US1744361A

US1744361A - Gas-lift starting valve

Info

Publication number: US1744361A
Application number: US208888A
Authority: US
Inventors: Charles C Carlisle
Original assignee: Individual
Current assignee: Individual
Priority date: 1927-07-27
Filing date: 1927-07-27
Publication date: 1930-01-21
Anticipated expiration: 1947-01-21

Description

Jan. 21, 1930. c. c. CARLISLE 'GAS LIFT STARTING VALVE Filed July 2'7, 1927 INVENTOR flssocic/e ATTORNEYS.

Patented Jan. 21, 1930 CHARLES o. CARLISLE, or CHEYENNE, wYoMmo GAS-LIFT STARTING VALVE Application filed July 27,

The invention relates to improvements in gas or air lift flow devices. by inserting at proper intervals one or more gas lift starting valvesas hereinafter described, in the eduction or in the induction pipe of the gas lift flow device, forthe purpose of admitting gas by successive stages into the column of liquid or fluid to be well.

0 The special object sought and attained by this invention is the production of eflicient apparatus capable of being placed and operated within wells of customary size and such as are already inexistence.- This is rendered possible primarily through the special construction of valves and controlling floats herein set forth, whereby they may be of small dimensions yet effective to function under varying pressures. Other objects are:

First, to provide a means whereby the gas 'lift may be started to operate by a ess pressure of gas than that usually required to start the gas'lift flow.

Second, to enable the'gas lift toresume operation in case the flow should be checked or retarded long enough to cause it otherwise to cease.

Third, to enable the gas lift flow to be started when the rock pressure is not sufficient to permit a gas ressure to be built up in the well to start a ow of liquid through the eduction pipe.

Fourth, in wells producing gas under low pressure, to provide means for starting flow under the low pressure and to flow oil or/and other fluid from such well, which flow .may be intermittent or continuous, depending upon the volume of gas entering the well/ Fifth, to permit the use of lower pressure more expensive ones which would be. required to withstand the high pressure necessary to be applied to start the flow, from gas raised or flowed fromia' appreciably adding weight to the column.

fittings, pipes, valves, etc., instead of the 1927. Serial No. 208,888.

dui'ts from the top of the well to the bottom of the tubing. The annular space around the tubing forms one conduit, and the inside of the tubing the other.

Gas is forced downward in a continuous stream in one conduit, passing thence into the other conduit at the bottom of the suspended tubing, or through ports in the tubng, where it mixes with the liquid to be raised. This liquid or fluid mixture flows upward and is discharged'from-the top of the well. When once started, the induced compressed gas, being delivered. usually in a continuous stream, breaks into bubbles upon entering the liquid column inrthe eduction pipe. These bubbles, in floating upward,'expand, since the pressure is reduced as the depth of immersion is decreased, until they are expelled from the top of the liquid or fluid column, or with the liquid thus gasified as it flows from the discharge pipe at the top of the well. The induced gas, added to the liquidto be flowed, increases the height of its column in the eduction pipe without As gas is added, the column is thereby lengtheneduntil its top extends above the outlet of the eduction pipe, and thus starts a flow as -from a well. Immediately after flow begins,

the pressure at the base of the liquid column beings to decease, due to its lessened weight, and more liquid, if the well will supplyvit',

continually enters at the bottom of the eduction pipe to be expelled in a continuous stream from the discharge pipe at the top as an emulsified fluid, a mixture of gas and fluid, or as an atomized spray. Since the induced compressed gas supply is continuous, if its pressure and volume be controlled, the stream 'offluid, com osed of gas and liquid, continues to flow rom the top of the eduction pipe. 1 While more liquid takes the place of that discharged, the gas pressure, when the flow is once started, may be gradually decreased (in some cases to onetenth or less of that required to start the flow), and yet maintain the flow at the reduced pressure.

Gas may be forced downward through the tubing or through the annular spaco sur- 10o rounding it. Usually, means are provided for admitting gas into either conduit at will, and suitable openings are provided in the top of both conduits from which the liquid or fluid may be flowed from the well.

The tubing through which gas is forced downward in the well is designated the induction pipe, and the one through which the liquid or fluid is flowed from the well is called the eduction pipe. If gas is forced downward through either pipe, as an induction pipe, liquid or fluid Wlll flow out through the other one, as the eduction pipe, and the operating principle will be the same.

Assuming that the annular space surrounding the tubing in the well is used for the induction pipe, which is the customary manner of operating the gas lift, thenthe rock pressure, which forces the liquid from the surrounding earth or sands into the well, must be reater than the starting pressure required or the gas lift, otherwise the compressed gas will be forced back into the liquid-producing sands, and the flow cannot be easily started through the eduction pipe by customary starting methods.

In order to start the gas lift to operating by the usual methods, gas is forced downward into the induction pipe, depressing the liquid or fluid level therein so that it falls to or below the ports or openings through which the as is to pass into the eduction pipe, but i there are no ports or openings into the eduction pipe, which ports are usually omitted in flowing oil wells by the gas 11ft, then the gas passes downward and enters into the fluid column at the base of the suspended tubing. Some of the liquid is forced backward into the producing sands, and the rest of thedisplaced liquid is forced upward in the eduction pipe, often filling it,

. and 'forcingsome fluid outv at the discharge umn in the eduction pipe.

pipe before gas begins to enter the fluid col- In that case the unit pressure of the gas must be equal to or greater than that exerted by the liquid column at the point where the gas enters it. In an oil well producing paraflin'e, to place a gas pressure greater than rock pressure into the well might force accumulated paratline back into the producing sands and damage or ruin the well.

Where maximum roduction is the controlling factor instead 0 efficiency of power used, as 1n the flowin of oil .wells, the gas ports or openings into t e eduction pipe are usually placed close to the bottom of the tubing and the bottpm of the well. In dee firessrng gas to high enough pressure to start a ow in a gas lift flow device. In order'to overcome the'high pressure diificulties encountered in starting a flow in a gas lift flow device, I have invented a gas lift starting valve, by the use of which a flow may be started in a gas lift at a pressure but little above that required to maintain flow when once started. A preferred form of my invention is illustrated in the accompanying drawings, in which:

Figure 1 is a vertical sectional view of a well provided with a casing, and containing a plurality of valves and attendant parts embodying my invention;

Fig. 2, a vertical sectional view of one of the valves and connected parts and of the housing containing the same, on the line BB of Figs. 3 and 4;

, Fig. 8, an elevation of a portion of the inner pipe or tubing of the well with the upper portion of a valve housing attached thereto; and

Fig. 4, a horizontal sectional view on the lines A-A of Figs. 2 and 3.

Referring first to Fig. 1:2 designates an education pipe and 1 the well casing (partly in section) encompassing said pipe and fitted with a casing head or cap 3, provided with an opening through which extends the tubingor eduction pipe 2, tightly fitted and sealed with packing (not shown) so as to form a gas tight joint between the suspended tubing and the supporting casing head. The casing head or cap 3 is provided with an opening into which is connected an induction pipe 4. In the event that the Well is drilled through firm material which will stand without casing, the casing head 3 is tightly secured to a short length of easing lightly fitted and advisably resting on a solid rock shoulder above the uneased portion of the well and cemented into place to seal the same.

The suspended tubing 2 is preferably left open at its lower end and is advisably-provided with holes or openings 5, just a few feet above its lower extremity.

At suitable points in its length, depending upon the depth of the well, the level to which the oil naturally rises and the pressure of the gas to be admitted into the induction pipe in any given case, the pipe 2 is provided With valve housings designated in Fig. 1 by the

numerals

6 and 6. These housings are preferably of cylindrical form and contain each a double valve of the poppet type, the construction of the housings and of the valves being illustrated in Fig. 2. Each

housing

6 and 6 is formed of two abutting sections connected by a hollow nipple or shell 15 having conical or beveled seats upon which seat valve plugs or disks l6 and 17 of corresponding form, carried by a common stem 18 which is extended above and below the valve disks, as shown. The upper end of stem 18 passes through a guide opening in a guide or bracket 20, one portion of which fits and fills the cylindrical housing so as to maintain its guide opening in position, or coincident with the ing 6, thereby separating the u per or valve space from the lower space or oat chamber. The

valve housings

6 and 6 are of sufliciently small diameter to clear the casing 1 when the tubing 2 is lowered into the Well with the valve housings attached thereto. Within'the float chamber is mounted a float 24 having at its upper end a rod or stem, the upper extremity of which is curled into ring form and coupled with the correspondingly formed lower end of valve stem 18, producing a linkage connection 23.

The upper and lower ends of the housing 6 are closed by threaded end plugs 7 and 8 which screw into the internally threaded extremities of the upper and lower sections of the housing. To these end plugs are attached by

screws

21 and 27 the guiding bracket 20 for the upper end of the valve stem 18, and a corresponding guide member or bracket 26 for the guidance of a stem 25 extending down- Wardly from the lower end of float 24. The external surface of nipple 15 is preferably tapered slightly from its rnidlength toward its upper and its lower end, to enter the cor- .30 respondingly internally threaded proximate ends of the upper and lower sections of housing 6, and to tighten as the nipple reaches its full seating in the respective secti'ons.

As seen in Fig. 2 the-lower valve disk or plug 17 is made separate from the valve stem 18 and provided with a central tapped opening to receive a correspondingly threaded portion of valve stem 18. This construction permits the valve stem to be inserted through 40 the top of the nipple and screwed through the central opening of valve 17 previously introduced into the nipple through the opening 19 in its wall and extending through the housing 6. At points above and below the nippic 15 are introduced tubular plugs 11 and 12, each oppositely tapered from a point between its ends toits extremity, said plugs being seated in the wall of the housing 6 and projecting into and making a tight fit in,

openings in the wall of pipe 2.

The plugs 7 and 8 are flattened attheir opposite ends and concaved on the side next to the pipe 2, to make close and continuous contact therewith. Tap bolts or screws 9 and 10 passing through the flattened ends or ears of the plugs 7 and 8 enter suitably tapped holes in ipe 2 and serve to attach the hous-j ing and raw it firmly into contact with said pipe. This pressure serves also to force the slightly coned or tapered plugs 11 and 12 .into their seats. Similar Ktubular plugs or Tnipples 13 and '14 are introduced slightly above and below the float 24. The nipples 11 and 12 establish communication between the valve housing and pipe 2, and the nipples a baflle to the stream of gas passing downward through the port of valve plug 17 when the valve plug is raised oif its seat. The guides 20 and 22 further serve to axially aline the valve plugs 16 and'17 with their seats.

A hole or ,holes 19 formed in the side walls of valve housing 6 and of the respective valve shells 15, the axes of said holes being perpendicular to the axes of the housing and valve shells, permit ingress of gas or air to the interior of the valve shells, and thence, when the valves areopen, through the passages 11 and 12 to the interior of tubing 2. The openings 19also permit introduction of the lower valve disk or cone 17 into the valve shell 15.

The tubular plugs or nipples 11, 12, 13 and 14 provide passages for fluid between the interior of the valve housing 6 and the eduction tube or pipe 2. These passages remain open at all times.

Float 24,'which is buoyed by oil or other liquid, entering the housing 6, through nipples 13 and 14, when the ungasified liquid is at a height suificient in tubing 2 so to enter the housing, affords suiflcient lifting force to unseat valves 16 and Y17 but the float 24 will lose its lifting power when the supporting liquid becomes gasified by gas entering the tubing 2 through a lower valve or a lower entrance and to the extent of its own weight I and that of the other movable parts supported by it, less an equal volume of gasified liquid in which the float is immersed will draw the valve disks or plugs 16 and 17 to their seats.

In other words, the specific gravity of the combined hollow float 24 and the movable .parts connected to it is less than that of the liquid to be raised from the well and greater than the gasified flowing liquid. Preferably the specific gravity of the combined float and the movable parts connected thereto should be'but little more than one-half that of the un asified liquid to be lifted from the well.

when ungasifled liquid is in tubing 2 and above ports 13 and 14, float 24 will be submerged andbuoyed upward, holding valve plugs or

disks

16 and 17 off their seat with valve 16 against its valve stem guide and stop '20, with valve ports open.'- When gasified is many times reduced (sometimes as low as one-tenth that of ungasified fluid) the float 24 will not be sup orted by it and drops downward drawing vave plugs or

disks

16 and 17 to their seats, closing their ports and cutting off communication between the induction and the eduction pipes at this point.

In Fig. 2, valve plugs or

disks

16 and 17 are shown resting upon .their respective seats, hence closing and sealing the shell 15 against the egress of gas from the induction pipe or annular space surrounding eduction pipe 2, thereby precluding the passage of gas through the ports of valve plugs or

disks

16 and 17 into the valve housing 6 and consequently through nipples 11 and 12 into eduction pipe 2. This illustrates the condition or adjustment of the valve plugs or disks l6 and 17 and the float 24, inside of the valve housing 6, of any valve assembly above any opening admitting gas into eduction pipe 2, or, in all cases where the valve assembly in valve housing 6 is above the fluid in eduction pipe 2. Also each valve assembly below the upper level or surface of nongasified liquid in the eduction pipe 2, and below any openings or ports admitting gas into the eduction pipe, will have its valves open while all above that level will be seated or closed.

From the foregoing explanation it will be seen that if gas or air be forced under adequate pressure into the annular space between

pipes

1 and 2, or, in other words, into the induction pipe, it will force down the oil in said space, causing it to rise in the eduction pipe 2. This movement will continue until gas in the induction pipe reaches a valve in the eduction pipe 2, below the surface of liquid in said eduction pipe. Since the liquid in the eduction pipe has entered the float chamber of housing 6 through ports or hipples 13 and 14, and lifted float 24 which has unseated valve plugs or

disks

16 and 17, gas.

will pass into theeduction pipe 2 through openings 19 of the housing inside of the valve shell 15, then divide, part passing upward through port of valve plug or disk 16 into the upper space of valve housing 6 and then through nipple or port 11 into the column of liquid in eduction pipe 2, while the other portion of gas from the inside of valve shell 15 will pass downward through port of valve plug or disk 17 into valve housing 6 above valve rod guide and bafile plate 22, be deflected by the baffle plate and pass out through nipple or port 12 into the column of liquid in eduction pipe 2. This induced gas will mingle and mix with the liquid in said eduction pipe and start a gas lift flow upward in eduction pipe 2, above these valves, which flow will continue as fluid rises from below until the fluid level in the induction pipe is depressed to the next valve below where gas will be admitted through the open valves as above, starting a gas lift flow from such lower valve or opening. As soon as the gasified liquid reaches the valve above, it will take the place of the ungasified fluid in the float chamber of this upper valve, and, since the gasified liquid will not support the float, the float will drop and draw its

valves

16 and 17 into their seats, closing off the flow of gas from that point.

In this way the flow of the oil is started, and the entrance of gas or air into the induction pipe or chamber is advisably made continuous. Such continuing inflow of gas will further depress the level of the oil in the induction chamber and gradually carry the level thereof to a point below the next succeeding valve, if there beanother, whereupon the gas will enter the eduction pipe through such valve while the valves above will be automatically closed. This continues until the level of the oil in the induction pipe or chamber is forced below the lowermost valve, and until the gas enters the lower end of the eduction pipe through the perforations in the lower end of the pipe, or if these be not provided, then through the open lower extremity of the pipe. the pressure of air or gas required to maintain a steady flow and remove the oil or other liquid from the well as fast as it enters will be found to be very low compared to that which, without the use of the gas lift starting valves, would have been required to start the flow. In some cases, the gas lift may be operated on a gas pressure as low as onetenth that required to start the flow by former methods. v

As stated, the description just given is predicated upon the placing of the valves and their actuating devices in the outer and annular chamber, or between the well casing or pipe 1 and the central and suspended pipe 2. The valves and the flow of oil may, however, be reversed, that is to say, the suspended central pipe may become the induction pipe, and the outer pipe or well casing may serve as the eduction pipe. In such case the valves would need to be reversed, and might be placed within the inner pipe.

As above pointed out, the wall of the bored or drilled well, when no casing is employed, constitutes the wall of the outer chamber, and this chamber may constitute either the gas induction or the oil eduction pipe or chamber. Similarly, the suspended central pipe may constitute either the oil eduction or the gas induction pipe, and the term pipe as used in the claims is to be understod as compre bending the bored or drilled well, when no casing is employed, and the casing when such casing is used. In other words, the uncased well and the well casing are the wellknown equivalents in this art and for the purposes of pressure-fluid lift or flow-starting devices.

The drawings illustrate the preferred form When this point is reached.

tions.

of structure but it is to be understood that so long as the mode of operation set forth,

and the general principles of the structure, are retained, modifications falling within the field of the mechanician or engineer may be adopted.

I claim:

1. A pressure-fluid oil-flowing apparatus of the character described, comprlsing a pressure-fluid induction pipe; an oil eduction pipe; a valve permitting or precluding, ac-

cording to its position, communication between said pipes; a float chamber in communication with the eduction pipe; and a float in said chamber in operative relation to said valve, the joint weight of the float, valve, and immediate connections being less than that of the ungasified liquid displaced by the float but greater than that of the gasified liquid displaced from the eduction pipe by fall of the float; whereby the valve is caused to unseat when the float is immersed .in the ungasified liquid but to seatwhen immersed in the gasified liquid.

2. A pressure-fluid oil-flowing apparatus of the character described, comprising a pressure-fluid induction pipe; an oil eduction pipe; a passage affording communication between said pipes; a valve controlling said passage; a float chamber in communication with the eduction pipe; and a float device in said chamber in operative relation to said valve, the joint weight of the float, valve, and their immediate connections being such that the float will rise and unseat the valve when immersed in liquid containing little if any free gas, but will fall and seat said valve when the wei ht of the volume of liquid displaced is slig tly less than the joint weight of the float, valve, and immediate connec- CHARLES C. CARLISLE.