US2022781A

US2022781A - Deep well pumping and pumps

Info

Publication number: US2022781A
Application number: US738883A
Authority: US
Inventors: Reginald J S Pigott
Original assignee: Gulf Research and Development Co
Current assignee: Gulf Research and Development Co
Priority date: 1934-08-07
Filing date: 1934-08-07
Publication date: 1935-12-03
Anticipated expiration: 1952-12-03

Description

Dec. 3,1935. R, J, 5. PIGOTT 7 2,022,781

2 I I DEEP WELL PUMPING AND PUMP Filed Aug. 7, 1954 9 Sheets-Sheet 1 Dec. 3, 1935. R. J. s. PIGOTT 2,022,781'

DEEP WELL PUMPING AND PUMP Filed Aug. 7, 1934 9 Sheets-Sheet 2 @5 1 v I J6- f r 76' v X mag-3' 44., v

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Dec. 3, 1935. R. J. 5. PIGOTT DEEP WELL PUMB ING AND PUMP Filed Aug. 7, 1934 9 Sheets-Sheet 3 W W J d a m w w Dec. 3, 1935. R J, 5 PlGOTT 2,022,781

DEEP WELL PUMPING AND PUMP Filed Aug. '7, 1934 9 Sheets-Sheet 5 Dec. 3, 1935. R. J. s. PIGOTT DEEP WELL PUMPING AND PUMP 9 Sheets-Sheet 6 Filed Aug. 7, 1934 w, 0 w w gwuc/wbom well 0a 1,126? ,7 27 r 71.2. 76 fieylngldffi P ya w 77w if 27.- r P I 3, 1935. R. J. 5. PIGOTT 2,022,781 Ii DEEP WELL PUMPING AND PUMP "Filed Aug. '7, 1934 9 Sheets-Sheet 7 WELL OIL INLET Dec. 3, 1935.

R. J, S. PIGOTT DEEP WELL PUMPING AND PUMP Filed Aug. '7, 1954 9 Sheets-Sheet 8 Dec. 3, 1935.

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a L I. 0n 0" g N 7 J4 Z 3 M 3 u A W Patented Dec. 3, 1 935 UNITED STATES PATENT OFFlC DEEP WELL PUMPING AND PUDIPS Application August 7, 1934, Serial No. 738,883

21 Claims. (Cl. 103-46.)

This invention relates to deep well pumping and pumps; and it has for its primary objects the provision of an improved, eflicient method for pumping oil from deep wells and the provision of an improved compact, efficient, high output deep well pumping apparatus adaptable for use in accordance with the method.

Another object is the provision of a pumping method wherein oil is pumped from deep wells by means of motor-driven pumps positioned far down the Well and driven by a flow of motive fluid pumped down from the surface under a moderate pressure, considerably less than the hydrostatic head of oil in the well.

Another object is the provision of a hydraulically operated pumping apparatus adapted to be lowered far down the well and comprising a battery of high volume hydraulic-motor-driven pumps and meansfo-r supplying the motors with motive fiuid under pressure from the surface.

With these and other objects in view, according to the method a battery of hydraulic-motordriven pumps is positioned far 'down the well and clean motive fluid is forced down from the surface, through the motors in parallel. The pumps are connected in series and are adapted to suck oil from the well bottom and force it upwards in the well. The pressure on the power fluid supplied to the motors is such that the total resultant pressure, developed by the pumps (the sum of the pressures developed by each pump) is sufficient to overcome the'hydrostatic head of oil in the well, so that the well pumps force 011 upwards "pumps in series,

pumped from the well.

and out. Motive fluid exhausted from the motors is allowed to mingle with the well oil and re turns to the surface therewith. The battery of motors, as distinguished from the pumps, run at a fraction of the hydrostatic pressure in the well.

In the method, the motive fluid for the motors is advantageously the same fluid as is being In oil well pumping, the well o-il pumped up by the well pumps may be returnedto the motors under pressure, after being cleaned or settled to remove sand, brine, etc.

The method is applicable to any type of pumps and hydraulic motors, but I have developed a pumping apparatus which presents particular advantages in performing the method. The apparatus comprises a plurality of hydraulic motor operated pumping units in an integral combination. Ports and passages are provided in the units so that power oil may be forced through all the motors in parallel by a force pump at the surface, and well oil is pumped through the The ppa a when p itioned in a deep well' and run from the surface, pumps oil upwardly; power oil exhausted from the motors is mingled with the pumped oil.

In some embodiments, the apparatus is made up of interchangeable pump-motor units. The units are alike and are adapted to be bolted together in any number and to function as a com bination.

In pumping oil from deep wells it is the general practice to position a reciprocating pump of the piston and cylinder type in or near the bottom of the well, and to work the piston of the pump, and thereby pump oil, by means of a string of sucker rods attached to the piston and operated from the top of the well. The rods are operated by means of a pumping rig, which usually comprises a. walking beam worked by an engine. a

This system presents several disadvantages. The frictional losses in the sucker rods and pumping rig ordinarily amount to as much as eighty to ninety per cent of the power input. Breakage or uncoupling of the sucker rods often occurs, and withdrawing broken rods from the well is a dimcult task. Wire cables are sometimes substituted for the rods, but this requires modification of the pump to adapt it for one-way operation, inasmuch as wire cables cannot transmit a pushing force. An additional disadvantage of reciproeating pumps in this relation is that they are not well adapted for gas bearing oils, and considerable loss of efficiency occurs when gassy oils are pumped.

Various attempts have been made to improve on the ordinary pumping devices and methods to avoid these disadvantages. One proposal is the substitution of hydraulic means for reciprocating the pump in the bottom of the well, the hydraulic means comprising a hydraulic reciprocating power device of some sort at the top of the well, a suitable pistonand-cylinder reciprocating device on the well pump, and a conduit from the power device to the 'pumpoperating device in the well. This system avoids the use of a reciprocating sucker rod, but certain disadvantages are introduced. The power supply pump at the surface must exert a high pressure; in some designs a pressure sufiicient to overcome the static head in the well (equal to 1800 pounds per square inch in a 4000 foot well). This is apt to cause leakage in the power supply conduit. Moreover, in some designs the entire column of liquid in the power supply conduit must be reciprocated, with accompanying high drag and frictional losses.

It has also been proposed to employ a single rotary pump in the well bottom, operated by a to the deep well pump, in practice many difficulties are encountered. The electric motor can not conveniently be lubricated by means of the well fluid, and a separate lubrication supply must be provided. Well oil often contains water or brine, which is destructive to electrical equipment. This type of pump must be raised to the surface every little while, to be inspected and to have the lubricating supply renewed. This is a tedious job, requiring hoisting and replacing of a mile or so of tubing; a job which is made even more difficult by the fact that the electrical cable must also be handled at the same time. The bottom of a deep well is not a good environment for an electric motor. Also, the available space is small and cramped, the interior diameter of the bottom well casing being only six to eight inches in most cases. A motor to fit in this space and yet give suflicient power requires special design.

By the present invention I provide a pumping system which avoids the disadvantages of these prior systems and secures new advantages not attained in these systems. In my pumping method I provide a plurality of pumping units adapted to bepositioned at or near the bottom of the well. Each unit comprises a pump and a hydraulic motor adapted to drive the pump. The pumps of the several units are connected in series, and are adapted upon being operated to draw oil from the well bottom and force it upwards. The pumps and motors are designed so that the net pressure developed by the plurality of pumps in series is sufficient to overcome the hydrostatic head in the well.

The motors are hydraulically connected in parallel, and oil is forced to them under pressure by means of a conduit in the well and leading to the motors. This power oil is advantageously oil pumped from the well which is cleaned before being returned. The power oil exhausted from the motors is allowed to mingle with the well oil being pumped upward and passes with the well oil into a storage tank or pool at the top of the well. A portion of this oil, after being cleaned of sand, salt water, etc., is used for the power oil supply. Thus a portion of the oil is continuously circulated through the pumps, the storage tank, the surface force pump, the hydraulic motors, and the well casing.

In my method the several well pumps are connected in series. Thus each pump is required to develop only a fraction of the total pressure necessary to overcome the hydrostatic head in the well. In the case of similar sized pumps the pressure to be developed by each pump, in order to equal the hydrostatic head, is equal to P/n', where P is the hydrostatic head in the well and n is the number of pumps. The motors being connected in parallel, then in the case of similar sized motors and pumps, the pressure necessary for the surface force pump to exert on the motors is equal to the pressure developed by each pump, that is P/n. In other words, the pressure required for the motive fluids furnished to the well motors is only a fraction of the hydrostatic pressure in the well. The advantages of this will be obvious to persons skilled in the art. In a Well 4000 feet deep, say, the hydrostatic pressure 5 at the bottom is about 1800 pounds per square inch. If a single pump-and-motor unit were used in the well, supplied from a. single force pump at the top of the well, each pump and motor would have to work at the full 1800 pounds. Leakage, strains, excessive bearing loads and loss of efliciency occur at these high pressures, which are avoided in my method and apparatus.

In the accompanying drawings I have shown more or less diagrammatically a diagram of my 1.,

' pumping method, and detail views of two modifications of pumping apparatus for a well. In these showings,

Fig. 1 is a diagram illustrating my method in a complete oil well pumping system; 20

Fig. 2 is a view in vertical section of the upper portion of one form of well pump;

Fig. 2A is a similar view of the lower portion, being a continuation of Fig. 2;

Fig. 3 is a. section taken along the line 3-3 of Fig. 2; Fig. 4 is a section taken along the line 44 of Fig. 2;

Fig. 5 is a section taken along the line 5-5 of Fig. 2;

Fig. 6 is a section taken along the line 5-5 of Fig. 2;

Fig. 7 is a section taken along the line 1-1 of Fig. 2;

Fig. 8 is a section taken along the-line 8-8 of Fig. 2;

Fig.- 9 is a section taken along the line 99 of Fig. 2A;

Fig. 10 is a section taken along the line Ill-10 of Fig. 2A;

Fig. 11 is a section taken along the line llll of Fig. 2A;

Fig. 12 is a section taken along the line l2-l2 of Fig. 2A;

Fig. 13 is a section similar to Fig. 12, of a-modification employing a flexible abutment;

Fig. 14 is a section taken along the line I l-I4 of Fig. 2A;

Fig. 15 is a view in vertical sect-ion of the well unit casing taken along the line |5l5 of Fig. 3 and showing the various ports and passages;

Fig. 16 is a similar view taken along the line l6--l6 of Fig. 3;

Fig. 17 is a. similar view taken along the line 5 Fig. 18 is a view in elevation of the booster impeller; Fig. 19 is asectional view taken along the line l9--l9 of Fig. 18;

Fig. 20 is an isometric phantom view showing the motor port system of the pump of Figs. 2 and 2A;

Fig. 21 is a similar view showing the pump port system of this pump;

Fig. 22 is an isometric view with some parts broken away of a single stage pump and motor combination;

Fig. 23 is an isometric phantom view showing the motor port system of a modified pumping combination having interchangeable units; and

Fig. 24 is a similar view showing the pump port system of this pump.

In these showings, in which like reference numerals indicate like parts throughout, Fig. 1 is a diagram of a complete well pumping system 76 to illustrate my method. As shown, I provide a plurality of motor driven pump units I, each comprising a hydraulic motor 2 directly connected to a pump 3. For the sake of concreteness I have shown three such units, though the invention includes combinations having 'more or less than three units. The motors are connected in parallel as shown and are supplied with oil under pressurefrom a force pump 5 at the top v of the well through conduit 4. The motors exhaiist through conduit 6 which may be a separate pipe from the well casing or may be the casing itself. The pumps have inlet conduits 1 and outlet conduits 8 as shown, and are connected in series. The flow from the pumps is merged with the exhaust from the motors as at 9. The combined flow is forced upward through conduit i0, which may be the well casing. The bottom-most pump draws oil from the well at H and expels it at a certain pressure. The upper pumps increase this pressure to a degree sufficient to overcome the hydrostatic head of the well, causing the oil toflow' out at the surface as at i2. A storage tank 13 is provided for the pumped oil. Sand, salt water and 'dirt are allowed to settle out from the oil in this tank, A certain portion of this oil is continuously withdrawn into a tank i4 and used as motive fluid. This oil may be strained or otherwise further' cleaned if desired. The amount of oil in supply tank It .may be controlled by an ordinary float valve l5 as shown. Clean oil is taken from the supply tank and forced down the motor conduit by means of a force pump 5 at the surface of the well, which pump is advantageously 'of the constant pressure type and may well be a ring gear and pinion pump of. the types described in my prior Patent No. 1,990,750, dated Feb. 12, 1935.

In a specific example of my invention, oil is to be pumped from a well 4000 feet deep. The pressure due to the hydrostatic head is 1800 pounds per square inch at the bottom of this well. If a single well pump were used for forcing oil from the well, a full 1800 pound pressure would have to be supplied by the force pump at the surface; As stated, use of such high pressure is to be avoided when possible; leakage and strains on the surface force pump, and in conduits, occur. In this example of my method I use three pump and motor units down the well. The force pump 'is run to develop 600 pounds pressure. Thus the total pressure-at the bottom of the motive fluid conduit 4 is 1800 plus 600, or 2400 pounds per square inch. The opposing pressure due to the column of oil in the well, is 1800 pounds, leaving a net 600 pounds to operate the motors. For the sake of simplicity the motors and pumps are shown the same in size; therefore in this case each pump-develops 600 pounds pressure. The three pumps being in series, the total pressure developed is-1800 pounds per square inch, and just enough to overcome the hydrostatic pressure of the well and discharge oil at the top. In this example, it will be seen that I am able to develop the high pressure necessary to pump oil from the well, using only a moderate pressure in the force pump at the surface. Since the motors are connected in parallel and the pumps in series, theoretically three times as much 011 must be pumped down as is forced upward by the well tors and well oil being pumped, is 120 gallons and for the motors is v per minute. The net flow of well oil is thus 30 gallons per minute.

In all embodiments of my system, the product of pressure times volume for the pumps equals the product of pressure times volume for the 6 motors. In the above example, neglecting volum trio and frictional losses, the product of pressure times volume for the pumps is RX V=600 (30+30+30) :54000 That is, the power oil pressure is one third the pressure exerted on the well oil, and the volume 16 of power oil circulated is three times the volume of well oil pumped from the well.

The above examples represent ideal cases. In practice, volumetric losses and frictional losses are bound to occur, and accordingly motive fluid 20 must be supplied at a greater pressure and in greater volume than in the above example. .The slip of the well pumps reduces their delivery below the theoretical displacement; the slip of the well motors raises their throughput above the theoretical displacement. Therefore, for well pumps and well motors having equal displacements, the volume ratio between the motive fluid circulated by the force pump and the oil pumped by the well pumps equals 11/ (volumetric efliciencyfi; where n is the number of pump and motor units. For three units this volume ratio equals 3.7 when the volumetric efliciency is 90 per cent; and 4.7 when the volumetric eificiency is 80 per cent.

The pressure ratio between the pressure required to be furnished by the force pump at the top of the well, and the hydrostatic pressure opposing the flow of liquid being pumped from the well, is affected by losses due to mechanical and fluid friction, as, distinguished from losses due to slip or leakage. The fluid friction occurs principally in the long conduits 4 and i0, respectively conveying motive fluid to the motors, and mixed oil from'the well. The pressure, P, required to be furnished by the force pump is given by the following expression, wherein n is the number of pump and motor units:

P=(hydrostatic pressure in well) equivalent head of fluid friction in conduit l0) Xn/ (mechanical efliciency) +(equivalent head of fluid frictionin conduit 4).

In the case of a'single force pump at the surface operatlng three well motors in series in a 4000 foot well I find the actual pressure tovary from 3.7:1 to 45:1, depending on the pumping rate and the size of the conduits.

My method is adapted for use with various other types of pumps and motors. Advantageously however, the pumps and motors are of the positive displacement type. The well pump and motor units may, for instance, comprise pistons and cylinders with suitable valve connections, and the units may be driven .by a reciprocating force pump at the surface. The method is particularly adapted for use in deep oil wells, but it may be applied to the pumping of water.

As stated, in deep wells I use a plurality of well motor and pump units. By thus having a separate motor drive for each pumping stage in 7 the well, the motors being connected in parallel, I secure perfect balance of work among the stages. This is an important consideration in the case of positive displacement pumps.

In the specific example given, I have described my apparatus each well pump and motor unit the method as applied to a 4000 foot well, with 1800 pounds hydrostatic head. In this case the use of three well pump and motor units is advantageous, so that each well pump, and the supply force pump at the top of the well, need. handle only 600 pounds pressure. In a 2700 foot well, having a 1200 pound head, I should need to use only two pump and motor units in the well, each developing a 600 pound pressure. In a shallow well of, forexample, 1300 foot, the hydrostatic head is only 600 pounds, and only a single pump and motor unit need be used. In general it is convenient to have the pressure developed in each stage, and the pressure supplied by the surface .force pump, somewhere between 500 and 900 pounds.

While I have described a system comprising pump and motor units in which the pumps and motors are of the same size, it is sometimes con- .venient to provide motors of different size from the pumps. For example, in the pumping sys tem for the 4000 foot well'described, I may provide a two stage well combination having two pumps each developing 900 pounds, and two motors each working at 600 pounds. In this case the motors would have 1%, times the volume of the pumps; in the case of rotary gear pumpsand motors in which the corresponding rotors are of the same diameter, the motors would be provided with rotors 1 times as long as the pump rotors. This combination would meet the re-v quirement that the product of pressure times volume for the pumps be equal to the product of pressure times volume for the motors. In the P P X Y: (900+900) X30=54000 and in the motors,

P X V=600X 1.5 (30+30) =54000 My system may also be embodied in a single stage pump and motor unit, in which the motor has a larger volume and works at less pressure than the pump. For example, I may provide three pumps connected in series and adapted to be driven on one shaft and a single motor driving the pumps, the motor having three times the volume of the pumps. Here again, the volume of power oil pumped would be three times the volume of well oil discharged, and the motor would work at one third the pressure developed by the well pumps.

It is usually convenient in practice, however, to provide similar pump and motor units, and a motor for each pump. Separate pump and motor units allow perfect balance to be maintained among the pumps and motors; and this is highly desirable in high pressure pumping of liquids which may contain gas.

As-stated, it is usually desirable in practice to provide in the pumping system that no pressures greater than about 900 pounds per square inch be applied to any one motor or be pumped by any one pump. With most pumps, excessive bearing a well.

comprises a pumping ring gear and pinion combination directly connected to a, similar motor ring gear and pinion combination. The gears are enclosed in a casing having suitable ports and passages, to form a single, compact structure which may be lowered down the well on a string of pipe. The pump and motor units are adapted to be lubricated by clean oil, that is the motive fluid pumped down to the well motors, which consists of well oil from which sand and salt water have been removed.

I show two modifications of my pumping apparatus. In one, the combination comprises a plurality of pump and motor units assembled as a unitary whole, each unit being designed for its particular position in the assemblage, and not being primarily adapted for separate use. In the other modification, the combination is built up or assembled of similar pump and motor units:

the pump and motor units are alike and are interchangeableso that the units to the desired number may be stacked and fastened together to function as a. combination. In either modification, I usually find it advantageous to 'mount a booster pump on the first unit in the well, discharging into the inlet thereof, so as to raise the pressure of the well oil slightly before it is pumped by the first pump. The purpose of this will be explained later. I r

Figs. 2 to 22 illustrate the first modification. Figs. 2 and 2A are views of th'e upper and lower valves of a complete bottom hole well pump positioned in its normal position in the bottom of The bottom hole well pump comprises three generally similar pump and motor units.

Each unit comprises a motor housing 20 in which run a motor pinion 2| and a ring gear 22 having a plurality of radial ports 22A between the teeth 223 (see Figs. 5, 6, 8, 9, 11 to 13) as shown. A sleeve 23 is fitted in the housing as shown. The sleeve 23 is held in place in the housing by means of lock rings 21.

The motor pinion is mounted for rotation in the motor housing by means of discoid end plates 28 bolted to each end of the pinion by means of bolts 29 and nuts 30 as shown. The periphery of each end plate is adapted to receive needle bearings 24 which cooperate with an eccentric 32 to mount the pinion for rotation inthe motor housing. An eccentric spacing ring 33 is provided between the race mounting 32 and the end of the motor housing. Floating sealing rings 33A bearing race 3| and an eccentric race mounting are provided between the end of the ring gear 5 and the end plates 28 as shown.

Adjacent each motor housing is a pump housing. similar in size and shape except for the interior ports. In the pump housing is mounted a pumping ring gear and pinion exactly alike the sleeve 23, the lower lock ring 21, and the lower 0 spacing ring 33, is,a center spacer ring 40, grooved as shown. Corresponding elements are in the adjacent end of the pump, and the spacer ring 40 of the pump is spaced from the spacer ring 40 of the motor by meansof a lock ring ll in the grooves.

The various sleeves, spacing rings, etc. mounted in the motor and pump housings are kept from rotation in the housings by means of a key 42 running the length of the two housings and engaging appropriate seats in the various elements and the housing.

The motor pinion and the pump pinion are held in contact with each other, and are kept from end play, by means of a tie shaft 43, having nuts 44 at each end. At the upper end of the motor housing and fitted thereto is a ported, disooid crossover 45. A chamfered, beveled ciroular recess 46, eccentric to the axis of the ring gears, is provided in this crossover, for the reception of a bearing assembly for the tie shaft. The bearing assembly comprises two outer ball races 41 ,fitting snugly in the crossover, and retained by an outer ring 48 bolted to the crossover by bolts 49. Two corresponding inner ball races 50 are provided. The inner races are mounted on shaft 43 by means of spacer rings 5| fitting snugly on the shaft. A sleeve 53 spaces the lower ring from the end plate 28 of the motor, and the upper spacing ring is held by nut 44 on the shaft. Bearing balls 52 are provided as shown. Sleeves 52A, advantageously made of bronze or the like, are provided between the tie shaft and the pinions locating the pinions axially but allowing each pinion to follow its bearing without sensible restraint.

The crossover, the motor housing and the pump housing, comprise one pump and motor unit. These elements are much the same in each unit.

' The ports in thehousing and the crossover are so arranged that two or more pump and motor units can be bolted together to form a pumping combination as shown. Each pump and motor unit is independent of the others, being connected only by fluid passages. This is a great advantage from anengineering point of view, for each motor and pump gear combination is aligned separately; no long shafts, with accompanying difficulties in alinement, are used. In a complete combinationadapted for use at the bottom. of a well as shown in Figures 2 and 2A, additional elements are required at the top and bottom. At thetop is an upper adapter plate 54 and an adapter 55, both of the same outsidedimensions as the housings and crossover. The plate carries appropriate ports, and the upper adapter is threaded to receive the lower end of a motive fluid pipe 56, as shown. The lower endmay be similar. In Fig. 2A, however, I have illustrated a booster pump in combination with the lowermost motor and pump unit.

The periphery of the ring gear in the well pumping apparatus runs at a fairly high speed. For instance the periphery may run at 35 feet a second; the liquid entering the inlet of the first pump at about 6 feet a second. The acceleration of the liquid from 6 to 35 feet per second is equivalent to a drop in head of about 18 feet, or 6.5 pounds per square inch. Now if the well oil is gassy, this drop in pressure of 6 or 7 pounds, will result in escape of gas in the suction side of the lowermost pump. The presence of gas in' the pump is deleterious; both the capacity andefficiency are reduced. In addition, vibration occurs. In order to prevent this objectionable evolution of gas I provide a centrifugal pump, drawing oil from the well bottom and discharging it to the inlet of the lowermost well pump, at a pressure of about 9pounds. The eye of the pump is adapted to take the well oil at the speed it travels in the suction of the well pump, thus there is no pressure drop in the oil entering the booster.

The booster pump comprises a simple centrifugal impeller, shown best in Figs. 18 and 19 and comprising a discoid rotor 51 having impeller 5 blades 58. The impeller is mounted on the lowermost pump pinion by means of an extension shaft 60 to which the impeller is keyed by a key 6|. A cap 62 and pin 63 serve to hold the impeller from endwise displacement. The extension shaft is bolted to the pinion by means of the bolt 29 and nut 64. The pump housing for the impeller comprises a lower adapter plate 65 appropriately channeled to provide discharge chamber 66 for the impeller and an inlet to the first well pump; and-a lower adapter 61 having a chamber 68 forming an inlet for the impeller and communicating. with a threaded portion 69 adapted to receive a short conduit I0. The conduit 10 is adapted to extend into the oil TI to be pumped, as shown, and may be provided with a screen or the like. A sealing sleeve is provided for the extension shaft as shown.

The several motor and pump units, the upper adapter, and the lower adapter, are all held 'together by means of a plurality of tie bolts 15 andv nuts 16.

Fig. 2A illustrates a construction I use when gassy oils are being pumped, in order to allow air lift effect" to assist in raising the oil from the well bottom. As shown, I provide a removable gas seal or packer" 18 of rubber, canvas or the like, fitting in the casing 19 and closing off the oil in the well bottom from the upper part of the casing. With this arrangement, all the gas in the well oil goes through the pumps, and on being freed at the discharge of the well pumping apparatus and starting to rise, the gas expands, thus decreasing the weight of the return column and hence the pressure against which the pump operates.

It is sometimes desirable in pumping gassy oil to dispense with the packer, and provide a separate return conduit for the oil being pumped. In this case gas coming into the well bottom with 5 the oil frees itself,passes up. the well in the space between the casing, the motive fluid conduit and the well oil return, and is removed at the top. The gas completely bypasses the pump.

Figs. 15, 16, and 17 are vertical sections taken along the lines l5l5, l6|6, and |1l1 of Figs.

3 to 12 and 14, which are cross sectional views taken at various points along the length of the pumping combination of Figs. 2 and 24. Figs. 3 to 17 are for the, purpose of showing the port arrangement, and various other constructional features of the apparatus.

Tracing out the port arrangement for the motive power fluid: power oil being pumped down the supply conduit-56 enters the upper adapter 55. The upper adapter plate 54 is provided with power oil inlets 85 (Figs. 15 and 17). Power oil passes through these ports and into the power oil conduit for the several units. This conduit comprises the power oilinlets 86 in eachcrossover, motor housing and pump housing, all of which inlets are alined so as to form a single bore, as shown in Fig. 15. In each motor shell is an entrance port 81, connecting the power conduit and the space around the motor ring gear. The .70 ports 81 and conduits 86 serve to admit power oil to the motors in parallel connection.

Exhaust of oil from the motors is through a similar series of exit ports 95, and conduits 96 in the crossovers, motor housings and pump I to the lowermost pump. Oil is discharged from the pump through outlet IN and conduit I02 in the pump housing, and passes upwardly through a similar conduit I02 in the motor housing, through the crossover, and into the second stage pump through conduit 99 and inlet I00 as shown. The oil is forced upward through the third stage similarly, and is discharged through peripheral ports I02A in the upper adapter plate and I03 in the upper adapter, to the well casing, where the oil mingles with the exhaust from the motors.

Figs. 20 and 21- are isometric phantom or shadow views for the purpose of showing as clearly as possible the portarrangement of the pumping combination of Figs. 2 and 2A. For the sake of clarity the pump port system and the motor port system are shown in two separate views. The actual apparatus of course has both sets of ports, as shown in detail in Figs. 3 to 17. Fig. 20

- shows only the motor port system, the pump ports only the pump port system, the motor ports being omitted. In each view (Figs. 20 'and 21) the gears and other parts of the combination are omitted, for the sake of simplicity; Figs. 2 and 2A showing these elements in detail.

The course of liquids through the apparatus is indicated by arrows in Figs. 20 and 21. Referring to Fig. 20, power oil under pressure enters the apparatus through the threepower oil inlets 85 (of Fig. 3). These deliver into the three power oil conduits 86. One of these conduits extends to the bottom-most motor, another only to the second stage motor, and the third reaches only to the uppermost motor. However, all the conduits 86 are in free liquid communication (of. Figs. and 8) and the pressure in all of them is hence substantially the same. The reason for providing three conduits rather than a'single large conduit is a structural one. As is shown in Fig. 4, the tie bolts I5 cut down the available space in the casing, and the power oil conduits are run between tie bolts. This arrangement makes for compactness. While all three conduits 86 could extend clear to the bottom unit, in the embodiment of the pump under consideration this is not done. It is not necessary to so extend the conduits 86, insofar as hydraulic requirements are concerned, because one-third of the volume of entering power oil is taken by the uppermost motor and one-third by the second stage motor, leaving but one-third for the bottor-most motor.

Referring to Fig. 21, showing the pump port arrangement, oil from the well is supplied by the booster to the lowermost pump through inlet 99. Inlet 99 takes the form of a triple passage,the three passages being in communication (cf. Fig. 2). This arrangement is for the same reason as explained in connection with Fig. 20: ,to secure compactness, the liquid conduits are located in the space between the tierods 15. Only one inlet passage is strictly necessary, but the three passages are provided to receive the output from the booster with maximum emciency; to minimize frictional resistance. Referring to Fig. 21, oil is drawn through inlet 99 and inlet chamber I00, to the lowermost or first stage and is discharged at raised pressure through passage I02 to inlet passage 99 of the second stage pump. Oil is discharged from the second stage pump into the third stage pump in a similar manner. It is finally discharged from the upper end of the apparatus through passages I02A and I03, into the well casing, under a, pressure at least equal to the hydrostatic head in the well, so as to cause oil to flow from the well at the surface.

Fig. 17 is a diagrammatic sectional view taken along line I'I-I'I of Fig. 3, for the purpose of showing only the lubrication system. It is desirable to use only clean oil for lubricating the pumps. The well oil being pumped often contains sand and salt water; these are removed by settling in the storage tank at the top of the well and the cleaned oil sent down again as power fluid for the motors. At the bottom of the well, this power fluid is at a greater pressure than exists anywhere else in the pumps or motors (2400 pounds in the specific example of a 4000 foot well). Hence this power oil may be used to supply clean lubricating oil to all the bearings and clearance spaces. The direction of flow of lubricating oil on the motors makes no difference as the lubricating fluid is all clean oil. In the case of the pumps, I provide ports so that the power fluid leaks inward through the bearings and clearances toward the dirty oil inside the pump. In this way I prevent sand and dirt from getting in the bearings; the only parts subjected to the action of sand and salt water are the gear teeth and the floating ring.

As shown in Fig. 17 power oil enters the apparatus through passage 85 and top-most conduit 86. A minor part of the flow is bled ofi through a port I04 to chamber 46 in the topmost crossover of the top unit. A port I05, common to the motor housing and pump housing as shown, allows oil to enter the space between the pump and motor and bleed into the motor and pump chambers. A lubrication port I05A (see Figs. 5 and 6) and a port I06 allow oil to reach the lower bearings of the first pump. In the first unit oil flows inwardly and to both pump and motor, and is bled into the pump similarly. Inlet port I04 in the two lower cross overs 28 doesnot show in'the section shown in Fig. 17. In the central unit flow of oil is outward from the motor. The lowermost pump and the motor unit is similar to the second.

In the two lower units bleed ports I20 are provided, to allow bleeding off of lubricating oil irom. the bearing ,spaces into the well oil discharge conduits. Bleed orifice members I2I (fine-bored nipples) are provided in ports I20, for restricting 50 I the bleed of oil.

The sectional views 3 to 14 also show the port arrangement in detail. Fig; 3 shows three power oil inlets 86 which communicate with the upper adapter chamber, and three power oil outlets 91 which communicate with peripheral ports '98 in the upper adapter and hence open into the well casing. Fig. 3 shows also a well oil discharge I03 communicating with the well casing. Fig. 4

shows the power oil inlets and outlets continuing vantages occur to a greater or less degree, due to wasteful compression and expansion of the gas. In a copending application Serial No. 626, 220 I have disclosed a gear pump or compressor of the ring gear and pinion type, having a flexible abutment for the purpose of adapting the pump to work with gases. For an explanation of the principles involved reference is made to the said copending application. As shown in Fig. 13 I provide a flexible abutment comprising an arcuate flexible member I01 of spring steel, bronze or the like engaging the discharge side of the pump ring gear and retained in the sleeve 23 by screws I08, as shown. For pumping gassy wells, I ordinarily use a flexible abutment on each well pump.

Fig. 22 is an isometric view, with parts broken away, of a single stage pump and motor combination, which is made up of the lowermost pump, motor and crossover of Fig. 2A enclosed between two similar adapters 55 and adapterplates 54 as shown. No booster pump is shown. This showing is for the purpose of making clear the general arrangement and location of the pump and motor gears and associated elements in the casing. The descriptions which have been "given in connection with the other showings apply to this figure.

As stated, I sometimes embody the invention in a pumping combination in which the several pump and motor units are interchangeable. This construction,'while it presents some additional complication in manufacturing, is advantageous in certain relations in that it allows pumping combinations to be assembled from separate pump and motor units in any practical number. Combinations comprising one to four units may be built up simply by bolting the units together and providing appropriate upper and lower adapters, and appropriate crossovers. In the modification already described, the pump and motor housings, gears and other parts are generally similar, and were it not that the port and channel arrangements differ in each housing, the units could be interchangeably stacked. In the interchangeable type the difference from the first described modification resides in the port arrangement in the pump and motor housings. Accordingly this modification is illustrated by phantom views in Figs. 23 and 24, showing the pump port arrangement and motor port arrangement respectively. The gears, bearings, housings and other parts are like those described ante in connectionwith Figs. 1 to 22.

Figs. 23 and 24 show a three unit combination,

power oil inlet conduits and the three power oil The casings areprovided outlet conduits extend through each unit of the combination. In the first-described combination there are three power oil inlet conduits and three outlet'conduits in the uppermost unit; two in the intermediate unit; and one in the lowermost unit. 5 In the apparatus of Figs. 23 and 24 well oil enters the lowermost pump through a single channel 99 instead of three channels 99 as in the firstdescribed modification. Also, oil for lubrication is forced directly from the power oil inlet, through 10 inlets I05 and I06. Well oil is forced upwardly through the three pumps in series as described in connection with Fig. 21, being finally discharged into the well casing through discharge outlet I03. The course of power" 011 to the motors is 15 similar to that in Fig. 20. Oil is delivered to the inlet side of the three motors in parallel, through inlet conduits and inlets 81, and is discharged from the motors through outlets 95 and discharge I conduits 96. Each crossover 45 contains six pas- 20 sages 86 extending therethroughfthree passages for incoming power oil and three passages for dis- The three power oil conduits 86 are all in free 0 fluid communication, and pressure is substantially the same in each. A single large conduit could be used in place of the three separate ones, but as described in connection with Figs. 20 and 21 it is convenient to provide the liquid passages in the spaces in the casing between the tie bolts I5. The reason for having all three power oil conduits extending to the bottom-most (first stage) motors is to make each casing unit exactly alike, and thereby secure interchangeability. In- 40 sofar as hydraulic requirements are concerned,

the power oil conduits could be arranged as shown in Figs. 20 and 21-only a single conduit extending to the bottom-but in such case the pumpmotor unit casings have different passage ar- 45 'rangements and are not interchangeable.

These units are interchangeable. For example, if it is desired to make up a two-stage combination for a well of moderate depth, the central pump, motor and crossover can be removed from 50 the combination of Figs. 23 and 24, and the remaining two units bolted together with shorter tie-bolts, whereupon a complete two-stage pumping modiflcationis formed. There is no problem of lining up the component units; the connec- 55 tions between units are only fluid connections.

The present apparatus is found in practice to have many advantages over other pumping apparatus for deep wells. The well pump works smoothly and without interruption, and the flow that can be pumped from a deep well is remarkably high. A three-stage pumping combination installed in a deep well, the pump and motor pinions having a pitch diameter of '2 inches and the outside diameter of the housings being 5.75 65 inches, pumped 1000 barrels per day when run by a surface force pump developing 850 pounds pressure. The pumping apparatus is much better adapted for handling gas than any other well pumps known to me.

What I claim is:

1. The method of pumping oil from deep wells hydraulically which-comprises forcing oil ina conduit down the well under pressure, passing such oil at substantially the same pressure in 75 parallel through and to drive a plurality of hydraulic motors located far down the well, operating the motors to drive a like plurality of pumps arranged hydraulically in series, causing oil to be drawn from the well bottom into and through the pumps in series, each pump raising the pressure in the well oil, the volume of oil passing through the motors being a plurality of times greater than that passing through the pumps, whereby the motors .and each pump work at a fraction of the pressure necessary to force oil from the well, and the pressure given the well oil by thepumps being sufllcient to cause oil to flow from the top of the well.

2. The method of pumping oil from deep wells hydraulically which comprises forcing cleaned oil in a conduit down the well under pressure, passing such oil at substantially the same pressure in parallel through and to drive a plurality of hydraulic motors located far down the well, utilizing the motors to drive a like plurality of pumps arranged hydraulically in series, lubricating the motors and the pumps by said cleaned oil, causing oil to be drawn from the well bottom into and through the pumps in series, each pump raising the pressure in the well oil, the final pressure developed by the pumps being sufficient to cause oil to flow from the top of the well, the volume of oil passing through the motors being a plurality of times greater than that passing through the pumps, whereby the motors and each pump work at a fraction of the pressure necessary to force oil from the well, and the oil issuing from the well is cleaned'and a part of it continuously returned through the motors in cyclical operation.

3. The method of pumping gassy oilfrom deep wells hydraulically which comprises forcing oil in a conduit down the well under pressure, passing such oil at substantially the same pressure in draulic motors located far down the well, operating the motors to drive a like plurality of pumps arranged in hydraulic series, the pumps being adapted to function as gas compressors, causing gassy oil to be drawn from the well bottom into and through the pumps in series, each pump raising the pressure in the well oil, the final pressure developed by the pumps being sufllcient to cause oil to flow from the top of the well, the volume of oil passed through the motors being a plurality of times greater than that passing through the pumps, whereby the motors and each pump ;work at a fraction of. the pressure necessary to force oil from the well, the pumps being separated from the gassy oil supply in the bottom of the well so that gases are constrained to enter the pumps and aid in lifting the oil by air lift effect.

4. The method of claim 1 wherein the well oil is subjected to slight pressure just before entering the first of the pumps, so as to prevent escape of gas in the inlet of the first of the pumps.

5. A hydraulically operated deep'well pumping apparatus comprising in combination a plurality of positive displacement pumps hydraulically connected in series, each pump having an inlet and an outlet, the inlet of the first pump in the series being in communication withthe oil in the bottom of the well, the pumps being located far down the well and being adapted to draw oil from the bottom of the well and force it upwards, a plurality of positive displacement hydraulic motors, each coupled and driving one of the pumps, a supply force pump at the top of the well for actuating the motors, a conduit connection leading from the force pump to the motors and supplying oil to all the motors at substantially the same pressure, and means for furnishing the supply pump with clean oil. i l 6. The apparatus of claim 5 wherein means are provided to adapt the well pumps to be lubricated 5 by clean oil forced down the well, this oil being under greater pressure than the well pump pressure and passing inwardly, to prevent seepage of the well oil outward into the bearings.

7. A hydraulically operated deep well pumping l0 apparatus comprising in combination a plurality of positive displacement pumps hydraulically connected in series, each pump having an inlet and an outlet, the inlet of the first pump in the series being in communication with the oil in the bot- 15 tom of the well, the pumps being located far down the well and adapted todraw oil from the bottom of the well and force it upwards, a plurality of positive displacement hydraulic motors, each coupled with and driving one of the pumps, a 20 supply force pump at the top of. the well for actuating the motors, a conduit connection leading from the force pump to the motors and supplying oil to all the motors at substantially the same pressure, means for furnishing the supply pump with 25 clean oil, the pumps positioned down the well being provided with flexible abutment means so as to adapt them to act efliciently as gas compressors, a packer separating the pumps from the oil supply in the bottom of the we.l, and an outlet for 30 the pumps above the packer, so that any gases contained in the well oil aid in lifting the oil in the well, by air lift effect.

8. The apparatus of claim 5 wherein a pump adapted to produce a slightpressure is positioned below the well pumps, between them and the oil" in the well bottom and adapted to deliver into the inlet of the first of the well pumps, so as to prevent escape of gas in the first of the well pumps with consequent vibration and loss of efliciency.

9. A hydraulically operated deep well pumping apparatus comprising in combination a plurality of rotary positive displacement pumps hydraulically connected in series, located near the bottom of the well and adapted to draw oil from the bottom of the well and force it upwards, a plurality of rotary positive displacement hydraulic motors, each being mechanically connected to and adapted to run one of the pumps, the pumps and motors being combined in a unitary structure with ports and passages enclosed in the structure for delivering well oil to the pumps and for de-' livering power oil to the motors and for discharging exhaust power oil and well oil froin'the pumps and motors, a constant pressure supply pump at the top of the well for actuating the motors, conduit connections in parallel from the supply pump to the motors so that the supply pump supplies oil to each motor at substantially the same pressure, and means for supplying the supply pump with oil. v

10. The apparatus'of claim 9 in combination with a rotaryv impeller pump adapted to deliver well oil into the inlet at a slight pressure and driven through one of the well pump motors.

11. A hydraulically operated deep well pumpin apparatus comprising in combination a plurality of positive displacement pumps of the ring gear and pinion type hydraulically connected in series,

substantially coaxial-1y arranged one above the other, the pumps being located near the bottom of the well-and being adapted to draw oilifrom the bottom of the well and force it upwards, a like plurality of positive displacement motors of ring gear and pinion type each being mechanically 76 connected to and adapted to drive one of the pumps, the motors being substantially coaxial with the pumps, the pumps and motors being mounted in a compact, elongated, substantially cylindrical housing with ports and passages enclosed therein for delivering well oil to the pumps and for delivering power oil to the motors and for discharging exhaust power oil and well oil from the pumps and motors, a constant pressure supply pump at the-top of the well for actuating the motors, conduit connections in parallel from the supply pump to the motors so that the supply pump supplies oil to each motor at substantially the same pressure, and means for furnishing the supply pump with oil.

12. In a system for pumping oil from deep wells by hydraulic power, fluid driving means near the top of the well, a plurality of pumping units near the bottom of the well, each unit comprising a positive displacement hydraulic motor and a positive displacement hydraulic pump, the motor being operatively connected to and adapted to drive said pump, a power fluid conduit connecting said fluid driving means and the motors of each unit, said motors being connected to said conduit in parallel so that each motor receives power oil at substantially the same pressure, fluid conducting means connecting well 011- in the well bottom with the inlet of one of said pumps, the remaining pumps being arranged in series with the outlet of said first named pump to form a multi-stage pumping device, the outlet of the flnal stage in said device being connected by a return conduit with a suitable reservoir at the top of the well, means connecting each motor exhaust with said return conduit, and conduit means connecting the reservoir with the inlet of said fluid driving means.

13. A pumping apparatus, comprising in combination a plurality of separable self-contained pumping units in contact, each comprising a hydraulic motor and a hydraulic pump driven thereby, a substantially cylindrical casing surrounding the motor and pump and having peripheral communicating ports and passages therein for supplying motive fluid to the motor and fluid being pumped by the pump, the ports and passages in each unit casing ending in open ports in the ends of the cylindrical casing and being so disposed that the several units in contact act as a complete pumping combination, fluid being pumped through the combination and motive fluid being passed through all the motors of the combination.

14. A pumping apparatus comprising a plurality of individual hydraulic pump and motor units-stacked together, each pump and motor unit having communicating passages and ports so that motive fluid is delivered to all the motors at substantially the same pressure and is passed through all the motors in parallel and fluid is pumped through all the pumps in series.

15. A pumping apparatus comprising incombination a pluralityof hydraulic motor and pump combinations and casings for motors and pumps having ports and passages for fluids, the motor and pump combinations being stacked together, ported crossovers being interposed between the combinations, the ports in each crossover making communicating fluid connections between combinations above and below the crossover.

16. A compact pumping unit comprising a hydraulic motor and a hydraulic pump and a cylindrical housing therefor, the motor and the pump each comprising a ring gear, a coacting pinion and bearings for the ring gear and for the pinion, a mechanical coupling operatively connecting the motor and the pump, the housing being provided with inlet and outlet chambers adjacent the inlet and outlet of the pump and the motor, ports and passages peripherally disposed in the cylindrical casing along the direction of the axis thereof for delivering fluid to the inlet; of the pump and from the outlet thereof and for supplying power oil to the motor, and 10 stacked together vertically, each unit comprising a ring gear and coacting pinion motor, a housing and bearings therein for the ring gear and pinion, and a similar pump, each unit further com-. prising a mechanical coupling operatively connecting the motor and pump, the housing being provided with inlet and outlet chambers adjacent the inlet and outlet o the pump and motor gears and with periphera 1y disposed ports and passages in the housing extending along the direction of the axis, for delivering fluid to the inlet of the pump and from the outlet thereof and for supplying power oil to the motor, and abutments adjacent the peripheries of the ring gears separating the inlet and outlet sides of each pump and each motor, the combination having means adjacent the topmost unit for con- 40 nection with a supply conduit for power oil and means adjacent the lowermost unit adapted to communicate with liquid to be pumped.

19. A pumping apparatus comprising incombination an elongated, substantially cylin- .drical casing, and a plurality of mechanically independent pumping units disposed one above the other in the casing, each unit comprising a hydraulic motor and a hydraulic pump mechanically coupled therewith and driven thereby, the casing having passages disposed" peripherally therein and extending in an axial direction, some or the passages communicating with the motors for. supplying motive fluid thereto, and other of the passages communicating with the pumps and carrying fluid being pumped from one pump to another in series, and an end piece on each end of the casing, one end piece having an inlet passage for delivering fluid to the lowermost pump and the other end piece having an inlet passage for delivering fluid to all the motors.

20. A pumping apparatus comprising in combination an elongated, substantially cylindrical and other of the passages communicating with the pumps and carrying fluid being pumped from i one pump to another, and an end piece on .each

end of the casing, one end piece having an inlet passage for delivering fluid to the lowermost pump and the other end piece having an inlet passage for delivering fluid to all the motors.

21. In a hydraulically operated pumping apparatus, a pumping unit comprising a, hydraulic pump, a hydraulic motor driving the pump, a

substantially cylindrical casing for the pump and motor, the casing being provided with peripheral ports and passages extending in an axial direction for flows of power fluid for the motor and for flows or fluid being pumped by the pump, said ports and passages opening at each end 0! the cylindrical casing, a crossover member at one end of the casing havingports and passages (:0 operating with certain of the ports and possages in the unit casing to direct aflow of power fluid to the motor, means for supplying power fluid to the crossover member, and means for supplying fluid to be pumped, to the said ports 10- and passages in the casing'tor fluid to be pumped.

REGINALD J. S. PIGOTT.