GB2079822A

GB2079822A - Chemical injection valve

Info

Publication number: GB2079822A
Application number: GB8121817A
Authority: GB
Original assignee: Otis Engineering Corp
Current assignee: Otis Engineering Corp
Priority date: 1980-07-16
Filing date: 1981-07-15
Publication date: 1982-01-27
Also published as: NO812429L; DE3126900A1; CA1158545A; GB2079822B

Abstract

A chemical injection valve, for use with either an outside mount or side pocket mount gas lift mandrel in production tubing has a tubular housing (13, 15) with fluid inlet ports 14 and fluid outlet means (12) with a longitudinal bore (16) connecting the inlet ports (14) and the fluid outlet means (12). A biased valve metering member (18) is positioned in the bore (16) between the fluid inlet port (14) and the fluid outlet means (12) to regulate the flow of fluids therebetween. A fluid by-pass (24) is provided in the housing which is opened and closed by the biased valve metering member (18) in response to the greater of the pressure of fluid entering the fluid inlet port (14) or biassing means 14' acting on said valve metering member (18). When opened, the by-pass (24) provides fluid communication between the fluid inlet ports (14) and the fluid outlet means (12). The biasing means is a spring (14') having a predetermined spring force. Means (19) are provided for adjusting the spring force. <IMAGE>

Description

SPECIFICATION Chemical injection valve The present invention relates to a chemical injection valve for regulating the flow of chemicals or other fluids from the exterior of well tubing to the interior thereof.

It is sometimes necessary to treat wells by injecting into the production tubing certain chemicals, fluids and/or hot oil. Hot oil is used to melt paraffin, that has built up on the walls of the tubing.

In order to introduce these fluids into the production tubing it is common to flow the fluids into the casing-tubing annulus and meter the treating fluid into the tubing through some valve device atrached to the tubing. The point of fluid entry is commonly a mandrel, connected in the tubing string, onto which is attached some fluid regulating device. Typical of the mandrels useful for this purpose is the Type B conventional gas lift mandrel manufactured by Otis Engineering Corporation, illustrated in their Gas Lift Equipment and Services catalogue OEC-5122b, page 28. A currently used chemical injection valve manufactured by Otis Engineering Corporation is their "NCV" valve, having assembly number 221 NCV 1001. This valve is a spring loaded ball valve connectable to the Type B conventional gas lift mandrel.

As a rule, chemical injection valves used currently have a metal to metal abutment type valve and valve seat. Pressure differentials between opening and closing of the valve against the seat usually cause dumping of the fluid being injected. As a consequence, it is difficult to obtain a true metering of injected chemicals. For proper treating of wells, using a chemical injection valve, it is desirable to have a rather constant, metered flow of injection fluid.

It has been a goal of the industry to have a single injection valve that can both meter constant, regulated flow of fluids while being capable of rapidly injecting large quantites of fluid, such as would be required to kill a well.

It is therefore an aim of the present invention to provide a chemical injection valve which will provide a constant, metered flow of fluid.

It is a further aim to provide a chemical injection valve that will permit a large flow of injected fluid therethrough.

Another aim is to provide a chemical injection valve having a constant back pressure operating to resist flow of fluid through the valve.

Yet another aim is to provide a chemical injection valve that does not have a metal to metal valve and seat arrangement.

It is further aim of the present invention to provide a chemical injection valve having a close fit spool and cylinder valve arrangement without seals for metering injection fluids.

According to the present invention there is provided a chemical injection valve comprising: a tubular housing having a fluid inlet means and a fluid outlet means, and a longitudinal bore connecting said inlet and outlet means, valve metering means slidably mounted in said bore to regulate the flow of fluid between said fluid inlet means and said fluid outlet means, fluid by-pass means, providing fluid communication between said fluid inlet means and said fluid outlet means upon movement of said biased valve metering means to a position opening said by-pass means, biasing means, acting on said valve means, for providing a predetermined resistance to fluid entering said fluid inlet means and acting on said valve metering means.

The present invention will now be further described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a quarter sectional view of a preferred embodiment of a chemical injection valve constructed according to the present invention, showing the valve in the closed position.

Figure 2 is a cross-sectional view of the valve of Fig. 1, taken along line 2-2.

Figure 2A is a cross-sectional view of the valve of Fig. 1, taken along line 2-2.

Figure 3 is a partially cut away elevational view of a portion of a well tubing string having a tubing mandrel connected therein with an externally mounted injection valve.

Figure 4 is a partially cut away elevational view of a portion of a well tubing string having a side pocket mandrel connected therein and having one embodiment of the invention received therein; and Figure 5 is a quarter sectional view of one embodiment of the present invention, adapted for placement in a side pocket mandrel.

Referring first to Fig. 1, the embodiment of the chemical injection valve 10 illustrated is designed for installation on the Type B conventional gas lift mandrel, such as manufactured by Otis Engineering Corporation. The Type B mandrel is illustrated in their catalogue OEC-6122B on page 28. The mandrel 42 is made up in the tubing string 44 with the chemical injection valve 10 mounted as shown in Fig. 3.

The chemical injection valve 10 may include any suitable housing. The preferred form of external mounting includes a tubular housing 1 3 and 1 5 having a longitudinal bore 1 6 having at least one open end 1 2. While the tubular housing 13, 1 5 shown in Fig. 1 has two separate threaded members 1 3 and 15, it is possible to have only a single tubular member.

Some means should be provided on the housing 1 3 and 1 5 for securing the chemical injection valve 10 to a mandrel. Preferably, suitable threads 36 other means are provided, on the tubular housing 1 5 for securing the injection valve 10 to the gas lift mandrel 42, as illustrated in Fig. 3. This illustration demonstrates installation of the chemical injection valve 10 in a well.

There is shown a casing 38 set in a typical well, with production tubing 44 run in the well with a Type B conventional gas lift mandrel 42 connected in the tubing string 44. In most chemical treatments and hot oil injection, the treating fluid is added to the tubingcasing annulus 39. The annulus 39 is pressured up by methods well known in the industry. The treating fluids entering the chemical injection valve are metered into the tubing bore 46, as previously described, passing through mandrel ports 48, as shown in the drawings and illustrated in the Otis Engineering Catalogue referred to above.

Fig. 4 illustrates an inside mounted embodiment of the chemical injection valve. The side pocket mandrel 50 illustrated is manufactured and sold by Otis Engineering Corporation. The mandrel 50 is shown and described in their catalogue OEC-5122b, page 34, along with the kickover tool useful for setting the chemical injection valve 52 in the mandrel 50.

Referring again to Fig. 1, there is provided a variable volume plenum chamber 1 7 within a portion of the housing 1 3. The chamber 1 7 is closed at one end by a cap member 11 connected to the housing 1 3. Means are provided for admitting fluids from the exterior of the injection valve to the interior of the variable volume chamber 1 7. This is preferably accomplished by providing a lateral housing port 14 which extends through the tubular housing 1 3 and terminates at the chamber 17.

The injection valve 10 of the invention is capable of very accurately metering small quantities of liquid from the tubing-casing annulus into the tubing string. At the same time, the injection valve is capable of passing enough fluid in a short enough period of time to kill the well. Remarkably, these things can be accomplished by providing a close fit metering member 18 mounted within a valve sleeve 20. The metering member 18 is biased to resist the pressure of fluids entering the variable volume plenum chamber 17, with at least one surface 26 of the metering member forming one wall of the plenum chamber 1 7.

The valve sleeve 20 is preferably provided with at least two tandem orifices 22 and 24.

When the metering member 1 8 is fully seated within the valve sleeve 20, at least one of the orifices 24 is closed to fluid flow. The other orifice 22 provides continuous fluid access from the exterior of the tubular housing 1 3 to the plenum chamber 1 7. As fluid under pressure enters the plenum chamber 17, through the fluid access orifice 22, the fluid pressure acts on metering member surface 26 to overcome the bias resistance. If the pressure is sufficient, the metering member commences to open the metering orifice 24, which permits the fluid entering the plenum chamber to bypass the metering member and traverse the bore 1 6 of the tubular housing, exiting through the open end 1 2 of the injection valve 10.

The metering member 1 8 is preferably provided with suitable diasing means 14', which can be adjusted to provide a known resistance to fluid pressure anticipated to be entering the plenum chamber 17. The biasing means 14' is shown in the drawings to be a suitable spring disposed within the bore of the tubular housing 1 3 and 1 5. The rate of the spring 14' may be adjusted by providing some means 1 9 to compress the spring 14'. Preferably, such adjustment means is disposed in the tubular housing 1 5 and has means in contact with the spring 14' for adjusting the overall height of the spring 14'. In the drawing, a threaded member 19, is in contact with one end of the spring 14', and may be adjusted to compress the spring 14'.

Preferably, one end of the biasing means 14' is in contact with a portion of the metering member 18. As illustrated in Fig. 1, the spring 14' engages beneath cap member 31 which can be engaged by the metering member 18. The cap member 31 of this embodiment is provided with a bore 28 for allowing the fluid traversing the metering orifice 24 to pass through the cap member 31. Figs. 2 and 2A illustrate two possible means 28 for allowing fluids to flow through the cap member 31. A plurality of orifices 28 can be provided or the cap member 21 can be specially shaped, as shown in Fig. 2.

It has been found that, depending upon the range of metering rates desired by the operator, any number of orifices 22 and 24 may be used successfully. However, an important aspect of the invention has been found to be the ability of the metering member 1 8 to uncover just fractions of the metering orifice without experiencing unwanted oscillation of the metering member 18. This can be done by applying pressure to the tubing-casing annulus. The spring bias 14' prevents the treating fluid from flowing into the well solely as a consequence of its greater density in comparison to the well fluids. Thus, the rate of flow through the injection valve is controlled essentially only by changes in pressure applied to the tubing-casing annulus.

It is further noted that no special seals are used to seal between the metering member 1 8 and the wall of the sleeve member 20.

Rather, it has been found that the snug fit of these two members provides sufficient sealing action to properly meter fluids entering the plenum chamber 17.

In the embodiment illustrated in Fig. 1 the cap member 31 has axial edge 30, which interacts with an inwardly projecting shoulder 32 on the tubular housing 15, to provide a limit on downward travel of the biased metering valve member 1 8. It is to be understood that various other means may be used in combination for this purpose. A stop shoulder could as easily be provided to interact with a shoulder or other limiting means on the sleeve member 20, thus allowing the tubular housing to be a single, uniform tube. Such a configuration would greatly simplify machining requirements in assembly of the chemical injection valve 10.

In the embodiment shown in Fig. 4, treating fluid must enter the mandrel 50 through suitable ports, to have access to the injection valve 52. The treating fluid which enters the mandrel 50 is confined between housing seal means 62 and 64, which provide a seal against the walls of the side pocket within the mandrel 50. Thus, fluid is forced into a housing fluid entry port 56 of the valve is metered by the injection valve 52, as hereinafter described, and passes through pocket exit ports 60 into the bore 58 of the mandrel 50 and tubing 44.

As seen in Fig. 5, the internal assembly of this-embodiment of the invention is essentially identical with the outside mounted injection valve 10 shown in Fig. 1. The inside mounted injection valve 70 has a tubular housing 72, 73, having a longitudinal bore 74. There is provided a lower housing member 79 having treating fluid exit means 78. For practical purposes, the exit means 78 can be ports as illustrated in Fig. 5, or other suitable openings as may be suitable for specific side pocket mandrels used in the industry.

A port 76 is provided through the tubular housing 72, providing access for treating fluids to a plenum chamber 77 in the upper portion of housing bore 74. The upper end of the tubular housing 70 is closed off by a suitable cap 80 or other closure means. The cap 80 is provided with suitable means 81, such as a threaded boss, for attachment to a kickover tool for setting and retrieving the injection valve 70.

External sealing means 82 and 84 are provided on the housing for sealing the injection valve 70 in the side pocket of the mandrel, as shown in Fig. 4. The sealing means 82 and 84 are positioned above and below the treating fluid entry port 76 so that treating fluid entering the side pocket is directed into the injection valve through the entry port 76.

A tubular sleeve 86 is positioned within the upper portion of the bore 74 of the tubular housing 72. Snugly received in a portion of the sleeve member 86 is a slidably movable biased metering member 90.

The sleeve member 86 has one or more lateral fluid entry ports 88 to provide treating fluid entering entry port 76 access to the plenum chamber 77. There is additionally provided one or more fluid by-pass metering ports 94 in the sleeve member 86, set beneath the sleeve fluid entry ports 88.

Movement of the biased valve member 90 in a downward direction opens the metering port 94, allowing treating fluid in the plenum chamber 77 to pass into the tubular housing bore 74 and thence through the fluid exit means 78.

It is preferred that suitable sealing means 93 be positioned between the sleeve member 86 and the housing bore wall to confine treating fluid within the plenum chamber 77 until the downward travel of. the metering member 90 permits fluid exit through the metering port 94.

It should be recognized by those skilled in the art that other means can be provided for receiving the metering member 90 and for providing a by-pass, such as the metering port 94. The tubular housing 72 could be machined to receive the valve member 90 and passageways drilled in the tubular housing 72 to provide a fluid by-pass. The assembly shown is, therefore, but one possible embodiment of the invention for, both the outside and inside mounted injection valves.

The valve member 90 is biased by a suitable resilient urging means, shown in Fig. 5 to be a spring 92 having a preselected spring force. Springs of varying force can be used, in all embodiments of the invention, depending on the pressure requirements of each particular well installation in which the injection valves will be used. Preferably, the spring can be shortened by suitable adjustment means.

While the spring 92 provides suitable preselected biasing of the metering member 90, working against pressure of fluid in the plenum chamber 77, it is preferred to have some means to limit downward travel of the metering member 90. Therefore, in the embodiment shown, a lower stop member 98 is provided on the metering member 90 which when forced downward contacts a stop shoulder 99 extending from the tubular housing member 73 into the bore 74. The metering member 90 has a piston surface 91 in communication with the upper chamber 77, against which the fluid pressure in chamber 77 acts to move the biased valve member 90 in a downward direction.

It is seen that the valve member 90 has suitable fluid passageways 96 for treating fluid, exiting the metering ports 94, to pass through the lower portion of the valve member 90 into the housing bore 74. Suitable configurations of the lower portion of the metering member 90 are shown in Figs. 2 and 2A.

It will be understood by those skilled in the art that modifications to parts of the invention can be made without departing from the full scope of the invention, which is claimed hereinafter. It has been found that the present invention provides constant back pressure due to the spring force resisting fluid pressure pushing down on the valve member. This has been found to provide a more uniform metering of treating fluids into the well. In addition, the injection valve provides a flow capacity for large fast flows of hot oil and kill fluids without serious injury to the valve member.

Claims

1. A chemical injection valve comprising: a tubular housing having a fluid inlet means and a fluid outlet means, and a longitudinal bore connecting said inlet and outlet means, valve metering means slidably mounted in said bore to regulate the flow of fluid between said fluid inlet means and said fluid outlet means, fluid by-pass means, providing fluid communication between said fluid inlet means and said fluid outlet means upon movement of said biased valve metering means to a position opening said by-pass means, biasing means, acting on said valve means, for providing a predetermined resistance to fluid entering said fluid inlet means and acting on said valve metering means.

2. A chemical injection valve as claimed in claim 1, including means for limiting the movement of said biased valve metering means away from said fluid inlet means.

3. A chemical injection valve as claimed in claim 1, in which said biasing means is a spring having a predetermined spring force and including means for adjusting said spring force.

4. A chemical injection valve comprising: a tubular housing having a fluid inlet means and a fluid outlet means, and a longitudinal bore connecting said inlet and and outlet means, a tubular sleeve positioned in at least a portion of said bore, and having fluid inlet means in fluid communication with said housing fluid inlet means, and a fluid by-pass means, a biased valve metering member, at least a portion of which is slidably received within said tubular sleeve, biasing means, acting on said valve metering member, for providing a predetermined resistance to fluid entering said fluid inlet means and acting on said valve metering member, said valve metering member being movable to open or close said fluid by-pass means in response to the greater of the pressure of fluid entering said fluid inlet means or said biasing means, respectively.

5. A chemical injection valve as claimed in claim 5, including means for limiting the movement of said biased valve metering member.

6. A chemical injection valve as claimed in claim 4, including means for limiting the distance of movement of said biased valve metering member in a direction away from said fluid entry means.

7. A chemical injection valve as claimed in claim 4, in which said biasing means is a spring having a predetermined spring force.

8. A chemical injection valve as claimed in claim 4, in which said fluid by-pass means is positioned below said sleeve fluid inlet means and which, when opened by said valve metering member, provides fluid communication between said fluid inlet means and said fluid outlet means.

9. A chemical injection valve as claimed in claim 4, in which said housing fluid inlet means are one or more ports extending laterally through said tubular housing above said valve member.

10. A chemical injection valve comprising: a tubular housing having a fluid inlet means and a fluid outlet means, and a longitudinal bore connecting said inlet and outlet means, a tubular sleeve positioned in the upper portion of said bore, said sleeve having fluid inlet means in fluid communication with said housing fluid inlet means, a biased valve member, for regulating the flow of fluid from said fluid inlet means to said fluid outlet means, at least a portion of said valve member being slidably received within said tubular sleeve, a variable capacity chamber in said tubular housing for receiving fluid entering said fluid inlet means, fluid by-pass means, in said tubular sleeve, regulated by said biased valve member, which when opened, provides fluid communication between said variable capacity chamber and said fluid outlet means, biasing means, acting on said valve member, for providing a predetermined resistance to fluid pressure in said variable capacity chamber, said valve member being snug fit in said tubular sleeve and movable to open or close said fluid by-pass means in response to the greater of the pressure of fluid in said variable capacity chamber or said biasing means, respectively.

11. A chemical injection valve as claimed in claim 10, including means for limiting the distance of movement of said biased valve member.

1 2. A chemical injection valve as claimed in claim 10, in which said biasing means is a spring having a predetermined spring force.

1 3. A chemical injection valve as claimed in claim 12, in which said spring is positioned in said bore, beneath and acting on said valve member.

14. A chemical injection valve as claimed in any one of claims 1,4 or 10, when adapted for connection to the outside of a gas lift mandrel.

1 5. A chemical injection valve as claimed in any one of claims 1,4 or 10, when adapted to be sealingly received within the side pocket" of a side pocket mandrel.

1 6. A chemical injection valve constructed substantially as hereinbefore described with reference to and as illustrated in Figs. 1,2,2a and 3, or Figs. 4 and 5 of the accompanying drawings.