US2001552A - Plunger lift control device - Google Patents

Description

C. N. SCOTT PLUNGER LIFT CONTROL DEVICE May 14, 1935.

Filed March 15, 1934 ATTORNEYS.

Patented May 14, 1935 UNITED STATES PATENT oFFIcE n z,oo1,55z PLUNGER LIFT CONTROL DEVICE Clarence N. Scott, Houston, Tex. Applicaun Mllch 1.5, 1934, Selill N0. 715.649

l 3 Chime. (Cl. 103-52) My invention relates to plunger lift devices employed in raising liquid from deep wells by pressure of air or gas below a yplunger and its load of liquid.

It is an object of the invention to provide means to control the flow of liquid and gas so that the gaseous fluid pressure in the casing and the eduction'tube and in the producing formation adjacent the well will be frequently relieved at the proper time so that the most effective flow of oil from the producing formation will he had.

It is also desired to so operate the pumping apparatus that the supply of gas available will be conserved.

A further object is to so control the flow of liquid and gas from the well that part of the gas supply may be employed in two or more lifting operations.

I also desire to so operate the lifting apparatus that the fluid pressure in the well will be taken ou the formation as far as possible.

It is also desired to so operate the lifting apparatus that the now in the producing formation adjacent the well of the fluid produced will be a frequently intermittent or violent pulsating flow so that the formation may be kept freed of material tending to pack and clog the same.

In the drawing herewith, I have shown an assembly of operating parts by which my invention may be carried out, the apparatus being largely in central vertical section.

'Ihe well casing I has a casing head 2 thereon, said head having a fluid outlet 3 and a fluid inlet 4, the latter being understocdas connected with some source of air or gas under pressure.

kSupported on casing head 2 is the discharge head 6 which is secured to the casing head by a flange and bolt connection 6. Said discharge head hasan outlet 1 for fluid from the well. Above the outlet is a latch bolt 8 slidable in a lateral housing 9 closed on its outer end by acap I0 of insulating material. The stem I2 on the bolt extends through said cap and into a solenoid II connected into an electric circuit including terminals I3 of a rotary switch I4. The bolt 8 is held projecting slightly into the tube to automatically engage the plunger by means of a spring I5.

Above this plunger latch is a gate valve I6, and above this valve the extension I1 on the eduction tube is projected upwardly a suitable distance and is closed by a cap I8 within which is a shock absorber I9 of rubber. Said rubber shock absorber has a central passage leading to a similar passage in the cap into which is connected the vent tube 28 controlled by the valve 2I.

absorber for the falling plunger.

yextending through an Within the casing is the eduction tube 22 which is supported upon a special collar 23 which has ka. radial vflange clamped between the flanges of the connection 6 in the casing head. Above the coupling the tube is perforated to discharge the fluid into the chamber 24 leading to the outlet 1.

The lower end of the eduction tube has a housing 26 within which is the stop plate 26, perforated to allow flow of fluid therethrough. Said plate is held in position against a shoulder in the tube by a spring v21 which acts as a shock Said spring is supported upon the nipple 28 connected at its lower end to the valve housing 29, having therein a valve seat 30 for the ball valve 3|. Below the valve an inlet tube 32 may extend downwardly into the liquid for the desired distance.

The plunger 33 is of the usual construction, and comprises a tubular body having an upwardly closing valve 34 thereon. 'Ihe valve is normally supported in open position by gravity and rests upon a lower support 35. 'I'he stem 36 projects below the support andacts to move the valve to closed position when it contacts with the stop plate 26.

'Ihe uid outlet 1 from the eduction tube passes by way of the T 31 and the elbow 38 to the ow line 39 which leads to the separator and to storage, not shown. The elbow 38 forms a chamber yfor a valve 48 seating downwardly upon the valve seat 4I to close the outlet. Said valve has a stem electrically insulating cap 42 into a solenoid 43 included in an electric circuit leading to the terminals 44 of the switch I4. A spring 45 tends to hold valve 40 seated but said valve may be opened by the solenoid acting upon the stem 46 of the valve.

'Ihe outlet 3 for gas from the casing leads by way of the T 41 vto an eblow 48 and therethrough to the flow line 39. The elbow 48 is similar in all respects to the elbow 38. It has a valve 49 seating at 50 to close the passage. The stem 5I projects into a solenoid 52 connected into a circuit including the terminals 53 of the switch I4. The valve is normally closed by spring 54.

The two tees 31 and 41 are connected by a bypass incluing ahousing 55 for a valve 56 normally held into a seat 51 by a spring 58. A stem 59 on the valve projects into the solenoid which is included in a circuit with the terminals 6I oi' the switch' I4.

'I'his apparatus may The plunger 33 is shown sure behind it, said gas be operated as follows: as rising with gas preshaving accumulated in the casing and depressed the liquid in the well casing until said gas enters the lower end of tube 32, and continues to enter the lower end of tube 32 from the formation as the plunger rises. When the plunger has discharged its load of liquid through the outlet l, it will be moved past the latch 8 upwardly into the extension l1 by the gas pressure and said gas will tend to escape also, but I arrange to close the valve 40 at this instant and prevent the outflow of gas. The plunger will be caught in the upper end of the eduction tube and as the vent valve 2i is closed, the fluid pressure in the closed upper end of the tube will open the valve 3d in the plunger and the latch 8 will engage the plunger and retain it in that position.

The switch i4 is rotated as shown, by a small motor of variable speed type shown at 63 and will be arranged to close the various circuits includ.- ing the control solenoids at the proper time. While the piunger is rising the valve 4% will be held open. It will be released at the moment the liquid has discharged and before the gas escapes. The valve .9 will then be opened by energizing the solenoid 52 and the gas from the casing or a compartment in said casing may escape to the flow lines relieving the pressure in the well and in the formation adjacent the well and allowing fluid to freely enter into the well and build up the liquid level in the casing.

The gas in the tube 22 which has not escaped is held trapped therein by the foot valve 3l and the outlet valve 4U. When the gas pressure in the casing has been released through valve 49 and liquid level has built up in the casing to the desired level, that valve is timed to close by opening the space between terminals 53 and allowing the spring 54 to close the valve.

I then open the valve 56 in the by-pass and allow the gas in the tubing to flow into the casing to begin building up gas pressure therein. The gas pressure in casing and tubing will soon equalize and the valve 5B will close by opening the switch 6I which is timed to remain closed only the desired interval. The switch then opera es to open valve 40 and allow any gas remaining in the tubing to exhaust to the flow line. This release of gas pressure from the tubing and the building up of gas pressure in the casing cause all or a part of the liquid which has built up in the casing to depress in said casing and build up in said tubing. The switch then opcrates to withdraw the latch 8 and allow the plunger to drop to the bottom, thus completing the cycle.

It is to be noted that the gas charge which operated to lift the load is trapped before it escapes and then is again allowed to enter the casing and form part of the pressure fiuid employed in raising the next load. The releasing of the gas pressure from the casing preceding the discharge thereinto of the gas from the tubing is to allow the fluid in the formation to freely enter for the next load of liquid. f

It will be noted that, by thus operating the plunger lift apparatus, I am enabled to almost entirely relieve the back pressure of the fluid in the well from the producing stratum and thus allow the oil and gas to enter freely at that time. I do not, however, have to waste all the gas in the well at that time to do so, but am enabled to use that quantity remaining in the tube by discharging it into the casing after the liquid has had time to enter the well and build up in the casing to the desired level.

What I claim as new is:

1. In a plunger lift apparatus including a well casing an eduction tube therein having a fluid outlet at its upper end and a plunger movable freely therein, the method of operation including accumulating a load of liquid above said plunger, employing gas pressure below said plunger to engage and to raise said plunger and its load of liquid to the surface and discharging said liquid, closing said outlet to prevent discharge of gas from below said plunger in said tube, releasing the gas pressure in the casing outside the tube to allow fiuid from the producing formation to freely enter the well and casing and build up liquid level in same,

closing the casing against further release of gas, and allowing discharge of gas from said tube to said casing, closing ofi the passage of gas from said tubing to said casing, opening the said outlet from the tube to release gas pressure from same, and accumulating gas from the formation builds up pressure and depresses it in said casing and build up said liquid in the tubing to the desired level, dropping said plunger into said tube to a point below the level of liquid in same, and repeating the operation.

2. In a plunger lift apparatus including a well casing, an eduction tube in said casing having a fluid outlet at its upper end, a plunger freely movable in said tube; the method of operation including, accumulating a load of liquid above said plunger, exerting gas pressure below said plunger to continuously act upon and raise the same with its load of liquid to the surface and discharge said liquid, retaining the gas in said tube, releasing the fluid pressure from said casing, closing said casing and discharging gas from said tubing to said casing and allowing said plunger to fall in said tube and venting the gas from above said plunger.l

3. In a plunger lift apparatus including a well casing closed at its upper end and extending down to the producing formation, an eduction tube in said casing, a plunger freely movable in said tube; the method of operation including, f'

accumulating a load of liquid above said plunger, exerting gas pressure below said plunger to raise the same with its load of liquid to the surface and discharging said liquid, retaining the gas in said tube, releasing the fluid pressure on the formation in and adjacent the well to allow fluid to freely enter the Well, discharging gas pressure from said tube to said casing, closing said casing and venting the gas from said tube.

CLARENCE N. SCOTT.

and trapping said gas allow liquid to transfer from the casing as

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