US2982355A

US2982355A - Pumping well apparatus

Info

Publication number: US2982355A
Application number: US711028A
Authority: US
Inventors: Rodgers Otis Ned
Original assignee: American Iron & Machine Works
Current assignee: American Iron & Machine Works; American Iron & Machine Works Company Inc
Priority date: 1958-01-24
Filing date: 1958-01-24
Publication date: 1961-05-02
Anticipated expiration: 1978-05-02

Description

4 Sheets-Sheet 1 May 2, 1961 o. N. RODGERS PUMPING WELL APPARATUS Filed Jan. 24, 1958 Of/J N90 Foo gems INVENTOR.

BYfi V ATTO/P/VE) y 2, 1961 o. N. RODGERS 2,982,355

' PUMPING WELL APPARATUS Filed Jan. 24, 1958 4 Sheets-Sheet 2 INVENTOR.

0. N. RODGERS PUMPING WELL APPARATUS I May 2, 1961 Filed Jan. 24, 1958 4 SheetsSheet Z5 Of/J A/ea Poo 76A;

INVENTOR.

ATTORNEY May 2, 1961 o. N. RODGERS PUMPING WELL APPARATUS 4 Sheets-Sheet 4 Filed Jan. 24, 1958 Of/J A/eo Poo yen:

INVENTOR.

ATTORNEY United States, Patent PUMPING WELL APPARATUS Filed Jan. 24, 1958, Ser. No. 711,028

Claims. c1. 166-68) This invention pertains to well pumping assemblies.

The objects of the invention are to prevent leakage of the tubing joints and wear of the pump rods on the tubing, without risking locking the tubing in the casing.

Other objects and advantages of the invention will appear from the following description of a preferred embodiment thereof, reference being made to the accompanying drawings wherein:

Figure 1 is a schematic section of a well incorporating a pumping assembly embodying the invention, the pump rod being on the downstroke;

Figure 2 is a view similar to Figure 1 except that the pump rod is on its upstroke;

Figure 3 is a vertical section through the tubing anchor used in the assembly;

Figure 4 is a horizontal section on line 4-4 of Figure 3;

Figure 5 is a horizontal section on line 5-5 of Figure 3;

Figures 68 are views similar to Figures 3-5 showing a modification; and 7 Figures 9' and 10 are views similar to Figure 1- showing installation of the modification.

Referring now to Figures 1 and 2, there is shown a well casing 10. The casing is perforated at 11 adjacent the producing formation to admit oil. The oil is pumped up and out of the well through a string of tubing 12. The tubing is hung concentrically inside the casing by means of a suitable slip suspension means 12A.

A tension in the tubing throughout its length in addition to that produced by its own weight is achieved by anchoring the tubing at its lower end and then pulling up on the tubing and holding it with the suspension means 12A. Thus, even at the lower end of the tubing where the tension due to its own weight approaches zero there will be at least a minimum tension of the desired amount.

The tubing anchor includes an upwardly pointing slip expander cone 13 on the lower end of the tubling. Around the cone are a plurality of slips 14 held in a cage 15-. The cage 15 does not allowthe slips to move vertically relative thereto but permits them to move radially in or out as the cone is moved down or up relative to the cage. When the tubing is being lowered intothe casing, the slip cage is held against axial movement relative to the expander cone by a slot 42 and pin 41 connection, the relative position of cage and cone being such that the slips are retracted. When it is desired to set the anchor the friction drag blocks 16 hold the cage against turning in the casing while the tubing is rotated to unlock the slot and pin connection. Upward movement of the tubing then causes the expander cone to move up relative to the slip cage to force the slips radially out into anchoring engagement with the casing.

The slip cage carries a pump barrel 20 at the lower end of which is a ball check standing valve 21. Beneath the standing valve is tailpipe 22. Instide the pump barrel is a piston 23w having a packing 24- therearound sealing to the pump barrel. A passage 25 through the piston is controlled at its upper end by a ball check traveling valve 2-6 connected to the upper end of the piston. The traveling valve is connected to the lower end of a string of sucker rods 27. The sucker rods are raised and lowered periodically by a suitable means, e.g. a hydraulic pumping unit 28. The traveling valve is open to the space inside of the tubing so that when the valve is open the tubing is in communication with the pump barrel through passage 25- as shown in Figure 1.

When, as shown in Figure 1, the piston and traveling valve are moving down the traveling valve is open and the standing valve is closed and the weight of the oil or other well fluid is on the well casing, being transmitted thereto from the standing valve through the pump barrel, slip cage, and slips. When, as shown in Figure 2, the piston and traveling valve are moving up, being pulled by the sucker rods, the traveling valve is closed and the standing valve is open. In this case the well fluid is entering the pump barrel through the standing valve and the weight of the well fluid in the tubing is on the sucker rods, being transmitted thereto from the piston and traveling valve.

It isclear therefore, that the tubing tension does not vary during the pumping cycle. On the upstroke the weight of well fluid is on the sucker rods and the tubing tension is taken by the slips and casing. On the downstroke the weight of the well fluid is on the slips thus helping the casing hold the tubing in tension. The initial minimum tension in the tubing is greater than the weight of the well fluid so that putting theweight of the well fluid on the slips does not increase the tubing tension, merely takes part of the force off the casing. Since the tubing tension does not vary, there is no working of the tubing joints during the pump cycle and hence no leaks are apt to develop.

Since the tubing is in tension it will be straight and consequently there will be little or no rubbing of the sucker rods on the tubing. It is to be noted that the sucker rods are also in tension since they hang freely under their own'weight or the added weight of well fluid on the upstroke. Therefore the sucker rod string will also be straight if the tubing is vertical. However if the tubing is not vertical there will be a slight catenary in the sucker rod string which may make it desirable to use sucker rod centralizersat a few points along the length of the string. The absence of kinks, buckling, and corkscrewing of the tubing makes it easy to use such centralizers if the need arises. The life of the sucker rods and tubing are thus prolonged due to the absence of wear caused by sucker rods rubbing on the tubing.

When it is desired to pull the tubing, for example to repair the pump, the tubing is lowered to drop the expander cone. Means such as dovetails on the slips engaging correlative slots in the expander cone cause the slips to be'retracted as the expander cone'moves down relative thereto, the slip cage remaining stationary due to the friction of the drag blocks against the casing. The locking means comprising the slot and pin connection are then re-engaged by rotation of the tubing, and the tubing string and parts dependent therefrom can all be removed.

Should the drag blocks fail to hold-the slip cage stationary during downward motion of the tubing, due to excess weight of pump barrel, standing valve, and tailpipe, or due to binding or jamming of the slips on the expander cone, whereby the slips are not fully retracted, the tubing can be lowered until the tailpipe touches bottom and positively prevents further downward movement of the slip cage. Suflicient weight of tubing can then be placed on the expander cone to force it down relative;

to the slips so that the slips are fully retracted and the Patented May 2, 1961 looking means can be engaged and the string withdrawn 7 from the well.

Referring now to Figures 3-5, there are shown the details of the tubing anchor which comprises a hollow mandrel 30 adapted to be connected to the tubing 12 and having tubular expander cone 13 screwed thereto. The hollow mandrel 30 thus provides tubular means for connecting the tubular expander cone 13 to the tubing 12; the cone 13 provides a tubular tapered slip expander means; and the mandrel 30 and cone 13 form a tubular body for the anchor on which the slips 14 and cage 15 are mounted. The slips 14 are disposed in openings 31 in the slip cage 15. Dovetails 32 on the slips engage slidably in correlative openings 33 in the expander cone. Friction drag blocks 16 are disposed in recesses 34 in the slip cage, being urged outwardly by springs 35 and limited in their outward motion by the heads of screws 36. The slip cage, drag blocks, and springs provide slip control means tending to hold the slips against axial movement relative to the casing while permitting radial in and out movement of the slips between a retracted position and an extended position in anchoring engagement with the casing.

There is a parting section of reduced wall thickness formed in the mandrel 30 at 37. In case the slips 14 cannot readily be freed from the expander cone 13, a suflicient upward pull on the tubing string will cause the mandrel 30 to break at parting section 37. The tubing will then contract quickly, and slip raising means in the form of flange 38, formed on the mandrel above the parting section, then cooperates with the slip control means by moving upwardly within annulus 39 between the mandrel and slip cage until it strikes inwardly extending radial flange 40 on the slip cage, the resulting impact on the slip cage jarring the slips free from the expander cone and raising the slips relative to the cone. If the first impact does not free the slips, the telescopic jointformed by the upper part of the mandrel and the slip cage can be operated as a jar by alternately lowering and raising the tubing string, the flange 38 alternately striking the lower part of the mandrel and the flange 40 to drive the cone and slips apart.

At the lower end of cage 15 is screwed pipe 15a adapted to slide on the cylindrical bottom extension 13a of the expander cone 13. Pipe 15a is limited in its upward movement relative to extension 13a by a downwardly facing shoulder 13b formed at the juncture of the upper part of cone 13 with its bottom extension 13a. It is at this shoulder that force is transmitted from the expander cone to the slip cage to force the latter down against the resistance of drag blocks 16 as the tubing string is lowered.

Pipe 15a carries a pin 41 which cooperates with inverted L-shaped slot 42 in extension 13a to form a means for releasably locking the cage to the expander cone against relative axial movement. rings 43, 44 seal between extension 13a and pipe 15a above and below the locking means to keep it free of dirt. By this means there is provided a fluid tight telescopic joint connecting the pump barrel to the tubing. In the position shown in Figure 3 the locking means is engaged, the pin 41 being in the upper part of the inverted L-shaped slot 42 and displaced azimuthally from the vertical part of the slot. The tubing can therefore be raised, if need be, without setting the slips. By turning the tubing clockwise a quarter turn the vertical part of the slot will come under pin 41 and the locking means will be released. The anchor can then be set by pulling up on the tubing, thus driving the slips radially outward with the cone until the slips bite into the casing. By the reverse procedure the slips are unset and the locking means re-engaged so that the tubing can be raised for removal or resetting at a different level. It is to be noted that the vertical extent of slot 42 is sufiicient to allow the slips to set. The vertical extent of annulus 39 is greater than the travel needed 4 to set the slips so that in the set position there is still space between flanges 38 and 40, thus providing a freedom of motion when the parting section 37 is broken and the slips are to be jarred free.

The teeth or wickers 50 on the slips 14 are neutrall directed so as to hold against both upward and down-- ward forces, although normally they will be called upon to hold only against upward pulls, that is, to function as holddown slips. However if the tubing tension should be initially set at less than the weight of well fluid being pumped, or if the tubing tension should slack off to such a value, then when the weight of well fluid is transferred to the slips they will transfer the load largely to the casing with very little added tension being placed 011 the tubing by the expander cone. In this latter case the slips serve as hold-up slips during at least half of each pump cycle.

In some wells the pump is desirably located at a level considerably above the producing formation, in some cases many hundreds of feet. In such cases there is a considerable length and weight of tailpipe extending down from the anchor. If the weight is greater than can be supported with certainty by friction drag blocks of reasonable size, the modified construction shown in Figures 6-10 may be used. This construction is in many respects identical with that of Figures 1-5 so that corresponding parts have been given the same number increased by 100.

Referring to Figure 6, the principal difference in the modified tubing anchor lies in the fact that the tailpipe 122 is hung from the downward extension 113a of the expander cone 113 rather than from pipe 115a screwed to the lower end of slip cage 115. This takes the tailpipe weight otf of the drag blocks 116 so that they can more certainly hold the slips axially stationary in the well casing when it is desired to set or unset the anchor.

It will be noted that in Figure 6 the anchor is shown in set position, the slips being moved radially outward from the position shown in Figure 3, so as to engage a well casing. When it is desired to release the anchor, the tubing is lowered and the drag blocks hold the slips axially stationary in the casing so that they are radially retracted as the tubing 130 and expander cone 113 move downwardly. There is no tailpipe weight tending to pull the slips down along with the cone. It is therefore possible to free the slips, and when pin 141 reaches the top of L slot 142, the tubing is rotated to re-engage this locking means preventing the slips from moving downwardly relative to cone 113 when the tubing is pulled up. The reverse procedure is followed in initially setting the anchor.

With the modified anchor of Figure 6, as with that shown in Figure 3, it is still possible that the slips may become so corroded after a long period in the well as to bind themselves to the expander cone so firmly that the resistance of the drag blocks cannot free them when an attempt is made to unset the anchor. Also, the springs of the drag blocks may lose their force or corrode to the point where they break, so that the drag blocks no longer engage the casing firmly enough to hold the slips axially stationary during the unsetting procedure. With the Figure 6 construction it is not possible to free the anchor by lowering the tailpipe to bottom, even if enough spare tubing length is available, for the slips are not connected to the tailpipe as in Figure 5. However the provision of the parting section 137 in the mandrel 130 and the telescopic joint between mandrel 130 and cage 115 provides a means of freeing the anchor and renders this modified construction practical.

The parting section construction shown in Figure 6 is slightly modified from that of Figure 3 in that mandrel portion below the groove 137 is of larger diameter, being equal to that of portion 161 above, so that the interior 162 of the mandrel opposite

portions

160, 161 and groove 137 can be machined and finished to a closer tolerance than the interior 163 of the rest of the mandrel whereby the thickness of the mandrel wall at the parting section is more accurately controlled.

The mandrel portion 160 below the groove also pro vides a shoulder 164 for sealing engagement with the upper end 165 of cone 113 when the threads between the mandrel and cone are fully made up.

Except as noted above, the tubing anchor construction of Figure 6 is thesame as that of Figure 3, and with the correlated numbering further description canbe obtained by referring back to the description of the Figure 3 construction. The same is true of Figures 7 and 8 when compared with Figures 4 and 5.

Referring now to Figure 9, there is shown a well including a pumping assembly and incorporating the modified tubing anchor of Figures 6-8. The part numbering corresponds to that of Figure 1, except for the addition of 100 to each number, so that the description of Figure 1 can be oorrelatedtherewith. Outside of the modified anchor construction, the only differences from the Figure 1 construction lies in the pump barrel 120, which instead of being of the same diameter as the tubing and tailpipe is of a smaller diameter so as to fit within seating nipple 170. After the tubing and anchor have been run into the well and the anchor set and the desired tension taken on the tubing, as with the Figure 1 construction, the whole pump including the standing valve 121, piston 123, packing 124, traveling valve 126, and barrel 120 are lowered through the tubing on thesucker rods 127 until the barrel rests on seat 171 in the seating nipple, whereupon conventional means, not shown, automatically latches the barrel in place.

The pump seating nipple is connected in the tubing string by means of

couplings

180, 187. The preferred location is just above the tubing anchor as shown in Figure 9; however the seating nipple and pump can be located above or below the preferred position, if desired, including locations below the anchor in the tailpipeas in Figure 1.

It is preferred to place the seating nipple above the parting section 137 so that if the sucker rods break, the impact of their weight as they fall and the pump piston is driven against the standing valve will not be taken by the parting section, which might otherwise part under such loading. Breakage of the parting section would necessitate pulling the tubing as well as fishing out the sucker rods. It will be noted from Figure 9 that the parting section 137 is of less wall thickness than the tubing 112, which is inherent in its function of parting under sufficient tubing tension.

Another reason for placing the pump seating nipple above the anchor is that the pipe below the anchor is not tensioned by the anchor.

It is preferred to place the seating nipple immediately above the tubing anchor so as to gain the stabilizing effect of the anchor which holds the tubing string to the casing. Also, any section of pipe below the pump need not be placed in tension.

Although in Figure 9, and also in Figure 10, as will be described, a pump barrel is shown that is run into the well intoa seating nipple after the tubing-has been run in, it will be understood that pump barrels forming part of the flow string as in Figures 1 and 2 can also be used with the anchor of Figures 6-8.

Figure 10 illustrates the installation of the Figure 6 anchor in a well similar to Figure 9 except that the tubing suspension at the well head is by means of a threaded flange 190 instead of slips 112A as in Figure 9. Such a suspension does not allow for taking an upward pull on the tubing to place it in tension. With this arrangement the tubing can be tension ed by filling the tubing with fluid, e.g. by operating the pump, which will cause the anchor to creep down the inside of the well casing, and then placing the weight of the sucker rods on the tubing through the pump piston, standing valve, pump barrel and seating nipple. This procedure will place a greater weight on the anchor than it will ever encounter during normal pumping operations so that there will be no slight movement of the anchor as the weight of well fluid is alternately imposed on the tubing and the sucker rods during pump operation.

It is to be noted that with the anchor of Figures 6-8 installed as shown in Figures 9 and 10, if the tubing tension is greater than the weight of well fluid in the tubing, there will be no variation in the tubing tension as the pump operates. Instead, there will be merely a periodic reduction of the load transmitted by the slips of the anchor to the casing Whenever the pump piston is on the downstroke and the column of well fluid in the tubing is supported on the standing valve. The anchor of Figures 6-10 then has all the advantages of the anchor of Figures l5 as to elimination of working of the tubing joints and consequent reduction of leakage as well as straightening of the tubing with consequent reduction of wear between. tubing and sucker rods, prolonging the life of both the sucker rods and tubing.

' Although the anchoring device described hereinabove has been indicated to be useful as a tubing anchor in combination with a pumping well assembly, it will find utility whenever it is desired to anchor a device in a well or the like where the slip expander means operates to set the slips by an upward pull, for through the operation of the load transfer means comprising the parting section and associated telescopic joint, the device can be transformed so that an upward pull tends to unset the slips. V

While preferred embodiments of the invention have been shown and described, many modifications thereof can be 'made by one skilled in the art without departing from the spirit of the invention and it is desired to protect by Letters Patent all forms of the invention falling within the scope of the following claims.

What I claim is:

1. A well pumping assembly comprising a well casing, a string of tubing inside said casing, means at the upper end of said casing for suspending the tubing from its upper end, a tubing anchor in said casing at a lower part of said tubing holding the tubing thereabove in tension throughout its length after said tubing anchor is set, and a pump in said tubing above said anchor; said anchor comprising a tubular body including a tubular tapered slip expander means and a hollow mandrel connecting said slip expander means to said tubing, a pluralityof slips around said slip expander means, and slip control means connected to said tubular body tending to hold said slips against axial movement relative to said casing while permitting radial movement of said slips between a retracted position and an extended position in anchoring engagement with the casing; said hollow mandrel including a parting section, said parting section comprising a length of said hollow mandrel having a reduced wall thickness and integral with adjacent portions of said mandrel, said reduced wall thickness of said parting section being less than the wall thickness of said tubing, and slip raising means on said mandrel above said parting section adapted to engage with said slip control means when said parting section has been parted to raise said slips relative to said slip expander means, whereby upon application of tension to said string of tubing suflicient to rupture said parting section an impact blow is produced on said slip raising means due to contraction of said string of tubing.

2. A pipe anchor comprising a tubular slip expander means, tubular means for connecting said slip expander means to a string of pipe, said tubular means including a parting section of tubular form having cylindrical interior and exterior surfaces, said slip expander means including an upwardly pointing expander cone, a plurality of slips around said cone, slip control means allowing radial movement of said slips but preventing axial movement of said slips relative to said slip control means, and means on said tubular means above said parting section adapted to be engaged with said slip control means when said parting section has been parted to raise said slips relative to said cone, said parting section comprising a length of said tubular means that has a reduced wall thickness as compared to the remainder of said tubular means, said parting section being integral with the portions of said tubular means on both sides thereof, said parting section having a reduced strength relative to axial tension as compared to the remainder of said tubular means.

3. A pipe anchor in accordance with claim 2 in which said slip expander means includes means on said cone engaging said slips to prevent relative motion therebetween except translation parallel to an element of the cone, whereby upward movement of said slips relative to said cone draws said slips inwardly.

4. A pipe anchor according to claim 2 in which said slip control means includes a tubular slip cage having windows therein receiving said slips, a tubular portion on the upper end of said slip cage surrounding and spaced from said tubular means providing an annulus therebetween, and a radial inturned annular flange at the upper end of said tubular portion, and said means on said tubular means adapted to be engaged with said slip con trol means includes a radial annular out-turned flange on said tubular means disposed within said annulus, and said slip control means further includes a pin and slot connection between said slip cage and said slip expander means, said slot having a vertical portion and a circum- '8 ferential portion at the upper end thereof, said vertical portion having a length greater than the axial travel of said slips relative to said slip expander means and less than the axial length of said annulus.

5. The combination of claim 2 in which said slip control means includes a tubular slip cage having windows therein receiving said slips, a tubular portion on the upper end of said slip cage surrounding and spaced from said tubular means providing an annulus therebetween, and a radial inturned annular flange at the upper end of said tubular portion, and said means on said tubular means adapted to be engaged with said slip control means includes a radial annular out-turned flange on said tubular means disposed within said annulus, and the slip expander means has a threaded socket at its upper end receiving a threaded pin on the lower end of said tubular means, a second radial out-turned flange on said tubular means above said threaded pin and below the first said radial out-turned flange forming a sealing shoulder engaging the upper end of said socket, and wherein said parting section is between said radial out-turned flanges, the inner surface of said parting section being a finished surface.

References Cited in the file of this patent UNITED STATES PATENTS 2,338,370 Wilson Jan. 4, 1944 2,350,973 Brumleu et a1. June 6, 1944 2,442,121 Earley May 25, 1948 2,564,240 Ware Aug. 14, 1951