US2690134A - Well pumping - Google Patents

Description

Sept. 28, 1954 R. c. RITCHEY 2,690,134

WELL PUMPING Filed July 2, 1951 INVENTOR.

hiToENEK Patented Sept. 28, 1954 2,690,134 WELL PUMPING Richard '0. Ritchey, Hamlin, Tex., assignor to The Texas Company, New York, N. Y., a corporation of Delaware Application July 2, 1951, Serial N 0. 234,769

. 1 Olaim.

This invention relates to well pumping and more particularly to a method and an apparatus for pumping deep wells such as those which produce oil. The principal object of the invention is the provision of means which will prevent vapor or gas lock in well pumps of the type having a piston or plunger and a working barrel or cylinder, a space being formed between these elements into which the oil is drawn on the suction stroke and from which it is expelled on the compression stroke.

Gas locking is a phenomenon which occurs quite frequently when gaseous fluids are being pumped. The compression space, i. e., the space between the suction and discharge valves becomes partially filled with gas and the gas being a very elastic material compresses and expands as the pump is operated, thereby preventing the proper opening and closing of the valves. In accordance with this invention, means are provided which serve to forcibly and positively open the discharge valve when the pump becomes gas locked. This action is automatic and is accomplished by providing a pin or finger-like extension disposed on the stationary pump element so that in case the moving pump element overtravels as a result of increased speed of operation when gas locking occurs, the pin will engage and unseat the discharging valve permitting the gas to be discharged and replaced by liquid from above the discharge valve.

In oil field production the usual procedure followed in an endeavor to eliminate or minimize gas-locking difliculties is to separate the gas from the oil before it enters the pump and to space the pump elements in such a manner that clearance is at a minimum. This procedure usually requires the provision of gas separating means and is frequently not successful.

For a better understanding of the invention, reference may be had to the accompanying drawing in which Fig. 1 is a vertical elevation partly in section through portions of a well pump;

Fig. 2 is a vertical section similar to the upper portion of Fig. 1, but showing the traveling valve and the anti-gas finger in their normal separated position; and

Fig. 3 is a diagrammatic illustration generally similar to Fig. 1 but illustrating a pump in which the piston or plunger is reciprocated while the barrel remains stationary.

Referring to the drawing, a well pump is shown which includes essentially a barrel or cylinder l and a piston or plunger indicated generally at l2.

These elements are disposed usually near the bottom of a well within the tubing indicated schematically at M in Fig. 3. In the embodiment shown in Figs. 1 and 2, the plunger I2 is held stationary in the well and may be secured within the tubing M by any suitable hold-down attachment such as that indicated at $6. The cylinder in this type of pump is usually called the working barrel or traveling barrel and surrounds the plunger 42 while being adapted to be reciprocated vertically by means of a string of pump or sucker rods I 8 from which the barrel is suspended.

The plunger l2 includes a pipe member 2?) projecting upwardly from the hold-down It, the liquid to be pumped passing upward-1y through this pipe into the working 'or compression space 2 2 between the plunger 12 and the barrel l0. One or more packers 2 3 are secured to the pipes 20 and are adapted to be squeezed downwardly and outwardly by tightening a nut 26 threaded to the upper end of the pipe. These packers 24 which are usually leather or rubber cup-like members engage, in the usual manner, the inner surf-ace of the barrel 10. As shown in Fig. 1 a lock nut 28 is also threaded to the upper end of the pipe member 2 0 and secured to and projecting upwardly from this look nut is a valve cage 33. Within the cage 30 is a valve seat 32 adapted to be engaged and closed by a ball valve 34 on the compression stroke of the pump. Secured to and projecting upwardly from the upper end of the valve cage 30 a finger-like extension or anti-gas finger element :36, the purpose of which will be explained hereinafter.

Secured to the upper end of the barrel I!) is a bushing 38 and threaded to the upper end of this bushing is a valve cage 40 having a seat 32 adapted to be engaged and closed by a ball valve 44 on the suction stroke of the pump. A connection 4'6 is shown on the top of the cage 4t adapted to be secured to a pump rod or sucker rod l8 string illustrated diagrammatically in Fig. 3.

It will be apparent that during normal operation, on the suction stroke of the pump, that is, when the barrel I 0 is being pulled upwardly, fluid will be drawn up through the pipe 20 past the ball valve 34 into the chamber 22. During this stroke the upper or traveling valve 44 will remain on its seat and the oil which has previously been pumped above the barrel will be raised toward the surface. On the downstroke or compression stroke, the valve 34 will remain closed and the oil in the chamber 22 will be squeezed upwardly past the valve it into the tubing space above the working barrel, When the pump is assembled in the well and prepared for operation, the barrel i is lifted a slight distance, usually a few inches above the bottom packing on the plunger i2. During normal operation when there is little or no gas in the oil and while the pump speed remains constant, this distance or separation between the lower end of the barrel in and the bottom packing will remain approximately constant for each stroke of the pump. When gas is present in the oil even in quite small amounts, this gas will accumulate in the chamber 22 and as the amount of this gas increases, the amount of oil drawn upwardly into the chamber 22 will decrease. Since gas is elastic and compressible, the pump becomes gas locked, or in other words, on the down-stroke of the barrel In the gas in the chamber 22 will be compressed and the traveling valve M will not open. Since the pump is then doing less work there will be a tendency for the driving mechanism to increase its speed and at the greater speed the rods I8 will stretch, sometimes by several inches. When this occurs, there will be several inches overtravel by the barrel it in a downward direction and the upwardly projecting stationary finger-like member at will, in a short time, be engaged by the downwardly moving traveling valve A l which will be pushed upwardly from its seat. When this occurs the oil above the valve will pass downwardly around the finger 36 into the chamber 22 displacing the gas therefrom and the pump will then continue its normal operation, i. e., the speed will decrease so that there will not be an excessive stretch in the pump rods and the working barrel will not move downwardly far enough for the ball valve i l to strike the finger member 36. This normal operation will then continue until or unless the pump again becomes gas locked, whereupon the chamber 22 will again be vented of the gas so that normal operation will again take place.

Although a pump has been described in which the plunger is stationary while the barrel or cylinder is reciprocated, it is believed obvious that these elements could be reversed. Fig. 3 shows very diagrammatically a pump in which the barrel its, is stationary and in which the hollow plunger lid is reciprocated vertically by :r ans of the rods 58. In this case the barrel lea is provided with an inwardly opening valve Lil; within a cage 5% and the lower end of the plunger 52a is provided with a valve 52 disposed ithin a cage 55. The upper end of the valve cage as has attached thereto a finger-like elemerit 36a corresponding to the element 36 of Figures 1 and 2. In this embodiment, the operation is substantially the same as that previously described. If the space 22a between the barrel ma and the lower end of the plunger i211 becomes gas bound, the plunger will overtravel on its downstroke and the valve 52 will strike the finger 356a and be pushed from its seat so that oil will pass downwardly into the space 22a to displace the gas therefrom. The small arrows show the direction of the flow during operation of the pump.

Although the invention has been described with reference to deep well pumps, it is to be understood that the principles which have been described are also applicable to any reciprocating pump adapted to pump a liquid in which gas may be present.

Obviously, many other modifications and variations of the invention as hereinbefore set forth may be made without departing from the spirit and scope thereof, and, therefore, only such limitations should be imposed as are indicated in the appended claim.

I claim:

A well pump comprising a vertically reciprocable cylindrical barrel element, a stationary plunger element within said barrel element, an inwardly opening valve on said plunger element and an outwardly opening valve on said barrel element, a compression space being formed between said elements, rod means for reciprocating said barrel element with respect to the plunger element so that on one stroke liquid will be drawn past said inwardly opening valve into said space and on the next stroke will be forced out of said space past said outwardly opening valve, and means for automatically eliminating gas lock due to the accumulation of gas within said space, said means comprising a finger-like member affixed to said plunger element and adapted to engage and open said outwardly opening valve on an abnormal increase in the downward travel of said barrel element, whereby the accumulated gas in said compression space will be displaced by liquid passing downwardly through the opened valve into said compression space.

References Cited in the file of this patent

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