US2051089A - Gravity down stroke pump - Google Patents

Description

2v Sheets-Sheet l H T LAMB, JR GRAVITY DOWN STRQKE PUMP Filed Aug. 26

Aug.

Aug. 18, 1936. H. T. LAMB, JR

GRAVITY DOWN STROKE PUMP 2 Sheets-'Sheet 2 Filed Aug. 26, 1935 'IIJ Patented Aug. 18, 1936 parte Zhtt GRAVITY DVVN STROKE PUMP Homer T. Lamb, 5r., yEulsa, Okla. Applicatien August 26, i935, Serial No. 37,909

9 Claims.

This invention relates to well pumping apparatus and more particularly to a gravity downstroke pump, especially for oil wells, to effect removal of oil from anoil bearing formation.

The principal object of the present invention is to provide a displacement pump of this character utilizing the weight of the rods, which is substantially greater than the weight of a column of fluid in the tubing, for forcing the well fluid to the surface of the earth, in such a manner that the rod reciprocating mechanism at the top of the well is loaded with the weight of the rods only.

Further objects of the invention are to provide a pumping apparatus carried within the well tubing which may be removed from the well without the necessity of removing the well tubing; t provide a static fluid chamber of considerably greater capacity than the capacity of the working barrel whereby friction is substantially eliminated; to provide an effective exhaust for the apparatus of greater cross-sectional area than the working barrel of the pump, whereby back pressure against the pump is prevented; and to provide an efficient apparatus of this type.

In accomplishing these and other objects of the invention, I have provided improved details of structure, the preferred form of which is illustrated in the accompanying drawings, wherein:

Fig. 1 is a Vertical elevation of my improved pump attached to the lower end of a well tubing, parts of the shell thereof being broken away to better illustrate the relative positions of the parts of the pump.

Fig. 2 is an enlarged vertical section of the pumping apparatus showing the connection with the pumping rods, with the piston starting its upstroke and the inlet valve in open position.

Fig. 3 is a vertical section showing the piston on its down-stroke with the oil inlet closed and exhaust valves in open position.

Fig. 4 is an enlarged detail vertical section showing the pilot on the working barrel partly removed from its seating shoe.

Fig. 5 is a horizontal section on the line 5 5, Fig. 2.

Fig. 6 is a horizontal section on the line 6 6, Fig. 2.

Fig. '7 is a horizontal section on the line 1 1, Fig. 2.

Fig. 8 is a horizontal section on the line 8 8, Fig. 2.

Fig. 9 is a vertical section through a well similar to Fig. 2, and showing a modified form of working barrel and piston.

Referring more in detail to the drawings:

(Cl. 103 l.55)

l designates a string of well tubing suspended by customary connections (not Shown) at the head of a well hole 2 and extending approximately to an oil bearing formation 3. The lower end l of the tubing is externally threaded and attached 5 thereto is an internally threaded collar 5. The collar suspends a nipple Ei by the externally threaded reduced upper end 'l of the nipple and a shell S is depended below the nipple Ei by means of an externally threaded collar 3 which engages the internal threads of the nipple and shell, the shell 8 containing my improved vpumping apparatus.

ID designates an externally threaded cylindrical block to the lower end of which is attached the shell Il by internal threads at the upper end thereof. The shell il is comparatively long and extends downwardly in such a manner that a static fluid chamber IZ of considerable capacity is provided for containing oil pumped from the formation as later described. The lower end of the shell Il is internally threaded to receive the external threads of a plug i3 which is centrally bored. as at Ul, and internally threaded at its lower end to receive the externally threaded upper end of the screening device l5. The screening device I5 preferably comprises a perforated length of pipe having a closed end (not shown) which extends well within the oil bearing formation but which precludes entrance to the tubing of matter foreign to oil.

The upper portion of the plug bore i4 is offset as at IE, to receive a valve seat ring I1 of the same inner diameter as the bore il and having a peripheral boss i8 adapted to seat on they upper end of the plug. The valve seat is provided with an integral central bearing portion i9 connected with the valve seat ring il by radial arms 2D, the bearing portion i9 being centrally bored to receive the valve stem 2l of a gravity valve 22. The lower face of the valve 22 is tapered inwardly as at 23 to seat on a corresponding outward taper 2li at the upper end of the ring il and the valve and valve stem are held in operable position relative to the ring il by a nut 25 or the like on the lower end of the valve stem. T he plug i3 is additionally offset inwardly and threaded, as at 2B, to receive an internally threaded collar 21 which fits over the valve seat ring ll and has an inwardly extending boss 28 for clampingly engaging the valve seat ring boss I8 to retain the valve seat within the plug.

The cylindrical block l, a cross section of which is shown in Fig. '7, has apertures 29 for passing cil in a manner later described. The ap- 55 ertures 29 are threaded at their upper ends to receive individual externally threaded extensions 3i] adapted to receive ball Valve seats 3i fitting within the aperture extensions and having bosses 32 engaging over the upper end of the extensions 30. The valve seats are centrally bored to a diameter sucient to pass oil from the formation and yet seat ball valves 33. Internally threaded ball valve cages 34 are screwed onto the aperture extensions 35, the threads of the cages being suiciently cut back from the interior of the cages to form shoulders 35 for retaining the valve seats 3l in position on the extensions. The valve cages are also provided with orifices 35 and 3'! in such a manner that the cages may retain the ball valves in operable position and yet pass a quantity of oil sufiicient to prevent any back pressure due to frictional inuences of the ow of oil on the valves in relation to pressure behind the oil owing through the valves.

The block I0 is also centrally bored, as at 38, and internally threaded, as at 39, to receive and retain a seating shoe 4G. The seating shoe 40 is inwardly tapered at its upper end, as at 4l, for guiding a pilot 42 to an enlarged pocket 43 at the lower end of the seating shoe, the pocket being inwardly tapered as at 44, as best shown in Fig.

4, to retain the pilot in the shoe, as later described.

Suspended within the tubing I and connected to a suitable prime mover (not shown) at the head of the well is a string of rods 45 extending below the tubing into the sleeve 6, as best shown in Figs.

2 and 3, and which is provided at its lower end with a squared internally threaded socket 46. Threaded into the socket 46 is the externally threaded upwardly projecting end 41 of a valve cage 48 which is provided with orices 49 for allowing escape of oil into the tubing, as later described. The lower end of the valve cage is internally threaded to receive an externally threaded lock nut 50 for retaining a valve seat 5| and ball'valve 52 in position within the valve cage 49. The lock nut 59 is centrally bored and threaded to receive an externally threaded hollow tube 53 which extends downwardly below the tubing rods and which is perforated as at 54, for admitting oil to the tubing for a purpose later described. The tube 53 is externally threaded at its lower end to mount a lock nut 55 and a piston 55.

The piston 5S comprises a cylindrical block of suitable metal which is tooled tov provide a series of grooves for receiving alternate, slotted and preferably bronze rings 5l and movable steel inserts 58. The bronze rings are slotted to provide for expansion and contraction and are held in position on the piston by a set screw (not'shown) set into theY piston. The rings are also positioned eccentrically on the piston so that a seal is always eected between the piston and the working barrel 59. 'I'he steel inserts are loosely mounted on the piston between the bronze rings and are recessed on their inner surfaces to collect abrasive particles and other foreign matter accumulating on the piston.

The working barrel 59 comprises, in part, a stuiling box iii) which is centrally bored and internally threaded for slidably tting over the perforated tube 53. The bore of the stuing box is provided with a packing gland 6 I of suitable material which is held in position by a stop collar 62 adapted, by the upper externally threaded end thereof, to be screwed into the stuiiing box Si).

The stop collar 62 is provided with an enlarged circumferential boss, below the threads at its upvassembled as described is as follows:

per end, oi the same diameter as the Working barrel 59, but is again reduced below the boss and threaded to receive the internal threads 63 of the upper end of the working barrel. The stop collar is further reduced and extended, as at 64, to 5 provide a sliding bearing surface for the piston tube 53 and a stop 64 at its lower end engageable by the lock nut 55 011 the piston, when the tubing rods are raised above the normal stroke of the pump at the surface of the well, for removing the 10 entire working barrel assembly.

The working barrel is further provided at its lower end with internal threads for receiving the external threads of the pilot 42. The pilot is tapered inwardly as at 61 to seat in the outward l5 taper 4l of the pilot shoe 4U and is then extended downwardly from the smaller diameter to terminate in an outwardly tapering ilange 68 which, when the working barrel is lowered, is caught in the pocket 43 of the shoe. The pilot is slotted as 20 at 69 to provide for compression thereof, in such a manner that as the inwardly tapered end 10 of the pilot is lowered into the shoe, the pilot will be compressed to smaller size. Upon continued lowering, however, into the pocket 43, the pilot, being 25 formed of a suitable spring steel, or the like, will resme its original shape to retain the pilot within the pocket by reason of the flange catching in the upper wall of the pocket.

The working barrel is retained in position with- 30 in the shell by the ngers 'll formed integrally with the sleeve 8 and extending radially inwardly thereof as shown in Fig. 5.

In assembling an apparatus constructed as described, the nipple and shell of the outer assembly 35 are connected with the well tubing, after which' the exhaust valves are secured in their block, including the pilot shoe, and connected to the lower end of the shell. The static fluid chamber shell is then screwed onto the block and the bottom :40 plug and inlet valve screwed onto the static fluid chamber. The piston valve is then connected with the tubing rods and the perforated tube to the valve, lafter which the working barrel, including the stuffing box and stop collar, is sleeved over the tube. The piston is then applied to the tube and the pilot finally screwed onto the lower end of the working barrel.

The operation of an apparatus constructed and 50 Y After assembling the outer shell, including the inlet and exhaust valves, on the well tubing, the tubing is lowered into the oil formation. The rods, including the working barrel and piston, are then lowered into the tubing and shell. As the 55 lower end of the working barrel engages between the exhaust valves, the pilot will be compressed by pressure exerted by the weight of the rods on the corresponding tapers so that it may enter the pilot shoe, after which its resiliency causes it to expand to its original shape to hold the working barrel in desired position Within the shell.

The operating mechanism at the surface is then started to reciprocate the piston, which, on its up stroke creates a vacuum to draw oil from the formation to ll the static fluid chamber. Several strokes of the piston are required to ll the chamber, after which, upon each down stroke thereof, oil will be forced out the exhaust valves, through the tubing, and up to the surface where 70 it can be collected and disposed of as desired. The rods are of substantially greater weight than the column of iluid in the tubing and it is, therefore, apparent that upon the down-stroke of the piston, the weight of the rods alone is sufficient to 15 raise a charge 'of well fluid in the tubing. It is also apparent that on the up-stroke of the piston the prime mover at the head of'the well is required to lift only the weight of the rodsA and not the column of fluid as is the present practice. Thisconstruction eliminates expensive counterbalances and larger motors at the head of the well, which' materially reduces installation and operating costs. It is also important to here point out that by providing the relatively large capacity of the static fluid chamber and an eX- haust of greater capacity than the working barrel, friction and back pressure are materially reduced. It is apparent that the oil drawn from the formation will not immediately be forced through the exhaust valves by the piston, but that some subsequent stroke of the piston will effect removal of the oil formerly admitted to the chamber.

It sometimes happens that oil from the formation seeps up above the piston in the working barrel, but compression from this source is avoided by provision of the perforations in the tube, which admits the oil to the interior thereof Vand passes it upwardly to the ball valve for escape into the tubing and thence to the surface.

When it is desired to remove the working barrel and piston for repair, the tubingrods are removed from the pump and drawn upwardly. The upward pressure raises the piston in such a 4manner that the lock nut on the piston engages the stop collar on the working barrel to tend to raise the assembly. The upward pressure compresses the pilot to permit its removal from the shoe, after which the working barrel and piston may be drawn to the top of the well for repair or replacement.

In the form of the invention shown in Fig. 9, the working barrel 'l5 is screwed permanently into the central bore 16 of the member iB, and has a plain upper end 1l through which a plunger tube 18 reciprocates to actuate the piston 'i9 under influence of the rods 5. The tube 'P8 is of a suitable diameter to afford a sliding t within the working barrel and has its upper end connected to the rods by means of a coupling 30 having apertures 8| therein through which the tube fills with well fluid. The lower end of the tube screws directly onto a threaded boss 82 on the piston. The tube is of sufficient length that when the piston is at the lower end of the working barrel the upper end of the tube projects therefrom. The tube and piston are thus guided the entire length of the barrel to prevent any buckling tendency in the barrel. Attention is here called to the fact that the effective diameters of the tube and piston are substantially that of the couplings for the rods so that there is notendency to lift oil on the 1.ip-stroke of the piston. It is also apparent that with the tube 18 filled with well fluid, buoyancy is avoided and weight added to aid in the pumping operation on the down stroke of the piston.

From the foregoing it is apparent that I have provided an improved down-stroke gravity pump in which the weight of the rods is utilized to lift oil to the surface of the earth.

It is also apparent that I have provided a novel construction for materially reducing friction and back pressure from the pumping apparatus as well as providing a removable working barrel and piston assembly.

What I claim and desire to secure by Letters Patent is:

1. A well pumping apparatus including tubing, a screened inlet valve at the bottom of the tubing,

an apertured block dividing the tubing into a fluid storage chamber and a fluid flow chamber and having a seating shoe, a working barrel mounted Vin the block having a pilot cooperable with the seating shoe for removably latching the working 5 barrel in the block, rods in the tubing, a piston mounted on the rods and slidable in the working barrel, and valves in the block for passing iiuid contained in the storage chamber to the iiow chamber upon actuation of the piston.

2. A well pumping apparatus including tubing, well fluid inlet means at the bottom of the tubing, a block dividing the tubing into a fluid storage chamber and a fluid flowing chamber, a working barrel mounted in the block'having substantially less capacity than the fluid storage chamber whereby friction of fluid against uid is prevented, rods in the tubing, a piston mounted on the rods and slidable in the working barrel, valves in the block having greater effective area than the working barrel for passing uid contained in the storage chamber to the flow chamber upon actuation of thepiston to prevent back pressure of fluid on the working barrel, and means on the working barrel and block for removably latching 2,5I the working barrel in the tubing.

3. A well pumping apparatus including tubing, a fluid inlet valve at the bottom of the tubing, a circularly apertured block dividing the tubing into a fluid storage chamber and a fluid flowing chamber, a working barrel mounted in the block, rods in the tubing, a piston mounted on the rods and slidable in the working barrel, a circular series of valves cooperating with the apertured block for passing fluid contained in the storage chamber to the flow chamber upon actuation of the piston, and compressible means on the working barrel cooperable with said block for removably latching the Working barrel in the tubing.

4. A well pumping apparatus including tubing, a screened fluid inlet gravity valve at the bottom of the tubing, a circularly apertured block dividing the tubing into a fluid storage chamber and a fluid flow chamber and having a seating shoe, a working barrel of substantially less capacity than the fluid storage chamber whereby friction of fluid against fluid is prevented having a pilot removably engageable in the seating shoe, rods in the tubing, a piston mounted on the rods and slidable in the working barrel, and a circular series of valves in the block for passing fluid contained in the storage chamber to the flow chamber upon actuation of the piston of greater effective area than the working barrel for preventing back pressure of fluid on the Working barrel.

5. A well pumping apparatus including tubing, well fluid inlet means at the bottom of the tubing, a block dividing the tubing into a fluid storage chamber and a fluid flowing chamber, a working barrel mounted in the block, rods in the tubing, a piston mounted on the rods and slidable in the working barrel, valves in the block for passing fluid contained in the storage chamber to the flow chamber upon actuation of the piston, means on the working barrel and block for removably latching the working barrel in the tubing, and means for exhausting fluid seeping into the working barrel above the piston.

6. A Well pumping apparatus including tubing,

a screened well fluid inlet gravity valve at the bottom of the tubing, a circularly apertured block for dividing the tubing into a static fluid storage chamber and a fluid flowing chamber, a working barrel mounted in the block having substantially less capacity than the storage chamber, rods in 4 2,051,089 .the tubing, a piston mounted on the rods and into a iiuidvstorage chamber and a-fuid flowing slidab 1n the working barrel, a circular series of chamber, a working barrel mounted in the block, valves cooperating with the apertured block for rods in the tubing, a piston, a tubular plunger ing, and means for exhausting iiuid seeping into apertured block for passing well fluid contained the Working barrel above the piston. in the storage chamber to the flow chamber upon 7. A well pumping apparatus including tubing, actuation of the piston. 10 a screened Well uid inlet gravity valve at the 9. A well p-umping apparatus including tubing,

LAbottornof the tubi-ng, a circularly apertured block a well iiuid inlet gravity valve at the bottom of ldividing the ltubing into a' static iiuid storage the tubing, an apertured block ldividing the tubcapacity than the static iiuid storage chamber working barrel havmg a pilot cooperable with whereby `frictionof iiuid against uid is presaid shoe for removably latching said working ven-ted, rods in vthe tubing, a piston slidable in the Y barrel in said block, said Working barrel having workingvbarre'l, a hollow perforated piston rod substantially less capacity than the static uid connecting the piston with the rods, a circular storage chamber whereby friction of iiuid against 20 series of valves cooperating with the apertured fluid is prevented, rods in the tubing, a piston block for passing iiuid contained in the storage slidable in the working barrel, a hollow perfoton to the tubing. ing into the working'barrel and passing through 30 `8. A well pumping apparatus including tubing, said perforations to the tubing.

a iiuid inlet valve at the bottom of the tubing,

`a circularly apertured block dividing the tubing HOMER T. LAMB, JR.

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