US3578078A

US3578078A - Earth borehole tool

Info

Publication number: US3578078A
Application number: US2115A
Authority: US
Inventors: Harold E Shillander
Original assignee: General Oil Tools Inc
Current assignee: General Oil Tools Inc
Priority date: 1970-01-12
Filing date: 1970-01-12
Publication date: 1971-05-11
Anticipated expiration: 1988-05-11
Also published as: JPS5021281B1; DE2100963A1; FR2080903B1; FR2080903A1; CA894661A; NL7100208A; GB1261490A; BE761491A

Abstract

An oil well drill string or stem having a tubular mandrel fast on its lower end and a drive sleeve assembly telescoped onto the mandrel. A resilient packer fastened at its upper end to the mandrel is slidable on the mandrel above the drive sleeve assembly, and a retractor secured to the lower end of the packer with a lost-motion connection is alternately latched to the mandrel when the packer is extended, unlatched by the drive sleeve assembly as the latter moves upwardly relative to the mandrel to compress the packer longitudinally and thus expand it radially, and latched to the drive sleeve assembly for positive longitudinal extension and radial collapse of the packer as it is returned to the latched condition. Circulation ports in the drive sleeve assembly are opened only when the packer is expanded, and a driving spline connection between the drive sleeve assembly and the mandrel has squared spline elements for increased bearing strength.

Description

United States Patent [72] lnventor Harold E. Shillander Albuquerque, N. Mex. [21] Appl. No. 2,115 [22] Filed Jan. 12, 1970 [45] Patented May 11, 1971 [73] Assignee General Oil Tools, Inc.

Phoenix, Ariz.

[54] EARTH BOREHOLE TOOL 20 Claims, 16 Drawing Figs.

[52] US. Cl 166/152, 166/196,175/321 [51] Int. Cl E2lb 23/00- [50] Field of Search 166/152, 187,196; 175/321;277/116.4

[56] References Cited UNITED STATES PATENTS 3,233,676 2/1966 Lynes 166/152 3,235,017 2/1966 Lynes 175/321 3,373,820 3/1968 Robinsonetal.

Primary Examiner.lames A. Leppink Attorney-Fulwider, Patton, Rieber, Lee and Utecht ABSTRACT: An oil well drill string or stem having a tubular mandrel fast on its lower end and a drive sleeve assembly telescoped onto the mandrel. A resilient packer fastened at its upper end to the mandrel is slidable on the mandrel above the drive sleeve assembly, and a retractor secured to the lower end of the packer with a lost-motion connection is alternately latched to the mandrel when the packer is extended, un-

latched by the drive sleeve assembly as the latter moves up wardly relative to the mandrel to compress the packer longitudinally and thus expand it radially, and latched to the drive sleeve assembly for positive longitudinal extension and radial collapse of the packer as it is returned to the latched condition. Circulation ports in the drive sleeve assembly are opened only when the packer is expanded, and a driving spline connection between the drive sleeve assembly and the mandrel has squared spline elements for increased bearing strength.

EARTH BOREIIOLE TOOL BACKGROUND OF THE INVENTION This invention relates generally to earth borehole drilling apparatus and, more particularly, to drilling apparatus of the general type disclosed in Lynes Pat. Nos. 3,233,676 and 3,235,0l7 with which the earth formations being penetrated can be sealed off and the contents tested or treated during the drilling operation without removing the drilling apparatus from the borehole. Testing involves the taking of samples of fluids from the penetrated formation, and treating involves the introduction of fluids, such as an acid, into the lower end portion of the borehole.

As explained in detail in the aforesaid patents, conventional formation testing has required the removal from the borehole of the entire drilling apparatus, including the drilling tool and the stem or the string of pipe from which the tool is suspended and by which it is driven,,followed by insertion of a separate tool for making the test, removal of the testing tool, and reinsertion of the drilling apparatus. Needless to say, these were time-consuming and costly operations with many disadvantages, particularly in view of the fact that many wells are as deep as 20,000 feet or more.

The disadvantages of such conventional testing techniques led to the development of drilling apparatus of the type disclosed in the Lynes patents with a so-called packer incorporated in the drilling tool above the drill bit and having a packer-setting mechanism actuated by manipulation of the. drill string to expand the packer radially into sealing engagement with the wall of the borehole preparatory to testing the formation at the bottom of the borehole, and then radially contracting the packer after the test is completed. In this way, the lower end portion of the borehole can be isolated from the remainder of the hole and from the drilling .fluid that is circu-' lated through the hole during the drilling operation, and formation testing of treating can be accomplished through the drilling apparatus while the latter remains in the borehole.

The Lynes packer takes the form of an elongated cylinder of resiliently flexible material, such as rubber, telescoped over an elongated, tubular extension of the drilling string, called the mandrel, and longitudinally secured at its upper end to the mandrel and abutting at its lower end against a tubular drive sleeve assembly telescoped over the mandrel and carrying a drill bit on its lower end. Below the packer is a spline connection between the mandrel and the sleeve assembly for drivingly coupling the two together in different angular positions in which the packer is either longitudinally extended and radially contracted (the normal drilling condition), or longitudinally contracted and radially expanded (the packing condition), the drilling tool being driven through the spline connection 'with the packer radially collapsed during normal operation.

To shift the mandrel and the sleeve assembly selectively from one position to the other, a cam-clutch mechanism also is included between the sleeve assembly and the mandrel of the later Lynes patent, to index the assembly step by step about the mandrel in response to up-and-down motion of the mandrel relative to the drive sleeve assembly.

While the Lynes developments have been a breakthrough in the drilling art, problems have been encountered at their use,

including wearing of the packer as a result of rubbing against the borehole wall, primarily because of failure of the packer to return to and remain in its fully collapsed condition. This may be attributable to the setting of the packer in a partially expanded condition, to the effect of fluid pressure acting on the packer from below, or to the upward force exerted by the drilling fluid circulating upwardly around the drill string. Another possible cause of packer wear may be the lateral displacement of the drill string in the borehole during drilling, the rotary mounting of the Lynes packer being less than totally effective in preventing wear as a result of the accompanying rubbing of the packer against the borehole wall.

2 SUMMARY or THE INVENTION The present invention resides in a drilling apparatus borehole wall and resulting wear on the packer in service use.

In addition, the portion of the too] including the packer is positively maintained in generally centered relation in the borehole to prevent rubbing contact between the packer and the wall that could result from lateral displacement of the tool or the drill string within the hole during drilling.

In the preferred embodiment of the invention disclosed herein for purposes of illustration, a novel retractor is interposed between the lower end of the packer and the upper end of the drive sleeve assembly and is connected at its upper end to the packer and normally latched at its lower end to the mandrel to hold the packer in its longitudinally extended, radially contracted drilling condition. During the relative movement of the drive sleeve assembly used to set the packer against the borehole wall, the retractor first is unlatched to free the lower end of the packer for movement along the mandrel, and then is moved along the mandrel with the packer as the latter is expanded into sealing engagement with the borehole wall. During radial collapsing of the packer, the

retractor is latched to the drive sleeve assembly. so that the packer is pulled positively back to the longitudinally extended, radially collapsed position, the retractor being automatically relatched to the mandrel when it reaches its original position in which the packer is stretched longitudinally along the mandrel.

In addition, the retractor is positioned between upper and lower washover-locks which are dis'engageable to permit ina it dexing of the drive sleeve assembly and reengageable to con--- nect the lower end of the packer nonrotatably to the upper end of the drive sleeve assembly, thereby to facilitate the fishing operation used to recover a disconnected tool, and at least one rotary stabilizer larger in diameter than the collapsed packer is mounted on the tool adjacent the packer to keep the packer generally centered in the borehole and prevent rubbing contact of the packer with the wall of the borehole.

Further improvements have been made in the Lynes-type of drilling apparatus by changing the spline connection to increase its load-bearing capacity and avoid deformation of the load-bearing elements of the connection, and by changing the arrangement of circulating ports in the tool so that the .ports are closed at'all times other than when the packer is expanded,

while also insuring that the ports are opened despite variations in the amount of relative movement of the mandrel and the sleeve assembly required to obtain complete sealing of the borehole around the tool.

Other objects and advantages of the invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an elevational view of an earth borehole drilling apparatus embodying the novel features of the present invention, the apparatus being shown suspended in a borehole preparatory to a drilling or-testing operation with the packer collapsed, portions of the apparatus being broken out for compactness of illustration;

FIG. 2 is an enlarged transverse cross-sectional view taken through the drilling apparatus substantially along the line 2-2 of FIG. 1, adjacent the upper end of the drive sleeve assembly, and also along the line 24 of FIG. 8;

FIG. 3 is a sectional view similar to FIG. 2 taken substantially along the line 3-3 of FIG. 1, and also along the line 3-3 of FIG. 8;

FIG. 4 is a sectional view similar to FIG. 2 taken substantially along the line 4-4 of FIG. I, and also along the line 4-4 of FIG. 8;

FIG. 5 is a sectional view similar to FIG. 2 taken substantially along the line 5-5 of FIG. 1, and also along the line 5-5 of FIG. 8;

FIG. 6 is a sectional view similar to FIG. 2 taken substantially along the line 6-6 of FIG. 1, and also along the line 6-6 of FIG. 8;

FIG. 7 is a sectional view similar to FIG. 2 taken substantially along the line 7-7 of FIG. 1, and also along the line 7-7 of FIG. 8;

FIG. 8 is an enlarged fragmentary cross-sectional view taken longitudinally of the drilling apparatus substantially along the line 8-8 of FIG. 1 with parts of the apparatus shown in side elevation;

FIG. 9 is a view similar to FIG. 8 with parts in moved positions showing the drilling condition of the apparatus;

FIG. 10 is a view similar to FIG. 8 with parts in moved positions showing the condition of the drilling apparatus as the packer is in the process of being collapsed;

FIG. 11 is a view similar to FIG. 8 with the parts in moved positions showing the condition of the drilling apparatus when the packer is fully expanded;

FIG. 12 is a perspective view of the retractor, the central portion being broken away for compactness of illustration;

FIG. 13 is a developed diagrammatic view of the spline and cam-clutch elements illustrating the indexing of the drive sleeve assembly about the mandrel;

FIG. 14 is an enlarged cross section taken within the arc 14-14 of FIG. 9 and showing the retractor latched to the mandrel and about to be unlatched;

FIG. 15 is a view similar to FIG. 14 showing the unlatched condition while the packer is expanded, the view being taken within the are 15-15 of FIG. 11; and

FIG. 16 is a view similar to FIG. 14 showing the condition of the latching elements as the packer is being collapsed, the view being taken within the arc l6-l6of FIG. 10.

DETAILED DESCRIPTION As shown in the drawings for purposes of illustration, the invention is embodied in an apparatus indicated generally at 20 (FIG. 1) for drilling an earth borehole 21, typically an oil well borehole, and generally comprising a hollow drill stem or string 22 suspended in the borehole from the surface of the earth, and a drilling tool mounted on the lower end of the string and including 'a hollow mandrel 23 (FIGS. 8-11) fastened to the lower end of the drill string by a connector 24, a flexible and radially expandable packer 25 telescoped over the mandrel for expansion into sealing engagement with the wall of the borehole, and a drive sleeve assembly 27 telescoped over the mandrel below the packer and carrying a conventional drill bit 28 on its lower end beyond the lower end of the mandrel. The packer 25 is secured at its upper end to the mandrel 23, through the connector 24, and is freely slidable along the mandrel below the connector, and the drive sleeve assembly, which is suspended below the lower end of the packer, is both rotatable and longitudinally slidable relative to the mandrel.

To couple the drive sleeve assembly 27 to the mandrel 23 for the transmission of driving force, both rotary and vertical, 7

from the drill string 22 and the mandrel to the drill bit 28, interfitting spline elements 29 and 30 (FIGS. 4, 6, 8-11 and 13) are mounted respectively on the interior of an intermediate portion 31 of the drive sleeve assembly 27 and upon the adjacent portion of the mandrel, the sleeve element 29 herein comprising a set of elongated, angularly spaced spline bars and the mandrel element 30 comprising a corresponding number of similarly spaced spline slots or grooves formed in a barrel 32 fast on the mandrel above the spline bars, for example, by welding. The spline grooves have open lower ends (see FIG. 8) for receiving the bars in snug fitting relation, and have closed upper ends 33 for abutting against the upper ends of the spline bars when the mandrel and the drive sleeve assembly are in a predetermined longitudinal relation constituting the drilling position of the various parts. Although various numbers of grooves 30 and bars 29 may be used, hereirithere i are three of each.

Between each pair of drilling grooves 30 is a similar but is turned a preselected amount about the mandrel, and permit the sleeve assembly to move upwardly relative to the mandrel, beyond the drilling position to a packing position when the spline bars are angularly aligned with the longer grooves 34.

The relative longitudinal movement of the mandrel 23 and the sleeve assembly 27 beyond the drilling position is used to compress the packer 25 longitudinally and thus to expand it radially into sealing engagement with the borehole wall for testing. For this purpose, the upper end of the packer, which is an elongated sleeve of suitable material such as rubber or a selected synthetic material, is secured to the mandrel by means of bolts 35 embedded in the upper end of the packer sleeve and extending upwardly through a bolting ring 37 bonded to the end of the packer sleeve, and also through a flange 38 on the lower end of the connector 24. The connector is threaded onto the lover end of the drill string 22 and onto the upper end of the mandrel. An O-ring 39 prevents leakage of fluid from the annulus 40 in the borehole around the tool into the space between the packer and the mandrel. On the lower end of the packer is a second ring 41 which is secured by bolts 42 to a head 43 which is slidable along the mandrel and is positioned to abut against a similar head 44 mounted on the upper end of the drive sleeve assembly 27 to transmit the relative upward motion of the drive sleeve assembly to the lower end of the packer.

Thus, such motion acts to raise the lowerend of the packer 25 along the mandrel 23 while the upper end of the packer is anchored to the mandrel, thereby squeezing the packer longitudinally to bulge it outwardly in the manner shown in an intermediate condition in FIG. 10 and in a packing condition in FIG. 11, the spline bars 29 being angularly aligned with the longer, packing grooves 34 during this motion. Conversely, downward, motion of the sleeve assembly, from the packing position shown in FIG. 11, stretches the packer back through the condition in FIG. 10 to the condition shown in FIG. 8.

To align the spline bars 29 selectively with either the longer packing grooves 34 or the shorter drilling grooves 29, a camclutch indexing mechanism, indicated generally at 47 in FIG. 8-11, in incorporated in the drilling apparatus to respond to successive up-and-down movements of the mandrel 23 within the drive sleeve assembly 27 and index and latter stepwise about the mandrel, one full step for each up-and-down movement. Preferably, this cam-clucth mechanism makes use of the elongated fingers 48 formed between

adjacent slots

29, 34 of the barrel 32, and also of the lower ends of the spline bars 29, and further includes a clutch cylinder 49 which is fast on the mandrel below the barrel, in longitudinally spaced relation with the lower ends of the spline fingers 48 to leave an annular space between the fingers and the clutch cylinder at least as long as the spline bars. The clutch cylinder herein is pinned to the lower end portion of the mandrel at 50.

Formed on the upper end of the clutch cylinder 49 are a plurality of indexing teeth 51 each having a longitudinally extending edge 52 on one side, the left side herein, and an inclined edge 53 on the other side, and the tip of each such clutch tooth is generally centered on one of the packing grooves 34 while the end of the inclined side 53 at the bottom of the notch between two teeth 51 is generally centered on the next drilling groove 30 to the right. Moreover, the lower ends 54 of the fingers 48 are inclined upwardly and to the right from their tips, each of which overlies one of the inclined clutch edges 53. The lower ends of the spline bars 29 preferably are beveled to be parallel to these edges.

As the-drilling apparatus 20 is lowered into the borehole 21 (FIGS. 1 and 8), the drive'sleeve assembly 27 and the drill bit 28 are suspended'from the mandrel 23 by means of the'spline bars 29, which are seated in three of the notches between'the clutch teeth 51, thereby limiting the downward telescoping motion of the sleeve assembly relative to the mandreL- After the drill bit engages the bottom 57 of the borehole, continued downward motion of the drill string lowers the mandrel through the drive sleeve assembly and thus shifts the clutch cylinder 49 downwardly away from, and free of, the spline bars 29.

Assuming that the spline bars 29 are angularly'aligned with three spline fingers 48 that are to the left of shorter, drilling grooves 30, as shown in FIG. 8, this lowering of the mandrel 23 brings the beveled lower ends 54 of the spline fingers into engagement with the upper .ends of the spline bars to cam the bars to the right, clockwise in FIG. 6, into alignment with the drilling grooves, thus indexing the drive sleeve assembly 27 in the same direction. The spline bars then slide into the drilling grooves and bottom" therein, as shown in FIG. 9, the accompartying longitudinal motion being insufficient to initiate expansion of the packer 25. Then the drill bit 28 is rotated and driven into the earth by rotary and vertical driving forces applied through the barrel 32 to the spline bars and thus to the drive sleeve assembly.

One important improvement in the present invention as compared to the later Lynesapparatus is the squaring of both the upper ends 58 of the spline bars 29'and'the upper ends 33 of the spline grooves 30 so that the opposed surfaces are substantially perpendicular to the longitudinal axis of the drilling apparatus. It has been found that the bevels on the upper ends of the Lynes spline bars were unnecessary for proper indexing of the drive sleeve assembly 27 and, in fact, that such bevels reduced the load-bearing capacity of the spline connection, sometimes became deformed in service use, and subsequently interfered with proper operation of the drilling apparatus. The squared ends distribute the load more effectively to eliminate this problem.-

When expansion of the packer 25 is desired, in order to seal off the lower portion of the borehole 21 for testing or treating, the drill string 22 is simply raised to raise the mandrel 23 within the drive sleeve assembly 27 until the clutch cylinder 49 engages the beveled lower ends of the spline bars 29 to cam the latter to the right, and the drill string then is lowered to shift the beveled lower ends 54 of the spline fingers 48 into engagement with the squared upper ends of the spline bars. This earns the bars and the sleeve assembly on to the right, and aligns. the bars with the longer packing grooves 34 so that continued downward motion of the mandrel through the sleeve assembly shifts the bars upwardly into and along the longer grooves, as shown in FIGS. and 11.

The accompanying relative longitudinal motion of the mandrel 23 relative to the drive sleeve assembly 27, beyond the motion that occurs during seating of the spline bars 29 in the drilling grooves 30, is applied to the packer 25 as longitudinal contracting or compressing motion which expands the packer into sealing engagement with the borehole wall. After testing its completed, another up-and-down motion of the drill string 22 raises and then lowers the mandrel, the spline barrel 32, and the clutch cylinder 49 to return the packer to its axially elongated, radially collapsed condition while indexing the drive sleeve assembly 27 to the position in which the spline bars 29 are seated in the shorter grooves 30 for resumption of drilling.

In accordance with the primary aspect of the present invention, the lower end of the packer 25 normally is latched to the mandrel 23 in a manner that holds the packer longitudinally extended and radially collapsed, is unlatched automatically as an incident to the movement of the spline bars 29 along the longer spline grooves 34 past the ends of the shorter grooves 30, thereby permitting the lower end portion of the packer to be moved along the mandrel to set the packer, and subsequently is positively returned to its extended position and relatched to the mandrel to insure that the packer is fully collapsed during drilling. To these. ends, a retractor 60 is incorporated in the drilling apparatus between the packer and the upper end portion of the drive sleeve assembly 27 and is securedto the lower end of the packer and slidably mounted on the mandrel. This retractor isprovided with at least one latch element 61 which is engageable with a detent 62 positioned on the mandrel within the drive sleeve assembly to receive the latch element when the packer is fully extended. On the inside of an upper end portion 63 of the drive sleeve assembly is a release element 64 that is engageable with the latch element, during downward motion of the mandrel, and is operable to disengage the latch element from the mandrel at a preselected point in the relative motion. Moreover, the release element simultaneously shifts the latch element into a second detent 65 on the sleeve assembly so that the retractor 60 can be positively pulled back along the mandrel to stretch and collapse the packer during the raising of the mandrel and the downward relative motion of the sleeve assembly.

In the present instance, the retractor 60 is an elongated, generally cylindrical sleeve, shown most clearly. in FIG. 12, having an inside diameter selected for a close-slidingfit with the mandrel 23, and having a plurality of angularly spaced fingers 67 extending downwardly from its lower end to. lie alongside the mandrel below the upper end of the drive sleeve assembly. On the lower end of each finger is a latch element 61 in the form of a lug having an upwardly facing shoulder 610 on its inner side for seating in an annular groove forming the detent 62 (FIGS. 8-11 and 14) in the mandrel.

The retractor fingers 67 herein are integral with the lower end portion of the retractor sleeve and preferably are made resiliently flexible to urge the latch lugs 61 radially inwardly toward the mandrel and into the detent groove 62 therein. For convenience of manufacture, the upper and lower portions of the retractor sleeve may be separately formed and the joined into a unitary element by a weld 68.

Encircling the upper end of the retractor 60 is a radial flange 69 which overhangs an upwardly facing-shoulder 70 (FIGS. 8, 10 and 11) in the head 43 fast on the lower end of the packer 23, the underside of the bolting ring 41 being spaced above this flange so that the retractor is secured to the packer by a lost-motion connection permitting relative motion of the retractor within the limits defined by the shoulder 70 and the underside of the bolting ring. This accommodates a limited degree of change in the length of the packer. An 0- ring 71 prevents leakage of fluid past the flange 69 and through the lower end of the packer.

It will be seen in FIG. 8 that the retractor 60 extends downwardly into the head 44 on the upper end of the drive sleeve assembly 27, the detent groove 62 of the mandrel 23 being located adjacent the underside of the head during lowering of the drilling apparatus 20 into the borehole 21. Immediately beneath the head 44 is an elongated cylinder constituting the upper portion 63 of the drive sleeve assembly, this cylinder being threaded at 27 into the head and telescoped slidably over the retractor, extending beyond the latch fingers 67 and along the mandrel with a clearance fit. The interior of this cylinder bears against the outer sides of the latch lugs 61 and normally holds the latter positively in the detent groove The release element 64-is disposed inside the cylinder 63 a selected distance below the latch lugs 61, as shown in FIG. 8, and herein is in the form of an annular cam which slides along the outside of the mandrel 23 and has an outwardly and downwardly inclined outer surface 73 for passing inside the lower sides of the lugs 61 and camming them out of the detent groove 62. The inner surface of the release cam is relieved to avoid marring of the mandrel.

Formed in the cylinder 63 immediately above the release cam 64 is the second detent 65, which is an annular internal groove in the cylinder for receiving the lugs 61 in the unlatched condition, this detent groove having a downwardly facing upper side that overlies upwardly facing shoulders 61b on the'outer sides of the lugs to latch the retractor 60 to the cylinder as shown in FIGS. and 16. Thus, as the mandrel is raised within the drive sleeve assembly 27 after a testing operation, the shoulders 61 are positioned to abut against the upper side of the detent groove 65 and maintain the retractor stationary relative to the sleeve assembly until the detent groove 62 moves back into alignment with the latch lugs 61'. Then the lugs snap into the detent groove in the mandrel and out of the groove in the cylinder, thereby to latch the packer 25 in the extended position as the mandrel continues to rise within the drive sleeve assembly. The packer and retractor thereafter remain stationary relative to the mandrel while the drive sleeve is indexed into the drilling position.

For convenience of manufacture, the cylinder 63 herein is formed in two sections that are welded together at 74 below the detent groove 65, the upper section being threaded into the head 44 and'the lower section being threaded at 75 into the upper end of a cylinder 77 hereafter referred to as the upper drive sleeve. As viewed in FIG. 8, the barrel 32 of the mandrel 23 is disposed within this drive sleeve.

it will be evident that the packer 23 is secured against rotation relative to the drilling string, in contrast to the rotary packers of the Lynes patents. Such rotation was not completely effective in preventing rubbing wear as a result of contact with the borehole wall, so the rotary mounting has been eliminated and such contact is prevented, first, by the positively acting retractor 60 and, second, by positively centering the packet section of the drilling tool in the borehole. For this purpose, a. least one rotary stabilizer 78 is included in the drilling apparatus close to the packer 25, herein on the upper end of the drive sleeve assembly 27. Such stabilizers have been used conventionally to assist in keeping a borehole going straight during drilling, and are formed with maximum outside diameters slightly smaller than the borehole diameter and substantially greater than the collapsed diameter of the packer. The stabilizer 78 used herein comprises a tough, longitudinally grooved sleeve 79 of wearresistant material fast on a metal cylinder 80 that is telescoped onto the cylinder 63 and confined thereon beneath a wear ring 81 below the head 44 and above an annular member 82 fast on the outside of the lower section of the cylinder 63.

Although only one stabilizer 78 is shown, a second can be similarly mounted immediately above the packer 25. It will be apparent that such a stabilizer or stabilizers limit the lateral deflection that is possible in the adjacent sections of the I drilling tool, and thus protect the collapsed packer against engagement with the borehole wall.

If the drilling too] should, for any reason, become disconnected from the drill string 22, it often is desirable to be able to fish" the tool out of the borehole 21 before normal drilling is resumed. Such fishing is a complicated and highly developed art involving special methods and special tools that are well known to those skilled in the art. The present apparatus is designed so that it can be washed over and fished out and, for this purpose, the

heads

43 and 44 are formed as so-called "washover locks having ratchet teeth 83 on their adjacent ends. These teeth are engaged when the two heads are pressed together, and thus lock the lower end of the packer 25 to the upper end of the drive sleeve assembly 27. Similarly, teeth 84 (F lGS. 8-11) are formed on the lower end of the stabilizer 78 to mesh with opposed teeth on the annular element 82 below the stabilizer, thus constituting two additional washover locks for holding the stabilizer against rotation.

During testing, the drill bit 28 is pressed against the bottom 57 of the borehole 21 as a result of the manipulation of the drilling apparatus with which the packer is expanded. Accordingly, it is possible, or even likely, that the normal fluid circulation ports (not shown) in the bit will be plugged, and it is desirable to provide an auxiliary path for the flow of fluids into and out of the drilling apparatus below the packer, the direction of flow depending upon whether a sample is being taken from a formation or a treating fluid is being introduced into the formation. Although ports have been provided for this generalpurpose before, the present invention, inone of its secondary aspects, contemplates the provision of auxiliary ports 85 in the drive sleeve assembly 27 above the bit 28,

which are open only when the apparatus is in the testing and treating condition, the ports being reliably opened during expansion of the packer 25 regardless of variations in the extent of motion of the mandrel 23 required to expand the packer into full sealing engagement with the borehole wall.

As shown in FIGS. 1 and 8, an annular series of such ports 85 is formed in a lower portion 87 of the drive sleeve assembly 27, hereafter called the lower drive sleeve, and a second annular series of ports 88 is formed in the mandrel 23 in communication with the interior of the mandrel and, therefore, with the interior of the drill string 22. These latter ports open at their outer ends through the clutch cylinder 49 into an elongated annular connecting chamber 89 around the clutch cylinder formed by reducing a substantial portion of the outside diameter of the cylinder within the lower drive sleeve. The connecting chamber extends both above and below the ports 85.

As the drilling apparatus 20 is being lowered into the borehole 21, the connecting chamber 89 is spaced well above the level of the ports 85 in the lower drive sleeve 87, as shown in FIG. 8, and is sealed therefrom by an O-ring 90 encircling the clutch cylinder 49 below the chamber. Thus, the ports 85 are closed. Another O-ring 91 below the ports prevents leakage past the lower end of the mandrel, on which a locking nut 92 is threaded, and locked in place by a double ring 92a of the type sold under the name Spirolox beneath the end of the clutch cylinder. in the drilling position of the parts shown in H6. 9, the ports 85 remain below the connecting chamber 89 and thus remain closed.

During the additional relative longitudinal motion used to expand the packer 25, however, the ports 85 in the lower driv'e sleeve 87 are shifted into alignment with the connecting chamber 89, and in this manner are brought into communication with the ports 88 through the clutch cylinder and the mandrel 23 and, therefore, with the interior of the mandrel. If there is a variation in the amount of endwise mandrel movement required to set the packer and seal the borehole 21, the ports 85 may be spaced somewhat above or below the exact center of the connecting chamber 89, but the elongation of the chamber insures the opening of the ports despite such variation.

It has been pointed out that the retractor 60 preferably is fabricated in two parts that are joined together by the weld 68, and that the cylinder 63 carrying the release cam 64 and the detent groove 65 similarly is made in two welded parts. To facilitate the manufacture of the drive sleeve assembly 27 with the spline bars 29 in the intermediate section 31, the sleeve assembly also comprises a plurality of separately formed parts that are coaxially joined by a weld 93 between the upper drive sleeve 77 and the intermediate or spline portion 31, and by a second weld 94 between the intermediate portion and a cylinder 95 which may be called the middle drive sleeve. This sleeve is threaded at 97 onto the lower drive sleeve 87, which has a sleeve connector 98 threaded into its lower end for coupling the sleeve assembly through one or more drill collars to the drill bit 28. O-rings are shown at appropriate places for sealing the fluids in or out of appropriate parts of the apparatus, and provision has been made for lubrication where this is desirable. These details need not be specifically described, as they are illustrated generally and are within the skill of those acquainted with this general type of apparatus.

SUMMARY OF OPERATION Although the manner of operation of the drilling apparatus 20, including the packer 25, should be readily apparent from the foregoing detailed description, a brief recapitulation of the steps and procedures should be worthwhile to emphasize more clearly the features of the invention. Assuming that the borehole 21 has been started in the conventional manner and that the drilling apparatus is spaced above the bottom 57 of the hole, the drill bit 28 is lowered into the hole until it reaches the bottom, the drive sleeve assembly 27 being suspended from the mandrel 23 as shown in FIG. 8 as a result of the engagement of the spline bars 29 with the toothed upper end of the clutch cylinder 49 pinned to the mandrel.

In this condition, the retractor 60 is latched to the mandrel 23 by the engagement of the lugs 61 with the detent groove 62, the packer 25 is longitudinally stretched to its full length and thus is radially collapsed to its smallest diameter, and the ports 85 in the lower drive sleeve 87 are out of communication with the connecting chamber 89 so as to be closed. If fluid is to be circulated through the drilling apparatus, its only exit path from the apparatus is through the bit 28.

After the bit 28 reaches the bottom 57 of the borehole 21, downward motion of the drive sleeve assembly 27 ceases and continued lowering of the drill string 22 pushes the mandrel 23 down through the sleeve assembly to disengage the clutch teeth 51 from the spline bars 29 and then shift the spline fingers 48 into engagement with the squared upper ends 58 of the bars so that the latter are cammed to the right (FIG. 8) into alignment with one set of the

grooves

30, 34. Assuming that the aligned set is the set of shorter, drilling grooves 30 and that drilling is to be resumed without a test or treatment, thedrill string is lowered until the squared upper ends of the bars seat against the squared upper ends 33 of the drilling grooves. Then the apparatus is in the drilling condition shown in FIG. 9 so that the tool can be rotated through the spline connection and simultaneously pressed into the earth.

If the spline bars 29 have entered the set of longer grooves 32, the apparatus is shifted to the drilling condition simply by raising the mandrel 23 and the clutch cylinder 49 until the spline bars are engaged by the aligned clutch teeth 51, thus indexing-the drive sleeve assembly 27 one-half step, and then again lowering the mandrel until the upper ends 58 of the spline bars are engaged by the beveled fingers 48 to index the drive sleeve assembly the remaining one-half step. The bars then slide into the shorter grooves 30 and bottom therein as previously described. During all of this motion, the retractor 60 remains latched to the mandrel 23 to maintain the packer 25 stretched to the radially collapsed condition.

To convert the apparatus 20 from the drilling condition (FIG. 9) to the testing and treating condition (FIG. 11), the mandrel 23 is raised until the aligned clutch teeth 51 engage the lower ends of the spline bars 29 and index the bars and the sleeve assembly 27 one-half step away from the shorter grooves 30, and then is lowered so that the beveled fingers 48 engage the upper ends of the spline bars and complete the indexing of the sleeve assembly to bring the bars into alignment with the longer, packing grooves 34. Continued lowering of the mandrel then slides the barrel 32 along the spline bars past the normal drilling position, and thus begins shifting the release cam 64 along the mandrel toward engagement with the latch lugs 61, beyond the position shown in FIG. 14, so that continued upward motionof the release cam along the mandrel results in spreading of the fingers 67 away from the mandrel to remove the lugs from the inner detent groove 62 while swinging them into the outer detent groove 65.

Accordingly, the retractor 60 is unlatched from, and pushed upwardly along, the mandrel as the washover locks 43 and 44 are engaged and the lower end of the packer 25 is raised relative to the upper end, all as shown in FIG. 10. This expands the packer radially within the borehole 21 until the periphery of the packer is pressed sufi'rciently tightly against the borehole wall to seal off and isolate the lower portion of the hole, as shown in FIG. 11. When this condition is achieved, the spline bars 29 typically are adjacent the upper ends of the longer slots 34, as shown in FIG. 11, and the connection chamber 89 is in overlapping relation with the annular series of ports 85 in the lower drive sleeve, thus establishing communication with the ports 88 for a bypass flow of liquid through the two sets of ports around the drill bit 28. In case a tight seal has been obtained before the spline bars 29 move the full extent into the longer grooves, expansion can be terminated with the ports in a differentlposition along the connecting chamber but reliably opened to communicate with the ports 88.

As described in Lynes Pat. No. 3,233,676, a bailer or swab (not shown) may be run into the drill string to remove sufficient drilling fluid to lower the pressure in the sealed-off lower portion of the .borehole 21, thereby permitting formation fluids to enter the borehole for removal through the drill string, or a selected fluid can be pumped down through the drill string before the packer is set to displace the drilling fluid from the apparatus. In the latter case, the pumping pressure is released after the packer is set, and the fluid is bled off as a gas to permit the test or treatment to be made.

When the test or treatment is completed, the drill string 22 is again raised relative to the sleeve assembly 27, thus shifting the mandrel 23 and the barrel 32 upwardly relative to the spline bars 29. The upper end of the packer 25 is raised with the mandrel 23 while the lower end is latched through the retractor 60 to the outer detent 65 in the cylinder 63 which, of course, is part of the drive sleeve assembly 27 and thus remains stationary. Accordingly, the packer is stretched longitudinally by this positive separation of its ends until the detent groove 62 of the mandrel is raised into alignment with the latch lugs 61.

At this time, the resilience of the fingers 67 of the retractor 60 cause the lugs 61 to snap inwardly into the inner detent groove 62, at the same time leaving the outer detent groove 65 so that the cylinder 63 is freed for movement relative to the retractor. Thus, the cylinder slides over the latch lugs to the position shown in FIG. 8 as the upward stroke of the mandrel is completed.

In this manner, the packer 25 is returned positively to its radially collapsed condition despite any tendency it may have to set in a partially expanded condition. Moreover, it is positively latched in the collapsed condition against inadvertent expansion by fluid pressure acting from below or by any other expanding force. This, together with the positive centering action of the stabilizer 78, insures against rubbing contact of the collapsed packer with the borehole wall during drilling.

From the foregoing, it will be evident that the present invention overcomes the problems encountered with prior drilling apparatus of the same general type, and does so in a novel, relatively simple and highly effective manner which makes the Lynes-type of apparatus commercially practical. Moreover, the invention is useable in special drilling situations as a downhole blowout preventer to seal the annulus around the drill therewith, and including-an elongated hollow mandrel attachable to said lower end, a packer telescoped over said mandrel and having an upper end secured thereto, said packer being a sleeve of resiliently flexible material that expands radially in response to longitudinal contraction of the sleeve, a drive sleeve assembly telescoped over said mandrel below said packer, and driving and indexing connections between said mandrel and said drive sleeve assembly for transmitting driving force to the drive sleeve assembly and selectively indexing the latter about the mandrel, said drive sleeve assembly being movable along said mandrel between packing and drilling positions, the improvement comprising: 7

a retractor sleeve telescoped over said mandrel and connected to the lower end of said packer, said retractor sleeve having a plurality of resiliently flexible spring fingers projecting downwardly along said mandrel inside the upper end portion of said drive sleeve assembly, and having latching lugs on said fingers pressed against the mandrel;

means forming a first detent in said mandrel latchingly receiving said lugs when said packer is extended and said drive sleeve assembly is in said drilling position;

an annular release element on the inside of said drive sleeve assembly disposed below said first detent when said drive sleeve assembly is in said drilling position, said release element being movable into engagement with said lugs to shift the latter out of said first detent as the drive sleeve assembly moves toward said packing position, whereby the lower end of said packer is released from said mandrel for longitudinal contraction and radial expansion of the packer;

and means forming a second detent in said drive sleeve assembly receiving said lugs as the latter are shifted out of said first detent, and operable as said drive sleeve assembly moves back toward said drilling position to positively slide said retractor along said mandrel until said lugs reach and reenter said first detent, thereby to collapse the packer radially prior to relatching of the retractor to the mandrel.

2. In an earth borehole drilling tool mountable on the lower end of a drill string to be raised, lowered and rotated therewith, and including an elongated hollow mandrel attachable to said lower end, a packer telescoped over said mandrel and having an upper end longitudinally secured to the mandrel, said packer being radially expandable in response to upward movement of its lower end along the mandrel, a drive sleeve assembly telescoped over said mandrel below said packer for longitudinal sliding movement along the mandrel, and selectively operable means for shifting said mandrel relative to said drive sleeve assembly between a drilling position in which the assembly is lowered along said mandrel and said packer is elongated and radially collapsed, and a packing position in which the assembly is raised along the mandrel and said packer is longitudinally contracted and radially expanded, the improvement comprising:

a retractor secured to the lower end portion of said packer and extending downwardly therefrom along said mandrel to said drive sleeve assembly;

first means on said retractor and said mandrel latching the retractor releasably to the mandrel when said packer is longitudinally extended and radially collapsed;

second means for unlatching said retractor from said mandrel as said drive sleeve assembly moves upwardly relative to the mandrel toward said packing position thereby releasing the packer for longitudinal contraction and radial expansion;

and third means for latching said retractor to said drive sleeve assembly when the retractor is unlatched from said mandrel and the assembly is moving back along the mandrel toward said drilling position, whereby said packer is longitudinally extended and radially collapsed with a positive action as the assembly returns to said drilling position, said first means operating to relatch said retractor to said mandrel when said packer again has been elongated and radially collapsed.

3. The improvement defined in claim 2 in which said first means include at least one latching lug on said retractor lying alongside said mandrel, and a detent on the mandrel for receiving said lug when said mandrel is in a preselected longitudinal position relative to the retractor.

4. The improvement defined in claim 3 in which said retractor is a sleeve telescoped over said mandrel and formed with a plurality of resiliently flexible fingers on its lower end extending longitudinally of the retractor, one of said lugs being carried on the free end portion of each of said fingers and resiliently urged toward said mandrel.

5. The improvement defined in claim 4 in which said detent is an annular groove around said mandrel.

6. The improvement defined in claim 3 in which said second means, for unlatching said retractor, includes a cam carried by said drive sleeve assembly below said latching lug to engage the'latter as the assembly moves toward said packing position, and operable to shift said lug away from said detent.

7. The improvement defined in claim 6 in which said drive sleeve assembly includes a second detent aligned with said lug to receive the latter as said cam shifts the lug out of the firstmentioned detent, thereby forming said third means for latching the retractor to the assembly during return movement.

8. The improvement defined in claim 2 in which the upper end of said retractor is secured to said packer with a lost-motion connection permitting limited longitudinal motion of the retractor relative to the packer.

9. The improvement defined in claim 2 further including an upper washover lock attached to the lower end of said packer, and a lower washover lock attached to the upper end of said drive sleeve assembly, said retractor being a sleeve telescoped onto said mandrel between said locks with its upper end secured to said upper lock and with its lower end portion extending into said lower lock.

10. The improvement defined in claim 2 in which said selectively operable means includes a spline connection between said mandrel and said drive sleeve assembly having interfitting spline elements formed with opposed end surfaces for transmitting downward force from the mandrel to the assembly, said interfitting ends being squared to lie in a plane substantially perpendicular to the longitudinal axis of said tool.

11. The improvement defined in claim 2 in which said mandrel and said drive sleeve assembly are formed with first and second ports for communicating between the interior of the mandrel and the exterior of said tool, said ports being brought into communication during relative movement of the mandrel and the assembly to said packing position and being out of communication in all other relative positions of the ports, thereby to open the ports in the assembly only while the assembly is in said packing position.

12. The improvement defined in claim 11 further including a connecting chamber formed between said mandrel and said drive sleeve assembly to establish communication between said first and second ports, said connecting chamber being elongated longitudinally of said tool to interconnect said first and second ports in a selected range of relative positions of the mandrel and the assembly, but out of communication with said first ports except when said packer is at least partially expanded.

13. In an earth borehole tool mountable on the lower end of a string to be raised and loweredtherewith, and including an elongated member attachable to said lower end, a packer telescoped with said member and having one end attached thereto and its other end slidable along the member, said packer being expandable in response to movement of said other end toward said one end and collapsible in response to extending movement of said other end away from said one end, the improvement comprising:

a retractor secured to said other end and movable therewit along said member;

first means acting between said retractor and said member to latch the two together when said packer is extended along said member;

second means selectively movable along said member toward said other end to expand said packer, said second means including a release element operable during such movement to unlatch said retractor for movement of said other end in a direction to expand the packer;

and third means acting between said second means and said retractor to positively return the retractor along said member as the packer is collapsed.

14. The improvement defined in claim 13 in which said second means is a sleeve assembly telescoped over said member for movement relative thereto toward and away from said other end of said packer, said retractor being disposed between said member and said sleeve assembly and having a latching element movable into engagement alternately with said member and with said sleeve assembly.

[5. The improvement defined in claim 14 in which said retractor is a sleeve telescoped over said member and into the sleeve assembly, said latching element comprising a plurality of lugs disposed around said member and carried on said second detent.

18. The improvement defined in claim 15 in which first and second washover locks are mounted respectively on said other packer end and on the adjacent end of said sleeve assembly, said retractor being secured to said first washover lock and extending into said second washover lock.

19. The improvement defined in claim l3 including at least one stabilizer rotatably mounted on said tool adjacent said packer, said stabilizer having an outside diameter substantially larger than the collapsed diameter of said packer thereby to prevent the latter from rubbing against the wall of the borehole.

20. The improvement defined in claim 19 in which first and second washover locks are mounted respectively on said stabilizer and on the adjacent end of said sleeve assembly for locking said stabilizer to said sleeve assembly.

Claims

1. In an earth borehole drilling tool mountable on the lower end of a drill string to be raised, lowered and rotated therewith, and including an elongated hollow mandrel attachable to said lower end, a packer telescoped over said mandrel and having an upper end secured thereto, said packer being a sleeve of resiliently flexible material that expands radially in response to longitudinal contraction of the sleeve, a drive sleeve assembly telescoped over said mandrel below said packer, and driving and indexing connections between said mandrel and said drive sleeve assembly for transmitting driving force to the drive sleeve assembly and selectively indexing the latter about the mandrel, said drive sleeve assembly being movable along said mandrel between packing and drilling positions, the improvement comprising: a retractor sleeve telescoped over said mandrel and connected to the lower end of said packer, said retractor sleeve having a plurality of resiliently flexible spring fingers projecting downwardly along said mandrel inside the upper end portion of said drive sleeve assembly, and having latching lugs on said fingers pressed against the mandrel; means forming a first detent in said mandrel latchingly receiving said lugs when said packer is extended and said drive sleeve assembly is in said drilling position; an annular release element on the inside of said drive sleeve assembly disposed below said first detent when said drive sleeve assembly is in said drilling position, said release element being movable into engagement with said lugs to shift the latter out of said first detent as the drive sleeve assembly moves toward said packing position, whereby the lower end of said packer is released from said mandrel for longitudinal contraction and radial expansion of the packer; and means forming a second detent in said drive sleeve assembly receiving said lugs as the latter are shifted out of said first detent, and operable as said drive sleeve assembly moves back toward said drilling position to positively slide said retractor along said mandrel until said lugs reach and reenter said first detent, thereby to collapse the packer radially prior to relatching of the retractor to the mandrel.

2. In an earth borehole drilling tool mountable on the lower end of a drill string to be raised, lowered and rotated therewith, and including an elongated hollow mandrel attachable to said lower end, a packer telescoped over said mandrel and having an upper end longitudinally secured to the mandrel, said packer being radially expandable in response to upward movement of its lower end along the mandrel, a drive sleeve assembly telescoped over said mandrel below said packer for longitudinal sliding movement along the mandrel, and selectively operable means for shifting said mandrel relative to said drive sleeve assembly between a drilling position in which the assembly is lowered along said mandrel and said packer is elongated and radially collapsed, and a packing position in which the assembly is raised along the mandrel and said packer is longitudinally contracted and radially expanded, the improvement comprising: a retractor secured to the lower end portion of said packer and extending downwardly therefrom along said mandrel to said drive sleeve assembly; first means on said retractor and said mandrel latching the retractor releasably to the mandrel when said packer is longitudinally extended and radially collapsed; second means for unlatching said retractor from said mandrel as said drive sleeve assembly moves upwardly relative to the mandrel toward said packing position thereby releasing the packer for longitudinal contraction and radial expansion; and third means for latching said retractor to said drive sleeve assembly when the retractor is unlatched from said mandrel and the assembly is moving back along the mandrel toward said drilling position, whereby said packer is longitudinally extended and radially collapsed with a positive action as the assembly returns to said drilling position, said first means operating to relatch said retractor to said mandrel when said packer again has been elongated and radially collapsed.

6. The improvement defined in claim 3 in which said second means, for unlatching said retractor, includes a cam carried by said drive sleeve assembly below said latching lug to engage the latter as the assembly moves toward said packing position, and operable to shift said lug away from said detent.

7. The improvement defined in claim 6 in which said drive sleeve assembly includes a second detent aligned with said lug to receive the latter as said cam shifts the lug out of the first-mentioned detent, thereby forming said third means for latching the retractor to the assembly during return movement.

13. In an earth borehole tool mountable on the lower end of a string to be raised and lowered therewith, and including an elongated member attachable to said lower end, a packer telescoped with said member and having one end attached thereto and its other end slidable along the member, said packer being expandable in response to movement of said other end toward said one end and collapsible in response to extending movement of said other end away from said one end, the improvement comprising: a retractor secured to said other end and movable therewith along said member; first means acting between said retractor and said member to latch the two together when said packer is extended along said member; second means selectively movable along said member toward said other end to expand said packer, said second means including a release element operable during such movement to unlatch said retractor for movement of said other end in a direction to expand the packer; and third means acting between said second means and said retractor to positively return the retractor along said member as the packer is collapsed.

15. The improvement defined in claim 14 in which said retractor is a sleeve telescoped over said member and into the sleeve assembly, said latching element comprising a plurality of lugs dispoSed around said member and carried on said sleeve by resiliently flexible fingers urging the lugs toward said member.

16. The improvement defined in claim 15 in which said first means includes said lugs and a first detent on said member, and in which said third means includes a second detent inside said sleeve assembly receiving said lugs when the latter are away from said first detent.

17. The improvement defined in claim 16 in which said release element is a cam inside said sleeve assembly movable along said member and operable to shift said lugs into said second detent.

19. The improvement defined in claim 13 including at least one stabilizer rotatably mounted on said tool adjacent said packer, said stabilizer having an outside diameter substantially larger than the collapsed diameter of said packer thereby to prevent the latter from rubbing against the wall of the borehole.