US3363880A - Cable-feeding apparatus - Google Patents

Description

United States Patent Ofiice 3,3633% Patented Jan. 16, 1963 3,363,880 CABLE-FEEDENG APlARATUS Leon Blagg, Channelview, Tex., assignor to Schiumherger Technology Corporation, Houston, Tex., a corporation of Texas Fitted Nov. 14, 1966, her. No. 594,931 Claims. (Cl. 254135) ABSTRACT OF THE DISCLOSURE As one embodiment of the invention disclosed herein, a fluid-tight enclosure is provided with a sealing member at its upper end through which a suspension cable may be introduced into the housing and a well bore therebelow. To drive the suspension cable, a flexible wire is introduced into the enclosure through suitable packing glands and held in frictional engagement along one side of the suspension cable by one or more pistons. By moving the flexible line in the appropriate direction, the suspension cable is pulled through the housing and sealing member.

Accordingly, as will subsequently become apparent, this invention relates to oil-well servicing apparatus; and, more particularly, this invention pertains to new and improved apparatus for facilitating the introduction and removal of cable-suspended well tools or instruments into and out of well bores that are at high pressure or flowing.

For one reason or another, it is frequently necessary to periodically introduce various cable-suspended well tools or instruments into producing oil wells during the course of their life. In those instances where a well is flowing or contains fluids at high pressures, the upper end of the well casing is closed by suitable valving and special equipment must be provided to introduce and remove such tools or instruments. This special equipment typically includes an upright section of pipe or riser for receiving the well tool that is temporarily connected to the cut-otf valves for the well. A so-called lubricator having a stufling box or line wiper on its upper end is connected to the upper end of the riser to provide a pressure seal around the suspension cable between the tool and the point where the cable exits from the apparatus. In this manner, while the well valves are closed, the well tool is inserted into the riser and its suspension cable brought out through the lubricator and stufling box. Then, after the well valves are opened, the well tool is lowered on into the well.

Particular measures must be taken, however, to overcome the upwardly acting forces exerted by the well pressure on the cross-sectional area of the cable Where it passes through the lubricator and stufling box in order to get the well tool far enough down into the well bore that the combined weight of the tool and cable already therein is sufficient to pull the remainder of the cable on into the well bore. One common arrangement for overcoming these pressure forces is to attach a number of weights or sinkers either just above or below the tool. Once suflicient weight has been added to overcome these pressure forces as well as the quite significant frictional drag on the cable as it passes through the lubricator, the cable may be freely unreeled as the combined Weight of the sinkers, tool, and cable pulls the tool on down into the well bore. It will be appreciated, of course, that with this arrangement, the riser must be of suflicient height to accommodate the combined length of the cable head and the well tool as well as whatever weights are attached thereto.

The combined height of the riser and lubricator becomes quite critical, however, since there is usually no permanent derrick at a producing well and such workover operations must be performed with relatively short, portable erection devices of a somewhat limited capacity that, for sake of convenience, are generally mounted on a truck. It is quite evident, therefore, that the total height of the cable-handling equipment that can. be used will be determined by the height of available erection devices. Thus, where a well is at a fairly high pressure, it is not too practical to rely solely on additional weights.

Accordingly, various proposals have been advanced heretofore as a substitute for weights. Most of these proposals have been directed to reciprocating devices that, in one manner or another, momentarily grip the cable and either push or pull it to overcome these frictional forces and upwardly acting pressure forces. Such pulling or pushing devices have not, however, proven to be very satisfactory. For example, if it is a cable-pushing device, the cable must be gripped outside of the lubricator and the effective pushing force will be dependent upon the stiffness or rigidity of that portion of the cable between the gripping device and the stufiing box. Moreover, Where a stranded cable is being pushed into the lubricator, the oppositely directed forces thereon will tend to swell the cable outside of the stufling box and, in time, begin separating the various cable elements. It will also be appreciated that such swelling further complicates the problem of sealing the cable where it enters the stufiing box.

On the other hand, although most cable-pulling devices known heretofore are fluidly sealed and mounted inside of the lubricator, such devices have tended to be quite cumbersome and bulky as well as greatly increase the overall height of the cable-handling equipment. Moreover, the nature of these prior-art cable-pulling devices makes it quite ditficult to effectively seal those elements of the device that must be brought out through the walls of the fluid-tight enclosure.

Accordingly, it is an object of the present invention to provide new and improved cable-feeding apparatus that are not subject to the above mentioned disadvantages. This and other objects of the present invention are provided by arranging suitable cable-sealing means on a fluid-tight enclosure having therein cable-driving means including a small-diameter flexible line in juxtaposition with the suspension cable and means for urging the flexible line into frictional engagement with the cable. By driving the small-diameter line in the desired direction, the suspension cable is easily pulled through the cable-sealing means with sufiicient force to overcome whatever reversely directed pressure or frictional forces may be acting thereon. As another aspect of the present invention, to reduce the overall height of the well-servicing apparatus, the fluid-tight enclosure may be extended and its direction reversed and a plurality of rotatable supporting members mounted therein to serve as an enclosed sheave for the suspension cable.

The novel features of the present invention are set forth with particularity in the appended claims. This operation together with further objects and advantages thereof, may best be understood by way of illustration and example of certain embodiments when taken in conjunction with the accompanying drawings, in which:

FIG. 1 depicts well-servicing apparatus arranged in accordance with the principles of the present invention;

FIG. 2 is an enlarged elevational view in cross-section of a portion of the apparatus shown in FIG. 1;

FIG. 3 is an enlarged cross-sectional view of another portion of the apparatus shown in FIG. 1; and

FIG. 4 is a cross-section view taken along the lines 4-4 of FIG. 2.

Turning now to FIG. 1, a preferred embodiment is shown of well-servicing apparatus 10 of the present invention as it appears when erected on top of a typical blowout preventer 11 mounted on the upper end of the well head 12 projecting above the surface of the ground. The well-servicing apparatus is basically comprised of an upright tubular riser 13 that is secured at its lower end to the blowout preventer 11 and has its upper end connected to one leg of an inverted, generally U-shaped, enclosed sheave 14. The other leg of the enclosed sheave 14 dependently supports an enclosed cable-feeding device 15 which is in turn tandemly connected to the upper end of a typical lubricator 1%. To maintain the apparatus 10 in its upright position, suitable supporting means such as a truck-mounted erection device (not shown) are provided to support a cable 17 on top of the enclosed sheave 14.

A suspension cable 18 spooled in the usual fashion on a powered winch (not shown) to one side of the wellservicing apparatus 11 is brought generally horizontally toward the apparatus and passed around the underside of a pulley 19 from whence it is directed upwardly toward the bottom end of the lubricator 16. After passing through the lubricator 16 and cable-feeding device 15, the cable 18 enters the enclosed sheave 14 where its direction is reversed to bring it downwardly into the upper end of the riser 13. The free end of the cable 18 is secured in the usual fashion, as by a cable head 20, to the upper end of a well instrument or tool 21 which, at the instance dcpicted in FIG. 1, is still confined in the riser 13 above the blowout preventer 11.

The riser 13 must, of course, be of sufficient length as well as have an internal diameter that will readily accommodate the well tool 21 and cable head 20. Thus, the particular dimensions of the riser 13 will be governed solely by those of the well tool 21. It will be realized, of course, that should the well tool 21 have a considerable length, the overal height of the well-servicing apparatus 10 would be of particular concern were it necessary to mount even the lubricator 16 on the upper end of the riser 13. Thus, as one particular feature of the present invention, the enclosed sheave 14 on the upper end of the riser 13 reverses the direction of the suspension cable 18 so that the cable-feeding device 15 and lubricator 16 are instead directed back toward the ground and the overall height of the apparatus 10 is greatly reduced.

The enclosed sheave 14 includes a U-shaped tubular housing 22 enclosing a plurality of longitudinally aligned pulleys or grooved rollers 23, with each being adapted to receive the cable 18 and, as best seen in FIG. 3, respectively journalled between the upright arms of a U-shaped support block 24. To secure these roller blocks in position around the inner surface of the tubular housing 22, a flat, arcuate metal strip or band 25 is fastened over the upright arms of each block 4, as by screws 26, and extended around the interior of the housing. Each end of the band 25 is secured to an adjacent screw 27 extending through a plug 28 (only one shown) shouldered in each end of the U-shaped housing 22. Accordingly, as seen in FIGS. 1 and 3, the cable 18 is confined between the rollers 23 and the underside of the arcuate band 25 so that it cannot escape as it moves through the enclosed sheave 14.

In FIG. 2, a somewhat schematically represented, enlarged cross-sectional view is shown of a preferred embodiment of the cable-feeding device 15 of the present invention and the uppermost portion of the lubricator 16 dependently coupled therebelow. The cable-feeding device 15 includes a tubular, thick-walled housing 29 of convenient dimensions that is open at each end and has an enlarged axial cavity 30 through which the suspension cable 18 passes. To guide the cable 18 along a predetermined path through the cavity 30, means are provided such as a plurality of stationary pulleys or grooved rollers 31 that are respectively rotatably journalled to U-shaped support blocks 32 separately disposed and sealed within longitudinally spaced lateral bores 33 in the housing 29. An appropriate closure member 34 along one side of the housing 29 closes the rear of the bores 33 and retains the support blocks 32 in position. In this manner, the rollers 31 are positioned in the cavity 30 slightly to one side of and in a line parallel to the path of the cable 18.

As best seen in FIGS. 2 and 4, cable-driving means are provided on the opposite side of the cavity 30 and include a small-diameter solid wire 35 that extends through the central cavity along a longitudinal path that lies parallel to and immediately adjacent to that side of the suspension cable 18 that is directly opposite from the rollers 31. In one preferred embodiment of the present invention, the wire 35 was 0.062 to 0.682-inch diameter and the cable 18 was di -inch diameter.

The ends of the wire 35 are brought out of the housing 29 over a number of stationary rollers 36 and 37 rotatably journalled and mounted along generally arcuate paths in offset or inclined passages 38 and 39 above and below the cavity 30 that are respectively terminated at small, inclined bores 46 and 41 through the walls of the housing. Suitable sealing members 42 and 43 mounted in the outer ends of the bores 46 and 41 fluidly seal the wire 35 relative to the housing 2%. As will subsequently become apparent, the small-diameter wire 35 is selectively urged against the suspension cable 18 by means or" a plurality of longitudinally spaced, piston-actuated rollers 44 on one side of the cavity 30 that are arranged to be moved laterally toward the stationary rollers 31 to confine the wire 35 and firmly urge it against the suspension cable 18.

To drive the small-diameter wire 35, means such as powered reels 45 and 46 are mounted outside of the housing 29 respectively above and below the outer ends of the inclined bores and 41 and adapted to spool a suflicient length of the wire. Appropriate selectively operable prime movers such as hydraulic motors, electric motors, or airdriven motors (not shown) are coupled to each of the reels and 46 and arranged to wind the wire 35 onto one or the other of the reels as required.

To seal the suspension cable 18 within the cable-feeding device 15, the lubricator 16 is dependently coupled below the housing 29 and has its lower end closed by suitable packing means, such as, for example, a hydraulicallyactuated packing device 47 (FIG. 1) as shown on page 747 of the Composite Catalog of Oil Field Equipment and Services (1962-63). As is typical, the lubricator 16 is comprised of preferably two or more tubular members 48 tandemly connected to one another by couplings 49 with each tubular member having an axial bore 50 that is just slightly larger than the diameter of the suspension cable 18. By using high-pressure grease-injection equipment (not shown) such as that shown on page 751 of the aforementioned Composite Catalog, grease is injected into the cavity 30 by way of a lateral port 51 at the upper end of the cable-feeding device 15.

The upper end of the cable-feeding device 15 is closed by a tubular member 52 having an axial bore 53 also only slightly larger than the outer diameter of the cable 18 for snugly receiving the suspension cable. A suitable pressure-regulating valve 54 of conventional design having its inlet 55 connected to the high-pressure greaseinjection equipment and its outlet 56 connected to the lateral port 51 is employed to maintain the pressure of the grease in the cavity 31) at a predetermined differential above the well pressure. To accomplish this, the pressureregulator element 57 of the valve 54 is connected by way of a lateral port 58 in the housing 29 to the space 59 above the tubular member 52.

It will be appreciated, therefore, that by using greaseinjection equipment that is capable of developing pressures greater than the well pressure, the pressure-regulator 54 will admit suflicient quantities of additional grease to compensate for whatever is exhausted through the narrow clearances in the bores 5d and 53 of the tubular members 48 and 52 around the suspension cable 18. It will be understood, of course, that the close fit of the cable 18 within the bore 59 will permit a pressure difference to be present across the tubular member 52. Similarly,

a pressure differential will also be maintained between the cavity and the coupling 49 as well as between the coupling and the exterior of the packing device 47.

As seen in both FIGS. 2 and 4, the piston-actuated rollers 44 are respectively journalled on a suitably arranged body having an enlarged piston portion 6 with each being cooperatively received within a complementary lateral piston bore 61 directly opposite and axially aligned with a corresponding one of the bores 33. Each of these lateral bores 61 are respectively communicated by way of a housing passage 62 to a piston chamber 63 that is in communication with the cavity 30. A piston 64 sealingly received within the piston chamber 63 is provided with an axial extension 65 that projects through an annular sealing member 66 mounted in a complementary bore through the side of the housing 29. The rearward portion of the piston bores 61, the passage 62, and the piston chamber 63 are filled with a suitable hydraulic fluid, such as oil or the like, which is confined therein by the piston 64.

It will be appreciated that the pressure of the grease in the cavity 34 acting against the piston 64 will be effective to develop a corresponding hydraulic pressure in the piston chamber 63. Inasmuch as the outer end of the piston rod 65 is exposed to the exterior of the cablefeeding device 15, the effective area of the piston face in contact with the hydraulic fluid will be somewhat less than the cross-sectional area of the opposite face of the piston 64 to the grease in the cavity 36. Thus, since the effective piston area in contact with the greaseis somewhat larger than the effective piston area in contact with the hydraulic fluid, the pressure of the fluid in the piston chamber 63 will be greater than the grease pressure in the cavity 30 by a degree directly proportional to the ratio of the cross-sectional areas of the opposite faces of the piston 64. This greater hydraulic pressure will, of course, be effective therefore to urge the piston-actuated rollers 4-4 against the wire and press the wire firmly against the adjacent surface of the suspension cable 13. It will be noted also that a still greater hydraulic pressure can be developed in the chamber 63 by adding a second piston 67 on the outer end of the extension 65 and admitting fluid under pressure into a piston chamber 68 receiving this second piston 67.

Accordingly, it has been found that whenever the reel 4-5 is driven so as to spool the wire 35 thereon, the frictional engagement between the wire and the suspension cable 18 developed by the piston-actuated rollers 44 will be effective to pull the suspension cable through the hydraulically actuated stufiing box 47 and lubricator 16 against the opposing frictional and pressure forces thereon.

Although the reels 4 5 and may be mounted on the same side of the housing 29 as the bores 46 and 41 as shown in FIG. 2, they are preferably mounted on the opposite side thereof as seen in FIG. 1. Where the reels 45 and 46 are mounted in this manner, free-wheeling sheaves 69 and 7d are mounted respectively above and below the outer ends of the bores 49 and 41 and to one side thereof. The Wire 35 coming from the reel 45 is passed on the far side of the housing 2'9 (as seen in FIG. 1) and carried under and on around the lower sheave 7d and up into the bore 41. Similarly, the wire 35 coming from the reel 45 is carried up across the near side of the housing 29, over the upper sheave 6'9, and then back down into the bore 4%. In this manner, the wire 35 will be free to travel back and forth across the reels 45 and 46 as the wire is being Wound or unwound, with the sheaves 69 and 7t) serving to keep the wire 35 axially aligned with the bores 40 and 41.

To erect the well-servicing apparatus 10 as shown in FIG. 1, the apparatus is initially laid on the ground. The free end of the suspension cable 18 is then pushed through the tubular members 48 of the lubricatior l6 and into the cavity 39. Since the piston-actuated rollers 44 will be retracted, the cable end can be readily thrrea-ded on past the rollers 31 and 44 and into the enclosed sheave 14. Similarly, it is quite easy to thread the cable end on through the sheave 14 between the rollers 23 and band 25 to bring the suspension cable 18 into the riser 13 and out its lower end. Once the cable 18 is through the apparatus it), its free end is connected to the cable head 20 and well tool 21. Once the apparatus 10 is completely assembled (if this has not already been done), the well tool 21 is drawn into the riser 13 and the apparatus erected onto the blowout preventer 11.

Operation of the apparatus 10 will, of course, be similar to conventional lubricators except that the reel 45 will, however, be employed to pull the suspension cable 18 into the apparatus. If desired, hydraulic pressure can be applied to the piston chamber 71 (FIG. 2) to move the pistons 64 and 67 inwardly to reduce the force that the piston-actuated rollers 44 are applying against the wire 35 and cable 18 to permit the suspension cable to move Without interference through the cable-feeding device 15. It will be realized, moreover, that the pressureactuated rollers 44 can also be used as desired to brake the suspension cable 18.

Accordingly, it will be appreciated that the present invention has provided a significant advance in the art by not only greatly reducing the overall height of a combined riser and lubricator assembly as has been used heretofore but also by providing a more positive means for driving a suspension cable. Of particular significance, a cable-feeding device arranged in accordance with the present invention pulls the suspension cable through the lubricator rather than pushes it. Thus, instead of tending to diametrically swell the suspension cable as will occur when such a cable is being pushed, the pulling action of the cable-feeding device will greatly prolong the effective life of such cables far more than has heretofore been possible. It is also of significance to note that by using a small-diameter solid wire, such as at 35, the wire is quite easily sealed where it enters and leaves the housing, as at 29. It will be appreciated, of course, that the small-diameter line could just as well be a short continuous loop rather than being the long wire as described.

While a particular embodiment of the present invention has been shown and described, it is apparent that changes and modifications may be made without departing from this invention in its broader aspects; and, therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of this invention.

What is claimed is:

1. Apparatus for introducing a well tool depedently suspended from a suspension cable into a well bore comprising: a housing having one end adapted for connection to a Well bore, said housing having a bore extending therethrough with a portion thereof being sized to receive a well tool; sealing means adjacent to the other end of said housing and adapted for slidably sealing around a suspension cable; and means for driving a suspension cable including a flexible line having a section thereof extending longitudinally through at least part of said housing along a path substantially parallel to the path of a suspension cable therein, means for urging said flexible line section into frictional engagement with a suspension cable, and means for driving said flexible line to pull a suspension cable through said sealing means and into said housing.

2. The apparatus of claim 1 wherein said housing includes portions which are spaced apart and generally parallel to one another with a U-shaped intermediate portion.

3. The apparatus of claim 2 further including roller means in said Ushaped housing portion for guiding a suspension cable.

4. The apparatus of claim 3 wherein said cable-guiding means include a plurality of rollers longitudinally spaced along the interior of said U-shaped housing portion and adapted to support a suspension cable, and means spaced above said rollers adapted to maintain a suspension cable on said rollers.

5. The apparatus of claim 4 further including support members for said rollers; and wherein said cable-maintaining means include a strap member extending through said U-shaped housing portion above said rollers, means securing said roller-support members to said strap member, and means for securing the ends of said strap to said housing.

6. Apparatus for introducing a flexible member into a Well bore comprising: a housing adapted for connection to a well bore, said housing having a bore extending therethrough to receive a flexible member; first means adjacent to one end of said housing adapted to fluidly seal a suspension cable with respect to said housing for sliding movement therethrough; second means adjacent to the other end of said housing for fluidly sealing said housing with respect to the control valve and means for driving a flexible member including first means for guiding a fiexible member along a generally longitudinal path through said bore portion, a flexible line having a section thereof extending longitudinally through at least part of said bore and along a path substantially parallel to said path of a flexible member, and second means for guiding said flexible line along its said path and for pressing said flexible line against a flexible member with sufiicient force for frictionally engaging said flexible line section with an adjacent portion of a flexible member, said flexible line being movable to pull a flexible member on into said housmg.

7. The apparatus of claim 6 wherein said first and second means include opposed rollers relatively movable toward one another to an adjacent position wherein said flexible line and flexible member are juxtaposed and con fined between said opposed rollers.

8. The apparatus of claim '7 further including means for engaging said rollers with said flexible line and flexible member respectively with a force proportionately related to the pressure of the well bore.

9. The apparatus of claim 6 wherein said first means include a plurality of longitudinally-spaced first rollers adapted to receive one side of a flexible member; said second means include a plurality of longitudinally-spaced second rollers in opposed relation to said first rollers; said rollers being relatively movable toward one another; and hydraulic means for urging said rollers toward one another to frictionally engage said flexible line section with the opposite side of the flexible member.

10. The apparatus of claim 9 wherein said flexible line is a solid wire.

11. The apparatus of claim 10 wherein the flexible member is a cable and said solid wire has a diameter less than the diameter of the cable.

12. Apparatus for introducing a well tool dependently suspended from a suspension cable into a well bore under pressure and capped by a control valve comprising: a housing having a longitudinal bore therethrough adapted to receive a suspension cable; first means adjacent to one end of said housing adapted to fluidly seal a suspension cable with respect to said housing for sliding movement therethrough; second means adjacent to the other end of said housing for fluidly sealing said housing with respect to the control valve means for driving a suspension cable including a flexible wire having an intermediate section thereof extending through at least a portion of said longitudinal bore in a path substantially parallel to the path of a suspension cable therein; a plurality of first rollers mounted in said housing at longitudinally-spaced intervals along one side of said longitudinal bore and adapted to receive one side of a suspension cable; a plurality of second rollers adapted to receive said flexible wire mounted in said housing at longitudinally-spaced intervals along the other side of said longitudinal bore and di rectly opposite from respective ones of said first rollers; hydraulic means for moving said rollers toward one another with sumcient force to bring said intermediate-section of said flexible Wire into frictional engagement against the other side of a suspension cable; and means for driving said flexible wire to pull a suspension cable through said first sealing means and on into said housing.

13. The apparatus of claim 12 further including passage means in said housing through which the terminal sections of said flexible wire are brought out of said housing; sealing means in said passage means for fluidly sealing said housing relative to said terminal wire sections.

14. The apparatus of claim 12 wherein said first means includes at least one tubular member sealingly coupled to said one housing end and having a longitudinal bore just larger than the outside diameter of a suspension cable; and said second means includes at least one tubular member sealingly coupled between said other housing end and the control valve and having a longitudinal bore with at least a portion thereof adapted to receive a well tool.

15. Apparatus for conducting a cable or the like into a Well bore comprising: a longitudinally-extending housing through which a cable can be passed; first means adjacent to one end of said housing adapted to fluidly seal a suspension cable with respect to said housing for sliding movement therethrough; second means adjacent to the other end of said housing for fluidly sealing said housing with respect to the control valve means for guiding a cable through said housing; a driving line arranged for insertion between a cable and said guiding means; and means for bringing a cable and said driving line into a frictional relationship, said driving line being movable for conducting a cable through said housing.

References Cited UNITED STATES PATENTS 2,810,439 10/1957 McCollough 166-77 2,926,001 2/1960 Mack 254-190 3,182,877 5/1965 Slater 226172 RICHARD E. AEGERTER, Primary Examiner.

EVON C. BLUNK, Examiner.

H. C. HORNSBY, Assistant Examiner.

Images