the mud or well fluid in the casing is at all times equalized throughout the entire well packer apparatus. Thus, the fluid below the lower packing assembly P passes into the area between the packing assemblies P and P' through the ports 36 and passes above the upper packing assembly P through the ports 53. Since the packing assemblies P and P are constructed with the sealing elements or

cups

12 and 14 and 12' and 14', respectively, facing toward each other, the equalization of the well fluid pressure above and below each of the packing assemblies likewise permits the well fluid to enter into the areas 11a and 11b between the sealing cups of each of the packing assemblies, whereby the pressure between the sealing cups is also equal to the pressures above and below each of the packing assemblies. Thus, the fluid pressure is equalized throughout the entire well packer apparatus during its lowering into the well bore. This eliminates any forcing or urging of the sealing cups of the packing assemblies against the wall of the well casing C in tight sealing engagement therewith and thereby prevents or reduces wear on the cups to a minimum.

When the well packer apparatus of Figures 4, 4A and 4B has been lowered to the predetermined point in the well casing for sealing off the well formation F, the control means K remains in its upper position by reason of the contact of the friction springs 32, with the casing C, thereby maintaining the ports 36 open.

Fluid can then be circulated from the surface of the well down through the tubular support 10, through the bore of the tube 40 and then through the passage 48 to the annular area 11 in the vicinity of the well formation F and between the packing assemblies Since the ports 36 are open the fluid can flow into the tubular support 10 from the area 11 adjacent the well formation F and can pass thence upwardly through the longitudinal passages 50, annular space 52 and then through the ports 53 into the annular area 11 above the packing assembly P for flow to the surface of the well. A continuous circulation is thus maintained to the well formation through the support 10 and back up to the surface of the well through the annulus 11 so that a cleaning fluid such as water, acid or other liquid can be pumped into the area adjacent the well formation for replacing the drilling mud which is present when the-well packer apparatus is initially lowered into the casing. After the drilling mud has been replaced with a cleaning liquid such as water, the well formation can then be produced if desired, but prior to such production, it is generally necessary to squeeze or force acid into the well formation.

Therefore, the acid is next injected into the formation by being forced downwardly through the tubular support and through the tube 40 for passage through the port 48 into the annular area 11 adjacent to formation F. It will be appreciated of course that prior to the lowering of the packer apparatus into the casing, such casing is perforated in the vicinity of the well formation F to establish fluid communication between the annular area 11 and the formation F. As soon as suflicient acid has been admitted into the annular area 11 between the packing assemblies P and P, so as to replace the water previously present, the tubular support 10 can be raised sufliciently by raising the tubing string at the well surface so that the control means K is moved downwardly rela tive to the tubular support 10 to the dotted line position shown in Figure l or the position shown in Figure 4A to thereby close the radial ports 36. The friction springs 32 prevent movement of the control sleeve 30 during such raising of the tubular support 10. It will be observed that no rotation of the tubular support 10 is required to slide or longitudinally shift the control means K relative to the support 10. Once the ports 36 have been closed by the valve cylinder 30, the acid cannot escape or circulate through the passages 36 since the valve cylinder 30 closes same and the upper and lower packing assemblies P and P close olf any flow of the acid above or below the formation. The acid will pass the lower sealing cup 14 of the upper packing assembly and would force the upper sealing cup 12 of the upper packing assembly radially outwardly into a distorted tight sealing engagement with the well casing by reason of the differential in fluid pressure above and below such sealing cup 12. Likewise, the sealing cup 14 of the lower packing assembly P' would be distorted or expanded into tight sealing engagement with the well casing C. The acid is thus squeezed under high pressure into the well formation and without forcing any drilling mud' in ahead of such acid. In previously known methods and apparatuses, the drilling mud has been forced ahead of the acid during the squeezing operation with the result that the drilling mud often plugged up the formation and prevented effective action of the acid on the formation. This is eliminated in the method and apparatus of this invention since the drilling mud is completely removed from the vicinity of the formation prior to the time that the acid is squeezed into the formation.

When the acid has taken effect, the pressure on the acid is released and the oil or gas from the formation F will then flow upwardly through the inlet port 48 into the tube 40 and will thence be carried through the tubular support 10 to the surface of the well.

In some cases this apparatus may be utilized for cementing the formation and in such instances the above procedure would be followed except that instead of squeezing acid into the formation, the cement would be squeezed into the formation in the same manner as the above procedure for squeezing acid into said formation. Other operations which could be performed involving '7 squeezing and circulating, in connection with a well formation will readily oecurto those skilled in the art.

In some cases it may be desirable to obtain production from an upper formation located above the well formation F. In such case, the well packer apparatus will be raised from the position shown in Figure l to a new position with the packing assemblies P and P disposed above and below the upper formation (not shown) which is above the formation F illustrated in the drawings. The formation F illustrated in the drawings which would be the lower formation will continue to produce through the open lower end of the tubular support and such gas or oil from the formation F will flow out through the ports 53 and through the annular area 11 above the upper packing assembly P to the surface of the well. The upper formation (not shown) is then acidized and produced in the same manner as described above in connection with the well formation F, such upper formation producing its oil or gas through the inner tube 40 and the tubular support 10 above the seal 45, so that there will be dual production, that is, production through the annulus 11 from the lower formation and production through the tubing string from the ,upper formation.

In the form of the invention shown in Figures 7, 7A, and 8, the control means K has been'modified and also the construction of the inner conductor or tube 40 has been modified, with the rest of the structure being identical with the form illustrated in Figures 4, 4A and 4B. The adapter sub 47 has been eliminated in this modified form of the invention and the inner conductor or tube 40 extends from its upper seal 45 (Figure 4) to substantially the lower open end of the tubular support 10, the lower end of the tube 40 also being open. In this form of the invention, the control valve sleeve 30a is substantially identical with the control valve sleeve 30 as shown in Figure 4A and includes the spaced seal rings 31a, with the upper set of seal rings 31a being spaced a sufl'icient longitudinal distance above the lower set of seal rings 31a to completely seal off the inlet flowports 36 in the tubular support 10 when the cylinder 30a is in its lower position. The upper end of the cylinder 30a has a retaining collar 34a threaded thereto to which are connected friction springs 32a by screws 55 or any other equivalent securing means. The upper ends of the friction springs 32a are connected by screws 55 to an upper collar 33a which is disposed around the tubular support 10.

During the lowering of the well packer apparatus into the well casing, when the control means K of Figure 7 is employed, the friction springs 32:: are held in a retracted or substantially straight position by means of a piston 56 which is disposed in a radial flow tube '57 and extends into a radial opening 58 in the upper collar 33a. Outward displacement of the piston 56 is prevented by a shear pin 59 which is mounted in the opening 58 of the collar 33a (Figure 8). The upward movement of the lower collar 34a is limited by a projection 60 on the external surface of the tubular support 10 so that when the piston 56 is in position (Figure 8), the collars 33a and 34:: are prevented from movement toward or away from each other, thereby holding the cylinder 30a in its raised position above the ports 36. By reason of this construction the springs 32a are prevented from contracting the well casing during the lowering of the apparatus into such casing. When it is desired to release the friction springs 32a so as to slide the valve cylinder 30a to its lower position to close the ports 36, a solid plug 61 of the Well known type of wire-line Otis plugs or any equivalent plug is positioned in the bore of the tube below the radial flow tube 57. Fluid pressureis then forced downwardly through the tube 40 to act against the inner surface of the piston 56 and when the pressureis 'suflicient to shear the pin 59, the piston 56 is :forced outwardly through the passage 58 in the collar 33a and is dropped into the casing. The inherent resilience of the springs 32a then pulls the upper collar 33a downwardly so that the springs 32a engage the wall of the well bore (Figure 7A).

Thereafter, the apparatus of Figures 7, 7A and '8 will be used in substantially the same manner as that described above in connection with Figures 4, 4A and 4B. Thus, fluid under pressure is forced downwardly through the tube 40 and passes out into the area adjacent the well formation F through the passage 57 and circulates back into the tubular support 10 through the ports36, whereupon such fluid will be carried upwardly through the tubular support in the annular space 52 between such support and the tube 40 for discharge into the annulus 11 through openings 53 above the upper packing assembly. It will be noted that the plug 61 prevents the fluid which circulates back into the annular space 52 of the support 10 from passing upwardly into the bore of the tube 40. When it is desired to carry out a pressure or squeeze operation, the apparatus is moved longitudinally without rotation to slide the cylinder 30a to its lower position wherein the ports 36 are closed. The stop member 60 on the external surface of the tubular support 10 will contact the lower edge of the collar 33a and will limit the extent of downward movement of the cylinder 30a so as to assure the positioning of the cylinder 30a across the openings 36 for closing same.

In the form of the invention diagrammatically illustrated in Figure 2, and illustrated in detail in Figures 9-9E, the packer apparatus differs from the form illustrated in Figures 4, 4A and 4B primarily in that the control means K is located below the lower packing assembly P and is adapted to be moved by rotation of the tubular support 10. Also, in this form of the invention, each of the packing assemblies includes a pair of downwardly directed upper sealing elements and a pair of upwardly directed lower sealing elements. However as will be apparent from the following description, such modification of the packing assemblies could be used in any of the other forms of the invention and likewise this particular form of the invention shown in Figures 9-9E could be utilized with each of the packing assemblies having the same packing assembly construction as illustrated in Figures 4-4B.

As shown in Figures 9 and 9A, the upper packing assembly P includes upper seal elements or cups 112, each of which is in all respects identical with the sealing element or cup 12 of the upper packing assembly P of Figure 4 and includes corresponding

parts

116, 117, 118, 119, 120, 121 and 122. Likewise the lower sealing elements or cups 114 are identical with the lower sealing element or cup 14 of and includes corresponding

parts

125, 126, 127 and 128. The upper sealing elements 112 are therefore distorted or radially moved into sealing engagement with the well casing when the fluid below the upper packing assembly is greater than the pressure thereabove, and the lower sealing elements 114 are distorted into sealing engagement with the well casing when the fluid pressure above the upper packing assembly P is greater than the pressure therebelow.

The lower packing assembly P illustrated in Figures 9C and 9D is identical with the upper packing assembly illustrated in 9 and 9A and includes the pair of upper downwardly directed sealing elements or cups 112' and the pair of lower upwardly directing sealing elements or cups 114'. The use of the additional upper and lower sealing element in each of these packing assemblies as compared with the packing assemblies of Figures 44B serves to assure the proper sealing with the well casing when the fluid pressure differential exists across such packing assemblies but it will be apparent that the packing assemblies of this form of the invention will function in the same manner as the assemblies shown in Figures In-this form of the invention, instead of utilizing the adapter sub 47, the lower end of the tube 140-is connected with a radial tube 148 which extends through the wall of the tubular support 10 for directing fluid from the tube 140 into the annular space 11 adjacent the well formation F. Instead of providing the ports 36 in the tubular support 10 as in the previous forms of the invention, this form includes an additional length of tubing 140' and a radial pipe 148' which is disposed below the radial pipe 148 but between the packing assemblies P and P. This additional pipe 140 extends downwardly within the tubular support 10 to a position below the lower packing assembly P where a seal 145 similar to the upper seal 145 is provided for sealing ofi the annular space 152 between the pipe 140 and the tubular support 10. The lower end of the tubular support 10 is closed off by a solid plug 65 (Figure 9B) but fluid flowing from the lower end of the tubular section 140' passes into the annulus 11 through radial openings 66 below the seal 145 and is then returned into the annular space 152 between the pipe 140' and the tubular support 10 through inlet ports 67 which is disposed above the seal 145'. The fluid then flows upwardly through the tubular support 10 and is discharged outwardly through the openings 153 in the tubular support 10 above the upper packing assembly P and below the upper seal 145 for continued flow to the surface of the well through the annulus 11.

The control means K illustrated in Figure 9B is similar in many respects to that illustrated in Figure 4A and includes a valve sleeve 130 to which is welded an upper retaining collar 133. Seal rings 131 are disposed on the interior of the valve sleeve 130 and the upper and lower sets of the seal rings 131 are spaced a sufficient longitudinal distance from each other so that when the sleeve is in its upper position, the seal rings 131 will close off the ports 66. Friction springs 132 are attached to the upper collar 133 by screws or other equivalent securing means and the lower ends of such friction springs 132 are attached by screws or the like to a lower retaining collar 134 which is held in fixed relationship to the tubular support 10 by a shear pin 70. The sleeve or cylinder 130 has internal threads 71 which co-act with external threads 72 on the tubular support 10 to effect a relative movement of the cylinder 130 relative to the tubular support 10 by a rotation of such support. The downward movement of the cylinder 130 is limited by an annular stop shoulder or projection on the external surface of the tubular support 10 and as shown in Figure 9E, when the cylinder 130 is in its lower position with its lower end in contact with the projection or shoulder 73 and when the pin 70 is connected between the collar 134 and the tubular support 10, the friction springs 132 are held in a straight unexpanded position. This permits the lowering of the well packer apparatus into the well bore without dragging the friction springs 132 against the wall of the casing C. When it is desired to shear the pin 70 to release the friction springs 132 for engagement with the well casing C, the tubular support 10 is moved longitudinally without the rotation downwardly relative to the collar 134. This is made possible because the lower end 10a of the tubular support 10 terminates above the upper surface 75a of a pilot 75 disposed at the lower end of the tubular, support so that longitudinal movement of the support 10 relative to the pilot 75 is permitted until the end 10a contacts the surface 76a. The pilot 75 has an inwardly extending shoulder 76 thereon with which the shoulder on the tube end 10a contacts during lowering of the apparatus into the casing. The apparatus is lowered until the pilot 75 hits the bottom of the well bore or cement in such bore at which time the downward movement of such pilot 75 is stopped but lowering of the tubular support 10 is continued until the lower end 10a thereof contacts the surface 76a. A movement of the support 10 relative to the pilot 75 and the collar 134 thus results so that the pin 70 is sheared. The inherent resiliency of the friction springs 132 then will move the collar 134 upwardly and stitcl't collar 134 will be free to move relative to the tubular support 10. With the friction springs 132 engaging the well casing, the tubular support 10 can be rotated by rotating the tubing string at the surface of the well and such rotation will eifect a longitudinal movement of the cylinder or sleeve upwardly relative to the tubing 10 a sufficient distance to position the upper set of seal rings 131 above the port 66 and the lower set of seal rings 131 therebelow. The upward movement of the cylinder 131 is limited by the engagement of the upper end of the collar 134 with the lower surface of the projection 73, so that it will be assured that the sleeve 130 is positioned to close the opening 66.

The operation of this form of the invention illustrated in Figures 9-9E is substantially identical with that described above in connection with Figures 4-4B. The fluid for cleaning the drilling mud from the area adjacent the well formation F is circulated around the tubular support 10 and is directed through the pipe or tube and thence through the outlet 148 into the annular space 11 between the upper and lower packing assemblies P and P. The fluid will then flow into the inlet 148 and downwardly through the tube 140 and will be then directed through the passages 66 into the annular space 11 and from there it will be flow back into the tubular support 10 through the opening 67. Such fluid will continue its flow up through the annular space 152 until it reaches the openings 153 above the upper packing assembly P where it will pass into the annular space 11 above the packer apparatus and will flow to the surface of the well. When the drilling mud has been completely removed from the vicinity of the well formation F, and replaced with water, acid or cement as explained above in connection with Figures 4-4B, the control means K is then actuated to close the radial passages 66 by a rotation of the tubing string for rotating the tubular support 10. With the passages 66 closed, the fluid then flowing down through the tube 140 into the annular space 11 adjacent to the well formation F is prevented from flowing out through the port 66 and therefore a high pressure can be developed between the packing assemblies P and P for the purposes of injecting or squeezing acid or cement into the well formation. As in the above forms of the invention, since the drilling mud has been removed from the annular area 11 be tween the packing assemblies P and P, the acid is' squeezed into the formation without forcing any drilling mud to ahead of same, thereby avoiding plugging of the formation with drilling mud and permitting the acid to have its full effect in opening up the formation for pro-' duction. It will also be noted that during the lowering of the apparatus into the well bore the pressures above and below the packing assemblies P and P as well as therebetween and the pressures between each of the sealing cups of each of the packing assemblies is equalized so that there is substantially no force applied to the seal cups to urge them into tight engagement with the well casing, whereby wear of the seal cups is eliminated or reduced to a minimum.

In the form of the invention diagrammatically shown in the Figure 3, and shown in detail in Figure 10, the upper and lower packing assemblies P and P are identical with the upper and lower packing assemblies P and P illustrated in Figures 4 and 4B. The upper packing assembly P includes an upper downwardly directed seal element or cup 212 and a lower upwardly directed sealing cup or element 214; the lower packing assembly P includes an upper downwardly directed sealing ele ment or cup 212' and a lower upwardly directed sealing element or cup 214. Since the structures of these sealing elements are identical with that shown in Figures- 4-4B, only the lower sealing element 214 of the upper packing assembly P and the upper seal element 212 of the lower packing assembly P are illustrated in detail in Figure 10. However, it will be appreciatedthat the 11 other-seal cups as diagrammatically shown in Figure 3 are essential to the structure.

The inner pipe or tube 240 is positioned within the tubular support in a manner similar to the mounting of the tube 40 in Figures 4-4B except that the tubular pipe 240 extends for substantially the complete length of' the tubular support 10. A seal 245 identical with the. seal 45 of Figure 4 is positioned between the upper end of the pipe 240 and the tubular support and an identical seal 245' is provided between the lower end of the tube 240 and the tubular support 10 (Figure 1). Radial ports or tubes are provided between the packing assemblies P and P in this form of the invention, with the upper tube being designated by the numeral 248 and the lower tube being designated by the number 243.

Instead of using the slidable valve construction illustrated in Figures 4-4B, this form of the invention shown in Figure 10 utilizes a solid plug such as an Otis plug shown at 261 in Figure 10. This plug is of conventional construction and is identical with the plug 61 illustrated in Figure 7. Such plug is of the wire line type and is adapted to be lowered through the tube 240 on a wire line and set and held in position in the pipe 240 by engagement in either of the

special adapter sections

80 and 81 disposed in the length of the pipe 240. One of these adapter sections 80 is disposed below the radial port 248 while another adapter section 81 is disposed between the radial openings or ports 248 and 248', the purpose of which will be hereinafter explained. It will be of course understood that any other suitable type of plug than that illustrated could be utilized so long as the .plug is adapted to be lowered into the well on a wire line and can be removed from its position when desired.

When the form of the well packer of Figure 10 is lowered into the well bore, the lower end of the inner tube 240 being open, fluid can readily flow upwardly therethrough and pass out through the ports 248 and 248' into the area between the packing assemblies P and

P. Openings

267 and 253 in the tubular support 10 permit the fluid below the lower packing assembly P to pass through the annular space 252 so that the pressure above and below the packing assemblies is equal- By reason of the construction of the seal cups of each of the packing assemblies, P and P, as above explained, in connection with Figures 4-43, these cups permit the well fluid to enter between such seal cups and to equalize the pressure in that area. During the lowering of the packer of this form into the Well bore, the plug 261 is not utilized, but when the packer has been lowered to its predetermined position, with the packing assemblies P and P above and below the well formation F, then the plug 261 is lowered into the tubular support and passes downwardly into the bore of the tube 240. Initially, the plug 261 is anchored to the interior of the tube 240 at the adapter section 81 so as to be between the flow ports 248 and 248'.

When the plug 261 is so positioned, between the

ports

248 and 248 and within the tube 240, fluid for cleaning the drilling mud from the vicinity of the well formation F can be pumped downwardly through the tubular pipe 240 and it will flow out through the port 248 and pass in the annular area 11 adjacent to the well formation F and return into the pipe 240 through the port 248'. The fluid will then continue to circulate downwardly through the open lower end of the tubular support 240 and will pass into the annular space 11 below the lower packing assembly and then will continue its flow upwardly through the lower opening 267 into the annular space 252 between the tubular support 10 and the inner tube 240. The flow of fluid will continue upwardly through the annular space 252 and pass outwardly through the upper openings 253 into the annulus 11 above the upper packing assembly P where it will be conducted to the surface of the well. The circulation will be continued as is explained above in connection with the other forms of the invention .until'the drilling mud has been removed fromthe annular space 11 between the packing assemblies P and P. If desired, acid can be circulated for a certain length of time to replace the water or other cleaning fluid previously circulated to remove the drilling mud. When the acid has displaced the water or other cleaning liquid from the annulus 11 between the packing assemblies, then the plug 261 can be removed from its attachment to the section 81 and lowered and attached to the adapter section so as to be below the port 248'. This closes ofl flow through the tubular support 240 below

such openings

248 and 248 and enables acid to be squeezed or injected under high pressure into the well formation F between the packing assemblies. Thereafter, when the acid has taken effect in its normal manner, the well formation will be produced by removing the pressure on the acid to permit the oil or gas from the formation to flow upwardly through the ports 248 and 248' into the bore of the inner tube 240 for conduction to the surface of the well through the tubing string connected to the support 10.

Porn the foregoing description, it can readily be seen that although there are various modifications of the well packer apparatus which can be employed in carrying out the process or method of this invention, in each of the forms of the apparatus, the well fluid pressure throughout the entire apparatus is equalized during the lowering of the apparatus into the well bore so that there is substantially no force on the sealing cups or elements of the packing assemblies during such lowering. This eliminates or reduces to a minimum the wear on the sealing cups or elements during such lowering and is a distinct advantage over the prior art. Also, in each form of the apparatus of this invention, it is possible to carry out various well operations and it is particularly important that a sequence of these operations can be carried out so that the drilling mud can first be removed from the vicinity of the well formation while subsequently, effecting a squeezing operation with acid or cement, thereby avoiding the injection of drilling mud ahead of the acid or cement into the well formation. This is especially valuable when injecting acid into a formation since it avoids the plugging up of a formation by the drilling mud which precedes the acid injection. It is also effective when injecting cement, as it avoids the mixture of the cement with the mud and the faulty sealing of such formation when such cementing operation is necessary. It will also be evident that any of the forms of the invention can be used for dual production as explained in connection with Figures 4-4B.

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

What is claimed is:

l. A well packer apparatus adapted to be lowered into a well bore for performing various well operations therein, comprising a tubular support, an upper packing assembly mounted on and surrounding said support, a lower packing assembly mounted on and surrounding said support and axially spaced longitudinally below said upper packing assembly, said tubular support having the lower end of its bore in communication with the area below the lower packing assembly and also having openings in its wall above the upper packing assembly and between the said assemblies whereby fluid in the well bore is present above, below and between said assemblies during the lowering of the apparatus into the well bore so as to equalize the pressure across said assemblies, each of said assemblies comprising an upper annular sealing element having its upper end only attached to said support and having its lower end adapted to move into sealing engagement with the support and the bore, and a lower assnsor annular sealing element having its lower end only attached to said support and having its upper end adapted to move into sealing engagement with the support and bore, the elements being spaced axially to form an annular space between said elements whereby the fluid pressure between said sealing elements of each assembly is also equalized so as to be substantially the same as the presure above and below each asembly, thereby eliminating any fluid force acting on said assemblies which would tend to urge said sealing elements radially outwardly.

2. The apparatus set forth in claim 1, wherein the tubular support includes an inner conductor within said support with its upper end extending above the opening in the wall of the support which is above the upper packer assembly, a sealing means between the inner conductor and the bore of the support above said opening whereby the upper end of the bore of the inner conductor is in communication with the bore of the support above the sealing means, the bore of the inner conductor communicating with the area around the support and between the packer assemblies, and a closure means for selectively closing ofi circulation through the opening in the wall of the support which is located between the packer assemblies, whereby pressure fluid introduced into the area between the packer assemblies through said inner conductor is confined in said area when said closure means is in a position closing ofi circulation through said last named opening.

3. A well packer apparatus adapted to be lowered into a well bore for performing various well operations therein, comprising a tubular support, annular packing assemblies mounted on said support in axially spaced relationship for sealing oil the annular space between the external surface of said tubular support and the wall of the well bore above and below a well formation in said well bore, each packing assembly comprising a pair of annular sealing cups having their open ends facing each other, an inner conductor within the support having its upper end in communication with the bore of the support at a point above the upper packing assembly, said conductor also having communication with the area outside the tubular support and between the packer assemblies whereby fluid communication between said area and the bore of the support above the upper packing assembly is established, the support having a port which provides communication between said area outside the support and between the packer assemblies and the lower portion of the bore of the support and also having a second opening providing communication with the annular space around the support above the upper packing assembly and between the point of communication between the bore of the support and the inner conductor, valve means surrounding the support and movable in an axial direction with respect to the port in said support to open and close the port in accordance with the relative position of the valve means on said support, and means for controlling the position of the valve means by a manipulation of said support.

4. A well packer apparatus as set forth in claim 3, wherein the valve means comprises a valve sleeve freely slidable on the support, said sleeve having friction springs 14- on its outer surface which are engageable with the wall of the bore in which said apparatus is disposed.

5. A Well packer apparatus as set forth in claim 3, wherein the valve means comprises a valve sleeve surrounding the tubular support and threaded thereon, and friction means on said sleeve engageable with the wall of the bore in which said apparatus is disposed for holding said sleeve stationary while the support is rotated to actuate said valve sleeve and move the same in an axial direction with respect to the support.

6. A well packer apparatus adapted to be lowered into a well bore for performing various well operations therein; comprising a tubular support; annular packing assemblies mounted on said support in axially spaced relationship for scaling 011 the annular space between the external surface of said tubular support and the wall of the well bore above and below a well formation in said well bore; each packing assembly comprising a pair of annular sealing cups having their open ends facing each other; an inner conductor within the support having its upper end in communication with the bore of the support at a point above the upper packing assembly; said conductor also having communication with the area outside the tubular support and between the packer assemblies whereby fluid communication between said area and the bore of the support above the upper packing assembly is established; the support having a port which provides a communication between said area outside the support and between the packer assemblies and the lower portion of the bore of the support and also having a second opening providing communication with the annular space around the support above the upper packing assembly and below the point of communication between the bore of the support and the inner conductor; the port, lower portion of the bore of said support and the second opening allowing a fluid circulation to occur from the area around the support and between the packer assemblies to the annular space above the upper packing assembly; and a closure means for selectively closing ofi the circulation from said area between the packer assemblies to said annular space; whereby fluid pressure directed through the inner conductor to said area between the packer assemblies is confined within said area.

7. A well packer apparatus as set forth in claim 6, wherein the closure means is a plug adapted to be lowered through the tubular support and into a position shutting off flow from the port into said second opening.

References Cited in the file of this patent UNITED STATES PATENTS Re. 20,546 Otis Nov. 2, 1937 2,055,515 Yarbrough Sept. 29, 1936 2,297,020 Page Sept. 29, 1942 2,315,012 Park Mar. 30, 1943 2,341,832 Verheul et al Feb. 15, 1944 2,360,311 Ausburn et a1 Oct. 17, 1944 2,466,305 Costello Apr. 5, 1949 2,493,962 Gray Ian. 10, 1950 2,575,603 Taylor et a1 Nov. 20, 1951 2,607,424 Taylor Aug. 19, 1952 2,607,425 Taylor Aug. 19, 1952