US2852080A - Chemical injector for well tubing - Google Patents

Description

Sept. 16, 1958 E. E. RoAcH CHEMICAL INJECTOR FOR WELL TUBING 2 Sheets-Sheet 1 Filed Aug. 29, 1956 IN VENTOR.

Sept. 16, 1958 E. E. RoAcH CHEMICAL INJECTOR FOR WELL TUBING 2 Sheets-Sheet 2 Filed Aug. 29, 1956 INVENTOR.

@iA/g- 4L/'MWD' United States Patent O CHEMICAL nuncron ron WELL TUBING Erskine E. Roach, Houston, Tex., assignor to Harold Brown Company, a corporation of Texas Application August 29, 1956, Serial No. 606,923

Claims. (Cl. 166-166) This invention relates to chemical injector or dispens- Iing apparatus and more particularly to mechanism for applying chemical agents, such as corrosion inhibitors or the like to the interior of well tubing or casing.

In the yoperation of wells and particularly in the operation of oil and gas wells it is often desirable to introduce chemicals such as corrosion inhibiting agents into the well tubing or casing to inhibit the corrosive effect of well tluids on the metal of such tubing or casing. Heretofore, it has been customary to introduce such chemical agents by adding them to the circulating lluid or in the form of sticks dropped into the tubing and allowed to fall to the bottom where disintegration may take place due to the increased temperature and the action of the well uids.

Corrosion inhibiting agents in stick form are very effective provided they are brought into contact with the metal to be protected. Such agents now in common use are of the organic polar type of material for which steel has a great ainity so that when these materials are brought into contact with the well tubing or casing in solution or in an emulsion containing them, the chemical plates out or cc-ats the steel to eifectively protect the metal against exposure to corrosive elements. The chemical lrn thus formed is extremely thin and is slowly eroded away, particularly in areas in the tubing or casing wherein the most turbulent ow conditions prevail. The areas in the vicinity of tubing collars are points at which early corrosion is particularly likely to occur because of the turbulence in such areas.

It has been found, however, that in wells wherein packers or similar equipment are :being used, the well tubing or casing cannot be chemically treated satisfactorily by circulating the corrosion inhibitor through the casing annulus and back through the tubing. Moreover, the use of chemical agents of this kind in stick form has also proven unsatisfactory -for the reason that they are more expensive than liquid inhibitors and also that they have a tendency to become stuck at some point in the well equipment, and do not provide a positive means of properly distributing the inhibitor throughout the zone to be treated.

The present invention has for an import-ant object the provision of a chemical injector which is adapted to be inserted in a well pipe for vertical movement therein and by which a chemical agent may be applied to the interior of the pipe.

Another object of the invention is to provide a chemical injector which is constructed to hold a supply `of a chemical agent and having means which is operable during vertical movement of the injector in a well pipe for distributing the agent upon the interior of the pipe.

A further object of the invention is the provision of a device adapted to be suspended in a well pipe -for vertical movement therein for dispensing a chemical agent, such as a corrosion inhibitor, in the pipe and including means for injecting a charge of the agent into each collar 2,852,080 Patented sept. 1s, 195s or pipe connecting element as the device moves through the same.

Another object of the invention is to provide a chemical injector for use in well pipes including a reservoir for a chemical agent and means for pumping the same into the interior of a well pipe and embodying means positioned to engage the interior ofthe pipe :and which is operable upon movement of the injector through a joint in the pipe to inject a charge of chemical onto the interior ofthe pipe at the joint.

The above and other important objects and advantages of the invention may best be understood from the yfollowing detailed description, constituting a speciiication of the same, when considered in conjunction with the annexed drawings, wherein- Figure 1 is a fragmentary, side elevational view, illustrating a preferred embodiment of the invention and showing the injector in position in a well tubing and connected to well plunger equipment for operation therewith;

Figure 2 is a vertical, central, cross-sectional view of the invention, on a somewhat enlarged scale, showing details of construction of the same, the injector being shown in a well tubing at a point just above a joint in the tubing in condition to dispense a charge` of chemical into the joint when the injector reaches the same;

Figure 3 is a view similar to that of Figure 2, illustrating the manner inwhich the injector operates to dispense a charge of chemical, the parts being shown in the positions which they occupy when the injector reachesa joint in the well tubing;

Figure 4 is a cross-sectional view, taken along the line 4 4 of Figure 3, looking in the direction indicated by the arrows; and

Figure 5 is a fragmentary, cross-sectional view, taken along the line 5 5 of Figure 3, looking in the direction indicated by the arrows.

Referring now to the drawingsv in greater detail, the invention is disclosed herein in connection with its use with well equipment of the type which is adapted to be introduced into a well tubing or casing, such as the tubing 10, which equipment may take the form of a well plunger 12 of conventional design, adapted to reciprocate in the well under the inuence of well pressure.

The tubing 10 may be of usual construction, made up of tubular sections, threadably connected together by connecting elements or collars 14, the adjacent ends of the sections being somewhat spaced apart within the joints, so that internal annular recesses 16 are formed within the connecting elements.

In well equipment of this kind the well plunger 12 moves` downwardly in the tubing 10 under the inuence of gravity, and is moved upwardly in the'tubing by well pressure to assist in the upwardilow of oil or other lluid in the well in a well known manner, such equipment forming no part of the present invention.

The injector of the invention comprises a tubular body 18 formed with an internal partition 20 intermediate its; ends', having a central opening 22 therethrough. At its upper end the body 18 is internally threaded for the connection thereto of an upper end closure 24, having a central upwardly extending, externally threaded projection 26, for connection to the lower end of the well plunger 12, as by means of a nut 28. A iilling opening 30 is provided in the closure 24, which may be closed by a screw plug 32, and the closure has an opening 34 therethrough, through which well pressure may enter the interior of the body.

The lower end of the body is also internally threaded to receive a lower end plug 36.-

An upper chamber 38 is formed in the body between the partition and the upper closure 24, within which a floating piston 40 is movably positioned, which piston has an external annular groove 42 within which a seal forming element, 4such Ias an O-ring 44 is carried to form a seal between the piston and the interior of the upper chamber.

'A second piston 46 is movably positioned in the chamber 38 beneath the oating piston 40, and is likewise provided with an external annular groove 48 within which a sealing element such as `an O-ring 50 is disposed to form a seal between the lower piston and the interior of the chamber. This lower piston has a hollow piston rod or stem 52 threadably connected thereto at its upper end, the piston having a central opening 54 therethrough which is in communication with the chamber 38 above the lower piston and with the interior of the hollow stem. The piston 46 also has an internal, annular, downwardly facing valve seat 56, surrounding the opening 54, and a valve element 58 is movably positioned in the stem 52 and is urged upwardly into closing contact with the valve seat 56 by a coil spring 59, whose upper end bears against the valve element 58, and whose lower end is seated upon an internal perforated partition 60 located intermediate the ends of the stem. The partition 60 is formed with a downwardly facing valve seat 62, surrounding the perforation 64 therethrough, and a second or lower valve element 66 is movably positioned in the stem beneath the partition 60 and is' urged upwardly into closing contact with the seat 62 by a coil spring 68, whose upper end bears against the valve element 66 and whose lower end is seated on the lower end wall 70 of the stem. One or more openings 72 are provided in the lower end wall of the stem 52, which are in communication with the interior of the stem and with the exterior thereof.

The stem 52 is slidably extended'through the opening 22 of the internal partition 20, which partition is provided with an internal annular groove 74 within which a sealing element, such as an O-ring 76 is positioned to form a seal between the exterior of the stem 52 and the partition. One or more side openings, such as that shown at 78, are provided in the stem 52, within the upper chamber 38, beneath the piston 46, through which uid in the chamber 38, beneath the piston 46 may enter the hollow stem S2.

At its lower end the stem 52 is provided with spaced apart, downwardly extending lugs 80, between which the upper ends of links 82 are pivotally connected to the stem, as by means of a pin 84, carried bythe lugs, which links are pivotally connected at their lower ends to the upper ends of links 86, which in turn are pivotally connected at their lower ends to 'an adjusting screw 88, as by means of a pin 90 extending between upwardly extending lugs 92 on the upper end of the screw. The screw 88 extends through the lower end of plug 36 through an opening 94 therein, and carries locking nuts 96 and 98 thereon, the nut 96 being rotatably mounted on the plug 36. Suitable means, such as rollers 100 are rotatably carried between the lower ends of the upper links 82 and the upper ends of the lower links 86, on the pivot pins 102 connecting these links, and a coil spring 104 is connected at its opposite ends to the pins 84 and 90, to exert a pull on the lower ends of the upper links whereby the rollers 100 are urged outwardly away from each other. The lower portion of the body 18 has window openings 106, through which the rollers 100 may extend into engagement with the surrounding well tubing 10.

In making use of the injector, constructed as described above, the chamber 38, between the pistons 40 and 46 is lled with the chemical agent to be applied to the interior of the well pipe, and the injector is inserted in the well tubing or casing attached to the well plunger, as seen in Figure l, the rollers 100 being in contact with the interior of the tubing or casing. In inserting the injector into the tubing or casing the rollers 100 will be moved inwardly toward each other to cause the links 82 and 86 4 to exert an upward thrust on the stem 52, to move the lower piston 46 upwardly in the chamber 38. Upon such upward movement of the piston 46, pressure will be exerted on the chemical agent in the chamber 38 above the piston 46, so that the valve 58 will be opened against the pressure of the spring 59 to permit some of the chemical agent to flow downwardly through the opening 54 into the stem 52 and outwardly through the openings 78 to lill the portion of the chamber 38 beneath the piston 46.

As the well plunger and injector move downwardly in the tubing or casing, when the rollers reach a joint, the rollers will enter the annular recess' 16 formed within the connector element 14, between the adjacent ends of the pipe sections, the rollers moving outwardly away from each other under the tension of the spring 104, to cause the stem 52 land piston 46 to move downwardly, to exert pressure on the chemical agent in the chamber 3S beneath the piston 46, whereby the valve 66 will be opened against the pressure of the spring 68, to eject a charge of the chemical agent out through the stem 52 into the portion of body 10 beneath partition 20 and thence through window openings 106 into contact with the interior of the joint.

As the injector moves past the joint the rollers 100 will again be moved inwardly toward each other by contact with the interior of the next section of pipe, to again move the piston 46 upwardly, so that a new charge of chemical agent is pumped into the chamber 38 below the piston 46, and when the injector reaches the next joint, the rollers 100 will again move outwardly into the recess 16 to eject another charge of chemical agent into the next joint.

Due to the opening 34 in the upper end closure 24, well pressure may enter the chamber 38 above the upper piston 40, to equalize the pressure inside and outside of the injector.

By adjusting the screw 88 by means of the nuts 96 and 98, the ,extent to which the rollers 100 will be moved outwardly may be adjusted for any desired size of well tubing or casing and such adjustment may also be used to regulate the quantity of chemical injected into each joint.

The injector may, of course, be attached to any suitable type of equipment, such as a wire line, whereby the injector may be moved upwardly and downwardly through a well tubing `or casing to repeatedly apply the chemical agent to the interior of the same.

It will thus be seen that the invention provi-des a chemical injector for well tubing and the like, Iby which axis and vice-versa. Thus, it will be seen that as the lazy- 4 tong structure is radially expanded and retracted along its transverse axis (the axis passing through pivots 102 102) as the rollers 100 move in and out of recesses 16, the structure will alternately be elongated and shortened along the longitudinal axis and stem 52 will be longitudinally reciprocated proportionally in response to the radial movements of the lever arms, and thereby pumping of chemical will be eiected. Coil spring 104 serves to resiliently bias the lever arms to their pipe-wall engaging position and to maintain a downward pull on stem 52 to thereby urge the latter toward the discharge position.

It will be evident that other types of pump actuating elements responsive to variations in the internal diameter of the pipe may be employed.

Openings 72 in stem 52 will preferably be oriented and shaped to direct the uicl discharging therefrom in the form of jets toward the openings 106 provided in the wall of body 10, so that the uid will be discharged in the vicinity of the thread portions lying within recesses 16. It will be understood that, if desired, openings 72 may be connected to nozzles or the like (not shown) by which the points of discharge of the chemical fluid may be positioned more closely to openings 106, so that the fluid will be discharged more directly on the threaded couplings through openings 106.

The invention has been disclosed herein in connection with a certain specific embodiment of the same, but it will be understood that this is intended by way of illustration only, and that various changes can be made in the construction and arrangement of the parts without departing from the spirit of the invention or the scope of the appended claims.

Having thus clearly shown and described the invention, what is claimed as new and desired to secure by Letters Patent is:

l. In a device for applying a chemical agent t-o the interior of a well pipe, a tubular body adapted to be inserted in a well pipe for vertical movement therein, chamber means in the body adaptedto contain fluid, a sea-led piston slidable longitudinally in the chamber and having a passageway therethrough from one side to the other side of the piston, means for closing the passageway against upward flow of uid therethrough upon downward movement of the piston and for opening the passageway to permit downward iluid therethrough upon upward movement of the piston, means forming an outlet from the portion of the chamber beneath said piston openings in the body beneath said chamber communicating between the interior and the exterior of the body and means operably connected to the piston and retractably engageable with the wall of the well pipe for causing upward and downward movement of the piston in response to variations in the internal diameter of the well pipe during vertical movement of the body in the Well plpe.

2. In a device for applying a chemical agent to the interior of a well pipe, a tubular body adapted to be inserted in a well pipe for vertical movement therein, chamber means in the body adapted to contain iluid, a sealed piston sli-dable longitudinally in the chamber and having a passageway therethrough 'from one side to the other side of the piston, means for closing the passageway against upward ow of fluid therethrough upon downward movement of the piston and for opening the passageway to permit downward flow of fluid therethrough upon upward movement of the piston, means forming an outlet from the portion of the chamber beneath the piston, openings in the body beneath the chamber cornmunicating between the interior and the exterior of the body, means operably connected to the piston and retractably engageable with the wall of the well pipe for causing upward and downward movement of the piston in response to variations in the internal diameter of the well pipe during vertical movement of the ybody in the well pipe and valve means mounted on the piston and operable for closing said outlet in response to upward movement of the piston and for opening said outlet in response to downward movement of the piston.

3. Ina device for applying a chemical agent to the interior of a well pipe, a tubular body adapted to be inserted in a well pipe for vertical movement therein, chamber means in the body adapted to contain iluid, means for admitting pressure from the exterior of the body into the upper end of said chamber, a sealed piston slidable longitudinally in the chamber and having a passageway therethrough from one side to the other side of the piston, means for closing the passageway against upward flow of fluid therethrough upon downward movement of the piston and for opening the passageway to downward flow of uid therethrough upon upward movement fof the piston, means forming an outlet from the portion of the chamber beneath the piston, openings in the -body beneath the chamber communicating between the interior and the exterior of the body, means operably connected to the piston and retractably engageable with the wall of the well pipe for causing upward and downward movement of the piston in response to variations in the internal diameter of the well pipe during vertical movement of the body in the well pipe and Valve means mounted on the piston and operable for closing said outlet against the inow of pressure from the exterior of the body into said Ichamber upon upward movement of the piston and for opening said outlet upon downward movement of the piston.

4. In a device for applying a chemical agent to the interior of a well pipe, a tubular body adapted to be inserted in a well pipe for vertical movement therein, said body having a transverse partition provided with a central opening and dening the lower end of a chamber in the body adapted to contain uid, a sealed piston slidable longitudinally in the chamber and having a passageway therethrough from one side to the other side of the piston, means for closing the passageway against upward ow of uid therethrough upon downward movement of the .piston and for opening the passageway to downward ow of fluid therethrough upon upward movement yot the piston, a hollow stern connected at its upper end to the piston for movement therewith and slidably extended through said opening, means forming a seal between the exterior of said stem and said wall in said opening, the bore of said stem being in communication with the portion of the interior of the chamber beneath the piston, openings in the body beneath said chamber communicating between the interior and the exterior of the body, means operably connected to the stem and retractably engageable with the wall of the well pipe for causing upward and downward movement of the piston in response to variations in the internal diameter of the well pipe during vertical movement of the body in the well pipe and valve means in the bore of the stem for closing the stem against the flow of fluid therethrough from the exterior of the body Vinto said chamber and for opening the stem to permit the ow of uid therethrough from the chamber to the exterior of the body in response toreciprocation of the piston.

5. In a device for applying a chemical agent to the interior of a well pipe, a tubular body adapted to be inserted in a well pipe for Vertical movement therein, chamber means in the body adapted to contain iluid, a sealed piston slidable longitudinally in the chamber and having a passageway therethrough fnom one side to the other side of the Ipiston, means for closing the passageway against upward flow of fluid therethrough upon downward movement yof the piston and for opening the passageway to downward flow of fluid therethrough upon upward movement of the piston, means forming an outlet from the portion of the chamber beneath the piston, openings in the body beneath the chamber communicating between the interior and the exterior of the body, means resiliently connecting the piston to the body for yieldingly urging the piston downwardly in the chamber and arm means connected to the piston and slidably engageable with the interior of said well pipe to limit such downward movement of the piston.

6. In a device for applying a chemical agent to the interior of a well pipe having diiTerent internal diameters at different locations throughout its length, a tubular body adapted to be inserted in the Well pipe for vertical movement, therein, chamber means in the body adapted to contain uid, a sealed piston slidable longitudinally in the chamber and having a passageway therethrough from yone side to the other side of the piston, means for closing the passageway against upward flow of fluid therethrough upon downward movement of the piston and for opening the passageway to permit downward flow of uid therethrough upon upward movement of the piston, means forming an outlet from the portion of the chamber beneath the piston, .openings in the body beneath the chamber communicating between the interior and the exterior of the body resilient means connecting the piston to the body for yieldingly urging the piston downwardly, a movable element mounted on the body for radial movement inwardly and outwardly of the body and positioned for engagement with the interior of said pipe and means forming a connection between said element and the piston to cause the piston to move upwardly in response to inward movement of said element.

7. A chemical injector for well pipes, comprising a casing adapted to be inserted in a well pipe for vertical movement therein, said casing having a chamber therein adapted to contain uid, and pump means carried by the casing communicating with said chamber, said pump means including pump-actuating means engageable with the interior Wall of the Well pipe and operable in response to variations in the internal diameter of said pipe to pump iluid from said chamber into the well pipe.

8. A chemical injector for well pipes, comprising, a casing adapted to be inserted in a well pipe for vertical -movement therein, said casing having a chamber therein adapted to contain fluid, reciprocating pump means mounted in the casing and connected for pumping fluid from said chamber into said well pipe, said pump means including actuating means engageable with the interior wall of the well pipe during movement of the casing therethrough and operable by variations in the internal diameter of said pipe to reciprocate the pump means.

9. A chemical injector according to claim 8, wherein said actuating means comprises generally radially extending lever means pivotally connected to the pump means and resiliently biased toward the pipe wall-engaging position.

l0. A chemical injector for well pipes, comprising, a casing adapted to be inserted in a'well pipe for vertical movement therein, said casing having a chamber therein adapted to contain uid, and pressure pump means carried by the casing and communicating with said chamber, said pump means including pump-actuating elements engageable with the interior wall 'of the well pipe and operable in response to variations in the internal diameter of the pipe as the casing moves longitudinally in the pipe to actuate said pump means to discharge fluid from said chamber into the well pipe under pressure applied to the iuid by said pump means.

References Cited in the tile of this patent UNITED STATES PATENTS 2,ll7,898 McDowell May 17, 1938 2,698,057 Kelly Dec. 28, 1954

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