US3251310A - System for oil well production - Google Patents

Description

May 17, 1966 w w R ETAL 3,251,310

SYSTEM FOR OIL WELL PRODUCTION Robert J. Wiffwer Ofhar M. Kiel INVENTORS'.

ATTORNEY May 17, 1966 ,w1 w ETAL 3,251,310

SYSTEM FOR OIL WELL PRODUCTION Filed June 25, 1964 3 Sheets-Sheet 2 INVENTORS.

7 ATTORNEY May 17, 1966 w w ETAL 3,251,310

SYSTEM FOR OIL WELL PRODUCTION 3 Sheets-Sheet 5 Filed June 25, 1964 w m Hu k J M mm 0m R O 6 M F %00 M ATTORNEY United States Patent 3,251,310 SYSTEM FOR OIL WELL PRODUCTION Robert J. Wittwer and Othar M. Kiel, Tulsa, Okla., assignors, by mesne assignments, to Esso Production Research Company, Houston, Tex., a corporation of Delaware Filed June 25, 1964, Ser. No. 377,946 8 Claims. (Cl. 103-212) This invention relates to the production of fluid from a subterranean formation. It relates especially to the pumping of fluid from subterranean formations .in which a pump is suspended at the lower end of a string of tubing and is actuated by the reciprocation of a string of sucker rods extending downwardly through the string of tubing to the pump.

Most oil wells are produced by flowing the oil upwardly through a string of tubing suspended concentrically within casing which is a larger diameter tubing located between inner tubing and Well bore. In many wells the pressure of the formation fluids is insufficient to force the oil upwardly through the tubing to the surface. In such a situation the most common means of producing the oil is by placing a pump in the lower end of the tubing in a vertical position or elevation which is below the normal or natural liquid level within the well bore. The pumpis actuated by the reciprocation of sucker rods which extend from the surface down through the interior of the string of tubing .to the pump. The upper end of the top section of the sucker rods is connected to a polished rod which extends upwardly through a stufling box which encloses the upper end of the string of tubing. Pumping power means are provided at the surface for periodically raising and lowering the sucker rods so as to reciprocate ,the pump. The oil is pumped upwardly through the tubing around the polished rod to the surface.

Frequently it is desired to know the weight which is supported by the polished rod.- This weight includes the Weight of the sucker rods, plus the weight of the fluid being pumped, plus certain dynamic loads. Equipment for measuring the loads during the pumping cycle is called a dynamometer. This invention provides a novel means of positioning a dynamometer into the pumping system.

The bottom-hole pump, that is the pump reciprocated by the sucker rods, has valves, which are normally some form of check valves, to regulate the direction of the flow of fluid. In some pumping wells, sand, scale, corrosion products, etc., foul the valves and cause them to stick. The valves must be freed before the pump will operate properly. This can usually be done fairly easily on the many wells pumped with gas-type engines which are variable speed engines. On these type prime movers, freeing of the' stuck valves can usually be accomplished by speeding up the engine. This makes the sucker rods reciprocate faster and increases the stretch in the sucker rods. The reciprocating part of the pump as a result of additional stretch hits the standing or fixed portion of the pump, thus jarring it. This jarring action can be referred to as hitting bottom and many times is adequate to free stuck valves. However, this trick cannot be used on wells pumped with conventional electric motors which are essentially constant speed motors. As will be seen, with applicants invention means are provided whereby the pump can be made to hit bottom to free stuck valves without increasing the speed of the engine.

Various other objectsv and an understanding of the invention can be had from the following description taken in conjunction with the drawing in which:

FIG. 1 is a view of a part of the well head pumping equipment showing the carrier bar spaced from the polished-rod clamp by a spacer bar;

FIG. 2 illustrates a wedge device and a dynamometer means positioned between the carrier bar and the polished rod clamp;

FIG. 3 illustrates, in enlarged form, the wedge means illustrated in FIG. 2;

FIG. 4 illustrates a load cell dynamometer;

FIG. 5 illustrates one form of spacer bar for use in the system of FIG. 1 and FIG. 2;

FIG. 6 illustrates, in simplified form, a down-hole well pump; and

FIG. 7 is a view taken along the line 77 of FIG. 3.

Turning 'to the drawing, FIG. 1 in particular, there is shown a casing 10 which extends from above the surface of the earth downwardly encasing'a well bore. The top of casing 10 is closed by cap 12 through which extends tubing 14. Tubing 14 has a horizontal port means 17 through which the pumped fluid is removed. Apolished rod 16 extends downwardly through stufiing box 18 and attaches to the sucker rods 11 which are attached to a bottom-hole pump as shown in FIG. -6. The polished rod, sucker rods, stufiing box, tubing and easing are conventional in their relationship to each other as is wellknown to those skilled in. the art.

Attention is now directed toward that part of the apparatus used for reciprocating the polished rod. Shown in FIG. '1 is that part of the pumping unit known as the walking beam 20 having a horse head 22 connected at the end thereof. As is well known, the walking beam 20 is pivoted in a conventional manner and causes the horse head 22 to move generally up and down Connected to horse head 22 are bridle means 24, such as wire rope. The lower end of bridle means 24 is connected to a car- ,rier bar 26 which loosely fits about rod 16. This is accomplished by carrier bar 16 having a hole 28 of slightly larger diameter than the polished rod 16.

Mounted above carrier 26 is a spacer bar 30 which is more clearly shown by itself in FIG. 5. Spacer bar v30 preferably has a slit 32 so that it can be readily placed about polished rod 16. Mounted above spacer bar 30 is a polished-rod clamp 34 which is longitudinally fixed with respect to the polished rod 16. In operation, upward movement of the horse head causes bridle 24 to be forced upwardly. The upward force is. transmitted through carrier bar 26 through spacer bar 30 to clamp 34 to polished rod 16. This forces the polished rod 16 upward to the top of the stroke. When the horse head 22 is lowered, the weight of the polished rod and sucker rods causes the rod 16 to go downwardly through stufling box 18. Clamp 34 moves withthe polished rod. The

vertical distance through which the polished rod moves is a measure of the stroke of the pumping system. Theupward movementof horse head 22 is commonly referred to as-the up-stroke and the downward movement as the down-stroke. Pumping of the well is effected by raising and lowering horse head 22.

As mentioned above, in some pumping wells, sand, scale, corrosion products, etc., foul the valves in the pump at the bottom of the tubing. It frequently becomes necessary to unstick valves. In order to better understand 3 this problem, attention is directed to FIG. 6 which shows in schematic and simplified form a down-hole reciprocating-type pump. Casing 10 is shown extending through the producing zone 57. The casing has perforation 63 through which oil flows into the well bore. The lower end of tubing 14 has a restriction 15 which is of a smaller diameter than the balance of the tubing. Shown in the bottom end of tubing 14 is a pump housing 61. The lower end of pump housing 61 is forced into restriction 15 to fix the housing with respect to the tubing. The lower end of housing 61 is provided with an annular bottom enclosure 60. The standing valve of the pump includes a ball 64 which seats on valve seat 66. When ball 64 is seated, the lower end of pump housing 61 is closed. It can readily be seen that the standing valve permits the flow of fluid only upwardly into the interior of the pump below plunger or piston 68. Web 59 forms a cage limiting the upward movement of ball 64. An upwardly facing annular shoulder 65 is aligned with the downwardly facing shoulder 67 of plunger 68. Bottom enclosure 60, web 59 and shoulder 65 are substantially stationary. The sucker rod 11 is connected to plunger 68 by lock nut 69. Piston or plunger 68 is machine fitted within the interior pump body. The polished rod and clamps are normally adjusted so that when the pump is at the bottom of its stroke there is a clearance x between plunger 68 and face 65 of about A to /2 inch. The stretch of the rod is greater when the fluid in the borehole is below the pump, i.e. when the well is pumped 01f, than when the well is pumping fluid. The unit is set to obtain the clearance x under maximum stretching.

Plunger 68 carries a traveling valve which includes a passage 74 having a seat 75 onto which a ball valve 76 is fitted. Web 77 limits upward movement of ball 76. Thus, fluid can flow only upwardly through passage 74 and out port means 84 in the upper end of cap 86 of pump housing 61. Fluid is pumped conventionally by reciprocating plunger 68 within pump housing 61.

When it is desired to determine the load carried by the rods 11, a dynamometer or load cell 36 is placed on top of carrier bar 26 as shown in FIG. 2. It is possible to insert the load cell because clamp 34 and carrier bar 26 are held apart by spacer bar 30. The wedge device 38 shown in greater detail in FIG. 3 and FIG. 7 is inserted between load cell 36 and the polished-rod clamp 34 as shown in FIG. 2. In the device as shown in FIG. 1 the force between carrier bar 26 and clamp 34 is carried through spacer bar 30. When it is desired to determine the load, the pump is stopped and wedge 38 is driven to its extended position. When in this position, spacer bar 30 is relatively free and can be removed, if desired. However, it is not necessary to remove spacer bar 30 but merely to extend wedge 38 until all force is transmitted through the load cell 36 and wedge 38 and none through spacer bar 30. After the wedge is extended, the pump is started and the load measured with the well pumping. When it is desired to remove the dynamometer, the pump is stopped and wedge 38 is retracted so that spacer bar 30 supports the load between carrier bar 26 and clamp 34. If spacer bar 30 has been removed it is again put in place before retracting the wedge means. The wedge and dynamometer are removed after retraction of the wedge. Suitable load cells 36 are commercially available. For example, a suitable dynamometer is a type No. 1011 manufactured and sold by Lockheed Electronics Company of Mutchen, New Jersey.

The wedge is shown in more detail in FIG. 3. It includes an upper section 40, a lower section 42, and a middle section 44. The lower side of upper section 40 has an inclined plane which mates with the upper side of middle section 44. The upper side of the bottom section 42 defines an inclined plane which mates with the lower surface of wedge member 44. Upper section 40, lower section 42 and middle section 44 are designed such that when placed together as shown in FIG. 3, the upper face of upper section 40 is parallel to the lower face of lower section 42. This remains true for any position, e.g. contracted or expanded, of the wedge. End blocks 46 and 48 are fitted in the end grooves of wedge sections 40, 42, and 44. As can be seen more clearly in FIG. 7, middle section 44 contains bores which are of slightly larger diameter than bolts 50 and 52. Bolts 50 and 52 extend through these bores. Upper section 40 and lower section 42 are provided with partial bores 82 and 83 which mate with bores 80 when the wedge is in its retracted position. Bolts 50 and 52, having heads 54 and 56, respectively, on the exterior of the blunt end of middle member 44, extend through the bores 80 and partial bores 82 and 83. The bolts 50 and 52 threadedly extend through end members 46 and 48. The wedge device is retracted or expanded by proper rotation of heads 54 and 56. In operating the wedge device, the upper member 40 and lower member 42 move only in a vertical direction or, stated differently, in a direction perpendicular to the movement of wedge member 44. End members 46 and 48 prevent horizontal movement of upper section 40 and lower section 42.

To momentarily summarize, when it is desired to determine the load on the polished rod 16, dynamometer 36 and wedge 38 are placed between clamp 34 and carrier bar 26. The wedge member 38 is then operated by turning bolt heads 56 and 54 until the wedge is extended suf-' ficiently to take any force oif spacer bar 30. Then, at this time, a load reading can be taken from dynamometer 36. After the load reading has been taken, the wedge 38 is retracted by turning the bolt heads 54 and 56 in the opposite direction and retracting the wedge. The wedge and the load cell dynamometer can then be removed and used at another well which contains a spacer bar assembly shown in FIG. 1.

During pumping operations, one of the ball valves 76 and 64 frequently becomes stuck. When this occurs, some action must be taken to relieve the sticking condition. A convenient way of doing this is to make the shoulder 67 of plunger 68 hit bottom by striking stationary shoulder 65. This jars the valves free. However, with an electric motor the stretch in the rods remains constant as the electric motor is normally of constant speed. To vary the speed, gears or sheaves must be changed. This is a very awkward way of doing things. However, with applicants system the clearance "x between the plunger 68 and face or shoulder 65 can be readily adjusted so that the device, when reciprocated, hits bottom and quickly unsticks the stuck valves. This is readily accomplished by placing wedge 38 about spacer bar 30 between carrier bar 26 and polished-rod clamp 34. The wedge is then operated into its extended position so that the spacer bar 30 can be removed. Then the wedge device is retracted so that clamp 34 is closer to carrier bar 26. This, in effect, lowers the entire length of polished rod 16, sucker rod 11, and also plunger 68 so that the clearance 2: between plunger 68 and face 65 is reduced to zero when the pump is reciprocated.

By lowering the polished rod this distance, when the pump is again started, the stroke is the same, but the entire moving assembly has been lowered a distance x. This enables plunger 68 on each downstroke to strike shoulder 65. The well is then started up and allowed to reciprocate for a short period of time, e.g. approximately one or two minutes, with the plunger 68 hitting bottom. This will normally unstick the valves. The well is then stopped, the wedge is expanded to a greater than normal extended position so that the spacer bar 32 can be placed about polished rod 16 between carrier bar 26 and clamp 34. The wedge is then contracted and removed. Normal pumping operations are then resumed. Alternatively, spacer bar 32 can be left out and wedge 38 remains between clamp 34 and box 36 to space the two apart. Then, whenever it is desired to move clamp 34 longitudinally with respect to carrier bar 26, all that is necessary is to retract or expand the wedge which is held firmly between clamp 34 and carrier bar 36.

While there are disclosed but a limited number of embodiments of the system of the invention herein presented, it is possible to produce other embodiments with-out departing from the inventive concept herein disclosed. It is therefore desired that only such limitations be imposed on the appended claims as are stated therein.

What is claimed is:

1. An apparatus for use in a system for pumping fluid from a well bore in which a polished rod extends through a stuffing box and an upward force is applied through bridle rope means, the improved combination which comprises:

a polished-rod clamp-connected to said polished rod in a longitudinally fixed relationship;

a carrier bar reciprocally mounted on said polished rod beneath said polished-rod clamp, said carrier bar connected to said bridlerope means; and

a spacer bar loosely fitting and surrounding said polished rod and spaced between said polished-rod clamp and said carrier bar, for maintaining said polished-rod clamp and said carrier bar a fixed distance apart.

2. An apparatus for use in a pumping system in which a polished rod is used to operate a down-hole pump, the improvement which comprises:

a polished-rod clamp rigidly clamped to said polished rod;

a carrier bar loosely mounted about said polished rod below said polished-rod clamp;

a spacer bar loosely mounted about said polished rod between said polished-rod clamp and said carrier bar, for maintaining said polished-rod clamp and said carrier bar a fixed vertical distance apart; and bridle rope means connected to said carrier bar for exerting a force on said carrier bar such that said spacer bar is held tightly between said carrier bar and said polished-rod clamp. 33. An apparatus wherein a polished rod is used to operate a down-hole pump, the improvement which comprises:

a polished-rod clamp rigidly clamped to said polished v rod;

a carrier bar loosely mounted about said polished rod below said polished-rod clamp;

a spacer bar means loosely mounted about said polished rod between said polished-rod clamp and said carrier bar;

bridle rope means connected to said carrier bar for exerting a force on said carrier bar such that'said spacer bar is held tightly between said callrier bar and said polished-rod clamp; and

means insertable between said polished-rod clamp and said carrier bar for forcing said clamp and said bar apart.

4. In the art of pumping fluid from well bores in which a polished rod is connected through a stuffing box to a pump suspended in a string of tubing, such pump having a plunger reciprocated by said polished rod and a stationary means holding a standing valve within said string of tubing and in which a polished-rod clamp is rigidly clamped to the polished rod and a carrier bar is loosely mounted about the polished rod below said polished-rod clamp and in which an upward force is periodically applied to the carrier bar so that the carrier bar and polishedrod clamp are reciprocated vertically in a fixed spacial relationship, and whereby there is clearance between the plunger and said stationary means when the plunger is at then reciprocating said polished rod until said stuck valve is jarred free; and

thereafter increasing the distance between said carrier bar and said polished-rod clamp by raising said clamp and said polished rod so that when reciprocating said polished rod the plunger does not strike said stationary means; 1

5. An apparatus for use in a system for pumping fluid from a well bore in which a polished rod extends through a stufling box and an upward force is applied through bridle rope means, the improved combination which comprises:

a polished-rod clamp connected to said polished rod in a longitudinally fixed relationship;

a carrier bar reciprocally mounted on said polished rod beneath said polished-rod clamp, said carrier bar connected to said bridle rope means; and

adjustable wedge means positioned between said polished-rod clamp and said carrier bar.

6. In the art of pumping fluid from well bores in which a polished rod is connected through a stufling box to a pump suspended in a string of tubing, such pump having a stationary means and a plunger means reciprocatable by said polished rod and in which a polished-rod clamp is clamped to the polished rod in a fixed longitudinal relationship and a carrier bar is loosely mounted about the polished rod below said polished-rod clamp and in which an upward force is periodically applied to the carrier bar so that the carrier bar andpolished-rod clamp are reciprocated vertically in a fixed relationship, whereby there is a clearance between the plunger means and said station ary means when the plunger means is at the bottom of its stroke, the improvement of freeing a stuck valve in said pump which comprises:

decreasing the distance between said carrier bar and said polished-rod clamp so that when said plunger means is at the lower end of its stroke it strikes said stationary means;

then reciprocating said polished rod so that said plunger means strikes said stationary means a number of times;

increasing the distance between said carrier bar and said polished-rod clamp;

and thereafter reciprocating said polished rod to pump fluid upwardly through said tubing.

7; An apparatus wherein a polished rod is used to operate a down-hole pump, the improvement which comprises:

a polished-rod clamp rigidly clamped to said polished rod;

a carrier bar loosely mounted about said polished rod below'said polished-rod clamp;

a spacer bar means loosely mounted about said polished rod between said polished-rod clamp and said carrier bar;

bridle rope means connected to said carrier bar for exerting a force on said carrier bar such that said spacer bar is held tightly between said carrier bar and said polished-rod clamp;

adjustable wedge means; and

dynamometer means; said dynamometer means andsaid adjustable wedge means being mounted about said spacer bar between said polished-rod clamp and said carrier bar. 8. An apparatus for use in a system for pumping fluid from a well bore in which a polished rod extends through a smiling box and an upward force is applied through bridle rope means, the improved combination which comprises:

a polished-rod clamp connected to said polished rod in a longitudinally fixed relationship;

a carrier bar reciprocally mounted on said polished rod beneath said polished-rod clamp, said carrier bar connected to said bridle rope means;

adjustable wedge means positioned between said polis parallel to the lower face of said lower memished-rod clamp and said carrier bar, said adjustable her; and wedge means including: means for forcing said middle member between an upper member having an upper face and a lower said upper member and said lower member,

face which are nonparallel;

a lower member having an upper face and a lower face which are nonparallel;-

a middle member having an upper face mating whereby the upper face of said upper member remains parallel to the lower face of the lower member as the two members are forced apart.

References, Cited by the Examiner with the lower face of said upper member and the lower face mating with the upper face of said 10 UNITED STATES PATENTS lower member, Said upper member, said IOWBI' 1 7 243 919 cousins 10 1 X member, and said middle member being con- 1:639:516 3/1927 Langham 61 451 X structed such that when said middle member is 2,107,556 2/1938 Watson between said upper member and said lower memr her that the upper face of said upper member 10 ROBERT M. WALKER, Primary Examiner.

Claims (1)

1. AN APPARATUS FOR USE IN A SYSTEM FOR PUMPING FLUID FROM A WELL BORE IN WHICH A POLISHED ROD EXTENDS THROUGH A STUFFING BOX AND UPWARD FORCE IS APPLIED THROUGH BRIDLE ROPE MEANS, THE IMPROVED COMBINATION WHICH COMPRISES: A POLISHED-ROD CLAMP CONNECTED TO SAID POLISHED ROD IN A LONGITUDINALLY FIXED RELATIONSHIP; A CARRIER BAR RECIPROCALLY MOUNTED ON SAID POLISHED ROD BENEATH SAID POLISHED-ROD CLAMP, SAID CARRIER BAR CONNECTED TO SAID BRIDLE ROPE MEANS; AND

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