US3050130A - Tool carrier - Google Patents

Description

Aug- 21, 1952 F. I-I. cuLvER ETAI. 3,050,130

Toor. CARRIER Filed April 20, 1959 HIS AGENT United States Patent O 3,050,130 TOOL CARRIER Frederick Howard Culver, McAllen, and Edward B.

Lagucki, Houston, Tex., assignors to Shell Oil Company, a corporation of Delaware Filed Apr. 20, 1959, Ser. No. 807,708 6 Claims. (Cl. 166-153) This invention relates to apparatus adapted to move an object through a pipe and pertains more particularly to a tool carrier adapted to move a tool, instrument, or other piece of equipment through a pipe string for example through the flowline and tubing string of an oil well.

During the drilling, completion, servicing and/ or reconditioning of oil wells many objects such as sections of tubular goods, strainers, bottomhole chokes, tools, surveying and logging instruments, etc., may from time to time be introduced into and positioned at a predetermined level within either the well tubing or the well casing. These objects are either dropped in the well so that they fall to a predetermined position by gravity, or they are lowered to the desired position on a wire line, or they are pumped into position. In pumping a tool into position within an oil well, the tool is generally provided with a packer or sealing means surrounding it of a diameter equal to that of the tubing string through which it is to be pumped. After putting the tool in the tubing string, a uid is pumped down the tubing string in back of it, with the iluid already in the tubing or in the oil well being circulated up the annular space between the tubing string and the well casing.

In the event that it is desired to retrieve the tool from the bottom of the well and remove it from the well, the flow of fluid into a well may be reversed so that the ow enters the annular space between the well casing and the well tubing, passing down through the well to the bottom of the tubing and up the tubing string, driving the tool ahead of it up the tubing to the top of the well. Alternatively, a wire line with a `fishing head may be lowered into the well to connect with the top of the tool and later remove it from the well by pulling it upwardly by the wire line, in a manner well known to the art. Various methods of introducing and removing objects from a well are described in U.S. Patents 2,805,718, issued September 10, 1957, and 2,810,442, issued October 22, 1957, to G. H. Tausch.

One drawback with the method of circulating a well tool or other piece of equipment in and out o-f a well is that the packer or sealing element carried by the tool, or by any retrieving tool sent to latch on to a well tool, is subject to wear due to the frictional contact between the sealing element and the inside wall of the tubing string. Thus it may be readily seen that if a tool and its packer is circulated to the bottom of a 10,000-foot well, considerable wear may take place on the packer so that by the time the tool and the packer reaches the bottom of the well there is no longer a perfect seal between the packer and the inside wall of the tubing string. 'I'his is especially true in the event that a tubing string is used having upset ends with exposed threads or a small space `between adjacent sections of the inner wall. Destruction off the seal between the packer and the tubing wall makes it diicult if not impossible later to circulate the packer and its tool upwardly to the top of the well. Additionally, without a perfect seal between the packer and the tubing wall at all times, it is impossible to determine the position of the tool in the well during either its upward or downward travel. On the other hand, with a perfect seal between a packer and the tubing wall, the position of a tool or instrument being circulated down the well may be known at any time by measuring the number of gallons of driving 3,050,130 Patented Aug. 21, 1962 ICG iluid being pumped into the well to -force the packer and its tool or instrument one direction or the other.

It is therefore a primary object of the present invention to provide an apparatus for moving a tool, instrument or other object to a predetermined position within a pipe.

Another object of this invention is to provide an apparatus for moving a tool, instrument -or other object through a pipe while at the same time maintaining a perfect seal within the pipe at all times.

A further object of the present invention is to provide an apparatus including sealing means which are designed to maintain a perfect seal within a pipe when passing therethrough, said sealing means being adapted to compensate for any wear on the outer surface thereof.

Still another object of this invention is to provide an apparatus having dual sealing means adapted to be selectively actuated when being run into and out of ya well so that a diierent sealing element is used when the apparatus is run in opposite directions.

A still further object of this invention is to provide a exible tool carrier adapted to pass around bends in a pipe, said carrier being provided with selectively inflatable sealing elements, one of which is inliated to maintain an eifective seal within a tubing string as the tool carrier is pumped therethrough, with the seals being adapted Ito expand continually to compensate for any lwear on the outer surface thereof.

These and other objects of this invention will be understood from the following description with reference to the drawing, wherein:

FIGURES 1 to 4 are diagrammatical views taken partially in longitudinal cross-section of different Aforms of a tool carrier or tool pusher in accordance with the present invention. The two carriers in FIGURES 3 and 4 are shown as moving upwardly in la pipe.

Referring to FIGURE 1 of the drawing, a tool carrier constructed according to the present invention is shown positioned in a vertical section of tubing such as employed in an oil well. The tool carrier comprises la central mandrel 11 on which are mounted a pair of sealing elements or packers 12 and 13 which surround the central mandrel 11 and are held thereon by suitable sealing-element or packer-retaining cups or rings 14 and 15, 16 and 17, respectively. The sealing elements 12 and 13 and their retaining cups 14, 15, 16, and 17 are held in position on the mandrel 11 by retaining nuts 18 and 19.

Preferably the mandrel 11 is provided with a iiexible linkage such as a ball-in-socket joint 21 at a point between the sealing elements 12 and 13 so as to facilitate movement of the tool carrier in curved sections of a well tubing or pipe. Since the possibility always exists that any tool attached to the tool carrier may become stuck in a well, the tool carrier is preferably provided with a iishing head 22 whereby a retrieving tool (not shown) attached to the bottom of a wire line may be lowered through the tubing string 10 to latch onto the rishin'g head 22, thereby allowing removal of the tool carrier by an upward pull on the wire line. n

As illustrated, the packer retaining elements or cups 14 and 15 surround the ends of the packer or sealing element 12 while at the same time being axially spaced from each other on the central mandrel 11 so that the packer element 12 is against, or may be expanded against, the inner wall of the tubing 10 to form a seal thereagainst. Preferably, the sealing elements 12 and 13 are formed having an internal diameter slightly larger than that of the mandrel 11 so that an undercut portion or annular space 23 is formed between the mandrel and the sealing element 12.

Fluid ports 24 and 25 are provided through the walls of the packer retaining cups 15 and 17 near t-he closed ends thereof so that fluid passageways are formed through the packer retaining cups in communication between the space outside the packer and the annular space 23. Since the sealing element 12 of FIGURE 1 may during use be caused to rotate slightly with regard to its retaining cups 14 and 1S, it is preferably designed so that the closed end of the cup terminates above port 24 so that the fluid passageway is maintained at all times in communication between the inside of the sealing element 12 and the space outside the tool carrier.

The packers or sealing elements 12 and 13 are made of any suitable inflatable resilient material such -as rubber, synthetic rubber, rubberized fabrics or certain plastic materials which may be expanded under the application of fluid pressure. The portion of the sealing element 12 in contactwith the inner wall of the tubing may have a thickened cross-section so as to provide for some wear on the seal as it is propelled through the tubing. In addition, the sealing element 12 may be bevelled to substantially a point, as illustrated, if desired.

Preferably, the sealing element 12 is formed so that its lower end, i.e., the end farthest from fluid port 24, fits closely about the central mandrel 11 near the lower retaining cup 14 in a luidtight manner. In the event that the packer 12 does not have a tight fit at this point, an O-ring seal 26 may be positioned between the retaining cup 14 and the mandrel 11.

When the tool carrier of the present invention is to be used to run a tool or instrument down a well tubing 10, the present tool carrier or pusher may merely be in touching engagement with the tool to be inserted, or alternatively may be fixedly secured to the tool in any suitable manner as by screw threads or, if desired, detachably connected by spring clips or other readily detachable latching means. In running a tool to the bottom of a well the tool would first be inserted in the top of the fiowline and tubing with the present tool carrier forced in behind it. The top of the tubing would then be closed and tiuid pressure would be applied to drive the tool and its tool carrier down to the bottom of the well. When pressure is applied above the tool carrier illustrated in FIGURE l, the pressure fluid flows past sealing element 13 and enters fluid ports 24 and 25 leading to the sealing elements 12 and 13, respectively. Since the fluid pressure on either side of the bevelled sealing element 13 would be the same there would be no tendency for the sealing element 13 to expand against the wall of the tubing 10 to form a tiuidtight seal thereagainst.

The pressure fiuid entering fluid port 24 would pass down into the annular space 23 and force the sealing element 12 against the inner wall of the tubular member 10 so that the lower sealing element 12 would act as a piston to be forced downwardly through the tubing string 10 by the application of further pressure uid above it. This action takes place since a usable pressure differential exists across the lower sealing element 12 of FIGURE 1 whereas no usable pressure differential exists across sealing element 13 on downward travel of the tool carrier. Thus it may be seen that, on the downward travel of the present tool carrier, the upper sealing element 13 would merely be a follower-piston which would not contact the tubing wall with any force to form a seal thereagainst and hence would not be subject to wear as the tool carrier passes downwardly through the tubing string 10. With the lower packer 12 maintaining a tight fit in the tubing string 10 at all times, the precise location of the tool carrier or pusher can be determined accurately at any time from a measure of the amount of pressure fluid injected or pumped into the top of the tubing string 10.

To return the tool carrier, with or without its accompanying tool (not shown), circulation of the driving fiuid in the well is reversed so that the pressure fluid would pass downwardly outside the tubing string 10 and upwardly through it. Thus the action of the sealing elements 12 and 13 would be reversed with sealing element 13 acting as the piston, and sealing element 12 acting as the follower.

In the event that the tool carrier is sent down to the bottom of the Well to retrieve a tool, instrument, or other object therein, the tool carrier is provided with suitable latching means 27, well known to the art, which may take the -form of the one described in U.S. yPatent 1,700,- 324, issued January 29, 1929, and entitled Letting-In Tool for Oil and Gas Well Appliances. This latching device 27 would normally be fixedly secured to the central mandrel 11 in any suitable manner, as by screw threads. Thus upon circulating the present tool carrier downwardly to the bottom of a tubing string it would latch on to the top of the tool, instrument, or other object therein and, upon reversing the circulation of the fluid in the well would pull the tool or other object upwardly with it when the tool carrier was circulated to the surface.

While the present tool carrier has been illustrated as having a sealing element 12 acting as a leading piston with a follower uninllated sealing element behind it, it is realized that the sealing elements of the tool carrier could be turned end to end as illustrated in FIGURE 2, in which case the sealing element 13a first exposed to upstream pressure would serve as the piston which would push ahead of it the uninfiated seal-ing element 12a on the downward trip tinto the well. On the upward trip the actions would be reversed with the lower packer 12a acting as the piston and pushing ahead of it the upper sealing element 13a. It is essential that one of the fluid ports, say port 25a, of one sealing element 13a be posi-v4 tioned on the downstream side thereof when positioned within the flow stream within a pipe, while port 24a of the other sealing element is positioned upstream. In this case the fluid pressure is considered as being applied upwardly through the tubing 10.

An alternative arrangement of the present tool is shown in FIGURE 3 with parts similar to those of FIGURE l, the main difference being that the tool of FIGURE 3 is not provided with a fishing head 22 or latching means 27, as shown in FIGURE l, In this arrangement the packers 12b and 13b `are mounted on tubular mandrels 11b and 9b, respectively. The ends of the packers or sealing elements 12b and 13b are held firmly in place by the retaining cups 141;, 15b, 16b, and 17b. The space 2311 is in communication with the space outside the packer 12b through port 24h, bore 28b and port 29b. It is evident from the construction of the tool of FIGURE 3 that, in the absence of any means for attaching the present apparatus to a tool or instrument, etc., the present apparatus can only be used to push a tool, instrument, etc., into place.

The arrangement shown in FIGURE 4 of the drawing is merely one-half of the apparatus shown in FIGURE 3 without the swivel joint 2lb of FIGURE 3. This tool may be employed as a one-way pumpable barrier, in the event that it is not desirable to return the apparatus to its starting point. It is essential that all of the packers 12, 12b, and 121,` be firmly secured at their ends by means of retaining cups which prevent the pressure of the fiulid stream from opening the packer up to an extent such that the fiexible packer member 12ol is caused to turn inside out. Thus in many present tools, an unrestrained swab cup arrangement is undependable because the edges of the cups, facing the direction in which the device is to be moved, often catch on the irregularities in the pipe wall, for example in the pipe joints, and furthermore the edges are often folded back over their sides where they are quickly damaged to a point of being inoperable.

Field operations with the present apparatus has established that it is useful in at least two types of tube cleaning operations for removing solids adhering to the interior of a pipe string positioned within an oil well. The present apparatus can be effectively used in removing parafiin from well tubing. In pumping the present apparatus down a paraliin-laden production string, most of the paraffin is pushed ahead of the apparatus into the heated zone near the well bottom where the paraffin is melted and re-entrained in the well production fluid.

On return of the present apparatus to the top of the well, by circulation 1in a manner herein described above, additional portions of the thin film of parain left on the interior wall of the tubing are pushed ahead of the present apparatus, and the warm paraflin entrained in the fluid immediately behind the present apparatus is moved through the tubing in a manner which inhibits or reduces the redeposition of solid paraffin in the cooler regions traversed by the tubing string.

The present apparatus can be similarly effective in removing hydrocarbon plugs which tend to form in tubing strings and owline in which production uids from high gas ratio wells are conveyed through zones in which the temperatures are low relative to that of the produced lluid. The formation of these rather complex hydrocarbon solids is an anticipated problem in underwater wells in which the production tubing string and owline are exposed to ocean floor temperatures in the order of 40 to 50 F.

The present appar-atus is also particularly useful in insuring that a selected portion of a pipestring is contacted by the treating tiuid, such as a corrosion inhibitor or a solvent. In field operations it has been established that the slippage of the driving uu'd past the present type of barriers is extremely small. For example, the metering of the amount of iiuid used in pumping the barrieralong the pipe string provides an accurate prediction of the time of arrival of the tube at Aa stop or a sharp bend which has a known location and produces a known fluctuation in the uid pressure. Since the slippage of fluid past the present apparatus is minor when a volume of treating fluid is introduced into a pipe string ahead of the present type of barrier and both are pumped to the bottom of a pipe string, the treatment of the entire length of pipe string can be definitely established. A barrier -in accordance with the present invention can be left in the tubing string to be circulated out by the production fluid of the well or can be immediately removed by pumping the fluid through the pipe string lin the opposite direction. lf a single barrier in -accordance with FIGURE 4 is to be employed, -it is essential that the length of the barrier or its mandrel 11c be greater than the inside diameter of the pipeline through which itis to be pumped so that the barrier will not tilt within the pipe and lose its seal. In the case of a single barrier as shown in FIGURE 4 it is essential that the shape of the packer 12C and the length of the central mandrel 11c be such that a seal is maintained at all times with the pipe wall.

We claim as our invention:

1. Apparatus adapted to be pumped through a pipe, said apparatus comprising a body element mandrel of a diameter smaller and a length longer than the diameter of the pipe through which it is to be pumped in an unsupported manner, expandable annular sealing means carried co-axially on said mandrel, retaining means fixedly securing opposite ends of the sealing means to said body element mandrel, and fluid passage means through said apparatus in communication between the inside of said seal means and the outside of said apparatus near one end thereof the other end of said body element mandrel being closed at all times.

2. Apparatus adapted to be pumped through a pipe, said apparatus comprising a mandrel element of a diameter smaller than the pipe string through which it is to be pumped in an unsupported manner, yat least a pair of selectively expandable annular sealing means carried 6h said mandrel in axially spaced relationship, and separate iiuid passage means in said apparatus adjacent each of said sealing means in communication between the inside and outside thereof, the opening of said liuid passage means to one sealing means being positioned on the upstream side thereof when positioned in a flow stream within a pipe, while that to the other sealing means is positioned on the downstream side thereof.

3. Apparatus adapted to be pumped through a pipe, said apparatus comprising a mandrel element of a diameter smaller than the pipe string through which it is to be pumped in an unsupported manner, at least a pair of selectively expandable annular sealing means carried on said mandrel in axially spaced relationship, separate fluid passage means insaid apparatus adjacent each of said sealing means in communication between the inside and youtside thereof, the opening to said iluid passage means of one sealing means being positioned on the upstream side thereof when positioned in a ow stream within a pipe, while that to the other sealing means is positioned on the downstream side thereof, and exible joint means in said mandrel element between said pair of sealing means.

4. Apparatus adapted to be pumped through a pipe, said apparatus comprising a mandrel element of a diameter smaller than the pipe string through which it is to be pumped in an unsupported manner, at least a pair of selectively expandable annular sealing means carried on said mandrel in axially spaced relationship, separate fluid passage means in said apparatus adjacent one end of each of said sealing means in communication between the inside and outside thereof, 'the opening to said fluid passage means of one sealing means being positioned on the upstream side thereof when positioned in a 'How stream within a pipe, while that to the other sealing means is positioned on the downstream side thereof, flexible joint means in said mandrel element between said pair of sealing means, and connecting means at one end of said m-andrel element for connecting said mandrel to another object within said pipe.

5. Apparatus adapted to be pumped through a pipe, said apparatus comprising a mandrel element of a diameter smaller than the pipe string through which it is to be pumped in an unsupported manner, at least a pair of selectively expandable annular sealing means carried on said mandrel in axially spaced relationship, separate uid passage means in said apparatus adjacent one end of each of said sealing means in communication between the inside and outside thereof, the opening to said fluid passage means of one sealing means being positioned on the upstream side thereof when positioned in a flow stream within a pipe, while that to the other sealing means is positioned on the downstream side thereof, flexible joint means in said mandrel element between said pair of sealing means, connecting means at one end of said mandrel element for connecting said mandrel to another object within said pipe, and a fishing head secured to the other end of said mandrel element.

6. Apparatus adapted to be pumped through a pipe, said apparatus comprising a mandrel element of a diameter smaller than the pipe string through which it is to be pumped in an unsupported manner, at least a pair of selectively expandable annular sealing means carried on said mandrel in axially spaced relationship, each of said sealing means having a portion thickened in crosssection adapted to contact the inner wall of said pipe string, separate fluid passage means in said apparatus adjacent one end of each to said sealing means in communication between the inside and outside thereof, the opening of said uid passage means of one sealing means being positioned on the upstream side thereof when positioned in a flow stream within a pipe, while that of the other sealing means is positioned on the downstream side thereof, flexible joint means in said mandrel element between said pair of sealing means, connecting means at one end of said mandrel element for connecting said mandrel to another object within said pipe, and a fishing head secured tothe other end of said mandrel element.

References Cited in the ile of this patent UNITED STATES PATENTS 451,841 Platt et al. May 5, 1891 971,042 Hill et al Sept. 27, 1910 2,221,775 Boynton Nov. 19, 1940 2,789,645 Curnutt et al Apr. 23, 1957

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