Shock absorption apparatus associated with well pump

A well sucker rod shock absorber apparatus employs cushion means located transversely of the rod string. Cushion means may also be located in association with the drive for the pumping unit that reciprocates the rod string.

BACKGROUND OF THE INVENTION 
This application is a continuation-in-part of my prior application of Ser. 
No. 186,499, filed Sept. 12, 1980. 
This invention relates generally to the pumping of wells, and more 
particularly concerns the cushioning of reciprocating load transmission 
during pumping. 
Sucker rod strings are typically reciprocated up and down in oil wells 
during pumping. It is found that sharp load reversals during such pumping 
inhibit oil production. Attempts have been made to overcome this problem; 
however, no such attempts have to my knowledge embodied the unusually 
advantageous apparatus, mode of operation and results achieved by the 
present invention. 
SUMMARY OF THE INVENTION 
It is a major object of the invention to provide load reversal cushioning 
apparatus of improved design and mode of operation and which will in 
operation improve or aid the production and flow of well fluid such as 
oil. 
Fundamentally the invention is embodied in: 
(a) upper and lower generally horizontal members to pass a pumping rod, 
(b) shock absorbing cushion means confined between the members, the cushion 
means defining an opening to pass the rod, the cushion means comprising 
cushions located at transversely opposite sides of that opening, 
(c) the upper member adapted to receive loading exerted downwardly by the 
rod, 
(d) the lower member adapted to be supported and stroked up and down by a 
pump unit. 
As will appear, the cushions may define hollows containing compressible 
fluid and which are vertically compressible against resistance imposed by 
the fluid, which may consist of gas; and the hollow cushions may be 
elastomeric (as for example in bellows configuration) and located at 
opposite sides of an axis defined by the sucker rod. Alternatively, the 
cushions may comprise multiple cylinders and pistons that work in such 
cylinders, and accumulator means may be provided and connected via ducting 
to such cylinders or to the cushion hollows, to adjust or control the 
compression of the cushion means. 
Further, guide means are typically associated with one or the other of the 
members, or both, to stablize at least one of such members, vertically, 
during stroking. As will be seen, the guide means may include guide rod 
means carried by one of the members, and sleeve means carried by the other 
of the members, to vertically guide the guide rods. 
In addition, other cushion means may be provided between a pumping unit 
working beam and a rotary drive therefor, as will be seen. 
The invention facilitates such improved cushioned stroking of the sucker 
rod as will cause significantly increased production of petroleum from a 
sub-surface pump or pumps operated by the sucker rod. 
These and other objects and advantages of the invention, as well as the 
details of an illustrative embodiment, will be more fully understood from 
the following description and drawings, in which:

DETAILED DESCRIPTION 
In FIGS. 1 and 2, a well sucker rod 10 is vertically reciprocable in well 
11 for pumping fluid such as oil to the surface and to a lateral flow line 
12. A pumping unit to reciprocate the rod 10 vertically may comprise a 
rocker arm 13 connected by link 14 to a rotary drive 14a. A horsehead 15 
on arm 13 (which is pivoted at 16) suspends cables 17 that wrap and unwrap 
on the horsehead as the latter moves up and down. Shock absorber or 
cushioning unit 18 is connected between the cables 17 and rod 10 to 
cushion the lifting and lowering forces transmitted between the rod 10 and 
cables 17, and thereby reduce wear, and aid in oil production. 
As better shown in FIGS. 2 and 3, the unit 18 includes a base 19 which 
extends laterally to be connected to the pumping unit via the cables. The 
latter may loop around notches 20 in the base, at opposite sides of 
vertical center line 21. The sucker rod 10 extends upwardly through a bore 
22a through bronze wear cushion or sleeve 22 in the base. Cables or 
"reins" 17 support or carry the base. A lower plate member 24, supported 
by the base, carries shock absorbing cushion means 25 which may take the 
form of hollow cushions 25a. There are pairs of cushions at opposite sides 
of a central opening or space 26 which passes the sucker rod 10, the 
cushions of each pair vertically spaced or stacked, as shown. 
The cushions are confined between lower transverse plate member 24 and 
upper transverse plate member 27, with suitable mounting plates or 
retainers 28-33 located at the upper and lower sides of each cushion, as 
shown, whereby the transversely annular cushions of each pair are 
vertically aligned. The cushions of each pair may comprise a single 
convolute, bellows type cushion as for example is produced by Goodyear 
Corporation, Model 2B6. See the interconnection between the air filled 
cushion hollows 34 and 35, at 36 in FIG. 2, and defining an "air spring". 
Single or multiple elastomeric cushions may be employed, and they are 
vertically compressible against resistance imposed by the air, or other 
fluid contained therein. 
Upper plate 27 is connected via insert 37 to clamp 38, which is in turn 
clamped to the sucker rod 10. Guide rods 39 connected to insert 37 extend 
vertically downwardly through sleeves or bushings 40 carried by base 19, 
to guide the relative up and down movement of the plate members 24 and 27 
and the cushions. Accordingly, guide means is provided to stabilize the 
members 24 and 27, the base 19 and the cushions, during stroking or 
pumping of the well. Rotary thrust bearing 37a supports the clamp 38 and 
rod string. 
Finally, an air tank or accumulator 41 is connected at 42 and 43 with the 
cushions, to provide pressurization therefor, and intercommunication of 
the cushions, for stabilizing and improved cushioning functioning. Such 
cushioning is adjustable by virtue of adjustable pressurization of the air 
tank, via inlet 44. The tank is shown as carried by upper plate 27. 
Turning to FIG. 4, the modified device 118 includes a transverse base 119 
having notches 120 to which "reins" or cables 17 are connected, as before. 
The shock absorbing cushion means comprises multiple cylinders and pistons 
that work in such cylinders. The cylinders are defined by vertical bores 
121 in block member 122 having a lower horizontal member 122a attached to 
base 119. The vertically extending pistons in bores 121 are indicated at 
123, and are integral with upper horizontal member 124. That member is 
clamped at 125 to well sucker rod 10. Shoulders 126 on skirt 127 integral 
with member 124 are engageable with shoulders 128 on block 122 to limit 
relative upstroking of skirt 127 relative to block 122, these being 
telescopically interfitting elements. As the base 119 is elevated, air in 
the cylinder zones 130 is compressed by the pistons. Zones 130 
intercommunicate as via lines 131-133 connected to accumulator 134 which 
is carried by base 119. 
In FIG. 6, the elements of the pumping unit which are the same as in FIG. 1 
are given the same numbers as used in FIG. 1. A shock absorber means is 
indicated at 218, and make for example take the form of the absorber 18 
described above. Other types may also be used. Further, additional cushion 
means is operatively connected between the rotary drive 14a and the 
working beam 13. One such additional cushion means is shown at 218a, to 
bear compressive load exerted downwardly by the link 14 on the beam 13. 
Link 14 passes up through the rod, and is connected to pivot joint 219 on 
a second beam 220. Downward load on joint 219 is exerted on cushion means 
218a carried by beam 13. Beam 220 at one end carries and laterally locates 
joint 219, and at its opposite end is pivotally connected at 221 to beam 
13, to allow up and down pivoting of beam 220. Cushion means 218a may take 
the same form as shock absorber 18. 
In FIG. 7, corresponding elements bear the same numbers as in FIG. 6. Here, 
the auxiliary beam 220a, is below beam 13; and cushion 218b and joint 219a 
are also below beam 13. Cushion 218b, which is compressed by the load, is 
at the horsehead side of pivot 16, in FIG. 7, whereas in FIG. 6 the 
cushion 218a is at the opposite side of pivot 16 from the horsehead. 
In FIG. 9 the additional cushion means 318 (which may be substituted for 
cushions 218a and 218b) includes an elastomeric cushion 331; a frame 332 
operatively connected at one end 332a to one end of the cushion 331, and a 
pusher 333 bearing against the opposite end of the cushion 332. A bronze 
bushing 334 passes pusher stem 333a. The frame 332 and pusher 333 may be 
operatively and respectively connected to the rotary drive and walking 
beam, shown at 14a and 13 in FIG. 8, which is like FIG. 6, with cushion 
means 318 in tension and in series with link 14. In FIG. 11, another form 
of absorber or cushion means 418 is shown. It includes cushion 431; a 
frame 432 connected at one end 432a to cushion 421, and a pusher 433 
bearing against the opposite end of the cushion 432. Bushing 434 passes 
pusher stem 433a. Cushion 418 is shown in FIG. 10 as connected in 
compression in series with link 14. FIG. 10 is otherwise like FIG. 7. 
In FIG. 12, the pumping unit includes the same elements as in FIG. 1, the 
elements having the same numbers. In addition, elements 18, 15, 10 and 11 
are repeated at the opposite end of the beam 13, so that two wells are 
pumped by the same drive unit, and via shock absorbers 18, as shown. 
The rod weight in one well is approximately balanced by the rods in the 
other well. On off-shore platforms, this double pumper saves valuable 
space. Balancing weights on the drive would only be needed if one well was 
deeper than the other well. Another advantage is that only one motor and 
one gear box would be wearing. There would be a savings in energy 
consumption because this unit would only be lifting fluid, no weights (if 
the well depth and pump size were the same) and no rods. 
In a conventional pumping unit the weight of the rods and the weight of the 
fluid must be lifted, and if there were no counter balance weight, the 
unit could not pump unless it were extremely over powered. If the weight 
of the rods were 8000 lbs and the weight of the fluid were 6000 lbs for a 
total of 14,000 lbs, about 7000 lbs of counter balance weights are used, 
so that the motor is pulling an even 7000 lbs on both the down stroke 
(when it is lifting the weights) and 7000 lbs when it is lifting the rods 
and fluid but with 7000 lbs of weights to assist. 
With applicant's unit, only the weight of the fluid would be lifted which 
would amount to 55% to 60% or 65% saving in electricity; also the shock 
absorber means 18 act to improve pumping efficiency as described above. 
In FIG. 13, a resilient, elastomeric cushion 500 is located between 
vertically spaced horizontal members 501 and 502. Member 501 is adapted to 
receive loading exerted downwardly by sucker rod 10, via clamp 503. Rod 10 
passes freely through a vertical opening 504 in cushion 500 and slider in 
a bushing 505. Base 502a, integral with member 502, has upper extensions 
506 operatively connected to cable "reins" 17 that engage horsehead 15, in 
FIG. 1. That operative connection includes a transverse load extender bar 
507 attached via links 508 to extension 506, and attached via couplers 509 
to the reins. This form of the invention is adapted for use where a rod 
load is so large that a shock absorber unit of extra large size is 
confined and received in the cup-shaped recess 510 formed by annular skirt 
511 of the base. 
In FIGS. 14, and 14a, the unit 618 includes a base 619 which extends 
laterally to be connected to the pumping unit via cables or reins 617 
suspending a transverse lift bar 660. The lift bar in turn suspends the 
base 619 via guide rods 639, as shown. The sucker rod 610 extends upwardly 
through a bore 622a in bronze wear bushing or sleeve 622 in the base. 
Transverse lower members 624, supported by or integral with the base 619, 
carry shock absorbing cushion means 625 which may take the form of hollow 
cushions 625a like cushions 25a in FIG. 2. There are pairs of such 
cushions at opposite sides of a centered opening or space 626 which passes 
the rod 610, the cushions of each pair being vertically spaced or stacked, 
as shown. 
The cushions are confined between lower transverse members 624, and upper 
transverse members 627, with suitable mounting plates or retainers 628-633 
located at the upper and lower sides of each cushion, as shown, whereby 
the cushions of each vertical pair be vertically aligned or stacked. 
Upper member 627 is connected to clamp 638, via integral (insert) block 
637, spacer sleeve 675 and rotary thrust bearing 637a. The clamp is 
connected to rod 610 and rests on bearing 637a. Guide rods 639 project 
upwardly through guide sleeves or bushings 640 carried by insert block 
637, to guide the relative up and down movement of the transverse members 
624 and 627, and the cushions confined therebetween. Accordingly, guide 
means is provided to stabilize the members 624 and 627, base 619, block 
637 and the cushions, during stroking or pumping of a well. Adjusting nuts 
670 are threadably attached to the upper threaded ends 639a of the rods 
639 to enable adjustment of the connection to the reins 617 to the base 
619, to facilitate smooth up and down sliding of the guide rods in the 
sleeves 640. Holes 639a in plate 660 pass the rods 639. 
An air tank or acummulator 641 is connected to the cushions in the same 
manner that tank 41 is connected to cushions 25a in FIG. 2. 
Note that rods 639 in the space between the cushions defined an upright 
plane which intersects all the cushions. The same is true of the guide 
rods in FIG. 2. Accordingly, access of the cushions is unobstructed, as is 
clear from the drawings.