GB2066328A - Full open sleeve valve well tool - Google Patents

Abstract

A full open sleeve valve type well tool useful for cased or open-hole single or multiple zone gravel packing is operated solely by upward vertical motion of an inner concentric tool string having disposed thereon an opening sleeve positioner and a closing sleeve positioner to effect the desired sleeve movement. The tool comprises a housing (32) having port means (38) therein, and a sleeve (58) slidable in the housing and having an aperture (80) therein, the sleeve being slidable relative to the housing to move the aperture (80) from a first position (as shown) out of alignment with the port (38), to a median position in alignment with the port, and then to a second closed position in which the aperture (80) is above and out of alignment with the port (38). <IMAGE>

Description

SPECIFICATION Full open sleeve valve well tool Unconsolidated formations, particularly those containing loose sands and soft sandstone strata, present constant problems in well production due to migration of loose sands and degraded sandstone into the well bore as the formation deteriorates under the pressure and flow of fluids therethrough. This migration of particles may eventually clog the flow passages in the production system of the well, and can seriously erode the equipment. In some instances, the clogging of the production system may lead to a complete cessation of flow, or "killing" of the well.

One leading method of controlling sand migration into a well bore consists of placing a pack of gravel on the exterior of a perforated or slotted liner or screen which is positioned across an unconsolidated formation to present a barrier to the migrating sand from that formation while still permitting fluid flow. The gravel is carried to the formation in the form of a slurry, the carrier fluid being removed and returned to the surface.

The proper size of gravel must be employed to eFfectively halt sand migration through the pack, the apertures of the liner or screen being gauged so that the gravel will settle out on its exterior, with slurry fluid carrying the gravel entering the liner or screen from its exterior.

"Reverse circulation" is a widely employed procedure by which wells are packed. Currently, a liner assembly having a perforated liner or screen is positioned across the unconsolidated formation, commonly referred to as the "zone" to be packed, after which a packer is set above the zone between the liner and the well casing, or, if unlined, the well bore wall to isolate that zone from those above. A tubing string is run inside the liner assembly at the area of the zone, there being created between the liner and inner tubing string an annulus.Gravel slurry is pumped into this annulus, out into the annulus between the liner and the casing or well bore wall at a suitable location above the zone where it descends and the gravel is deposited in the area of the screen as the carrier fluid re-enters the liner assembly through the screen, being removed through the inner tubing string. A crossover device incorporated in the packing apparatus routes the returning fluid back outside the liner assembly, the fluid then traveling up to the surface. A pressure buildup is noted at the surface as the gravel level reaches the top of the screen, indicating that a successful pack has been achieved. Thereafter, the flow of gravel-laden fluid is stopped.If desired the crossover may be closed and pressure applied in the same direction as the slurry flow to squeeze the slurry into the formation, thus consolidating the gravel pack. After squeezing, the crossover is opened again and the circulation of fluid is reversed, a clean fluid being pumped down the inner tubing and back up the annulus between it and the liner assembly in order to flush out this area. Subsequently, the well may be subjected to other treatments if necessary, and produced.

The apparatus by which the gravel slurry is directed to the annulus between the liner and the casing or well bore wall, at which point it descends to the gravel screen, is generally simple in design, often being merely holes or ports in the liner above the gravel screen. Such a configuration is disclosed in U.S. Patent No. 3,987,854.

Alternativeiy, some sort of provision for closing the gravel ports after the gravel pack operation may be made. U.S. Patent No. 3,710,862 discloses a method of closing the ports by running a port seal down into the hole after the tubing string has been withdrawn. U.S. Patent No. 3,726,343 takes a different approach, that of mounting a sealing sleeve on the exterior of the liner, which sleeve is released to close the gravel ports by the shearing of a pin after gravel packing is completed. Yet another attempt to provide for the closure of gravel ports after packing is disclosed in U.S. Patent No. 3,963,076, where a sliding sleeve is moved by the downward reciprocation of shifting tool from an open position to a closed position; the sleeve is locked open or closed by a collet finger mechanism. U.S.Patent No.4,105,069 utilizes a sliding sleeve gravel collar for the closing of the gravel ports, which sleeve is operated by upward and downward reciprocation of tools disposed on an inner concentric string. A further alternative employed in the prior art is a gravel collar utilizing rotational motion of a sleeve to open and close the gravel ports.

The prior art devices, in whatever form chosen, suffer from a number of serious deficiencies. Ofgreat concern is the safety hazard encountered when a liner is being instalied in a well having one or more zones under high pressure contained by a mud column. The open ports prevent any sort of effective blowout control. The blowout problem is also a consideration after the zone has been packed when an open port is left in the well permanently or while the tool string is withdrawn and a seal inserted across the ports. If the gravel pack has not been completely consolidated across the gravel screen, formation components can bypass it and enter the liner through the ports.

Furthermore, whether a separate seal is employed or an integral sleeve is reciprocated, a second trip into the well is necessitated to perform this one operation.

Rotational sleeve gravel collars are also inserted with the gravel ports open, again representing a safety hazard with respect to blowout prevention, or lack thereof. Additionally, rotational sleeve collars may be difficult to operate as the amount of torsional force which can be applied at the well bottom is difficult to control.

This, coupled with the fact that there is no way to determine how much rotation on the surface will effect the required amount downhole, presents a problem to the operator in that he has no way of knowing whether or not a valve is fully open, partially open or fully closed after he has applied force to the string.

The apparatus disclosed in U.S. Patent No. 4,105,069 overcomes many of those deficiencies, yet relies on both upward and downward reciprocation of the tool string to effect opening and closing of the collar sleeve.

Furthermore, as the sleeve is opened with an upward motion, there is a marked possibility that one or more collars will be inadvertently opened as the tool string is pulled out of the well, should the sleeve opening tool malfunction. In addition, the opening tool is operated by rotation of the tool string as well as reciprocation thereof, a particular problem in deviated holes due to hangups between the liner and tool string.

We have now devised an improved sleeve valve well tool by which many of the disadvantages of the prior art described above are reduced or overcome.

According to the invention, there is provided a sleeve valve type well tool comprising: housing means having port means therein; said port means having two closed positions and one open position.

The invention also provides a sleeve valve type well tool comprising: housing means having port means therein; sleeve means longitudinally slidably disposed within said housing means; said port means being open when said sleeve means is in a median position, and being closed when said sleeve means is in upper and lower positions.

The invention further provides a sleeve valve type well tool comprising: a housing having peripheral port means therein; a sleeve longitudinally slidably disposed within said housing and having peripheral aperture means therein; said housing port means communicating with said sleeve aperture means when said sleeve is in a median position, being isolated therefrom when said sleeve is in an upper or lower position.

In another aspect, the invention provides a method of operating a well tool having a housing and a sleeve slidably disposed therein, said housing and said sleeve each having at least one aperture therethrough, comprising: aligning said apertures through longitudinal movement of said sleeve; and isolating said apertures through subsequent longitudinal movement of said sleeve in the same direction.

The invention also provides a method of operating a well tool having a body, a sleeve slidably disposed therein, and port means, comprising: opening said port means by longitudinal movement of said sleeve; and closing said port means by longitudinal movement of said sleeve in the same direction.

The invention further provides a method of operating a gravel collar, comprising: opening said gravel collar by application of longitudinal force; closing said gravel collar by application of longitudinal force in the same direction.

In a preferred embodiment of a three-position full open sliding sleeve type gravel collar of the invention, the sleeve is located in each position after movement by a ring of collet fingers, and the sleeve is moved by engagement with spring arms on an inner concentric tool string. The spring arms release automatically as each position of the sleeve is reached. All movement of the sleeve necessary to effect both opening and closing of the collar is upward, thus saving an extra operation at the completion of packing to close the tool, and ensuring the closing of the gravel collar as the inner tool string is pulled upward out of the well or to the next higher zone.Closing with an upward pull also facilitates the maintenance of all bypass valving in the isolation gravel packer of the inner tool string in the open position, which closing with a downward movement (due to the necessary force involved in pulling a sleeve downward) would oppose. Should the bypass in the isolation gravel packer be closed, the isolation gravel packer, by virtue of its downward-facing packer cups would push a column of fluid below it into any exposed formations, as well as possibly damaging or rupturing the packer cups themselves preventing any additional packing without pulling the tool string.As it is difficult to control the exact amount of upward and downward motion of the tool string, operation of the gravel collar of the present invention by an upward pull with an automatic release at the open position, followed by a second upward pull, with a second automatic release at the closed position, presents obvious advantages to the operator.

The present invention is described hereafter in conjunction with a particular isolation gravel packer by way of illustration and not by limitation.

It will be evident to those skilled in the art that other isolation gravel packers, such as that disclosed in U.S. Patent No. 4,105,069, may be employed.

It will also be clear that the principal of the present invention may be utilised for other types of apparatus, such as a cementing collar. This would present an advantage in that a three position full open cementer in the upper closed position could not be re-opened by pulling a swab through the tool as is sometimes the result with existing tools.

In order that the invention may be more fully understood, an embodiment thereof will now be described, by way of example only, with reference to the accompanying drawings, in which: FIGURE 1 is a detailed vertical half-section of a gravel collar of the invention in the lower closed position, with the spring arm of an opening sleeve positioner engaged; FIGURE 2 is a detailed vertical half-section of the gravel collar in the open position, with the spring arm of an opening sleeve positioner about to disengage; FIGURE 3 is a detailed half-section of the gravel collar in its upper closed position, with the spring arm of a closing sleeve positioner about to disengage; FIGURES 4A, 4B, 4C and 4D are a simplified vertical cross-sectional elevation of the gravel collar as used with a full tool string during gravel packing; ; FIGURE 5 is a simplified vertical cross-section of the gravel collar during reverse circulation; and FIGURES 6A, 6B, 6C and 6D are a detailed vertical half-section elevation illustrating the three position gravel collar of the present invention in the open position with an inner tool string in position to gravel pack.

Referring to the drawings, FIGS. 1,2 and 3 illustrate the operation of the sleeve of a three position gravel collar, while FIGS. 6A through 6D depict an open three position gravel collar with an isolation gravel packer in place to effect gravel packing.

FIG. 1 shows a well casing 24, within which are located liner 22 and tool string 20. As a part of liner 24, above each of the one or more producing formations or "zones," is located a three position gravel collar, generally designated by reference character 30. Gravel collar 30 is closed as shown, during its insertion into the well as part of the liner having a float shoe at the bottom thereof. Gravel collar 30 comprises housing 32 with at least one gravel port 38 therethrough, threadably attached and welded to adapter 34 at its upper end, and adapter 36 at its lower end. Adapters 34 and 36 are in turn threadably attached to the liner 22.

Upper adapter 34 possesses a constricted or necked-down inner diameter 40, below which is beveled surface 42. The majority of the interior of housing 32 comprises uniform cylindrical surface 44, through which gravel port 38 extends. By way of illustration, two, three, four or more gravel ports may be employed to increase flow through the tool. Below and contiguous with cylindrical surface 44 is upper annular groove 46, followed by upper annular surface 48, median annular groove 50, lower annular surface 52 and lower annular groove 54. Lower annular groove 54 is followed by shoulder 56 formed by the upper edge of lower adapter 36. Inside housing 32 is slidably disposed sleeve 58, comprising flat upper edge 60, leading on its radially inward extremity by a beveled inner surface, and under which is located a downward-facing radially inward extending annular shoulder 62.Below annular shoulder 62, an area of increased inner diameter 64 forms a recess on the inside of the sleeve 58 followed by a ,tapered surface leading to cylindrical surface 66 of reduced inner diameter, which extends to skirt 68, at the lower end of which are formed a ring of Follet fingers 70 having outwardly radially extending protrusions at their lowermost extremity. The inner surface of skirt 68 is characterized by annular recess 69, having upward-facing annular shoulder 71 at the lowest point thereof. Annular seals 72, 74, 76, and 78 surround sleeve 58, and aperture 80 (as well as others, if a plurality of gravel ports are employed) extends therethrough between seals 74 and 76.

Below annular seal 78, downward-facing beveled annular shoulder 82 leads to the exterior of skirt 68. It can readily be seen that contact of shoulder 82 with the axially upper edge of upper annular surface 48 will limit any downward travel of sleeve 58 in the event that lower adapter 36 is not threaded to housing 32 a sufficient distance to act as a stop against collet fingers 70. The gravel collar 30 as depicted in FIG. 1 is in its lower closed position, in which it would enter the casing 24 as part of liner 22. Gravel port 38 is bracketed by annular seals 72 and 74, and aperture 80 by annular seals 74 and 76. Opening sleeve positioner 90 is used to open gravel collar 30, opening sleeve positioner 90 being a part of tool string 20 and attached thereto by adapters 92 and 94.Mandrel 96 of opening sleeve positioner 90 has disposed thereabout spring arm collar 98, from which one or more spring arms designated by reference character 100, depend. Spring arm collar is constrained on mandrel 90 by upper adapter 92. Spring arm 100, which is facing downward, possesses on its outer surface median spring arm shoulder 102, bounded by upper and lower beveled edges. Median spring arm shoulder 102 may have embedded therein a carbide button (unnumbered) as shown to enhance its wear characteristics during contact with the inside of liner 22. At the lower end of spring arm 100, protrusion 104 includes upward facing and radially outward-extending shoulder 106, and outer inwardly-inclined edge 108 leading to a pointed lower tip.Below spring arm collar 98, spline collar 110 with one or more splines disposed thereon, one of which is designated at 112, circumferentially aligned with spring arm 100 (other splines, not shown, being aligned with other spring arms about the circumference of opening sleeve positioner 90). Spline collar 110 is keyed to prevent rotation about mandrel 96. The outer extent of spline 112 is on substantially the same radius as the tip of spring arm 100, whereby spline 112 protects spring arm 100 from damage as tool string 20 is lowered into the well, facilititates the avoidance of hangups by spring arm 100 on irregularities in the liner or casing, and centralizes the spring arm in the liner.

To open gravel collar 30, upward-facing shoulder 106 on spring arm 100 of opening sleeve positioner 90 is engaged with sleeve shoulder 62 on gravel collar sleeve 58. The recess formed by area 64 on the inside of sleeve 58 allows spring arm 100 to expand radially outward, the two shoulders thus engaging. Median spring arm shoulder 102 will not engage the sleeve shoulder 62 due to the beveled nature of its edges and the compression of the spring arm 100 by contact of spring arm protrusion 104 with inner surface 66 of sleeve 58, which prevents entry of median spring arm shoulder 102 into the recess adjacent area 64. When tool string 20 is pulled upward, spring arm 100 pulls sleeve 58 to its median position, illustrated in FIG. 2, at which point gravel collar 30 is opened, gravel port 38 being aligned with aperture 80.It may be noted again that other gravel ports, similar to 38, and apertures, similar to 80 would normally be located around the circumference of the collar, to increase the volume of flow. As shown in FIG. 2, annular seals 74 and 76, bracketing aligned gravel port 38 and apertures 80, prevent any fluid or particulate matter from impinging between housing 32 and sleeve 58 during gravel packing operations.

Sleeve 58 is locked in its open position by the entry of the protrusions on outwardly biased collet fingers 70 into median groove 50 after riding up and over lower annular surface 52. Further upward movement of sleeve 58 in response to the pull of opening sleeve positioner 90 is eliminated by the contact of median spring arm shoulder 102 on spring arm 100 with beveled surface 42 leading to necked-down portion 40 on upper adapter 34. The longitudinal disposition of median spring arm shoulder 102 on spring arm 100 is calculated to cause the aforesaid contact when sleeve 58 reaches a position whereby gravel collar 30 is opened, after which the contact and subsequent inward urging of beveled surface 42 and necked-down portion 40 on spring arm 100 through median spring arm shoulder 102 will cause upward-facing shoulder 106 on spring arm protrusion 104 to release sleeve shoulder 62.

When tool string 20 is subsequently lowered, as will be discussed hereafter with respect to a gravel packing operation, inclined edge 103 on protrusion 104 riding first on beveled sleeve edge 60 and then on the beveled edge leading to cylindrical inner sleeve surface 66 will allow opening sleeve positioner to move freely downward, by downward force exerted on sleeve 58 being adequately compensated for by the engagement of outwardly biased collet fingers 70 with median annular groove 50.

When gravel collar 30 is to be closed again (as shown in FIG. 3), closing sleeve positioner 120, located on tool string 20 below opening sleeve positioner 90, is employed. Closing sleeve positioner 120 is similar to opening sleeve positioner 90, comprising mandrel 126 having disposed thereon spring collar 128 with one or more spring arms designated at 130 and spline collar 140 with one or more splines 142 aligned with spring arms 100. The spring arms and splines are circumferentially aligned and held in a similar manner to those of opening sleeve positioner 90.

Mandrel 126 is attached to tool string 20 by adapters 122 and 124, which also serve to constrain spring arm collar 128 and spline collar 140, respectively. Spring arm 130 has located thereon median shoulder 132, bounded by beveled edges. Median shoulder 132, however, unlike median shoulder 102 on spring arm 100, is located closer to the protrusion 1 34 at the end of the spring arm 130, spring arm 1 30 also being shorter than spring arm 100. When upward-facing shoulder 1 36 on protrusion 1 34 biases outwardly into the recess adjacent area 64 and engages sleeve shoulder 62, as described previously with respect to opening sleeve positioner 90, an upward pull on tool string 20 will cause gravel collar 30 to change to its upper closed position.As seen clearly in FIG. 3, median spring arm shoulder 132 contacts beveled surface 42 leading to necked-down portion 40 of upper sleeve adapter 34 when sleeve 58 reaches its closed position, and further upward movement on tool string 20 causes spring arm 1 30 to compress and release the sleeve 58, the shorter length of spring arm 130 and the placement of median sleeve shoulder 132 thereon being calculated to effect the release of sleeve 58 where desired. In the upper closed position, annular seals 76 and 78 bracket gravel port 38 in housing 32, thus preventing any flow therethrough. When closing sleeve positioner is lowered into the well on tool string 20, spline 142 protects spring arm 130, and prevents hangups, as does inclined edge 138, the top of which is on substantially the same radius as the outer extent of spline 142.

Referring now to FIGS. 6A through 6D, gravel collar 30 is in its open position as shown in FIG. 2.

The tool string 20 has been positioned so that isolation gravel packer 300, on tool string 20 is in place to begin gravel packing. Isolation gravel packer 300 includes both gravel packing components per se, combined with a bypass and dump valve assembly to facilitate movement of the device through the liner, as will be explained in detail hereafter.

Isolation gravel packer 300 is hung in the liner from concentric pipes 208 and 210. Bypass sleeve 302 is threadably attached to outer concentric pipe 210, and has fixedly disposed thereon annular collar 306, through which vertical passage 440 extends (it being understood that there is a similar passage on the righthand side of the tool, it being a mirror image of the lefthand side, as shown in simplified form in FIG. 4C). Slidably disposed within the bore of annular collar 306, slip joint mandrel 304, threadably attached to inner blank pipe 208, extends to encompass the upper end of inner mandrel 420, a fluid seal created therebetween by O-rings 416 and 418.Sleeve dump port 318 and sleeve bypass port 324 extend through the wall of bypass sleeve 302, with annular seals 314 and 316 bracketing dump port 318 and annular seals 320 and 322 bracketing bypass port 324. At the lower end of bypass sleeve 302 is disposed a ring of downwardly extending fingers 326 having lugs 328 at the lower end thereof. Below the junction of outer blank pipe 210 and bypass sleeve 302, the outer surface thereof is of a reduced diameter, shown at 308 and 312, having an annular shoulder 310.

thereon with tapered edges. The outer diameter of bypass sleeve 302 remains substantially constant down to collet finger apron 326, where it is somewhat reduced. Encircling bypass sleeve 302, bypass housing 330 is in slidable relationship thereto, annular seals 314, 31 6, 320 and 322 being in slidable sealing contact with bypass housing 330. Housing dump port 332 and housing bypass port 334 extend through the wall of bypass housing 330, which is fixed to upper packer housing 350. At the upper extent of bypass housing 330, a ring of slender collet fingers 336 being radially inward extending upper extremities 338, lies juxtaposed with annular shoulder 310 on the outer surface of bypass sleeve 302. Below collet fingers 336, bypass housing 330 is of substantially uniform inside diameter extending to annular stop 340, of reduced inner diameter.Below stop 340, the inner diameter of bypass housing 330 is again increased at area 342, to accommodate lugs 328 of collet fingers 326. In addition, shown in broken lines at 344, splines are cut in area 342 to cooperate with collet finger lugs 328 and prevent the relative rotation of bypass sleeve 302 and bypass housing 330, which will ensure the circumferential alignment of the dump and bypass ports in the sleeve with those of the housing.

Packer housing 350 is of substantially uniform outer diameter to its lower extremity, at which point area 362 of reduced diameter has disposed thereon packer ring 352, below which is downward-facing packer cup 354, packer spacer 356, downward-facing packer cup 358, and tubular packer standoff 360. As shown in FIG. 6B, the packer cups are axially constrained by the threaded engagement of upper casing 364 with packer housing 350, upper circulation housing acting against packer standoff 360. Fixed to the lower end of upper casing 364 is gravel passage casing 366, having gravel aperture 368 therethrough, gravel passage casing 366 being welded to the interior thereof, gravel passage block 410 having gravel passage 412 therethrough in communication with aperture 368.Gravel passage block 410 is designed to admit fluid therepast, from outer annular passage 448 to annular chamber 450. The inner face of gravel passage block 410 is welded to outer .mandrel 404 at the lowest extent thereof, which in turn is welded to ring 414, a fluid seal between ring 414 and inner mandrel 420 being effected by O-rings 422 and 424. The upper end of outer mandrel 404, as shown in FIG. 6A, rides inside of bypass sleeve 302 at an area of reduced inner diameter thereof, a fluid seal between the two being effected by O-rings 406 and 408 during the full extent of any axial travel by bypass sleeve 302.

Below gravel passage casing 366, lower casing 370 extends to circulation casing 374 being disposed thereabout upward-facing packer cup 376, packer spacer 378, upward facing packer cup 380, and threaded packer ring 382, fixed to the outer surface of circulation casing 374. The threaded engagement of lower casing 370 and circulation casing 374 provides a constraining shoulder on the upward travel of packer cups 374 and 380 due to the greater outer diameter 372 of lower casing 370 as shown in FIG. 6C, their downward travel being limited by threaded packer ring 382.Adjacent to and below threaded packer ring 382, circulation aperture 384 extends through the wall of circulation casing 374, the inner wall of which has circulation block 426 welded thereto, the latter being circulation passage 428 extending therethrough in communication with circulation aperture 384.

Inner mandrel 420 is welded to the interior of circulation block 426, which, as with gravel passage block 410, is designed to permit the passage of fluid axially therearound, from the upper portion of annular chamber 450 to the lower portion thereof. Axial circulation passage 452 of inner mandrel 420, as shown, is in communication with circulation passage 428.

Below circulation aperture 384 upward-facing packer cups 386 is backed by packer ring 388, which is turn backs downward-facing packer cup 390. Movement of packer cups 386 and 390 are axially constrained by a slight shoulder on circulation casing 384 above packer cup 386 as shown in FIG. 6D, and by a like shoulder in end casing 392 below packer cup 390. Lower bypass port 394 extends through the wall of end casing 392, connecting the liner annulus 454 below isolation gravel packer 300 with annular chamber 450 thereon. End casing 392 has O-rings 396 and 398 therein, effecting a fluid seal between the interior of end casing 392 and the exterior of the lowest extremity of inner mandrel 420.

Fixed to the lower end of end casing 392, ball check valve 460 comprises upper valve housing 462 and lower valve housing 464 with ball 468 inside. Upper valve housing 462 possesses bypass spider 466 permitting fluid flow therepast even with ball 468 in place. Lower valve housing has seat 470 therein, so that fluid flow in a downward direction is prohibited when ball 468 is seated thereon.

It can be seen that gravel aperture 368 (FIG.

6C) is adjacent gravel port 38 and aperture 80 in gravel collar housing 32 and sleeve 58, respectively, thus enhancing the flow of gravel to casing annulus 26. The flow of gravel slurry entering packer annul us 444 from gravel aperture 368 is constrained at its upper end by packer cups 354 and 358, and at its lower end by packer cups 376 and 380, all being responsive to the fluid pressure of the slurry. Slurry reaches packer annulus 444 from blank pipe annulus 209, vertical passage 440, inner annulus 442, gravel passage 412 and gravel aperture 368. Upward flow from check valve 460, such as would occur during return of slurry carrier fluid through a tail pipe during gravel packing, traverses the length of isolation gravel packer 300 through axial circulation passage 452 of inner mandrel 420, traveling subsequently to the surface through the bore of inner blank pipe 208.

During reverse circulation, when clean fluid is pumped down blank pipe 208 and axiarcirculation passage 452 of inner mandrel 420, ball 468 of check valve 460 will seat on seat 470, causing the fluid to enter circulation passage 428 through aperture 429, and exit isolation gravel packer 300 through circulation aperture 384. This pressurized fluid will then collapse upward-facing packer cups 376 and 380 (as shown in simplified form in FIG.

5) and enter the area of packer annulus 444, further upward movement of fluid being prevented by downward-facing packer cups 354 and 358.

The fluid will thus be directed into gravel aperture 368, gravel passage 412 and up inner annulus 442 to blank pipe annulus 209 leading to the surface.

When the tool string 20 is moving through the liner bore, it is imperative that fluid be allowed to bypass it so as to avoid swabbing, which could drive fluid into the formations through the gravel screens as well as damage packer cups. To effect this result, bypass sleeve 302 slides within bypass housing 330, so that an upward pull on pipes 208 and 210 will result in the upward movement of bypass sleeve 302 with respect to bypass housing 330. Annular shoulder 310 on bypass housing 302 rides upward under collet finger extremities 338, which provide a locking arrangement against small upward and downward forces. The. upward movement of bypass sleeve 302 is restricted by contact of stop 340 in bypass housing 330 with the lugs 328 of fingers 326 at the lower end of bypass sleeve 302.In the extended position by bypass sleeve 302, dump port 318 in bypass sleeve 302 is juxtaposed with dump port 332 in bypass housing 330. This permits communication between annulus 446 above isolation gravel packer 300 and packer annulus 444 through dump port 332, dump port 318, inner annular passage 442, gravel passage 412, and gravel aperture 368. Thus, during upward movement, which will collapse packer cups 354 and 358, and set packer cups 376 and 380, the column of fluid above packer cups 376 and 380 can exit the area of the packer annulus 444 and return to the top of the isolation gravel packer as it displaces fluid during its upward movement. Similarly, when bypass sleeve 302 is extended, bypass port 324 will be aligned with bypass port 334 in bypass housing 330.In this case, the annulus 446 above isolation gravel packer is put in communication with annulus 454 therebelow through dump port 334, dump port 324, outer annular passage 448, past gravel passage block 410 into annular chamber 450 past circulation block 426 and through lower bypass port 394. Downward movement of isolation gravel packer 300 is thus facilitated as the column of fluid held by downward-facing packer cups 390 can exit the annulus 454 and travel up to the annulus 446 above the isolation gravel packer 300 as it displaces the fluid.

The bypass portion of isolation gravel packer 300 is disposed so that a substantial downward force, for example 20,000 pounds, must be applied to close the dump and bypass ports. Upper extremities 338 prop up bypass sleeve 302 by their contact with the lower side of annular shoulder 310 when bypass sleeve 302 is extended. When the isolation packer is anchored in place for packing, as will be discussed hereafter, then such a downward force may be applied.

When upward movement of the tool string 200 is effected after packing, the initial drag of fluid and the force exerted before the tool string is unanchored will open the dump and bypass ports.

Full open gravel collar 30 is designed to require approximately 10,000 pounds of force to move sleeve 58 upward, during which operations the dump and bypass ports of isolation gravel packer 300 may be open, as they will be closed again if the tool string 20 is anchored for packing and downward force is applied. Thus, there is no problem encountered if the 10,000 pound force is exceeded momentarily as in all likelihood the dump and bypass ports are already open, and in any event will be reclosed before gravel packing.

Referring now to the drawings, and to FIGS. 1 A through 1 D and 5 in particular, full open gravel collar 30 and an isolation gravel packer 300 iri a liner and tool string, respectively, are illustrated in simplified form for the sake of clarityin depicting a gravel packing operation. The tool string is generally designated by the reference character 20, while the liner concentrically surrounding it is designated by the reference character 22.

Disposed about the two concentric strings is well casing 24, having perforations therethrough at the levels of two unconsolidated producing formations 1 50 and 152, through which the well bore passes.

Should the gravel pack procedure discussed herein be employed in a well that does not employ a liner, the components referred to as incorporated therein, such as full open gravel collars, may be incorporated in the well casing 24, utilizing a suitably sized tool string within.

Liner 22 is secured within well casing 24 by means of a suitable liner hanger casing packer 156, as illustrated schematically. Liner hanger 154 is positioned in casing 24 by means of slips 160 employed in mechanically setting packer 1 56. Threaded collar 1 58 is employed to secure liner 22 to a drill string during its installation in the well bore inside the well casing 24.

Moving downwardly from liner hanger assembly 154, the liner comprises a length of blank pipe 162 to a location just above the highest zone to be packed. At that point is located a casing inflation packer, illustrated schematically at 164. Annular space 166 defined by mandrel 168 and elastomeric outer wall 170 is inflated by pumping fluid through schematically illustrated check valve 1 72 to a predetermined pressure.

Below packer 164 is located a full open gravel collar 30, as heretofore described but shown in simplified form comprising housing 32 within which is slidably disposed sleeve 58. At the top of housing 32 is located necked-down portion 42, bounded by beveled edges. Below necked-down portion 42 is inner cylindrical surface 44, through which gravel ports 38 and 38' extend. Below inner surface 44 is shown annular surface 48, followed by median annular groove 50, annular surface 52 of substantially the same inner diameter as annular surface 50, and lower annular groove 52.

Upper annular groove has not been shown for simplicity. Inside housing 32 sleeve 58 has disposed thereabout annular seals 72, 74, 76 and 78. At the top of sleeve 58 is located downward facing annular shoulder 62. Between annular seals 74 and 76 apertures 80 and 80' communicate with gravel ports 38 and 38' when aligned therewith. At the lowest extremity of sleeve 58 are located a ring of collet fingers 70 having radially outward extending lower ends.

Polished nipple 174 is below gravel collar 30, below which is anchor tool 1 76. Anchor tool 176 has upward-facing annular shoulder 178, bounded by annular recesses. Blank pipe 180 is immediately below anchor tool 176.

Gravel screen 1 82 is disposed across the upper producing formation or zone of interest 1 50 below blank pipe 180.

Referring to the lower zone of interest, casing inflation packer 184, substantially identical to packer 164, is located below gravel screen 1 82 to isolate the upper zone of interest from the lower zone. Space 1 86 defined by mandrel 188 and elastomeric outer wall 1 90 is inflated by pumping fluid through schematically illustrated check valve 192 to a predetermined pressure.

Below packer 184 is located a second full open gravel collar 30 in the open position, gravel ports 38 and 38' being aligned with apertures 80 and 80'.

Second anchor tool 196 is located below polished nipple 194, below lower gravel collar 30.

Anchor tool 1 96 possesses upward-facing annular shoulder 198, bounded by annular recesses.

Gravel screen 202 is disposed across the lower producing formation or zone of interest below blank pipe 200. Gravel screens 182 and 202 are fore-shortened in the drawings herein, and actually may be a number of feet in length, the length being determined by the thickness of the producing formation to be gravel packed, all of which is evident to those skilled in the art, it being further evident that the gravel screens may have perforations, as shown, or may employ wirewrapped slots to form the desired perforations.

Another length of blank pipe 204 is attached below gravel screen 202, and the lowest end of the pipe is capped with a float shoe 206.

It should be noted that the proper orientation of tool string 20 with respect to liner 22 is dependent upon the polished nipples 174 and 1 94 being of the appropriate length to position isolation gravel packer 300 (see FIG. 1 C) across gravel collar 30 when the tool string 20 is anchored in place at the zone being packed.

The liner 22 having been described, the tool string 20 will now be described from the top thereof downward.

Inner blank pipe 208 and concentric outer blank pipe 210 extend downward to isolation gravel packer 300 from the surface. As the two lengths of pipe cannot be matched exactly, it is of course necessary to include a fluid-tight slip joint and swivel assembly illustrated in simplified form at 212 in the inner string of pipe.

Blank pipes 208 and 210 enter the top of isolation gravel packer 300, heretofore described in detail. At the top end of isolation gravel packer 300 is located upper body 302, at which point blank pipe 208 communicates with axial circulation passage 452 and the annulus 209 between pipes 208 and 210 communicates with outer passages 440 and 440'. The components of isolation gravel packer 300 in FIG. 4C are numbered to correspond to the components heretofore described in detailed FIGS. 6A through 6D, it being noted, however, that some components have been ommitted in FIG. 4C for the sake of clarity as not essential to the description of a gravel-packing operation.

Shown in FIG. 4C at approximately the same location as ball check valve 460 is opening sleeve positioner 90, comprising spring collar 98 and spring arms 100 and 100', possessing radially outwardly extending median shoulders with beveled edges. At the ends of the spring arms are located protrusions, each having an upward-facing radially outward extending shoulder 106 and 106' at the top thereof, the lower outside face of each protrusion being beveled inwardly in a downward direction. Spring arms 100 and 100' are shown in a slightly compressed position against the interior of liner 22 at polished nipple 1 94.

Below opening sleeve positioner 90 in tool string 20 is located anchor positioner 220.

Anchor positioner 220 comprises drag block assembly 222 and spring arm body 224. Drag block assembly 222 is slidably mounted on mandrel 226, in which is located J-slot 228. Pin 230 is fixed to drag block assembly 222, and slides within J-slot 228. On the interior of drag block assembly 222 are spring-loaded drag blocks 232 and 234, shown schematically, which press against the inside of liner 22, thus centering the anchor positioner 220. The lower face 236 of drag block assembly is frustoconical in configuration, being inclined inwardly and upwardly from the lowest extremity thereof. Below drag block assembly 222, spring arm body 224 possesses upward-facing spring arms 238 and 240, similar to those of opening sleeve positioner 90: Spring arms 238 and 240 possess radially outward extending median shoulders, as well as protrusions at their upper ends.The shoulders have beveled edges, and the protrusions have downward-facing radially outward extending shoulders at the bottom, and upwardly extending inwardly-beveled faces at the top. The uppermost points of these faces are disposed on a radius less than the lowermost extremity of drag block assembly 222, thus permitting the inclined face 236 to slidably engage and compress the spring arms 238 and 240 when operating string 20 is pulled upward. As J-slot 228 is truly "J" shaped, pulling up on tool string 20 will cause pin 230 to travel to the bottom of slot 228, which is below the shorter longitudinal portion of the "J", anchor positioner 220 locking in a retract position when the tool string 20 is set down, pin 230 entering the shorter longitudinal portion of the "J".

Below anchor positioner 220 is located closing sleeve positioner 120, comprising spring arm collar 128 on which are mounted downwardfacing spring arms 1 30 and 130'. Each spring arm possesses outward radially extending median shoulders 132 and 1 32', the edges of which are beveled, and at the lowest end of the spring arms are located protrusions, having upward-facing outwardly radially extending shoulders 136 and 136' at their upper edges, and downward inwardly beveled edges on their lowermost exteriors. Spring arms 130 and 130' are shown in slightly compressed positions against the interior of liner 22 at blank end pipe 204.

At the lowest extremity of operating string 20 is tail pipe 250, having bore 252 which communicates with bore 254 extending through anchor positioner mandrel 226 up to check valve 460.

Referring again to FIGS. 4 and 5, a gravelpacking operation will be described. After the well is drilled and casing 24 inserted it is perforated at the appropriate intervals adjacent formations 1 50 and 152, washed and possibly treated in some manner. At this point, liner 22 is lowered into the well bore and hung within casing 24 by liner hanger assembly 154.

The liner 22 as installed in the casing, comprises as many full open gravel collars as there are zones to be packed, designated by the reference character 30. As stated previously, the upper and lower gravel collars 30 are located above their respective zones to be packed, while corresponding gravel screens 1 82 and 202 are located adjacent to and spanning these zones.

Between each gravel collar and its corresponding gravel screen are located polished nipplies 174 and 194, and anchor tools 176 and 196, respectively, which accurately position the tool string 20 at each zone when the anchor positioner 220 is engaged in the appropriate anchor tool.

Above the upper zone is located suitable casing inflation packer 164, and below the zone is suitable casing inflation packer 184, which, when inflated isolate the upper zone from the zone below and the well annulus above. If the upper zone is extremely close to liner hanger assembly 154, packer 1 64 may be deleted as redundant when a liner hanger with a sealing element is employed such as illustrated schematically at 1 56.

If it is desired to isolate zones not only from each other but from the intervals between formations, packers may be employed above and below each zone. For example, if the upper zone in the present instance was far above the lower zone, an additional casing inflation packer might be utilized in the liner 22 above packer 184 and yet below the upper zone, additional anchor tools being placed at proper intervals in the liner.

After the liner 22 is hung in the casing, the tool string 20 is run into the well bore. The operator has the option of inflating casing inflation packers 164 and 184 as the tool string 20 is going down the well bore, or he may elect to inflate the packers from the bottom as he proceeds upward.

He may, in fact, inflate the packers in any order but for purposes of discussion the methods of inflating packers from the bottom up will be more fully described hereinafter.

With anchor positioner 220 in its retract mode (drag block assembly 222 compressing spring arms 238 and 240), tool string 20 is lowered to the approximate location of the lowest zone and anchor tool 196. The tool string 20 is then reciprocated upward, rotated 300 to the right and set down to effect the release mode, anchor positioner being then lowered to engage shoulder 198 of anchor tool 196 as shown in FIG. 4D. If the anchor positioner happens to be released below anchor tool 196, it may be raised through it even in the release mode, as the inclined outer edges of the protrusions thereon will guide spring arms 238 and 240 past shoulder 198.Anchor positioner 220 is locked in position when the downward-facing shoulders on the protrusions at the ends of spring arms 238 and 240 are resting on shoulder 1 98. At this point, unlike FIG. 4C, full open gravel collar 30 will be closed (as shown in FIG. 4B), as no steps have yet been taken to open it. Thus, inflation port 1 92 of casing inflation packer 1 84 is spanned by downward-facing packer cups 354 and 358 and upwardfacing packer cups 376 and 380 of isolation gravel packer 300. As the packer cannot be inflated while the dump and bypass ports in isolation gravel packer 300 are open, it is necessary to set approximately 20,000 pounds of weight on the anchor to close them as noted previously herein.

When the weight is set bypass sleeve 302 moves downwardly with respect to bypass valve body 330, to the position shown in FIG. 4C, isolating the dump and bypass ports in bypass housing body 330 from their cooperating ports in bypass sleeve 302, preventing fluid movement between annulus 446, and packer annulus 444 and annulus 454 below isolation gravel packer 300. It is understood, of course, that the bypasses are open during the trip into the well and remain so until a substantial downward force is exerted.All necessary bypasses being closed, the tool string 20 is then pressured to the desired pressure through blank pipe annulus 209 to inflate casing inflation packer 1 84. The pressurized fluid reaches packer 1 84 through blank pipe annulus 209, outer passages 440 and 440', inner annular passage 442 then gravel passages 412 and 412' which exit into packer annulus 444 defined by the interior of liner 22, the exterior of isolation gravel packer 300, packer cups 354 and 358 at the top, and 376 and 378 at the bottom. From packer annulus 444, fluid enters casing inflation packer 1 84 through check valve 1 92, inflating it to a predetermined pressure. The casing inflation packer being inflated, gravel packing may now proceed at the lowest zone as described hereafter.

Full open gravel collar 30 at the lower zones opened by pulling up tool string 20 to retract the anchor positioner 220, and raising the tool string 20 so that opening sleeve positioner 90 engages sleeve 58 of full open gravel collar 30. Spring arms 100 and 100' of opening positioner 90 expand and the shoulders on protrusions 106 and 106' engage annular shoulder 62 on sleeve 58. A pull of approximately 10,000 pounds will align apertures 80 and 80' of sleeve 58 with gravel ports 38 and 38' of housing 32, thereby opening the gravel collar 30. As the open position of full open gravel collar 30 is reached, radially outward extending median shoulders 102 and 102' have contacted the beveled edge leading to neckeddown portion 42, which contact compresses spring arms 100 and 100' causing them to release from sleeve 58, leaving gravel collar 30 in the open position. The tool string 20 is then lowered to the approximate location of the anchor 198, picked up, rotated to the right and then lowered to release the anchor positioner 220, and engage anchor 1 98.

A slurry of carrier fluid containing gravel is pumped down blank pipe annulus 209 into passages 440 and 440', inner annular passage 442 and out through gravel passages 412 and 412' into packer annulus 444, then through gravel ports 38 and 38' of full open gravel collar 30 into lower zone annulus 260, where the gravel is deposited to form pack 262. The carrier fluid returns into liner 22 through gravel screen 202, the gravel being retained on the outside of the screen 202 by virtue of the proper sizing of the apertures thereof. The gravel-free carrier fluid then enters tail pipe bore 252, and returns past ball check valve 460, the ball 468 of which is unseated by fluid passing in an upward direction.

The fluid then proceeds through axial circulation passage 452 in isolation gravel packer 300, then up through inner blank pipe 208 to the surface.

Circulation of the gravel slurry is continued to bluid up the gravel pack 262 from below gravel screen 202 to a point above it, thus interposing a barrier to sand migration from the zone into the liner 22. When pressure resistance is noted at the surface, this indicates that gravel in the lower zone has been deposited (packed) higher than the top of gravel screen 202, and the pack has been completed. It is evident that no fluid movement has been induced across upper zone 26, during packing, as both gravel slurry and returns are contained within the tool string 20.

If desired at this point, the gravel pack may be further consolidated by applying pressure to it, referred to as squeezing. Pressure is applied down blank pipe annulus 209, after closing flow from inner blank pipe 208 at the surface, which pressure will act upon the pack through the same circulation path as described previously. Fluid is contained below isolation gravel packer 300 by downward-facing packer cup 390, as during normal circulation. In order to clear the interior of the tool string 20 of residual slurry, circulation is then reversed using a clean fluid. This operation is illustrated in FIG. 5. No movement in the well bore is required to effect this operation, the only action on the part of the operator being necessary is a reversal of flow direction.Clean fluid is sent down blank pipe 208 to axial circulation passage 452 in isolation gravel packer 300. When the fluid reaches check valve 460, ball 468 is seated on valve seat 470 preventing flow downward. At this point, the clean fluid will then exit isolation gravel packer 300, through lateral circulation passages 428 and 428', and flow upward past collapsed packer cups 380 and 376, and back through gravel passages 412 and 412' into inner annular passage 442, through outer passages 440 and 440' to blank pipe annulus 209. When clean fluid is returned to the surface, the packing job is complete.It is noteworthy that the reversing fluid is prevented from circulating below isolation gravel packer 300 by upward-facing packer cup 386, responsive to the pressure of fluid flow through lateral circulation passages 428 and 428', and as a result of this seal as well as the closing of check valve 460, reverse circulation is effected without fluid movement across the zone just packed.

At this point, the tool string may be moved upward to the next zone of interest 150, in this case between the casing inflation packers 1 64 and 1 84. The tool string 20 is reciprocated upward, thus retracting the anchor positioner 220 and disengaging anchor tool 1 98. As the tool string 20 is pulled up to the next zone, the passing spring arms 1 30 and 130' of closing sleeve positioner 1 20 pulls sleeve 58 of lower full open gravel collar 30 upward. The upward facing outwardly radially extending shoulders 1 36 and 136' of the protrusions on spring arms 1 30 and 130' engage downward facing annular shoulder 62 in sleeve 58.As the tool string is pulled up, the spring arms 130 and 130' close gravel collar 30, at which point shoulders 1 32 and 132' encounter necked-down portion 42, which compresses spring arms 1 30 and 130', releasing them from shoulder 62 of sleeve 58. At this point, annular seals 76 and 78 bracket gravel ports 38 and 38', sealing them. At the next zone, the tool string 20 is turned right and then lowered downward into anchor tool 1 76. If the casing inflation packer 1 64 above the upper zone has been previously inflated, this final upward reciprocation can effect the opening of upper gravel collar 30, by engaging sleeve 58 with spring arms 100 and 100' of opening sleeve positioner 90.If casing inflation packer 1 64 has not been inflated, inflation may proceed as described with respect to packer 1 84.

When spring arms 100 and 100' have opened the upper collar 30 by pulling sleeve 58 upward, they will automatically disengage as the median shoulders thereon encounter necked-down portion 42 which will in turn compress the spring arms.

When the anchor positioner 220 has engaged anchor 176, gravel packing may proceed at this zone (if the packer 1 64 above it is inflated) as described previously with respect to lower zone 1 52. After packing of the upper zone of interest 1 50 is effected, the tool string 20 is withdrawn. In coming out of the well, closing sleeve p'ositioner will contact every gravel collar 30, thus ensuring a closed liner except at gravel screen locations. The well may now be produced after any other desired operations have been performed.

The gravel packing operation has been described herein as employing concentric blank pipes running to the surface; however, a crossover device may be placed above the uppermost zone to be packed, and fluid run down a drill pipe to the crossover, return fluid being taken up the annulus surrounding the casing. A crossover device with a shutoff capability may be employed to close the return downhole during a squeeze, rather than at the surface.

While the full open gravel collar has been described as both opening and closing in response to upward force, it is not so limited due to the presence of recess 69 and shoulder 71 at the lower end of sleeve 58. This recess permits released anchor positioner spring arms (which face upward and have downward-facing shoulders thereon) to engage the sleeve and reopen the gravel collar, if necessary for example in repacking a zone at a later date or reclose to the lower position if a gravel collar has been inadvertently opened before the casing inflation packer at that level has been inflated. The median shoulders on the anchor positioner spring arms act to release the spring arms in the same manner as those on the opening and closing sleeve positioners.

Although the invention has been described in terms of a certain embodiment which is set forth in detail, it should be understood that descriptions herein are by way of illustration and not by way of limitation of the invention. Alternative embodiments of the apparatus and operating techniques of the method will be readily apparent to those of ordinary skill in the art in view of the disclosure. For example, the number of gravel ports may be varied as claimed, the sleeve collet fingers and cooperating grooves in the housing employed to lock the sleeve in position may be placed at the top of the sleeve and housing rather than the bottom, a sleeve skirt of flat fingers having appropriately spaced grooves on their outer surface which interact with an inwardly radially extending shoulder on the housing may be employed in lieu of the collet arrangement disclosed, the annular seals may be disposed within grooves on the inside of the housing, or the main portion of the sleeve could be splined to the housing to avoid rotation.

Claims (40)

1. A sleeve valve type well tool comprising: housing means having port means therein; said port means having two closed positions and one open position.

2. Apparatus according to claim 1, further comprising: sleeve means longitudinally slidably disposed in said housing means, longitudinal movement of said sleeve means effecting the opening and closing of said port means.

3. Apparatus according to claim 1 or 2, wherein said port means comprises: at least one peripheral port in said housing means and at least one peripheral aperture in said sleeve means circumferentially aligned with said housing means port, said port and said aperture being juxtaposed in said port means open position.

4. Apparatus according to claim 3, wherein said closed positions of said port means are effected when said at least one sleeve aperture and said at least one housing port are not juxtaposed.

5. Apparatus according to claim 4, wherein said closed positions of said port means are effected when said at least one sleeve aperture is longitudinally above and longitudinally below said at least one housing port.

6. Apparatus according to claim 5, wherein said well tool includes locking means to lock said sleeve means in positions wherein said at least one aperture is below, juxtaposed with or above said at least one housing port.

7. Apparatus according to claim 6, wherein said locking means comprises collect means.

8. Apparatus according to claim 7, wherein said collet means comprises collect fingers at an extremity of said sleeve means, and cooperating annular grooves in said housing means.

9. Apparatus according to claim 8, wherein said sleeve means possesses a radially inwardly extending downwardly-facing shoulder thereon.

10. Apparatus according to claim 9, wherein said sleeve means possesses an annular recess immediately below said downward-facing shoulder.

11. Apparatus according to any of claims 3 to 10, wherein said at least one housing port comprises a plurality of ports, and said at least one sleeve aperture comprises a like plurality of apertures.

12. A sleeve valve type well tool comprising: housing means having port means therein; sleeve means longitudinally slidably disposed within said housing means; said port means being open when said sleeve means is in a median position, and being closed when said sleeve means is in upper and lower positions.

13. Apparatus according to claim 12, wherein said port means comprises at least one port in said housing and at least one aperture in said sleeve means; said median sleeve position aligning said at least one housing port and said at least one sleeve aperture; and said upper and lower sleeve positions misaligning said at least one housing port and said at least one sleeve aperture.

14. Apparatus according to claim 13, wherein said well tool includes locking means to lock said sleeve means in position wherein said at least one aperture is below, juxtaposed with or above said at least one housing port.

1 5. Apparatus according to claim 14, wherein said locking means comprises collet means.

1 6. Apparatus according to claim 15, wherein said collet means comprises collet fingers at an extremity of said sleeve means, and cooperating annular grooves in said housing means.

1 7. Apparatus according to any of claims 12 to 16, wherein said sleeve means possesses a radially inwardly extending downward-facing shoulder thereon.

1 8. Apparatus according to claim 17, wherein said sleeve means possesses an annular recess immediately below said downward-facing shoulder.

19. Apparatus according to claim 18, wherein said at least one housing port comprises a plurality of ports, and said at least one sleeve aperture comprises a like plurality of apertures.

20. A sleeve valve type well tool comprising: a housing having peripheral port means therein; a sleeve longitudinally slidably disposed within said housing and having peripheral aperture means therein; said housing port means communicating with said sleeve aperture means when said sleeve is in a median position, being isolated therefrom when said sleeve is in an upper or lower position.

21. Apparatus according to claim 20, wherein said housing port means comprises at least one port through said casing; and said sleeve aperture means comprises at least one aperture through said sleeve.

22. Apparatus according to claim 20 or 21, further comprising: downward-facing shoulder means on said sleeve means.

23. Apparatus according to claim 22, wherein said sleeve positions are changed by engagement of a positioning tool with said shoulder means, and longitudinal movement of said positioning tool.

24. Apparatus according to claim 23, wherein said positioning tool comprises at least one spring arm; said spring arm engaging said shoulder.

25. Apparatus according to any of claims 20 to 24, further comprising: locking means to lock said sleeve in each of said sleeve positions.

26. Apparatus according to claim 25, wherein said locking means comprises outward-facing collet fingers on said sleeve, and cooperating groove means in said housing corresponding to each of said sleeve positions.

27. Apparatus according to any of claims 20 to 26, further comprising upper and lower seal means disposed around said sleeve above and below said sleeve aperture.

28. Apparatus according to claim 27, further comprising: a plurality of additional seal means disposed around said sleeve; one of said secondary seal means being disposed above said upper seal means at least a distance greater than the height of said housing port; another of said additional seal means being disposed below said lower seal means at least a distance greater than the height of said housing port.

29. Apparatus according to claim 28, wherein said first additional seal means and said upper seal means bracket said housing port in said lower position; said upper and lower seal means bracket said housing port in said median position; and said lower seal means and said second additional seal means bracket said housing port in said upper position.

30. Apparatus according to any of claims 20 to 29, wherein said sleeve possesses an upwardfacing radially inward extending shoulder thereon, with an annular recess thereabove.

31. Apparatus according to claim 30, wherein said sleeve may be moved in a downward direction from its upper or median position by application of force to said upward facing shoulder.

32. Apparatus according to any of claims 20 to 31, wherein said well tool is a gravel collar.

33. Apparatus according to any of claims 20 to 32, wherein said well tool is a cementing collar.

34. A method of operating a well tool having a housing and a sleeve slidably disposed therein, said housing and said sleeve each having at least one aperture therethrough, comprising: aligning said apertures through longitudinal movement of said sleeve; and isolating said apertures through subsequent longitudinal movement of said sleeve in the same direction.

35. A method according to claim 34, wherein said direction of said longitudinal movement is upward.

36. A method of operating a well tool having a body, a sleeve slidably disposed therein, and port means, comprising: opening said port means by longitudinal movement of said sleeve; and closing said port means by longitudinal movement of said sleeve in the same direction.

37. A method according to claim 36, wherein said direction of said longitudinal movement is upward.

38. A method of operating a gravel collar, comprising: opening said gravel collar by application of longitudinal force; closing said gravel collar by application of longitudinal force in the same direction.

39. A sleeve valve type well tool substantially as herein described with reference to the accompanying drawings.

40. A method according to claim 34, 36 or 38,, substantially as herein described with reference to the accompanying drawings.