US2018206A - Apparatus for plunger lift control - Google Patents

Description

L O R T N O C O F S Filed Sept. 29, 1934 llllllllll m m m m l. (\1 Harald WFleuhez' BY Q biz WTTORNEYS.

Patented Oct. 22, 1935 UNITED STATES oFFicE.

APPARATUS FOR PLUNGER LIFT CONTROL poration of Texas Application September 29, 1934, Serial No. 746,063

5 Claims.

discharges from the eduction tube and the plunger drops back in the tube to the lower end thereof to engage another load of liquid and repeat its cycle. However, the plunger tends to fall in the eduction tube before the charge of air or gas which was employed to raise the plunger has had time to exhaust. The result is that the plunger may be caught in the rising flow of gaseous pressure fluid and be blown back up to the top. The valve in the plunger which was opened after the load was discharged may sometimes be closed and the falling of the plunger through the gas and liquid in the tube may be greatly interfered with and the operation of the device rendered ineflective. This is especially a serious problem when the well is a small producer and the load discharged at each stroke of the plunger is small.

It is an object of this invention to regulate the discharge of fluid from the well in such a manner that the falling of the plunger will not be impeded.

I desire to delay the exhaust of the gaseous pressure fluid until the plunger has had time to fall sufliciently to avoid being caught by the blast of pressure fluid.

The invention contemplates the use of an air or gas relief valve, operating to release the pressure fluid when a predetermined pressure in the well is attained. The lowering of pressure is' delayed by the charge of liquid lifted by the plunger.

In the drawing herewith, Fig. 1 is a side view showing the assembly of apparatus employed in my invention, the well casing and tube being in central vertical section.

Fig. 2 is a vertical section showing the lower end of the well equipment.

Fig. 3 is a longitudinal section of my pressure relief valve.

The plunger lift device to which my invention is applied is now in common use. The well is equipped with a casing I, extending down to the producing stratum. It has a casing head 2 formed with a lateral fluid outlet 9. Above the head is a cap or nipple 4 closing the upper end of the casing head and connecting to the eduction tube extension 5.

The eductiontube 6 has a fluid tight support at l in the casing head. It is perforated at 8 in the casing head to allow discharge of fluid 5 from the eduction tube to the flow line 9. The lower end of the eduction tube, shown in Fig. 2, is provided with a perforated intake plug [0 connected to the tube by a coupling H. Within said coupling is a cross shaped stop member 12 which is adapted to be engaged by the valve stem 13 on the valve M in the plunger I5. Said plunger is shown at the lower end of its stroke with the valve in closed position at the lower end of the passage through the plunger. 15

At the upper end of the eduction tube extension 5 is a cap it which closes the tube and also houses a shock absorbing sleeve H of rubber or similar resilient material. There may be a by-pass [8 from the upper end of this cap to the flow line 9 equipped with a valve I9, to allow the escape of fluid from the tube extension when the plunger is to be allowed to enter the said extension.

To control the discharge of liquid and gas or air, I employ a container 20 in the flow line 9. At the lower end of said container is a liquid outlet 2| having a choke valve 22 therein. At the upper end of container 20 is a gas outlet 23 which connects into the flow line beyond the valve 22.

In the gas conducting pipe 23 is an automatically operating valve, working Within the casing 24. This valve is shown best in Fig. 3. The passage 25 through casing 24 is controlled by a balanced valve 26 mounted upon a stem 2? working through the upper wall of said casing. The upper end of said stem is secured to a flexible diaphragm 28 within a casing 29. Said diaphragm divides the casing it into a lower closed chamber 30 and an upper chamber 3! which has connection by means of pipe 32 to the upper end of the casing head at 33. The valve is acted upon by a weight or spring acting to normally move the valve to open position. I have shown a weight 3'5 mounted upon a lever arm 34, pivwill exert pressure upon the liquid in the well and depress the level in the casing and raise it in the tube until the gas can enter the perforations at H] and bubble up below the plunger and there accumulate until the pressure is suflicient to raise the plunger and its load to the surface.

The liquid will discharge into container 20 where its outflow will be regulated'by the choke valve 22. The outlet for the gas will be closed by the pressure of fluid exerted through the pipe 32 to the upper end of the valve rod 21. Gas cannot escape, therefore, until the liquid has passed from the container 20. I arrange the weight 3? on the valve to open'the valve at a predetermined pressure against the upper side of the diaphragm 28.

When the liquid is discharged from the eduction tube the plunger will pass into the closed upper end of the eduction tube where it will be stopped by the back pressure of gas and liquid in the tube above it. The valve in the plunger will be forced open and the plunger will then fall. As the gas in the tube cannot exhaust at once, the plunger will not be impeded in its fall until it has reached the desired level below the top of the tube.

When the liquid has discharged from the container, the gas will immediately tend to also escape through valve 22 and the gas pressure will soon be lowered in amount so that the air valve 26 will also open and allow full and rapid exit of the pressure fluid from the well. The device is timed by the setting of the liquid outlet valve 22 and the control valve 28 so that the plunger is allowed to fall as far as is necessary to avoid the flow of gas or air which occurs at the upper end of the tube when the outlet therefor is opened. Thus if the working pressure is pounds per square inch, it might be found correct to set the valve,25 to open when the well pressure drops to '75 pounds. When this point is reached the plunger will have dropped sufficiently 7 and the control valve may open to allow full and rapid exhaust of gaseous fluid pressure in the eduction and permit the entrance of liquid to the lower end of the tube before the plunger arrives at the'bottom'. g

The use of the control valve 25 efiects a better control of the gas discharge than would be possible by the use of the choke valve 22 above. For, if the valve 22 is choked down enough to properly time thedischarge of liquid from the container, it will also interfere with the rapid discharge of the gas. By allowing the gas to bypass rapidly at the proper time, the plunger is more efficiently operated and liability to-the blowing of the plunger back is eliminated.

What I claim as new is:

1. A plunger lift device including a well casing,

an eduction tube therein, a pneumatically operated plunger movable freely from end to end of said tube, a container positioned to receive the liquid raised by said plunger, a discharge outlet from said tube to said containena flow line connected with the lower end of said container,

a choke valve in said line to control the rate of emptying of said container, a gas bypass from the let from said tube to said container, a flow line connected with the lower end of said container, a choke valve in said line to control the rate of emptying of said container, a gas bypass from the upper end of said container to said flow line downstream from said valve, and means to bypass gas from said container past said choke valve responsive to a predetermined minimum fluid pressure in said discharge outlet.

3. A plunger lift device including a well casing, an eduction tube therein, a pneumatically operated plunger movable from end to end of said tube, and an outlet line from said tube for fluid raised by said plunger; in combination with a container connected with said outlet to receive the full load of liquid raised by said plunger, means to control the rate of flow of liquid from said container, an exit for gas from saidcdntainer, a valve controlling said exit, and a control device on said valve acting in response to the operating fluid pressure in the well to close said valve when the liquid is discharged to said container and to again open said valve in response f to a drop of fluid pressure in said outlet line to a predetermined minimum.

4. A plunger lift device including a well casing, an eduction tube therein, a pneumaticallyoperated plunger movable from end to end of said *1 tube, and an outlet line from said tube for fluid.

raised by said plunger; in combination with a container connected with said outlet to receive.

the full'load of liquid raised by said-plunger,

means to control the rate of flow of liquid from said container, and separate means to control the escape of gas from said container operating in response to a predetermined fluid pressure in said outlet line after said liquid has emptied from said container. 7 r

5. A plunger lift device including a well c asing, an eduction tube therein, a pneumatically operated plunger movable from end to end ot said tube, and an outlet line from said tube'for fluid raised by said plunger; in combination with a container connected with said outlet to receive the full load of liquid raised by said plungen' means to control the rate of flow of liquid from said container, and separate. means controlled by the fluid pressurein said outlet line to allow escape of gas from said container. after said plunger has dropped in said tube a desired distance. r

HAROLD w. FLETCHER..."

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