US2005767A

US2005767A - Method and apparatus for operating oil wells

Info

Publication number: US2005767A
Application number: US724381A
Authority: US
Inventors: John A Zublin
Original assignee: Individual
Current assignee: Individual
Priority date: 1934-05-07
Filing date: 1934-05-07
Publication date: 1935-06-25
Anticipated expiration: 1952-06-25

Description

J. A. ZUBLIN June 25, 19.35.

METHOD AND APPARATUS FOR OPERATING OIL WELLS Filed May '7, 1934 4 Sheets-Sheet 1 JOHN A. ZUBLIN INVENTOR %W/% ATTORNEY June 25, 1935. J. A. ZUBLlN 99 1 67 METHOD AND APPARATUS FOR OPERATING OIL WELLS Filed May 7, 1934 4 Sheets-Sheet 2 JOHN A. ZUBLIN INVENTOR ATTORNEY vii! will!!! June 25, 1935. J. A. ZUBLIN METHOD AND APPARATUS FOR OPERATING OIL WELLS 4 sheets-sheet 5 Filed May 7, 1934 JOHN A. Z lNVENTOR ATTORNEY June 25, 1935. J. A; ZUBLIN METHOD AND APPARATUS FOR OPERATING OIL WELLS Filed May 7, 1934 4 sheets-sheet 4 JOHN EZUBLI ATTORNEY Patented June 25, 1935 METHOD AND APPARATUS FOR OPERATING OIL WELLS John A. zubun, Bel Air, Calif.

Application May 7, 1934, Serial No. 724,381

31 Claims.

This invention relates generally to the production of petroleum, and more particularly to the production of petroleum from flowing wells in such a manner as to retain and conserve as much as possible the gas which supplies the energy for lifting the oil to the surface.

This application is a continuation in part of my copending applications Serial No. 627,317, filed August 3, 1932, on Method of and apparatus for removing oil from the ground, and Serial No. 663,018, filed March 2'7, 1933, on Method of removing oil from an oil well. Briefly, this invention has been developed for the purpose of releasing from the oil, while still under well pressure and as yet not delivered to the ground surface, a much larger portion of the gas content than can possibly be released by pressure drop alone, or by devices now known. Subsequently a major portion of the released gas is separated from the oil and discharged from the eduction tube into the well space exterior to the tube, from whence it passes back into the depleted oil sands for storage and maintenance of formation pressure until such time as it can be more efliciently used.

As is well known, oil and gas usually occur together, and are under a tremendous pressure while in the oil bearing formation. Although conditions vary widely from one oil field to another, some gas generally is found in the free gaseous condition, while a large amount is dissolved in the oil; and also some gas is generally believed to be occluded by the oil. Also, under the high formation pressure, some constituents will be found existing as liquids while at atmospheric pressure these same constituents will be gaseous; and it will be readily understood that I such volatile fractions when in the oil sand in liquid form are mixed or dissolved in the heavier non-volatile fractions, that constitute what may be termed fixed oil. used refers to all substances that will become gaseous when the oil is raised to the ground surface, and includes not only the gas which exists free as such in the oil sand but also all dissolved and occluded gas and volatile fractions of the oil which become gaseous under relatively lower pressures that may exist in the well or under atmospheric pressure. Within the oil sand the fixed oil and gas are so thoroughly intermingled as to form a substantially homogeneous fluid in which the liquid and gaseous phases are indistinguishable. The oil in its original condition including gas, whether dissolved or occluded, or as a volatile constituent, is herein termed The term gas as herein native or gas-charged oil in contrast with the fixed oil remaining after delivery to the ground surface and loss of the gas content.

The formation pressure forces the native oil into the well bore, and, together with the energy 5 released by the expanding gas under reduced pressures, lifts the oil to the ground surface. The energy available to lift the oil may be considered that produced by the expansion of the gas during its removal from the well. The gas, being much less viscous than 011: passes through the formation more easily and reaches the well more rapidly, having a tendency to escape from or side-track the oil, leaving the latter behind in the sands. At first there is a large excess of energy available in the gas present and the oil is easily lifted to the surface; but sooner or later the quantity of gas available decreases and there is no longer sufficient available energy to lift the oil. When the well no longer flows, it is necetsary to install pumps to extract the oil, obviously increasing the cost of production, and this is important when it is-realized that the oil remaining in the sands when-pumping becomes necessary may be as much as 90% of the original quantity of oil.

Experience has shown that when a well is allowed to flow freely, the gas content is relatively quickly exhausted, leaving behind a large part of the oil which must be pumped out. And 30 furthermore the escape of gas from the sand removes the pressure forcing the oil into the well so that a large part of the total oil in the formation, perhaps as much as 80%, cannot be recovered at all.

When a well is operated in such manner as to limit the rate of flow of oil and gas to some point below free flow, the result is to increase the life of the well and increase the proportion of oil recovered as well as decrease the unit p1 oduction cost.

The quantity of gas usually amounts to several thousand cubic feet for each barrel of oil; and since irregular productions of large amounts of gas cannot be used commercially but are largely wasted, state regulations customarily place a limit on the maximum gas-'oil ratio allowable where the gas is not used. This ratio is the volume of gas produced per unit volume of oil. When the well cannot be regulated so as to flow at less than the maximum allowable gas ratio, the well is shut down and it means that an investment of many thousands of dollars becomes non-productive.

Heretofore this regulation of a flowing well, 55

i. e. a well emitting oil under its own gas pressure, has been done by means of a casing head or some plug in the well permitting the retention of gas pressure (commonly known as back pressure) on the well liquid, and by a valve at the top end of the oil eduction tube regulating the flow of oil and, consequently, the pressure in, the well.

Retaining a well under pressure by limiting its rate of flow lessens the gas wastage and tends, with narrow limits, to decrease the gas-oil ratio, but is still not suflicient in most instances to reduce the gas-oil ratio to less than the allowable maximum. The reduction of this ratio cannot be accomplished by mere restriction of flow, since this operates to increase the casing pressure in the well, creating a back pressure on the sands that reduces the seepage of oil and, if great enough, eventually increases the gas-oil ratio by stopping oil flow. Furthermore, at the top of the well the gas has expanded to a relatively large volume while the oil has retained its original volume and is relatively much smaller than the gas, so that the bulk of the fluid volume regulated by restriction means at the well top, is gas and the result is to reduce oil flow at a greater rate than gas flow is reduced. For these reasons, attempts to materially reduce the gasoil ratio by simple flow control at the top of the well fails to attain the desired end.

After natural flow has ceased, flow may again be had artificially by repressuring, which involves the pumping of gas under high pressure into a well to force oil through the sand to adjoining wells. This method is expensive, since energy is put back into the gas by compressing it, and the method, being used only after natural flow has ceased, accomplishes no conservation or regulation of the potential energy. in the original well fluids.

It thus becomes a general; object of my invention to decrease the quantity of gas removed from a well relative to the oil removed, 1. e. the gasoil ratio, to within the legallimits, and preferably to approximately that quantity that will produce the energy required to bring the oil to the ground surface. In this manner the gas flow is relatively uniform over a longer period of time and can be used to better commercial advantage.

Another object of my invention is to use as much as possible of the potential energy in the well fluids for raising oil to the surface to the end that more of the oil may be recovered from a given well, and that the production costs will be as low as possible.

Another object of the invention is' to extract from the gas charged oil a portion of the gas or energy contained in excess of that required to lift the oil to the surface of the ground, and to store this energy in the form of compressed gas for further use in delivering to the ground sur face additional amounts of oil.

A further object is to store and use the extracted gas within the same well and adjoining sands wherein the gas originated without removing the gas from the well for storage ,or between extraction and its final use.

These objects are accomplished by releasing gas from the gas-charged oil in excess of the amount normally released by the pressure reduction occurring as the oil passes from the-remote sands into the well bore. In general, this release is accomplished by violently agitating the oil. A

portion of the gas so released is collected under pressure which, because of the agitation of the oil, becomes greater than the fluid pressure in the upper portion of the producing sand of the well, so the collected gas is discharged into the well, from which it passes into the gas zone or top portion of the oil sand by virtue of the high well pressure. After return to the sand, the gas is again available to force additional oil out of the sand and up the eduction tube so that a higher percent of the total oil is recovered and the lifting power of the gas is more effectively used over a longer time.

In a device embodying my invention I provide means to violently agitate the gas-charged oilas it rises in the oil stringto release the gas which is then separated from the oil and collected in a suitable chamber.v Gas pressure in the chamber, when greater than the well pressure, forces gas thi ough a suitable outlet into the well exterior to the eduction tube, which is kept at a predetermined pressure sufllcient to force gas into the gas zone, by means of a casing head or other suitable pressure retention means. The oil still contains at least s'uflicient gas to lift it to the surface. A large amount of released gas is not separated but remains in the oil stream, so there is.

formed a highly gasifled fluid the fixed oil.

A true understanding of my invention will be more easily had if the distinction between the steps of releasing gas andvseparating gas from oil is kept in mind. The native oil contains gas in one or more of these conditions:'dissolved either as a vapor phase in a liquid phase or as a liquid phase (the gas which is liquefied at formation pressure) in a liquid phase; occluded by the oil; free gas mixed with the oil. The free gas is physicallydistinct from the oil and needs only to be separated out by a suitable method.

The dissolved and occluded gas is physically inof less density than distinguishable from the oil and the first step in its extraction is to release it from solution or occlusion so that'it becomes "free gas which first oil mixture of which the components can be-separated by several methods, the commonest being a gravity separation utilizing the difference in densities.

The term release is used herein to designate the formation of gas as a distinct physical phase from the gas which is dissolved or occluded in the oil, while separation" refers to the subsequent step of separating the two different phases when they are together in a gas-oil-mixture.

The distinction made is essentially that which exists between segregating the constituents of a solution and the constituents of a mixture, and the steps are distinct just as a solution is distinct from a mixture. For example, a true solution is relatively stable, but a mixture will segregate when the components are of different densities. Of course solutions and 'mixtures blend. and so may the steps of release and separation.

Indeed the two steps may be carried on together tion, wherein are described various forms of my invention, and the annexed drawings, in which: .Fig. l is a diagrammatic vertical section of one [arm of my invention in position in a well;

Fig. 2 is a vertical median section, longitudinally contracted, of gas and oil agitating and separating means constructed in accord with my invention;

Fig. 3 is a horizontal section on line 3-3 of Fig. 2;

Fig. 4 is a horizontal section on line 4-4 of i 2;

Fig. 5 is a horizontal section on line 5-5 of Fig. 2;

Fig. 6 is a perspective view of a single rotor removed from the remainder of the device;

Fig. 7 is a vertical median section, longitudinally contracted, of a variational form of my invention;

Fig. 8 is a broken horizontal section on line 8-8 of Fig. '7;

Fig. 9 is a horizontal section on line 98 of Fig. 7;

Fig. 10 is a horizontal section on line I0-l6 of F 7;

Fig. 11 is an enlarged fragmentary vertical section, partially in elevation, of the oil agitating elements of Fig. 7;

Fig. 12 is a horizontal section on line l2l2 of Fig. 11;

Fig. 13 is a fragmentary vertical median section showing a variational form of gas discharge valve;

Fig. 14 is a fragmentary vertical median section showing a variational form of agitating and separating elements;

Fig. 15 is a horizontal section on line |5-l5 of Fig. 13;

Fig. 16 is a horizontal section on line l6|6 of either Fig. 7 or Fig. 13;

Fig. 17 is a-horizontal section on line I1-l| of Fig. 14.

Without any further preliminary discussion of operation, I shall now proceed to a detailed descriptior. of my invention, one form of which is shown diagrammatically in Fig. 1, in place in a typical well. The well is provided with a casing 20 cemented at 2| to the hard formation 22 overlying eil sands 23. Within casing 20 there is an oil string 25 provided with a perforated bottom portion 26 extending into the oil sands and through which the oil passes to reach the oil eduction tube. The oil is delivered to the surface of the ground through eduction tube 28, located within the oil string, and provided at its upper end with regulation valve 30 oriany other suitable means of controlling the rate of flow of oil through tube 28. The upper ends of casing 20 and oil string 25 are sealed by

heads

32 and 33 respectively in order that a predetermined pressure may be maintained upon the well liquid, although it will be understood that any other suitable type of plug or sealing means may be used in order to retain gas pressure within the well.

There is generally indicated at 35 a shell which, as will be explained, may be considered as an enlarged end portion of eduction tube 28, and which houses the agitating and separating means illustrated in greater detail in Figs. 2 to 6. In these latter drawings, it will be seen that there is secured to the lower end of tube 28 coupling 36 and sleeve 31 provided with a hard metal lining 38 forming an orifice 39 through which the upwardly moving oil passes before. entering tubing 28. To the lower end of sleeve 31 is secured valve section 48 containing ball-check valve 4| having a valve seat 42. Valve section 40 is formed with a transverse gas passage 43 above the valve 4|, and with longitudinal oil passages 44, as may be seen by reference to Fig. 3.

rising within shell 35 flows through annular space 48, between

tubings

35 and 56, and passages 44, in valve section 40, and thenceinto upper portion 28 of the eduction tubing.

Means for agitating the gas-charged oil and for separating the released gas from the oil are attached to the lower end of tubing 50. The topmost element of said means is section 54 which for convenience of designation will be hereinafter referred to as a bell. This section may be provided with radial fins 55 which center the bell within shell 35. Spaced a short distance below bell 54, is a second similar bell member 56 which is supported from the upper hell by shaft 51 that t has its ends screwed into

hubs

58 and 59 of the upper andlower bells respectively. As illustrated in Fig. 4, hub 59 is-provided with vertical passages 69 through which fluids may move upwardly. Similar passages are provided in hub 58.

In the space between the two bells there is located a centrifuging rotor 63 journaled on shaft 51 and adapted to be revolved by the fluids leaving passages 60 located immediately beneath the rotor. Although the rotor may take any suitable shape, a preferred form is illustrated in Figs. 5 and 6 in which the rotor is generally cup-shaped with upwardly extending vanes 64 formed in the sides by means of inclined slots 65.

The agitating and separating means accompli"hing gas extraction is made up of a series of bells56 connected by means of shafts 51 in the manner described, and a plurality of rotors 63 journaled one upon each of the shafts in the spaces between the successive bells, as illustrated.

Any desired number of alternating rotors and bells may be used depending upon the physical characteristics of the oil in the well and the amount of gas that it is desired to extract from theoil. Thus it will be seen that gas-carrying oil'entering the lowermost bell 56a ofv the series, rises through passages 60 and strikes vanes 64 of rotor 63 with the result. that the rotor is revolved and a centrifuging motion is given to the oil. The rising oil stream first strikes lower face 61 of the bell hub, then enters passages 60. and upon leaving the passages is choppedup as it strikes a rotor 63, so that sufficient agitation is created to release a portion of the gas. The fluid stream now contains constituents of varying densities so that as a result of the centrifuging the heavier liquid is thrown outwardly and the lighter gasand liquid is displaced inwardly. The heavier liquid is then carried by the upward current through passages 68 between tubing 35 and bell 56; while the lighter gas and liquid rise into the central portion of the bell 56 and through passages 60 of that bell to again be centrifuged by the rotor next above.

By repeated and alternated agitation and centrifuging, an increasingly large portion of gas is released, and the gas and oil are gradually separated by virtue of their difference in densities so that as the fluids rise within shell 35 they form two increasingly distinct columns, a column of oil which has been deprived of a large amount of its contained gas and is rising through passages 68 into space 48 around the gas separation chamher, and acentral column of lighter fluid containing mainly gas which rises through passages 80 of top bell 54 into chamber 5|.

' The elements so far described may be considere'das constituting a complete stage of gas extraction elements, and it will be readily seenthat a plurality of such stages may be used if necessary to effect the desired release and separation of gas and oil. As an example, Fig. 2 illustrates a second stage provided with valve section 40a connected to the lower end of the first stage by means of section 10. The lower stage is identical with the one described, and is so arranged that the gas from chamber 5| passes out into the well exterior to the eduction tube while the oil that hasalready given up part of its gas content flowsupwardly thniigh passages 44, of section 48a, and section 18 into the lower. end of the upper stage where further release and separation of oil and gas takes place.

In order to eifect a preliminary separation from the oil of the free gas occurring in the oil sands and the gas released from the oil by the reduced pressures within the well, it is preferable to provide a gas anchor which may be of any conventional type. The anchor illustrated in Fig. 2 is attached to the lower end of the bottom extraction stage by couplings H, 12, and 13, and

comprises an upper length of perforated pipe 14 to which is connected a lower length of imperforate pipe 15 terminating in a bullnose 16,

and an inner pipe 18 which extends downwardly some distance below the perforated pipe 14, preferably to a point near the bullnose 18. Oil enters the eduction tubing by passing through perforations 11 of pipe I4 and then flowing downwardly in the annular space between pipe I4 and tubing 18 before rising within tubing 19, as indicated by arrows 18.

within tubing 15, andv will collect outside of pipe I4 at the top of the gas anchor. This gas then returns to the well by passing outwardly through perforations 11. In practice, it is not necessary that all free gas be separated from the oil at this point; and indeed a considerable proportion of it will be carried along by the oil and will enter the agitating and separating means. vHowever, such gas will be returned to the well along with that gas which is released from the .oil by the agitation occurring as it passes through the rotors and separatingbelts.

Functionally, the eduction tube as an entirety includes tube 28, shell 85, and pipe 19. The eduction tube begins at the only point of oil or gas entry, bottom 88 of pipe I8, and is not open to the well at any point except through the valvecontrolled gas ports 43 which permit'gas, but not oil, to leave the eduction tube.

The operation of the device is as follows, rei'erring to Fig. 1, which illustrates conditions representative of actual conditions in a flowing we as far as can be ascertained. Y I

- Gas-charged oil flows from the sands into the well and is withdrawn through the eduction tube 28 at a rate to maintain a fluid level 80 which may be definite or indefinite, as the sharp line The free gas, being much lighter, will rise through the oil as it flows downwardly between fluid, foam and gas may. be impossible well under reduced pressure the solution becomes supersaturated or unstable. Extraction of additional gas, over and above that released by normal pressure drop, is most easily accomplished, without further reduction in the well pressure, by agitation of theupwardly flowing oil.

This gas released from solution can then be separated from the oil and returned to the well outside the eduction tube, from whence it may be forced into the gas zone above-oil front 85. For example, assume an original oil front to be at 86; if any oil is now withdrawn so that the front recedes to 85, the pressure will drop correspondingly. However, if a volume of gas equal or nearly equal to the oil withdrawn is returned to the formation, then there will be little or no pressure drop. Pressure suflicient to return gas to the depleted upper portion of the sands'may be developed in a relatively thick oil sand because the pressure at the entrance 88 to the eduction tube may be several hundred pounds greater than the pressure at the top of the sand. Naturally it is impossible to maintain a constant pressure in the formation, but large quantities of gas, otherwise withdrawn from the well, may be separated and returned to the gas zone with the result of maintaining a higher average pressure and of greatly increasing the producing life of the well.

Before the oil enters the mouth 88 of the eduction tube, part of the gas will be separated out as a result of a pressure drop and gravity separation; and theoil, as it passes through gas anchor 14, will have additional gas separated out.

The physical state of the oil entering the eduction tube will vary. It may be a liquid with the gas ,in solution; or with high pressure and high gas production it may be carried by the gas in the form of afog or afoam. Whatever the form ,of the gas-oil mixture, it is forced upward by free gas deposit on the rotor surfaces while liquid oil "entraining free gas is'broken. up by the rotor which, is revolved by the upwardly moving stream of gas and oil. Successive slots in the rotor passing over openings 60 causea pulsation in the oil stream as it jets through the lower openings 68.

Centrifugal action of the rotor throws ofif liquid to its periphery which displaces gasinwardly, thus having a tendency to concentrate ,the gas centrally out of the separating bells. This process is repeated at each of the separate rotors, more and more of the gas being released by the continued agitationuntil there is formed a relatively highly'gasiiied column of fluid of relatively less density rising centrally of the devi'ce through openings 50, and a second column of fluid con taining a large proportion of liquid and consequently of greaterdensity rising in the annular space 68 around the separating bells.

The central column of gaseous fluid empties into gravity separation chamber 5| where the released gas separates out and rises to the 'top of the chamber, there thus being more or less clearly defined

liquid levels

83 and 83a in the upper and lower stages. In each of these stages, gas will collect in chamber 5| until the pressure therein becomes sufficient to open valve 4| and discharge the gas through ports 43 into the well space. At the open lower end of each chamber 5| the pressure within the chamber will balance the pressure around the chamber at 48. However, the gas in the chamber will have substantially the same pressure throughout its entire length, and will consequently communicate to the under side of valve 4| 9. pressure substantially equal to that existing at liquid level 83 which pressure increases as the liquid level drops. Thus level 83 will move downwardly until the pressure is sufficient to open valve 4 I against the pressure on top of the valve through port 43. In practice, the vertical length of chamber 5| may be from 100 to 600 or more feet, allowing a similar range in the position of level 83, so that it may drop to a point such that the pressure underneath valve 4| will exceed the pressure external to the eduction tube at port 43 and discharge gas into the well space.

Under initial or irregular flowing conditions, the external pressure at port 43 will close valve 4|, but normally this valve will continually exhaust gas.

Agitation of the gas-charged oil has released such a large quantity of gas that even after separating and removing some of it for return to the oil sands, the column in the eduction tube is highly gasified and contains sufiicient energy to lift it to the ground surface. Further, this release and expansion of gas supplies energy which compensates for the relatively high friction losses as the fluid passes through the device.

Any change in flow conditions influencing the rate of oil entry into the well automatically changes the operation of the device to correspond, since the rate of flow of gas-charged oil controls the rate of gas release. Changes in flow may also be produced by manual operation of flow beans in the outlet of the eduction tube as illustrated at valve 30.

The device has the particular advantage that by manual operation of flow control means at the top of the w;ll, the flow of both oil and gas is actually changed by the device at the bottom of the eduction tube where, because of smaller volume, control is easier and more effective.

Fig. '7 illustrates a variational form of apparatus embodying my invention. The operation of this form is identical with that described, the only difference being in the structure, which includes a diil'erent form of gas discharge valve, a change in the relative positions of the gas collection chamber and eduction tube, and a change in the agitation means. As before, the agitating and separating means is carried within oil string 26 on the lower end of tube 28, and connected to the latter member by means of couplings I05 and I06, which contain a hard metal lining I01, forming orifice I08, through which the oil passes to reach tube 28. Attached to the lower end of coupling I06 is valve section IIO that is provided in its upper portion with a plurality of gas outlets closzd by means of valve I I2 adapted to slide vertically upon the upper end of valve section I I as shown. A spring 3 bears upon valve II2 to insure proper seating of the valve and closure of outlets III. This construction is illustrated in further detail in Fig. 8.

Attached to the bottom of valve section 0 by coupling 5 is shell 35 which, as before, may be considered as an enlarged extension of the eduction tubing. Also carried from valve section 0 but within shell 35 is tubing I20 which communicates directly with oil passage H9 in the valve section, and forms an annular space I25 between it and shell 35, to which space gas outlets III open directly. At intervals throughout the length of tube I20 holes |2| are cut, and at each one of these holes there is provided a semicylindrical member I22 secured to the outside of tube I20. By means of members I22 there are provided a plurality of downwardly extending passages I23 which open at their upper ends to the annular space I25 and at their lower ends to holes I2I, thus providing a direct communication between the interior I26 of tubing I20 and the exterior chamber I25. This construction may be seen clearly in Fig. 16.

The means for agitating the oil is carried on the lower end of tubing I20 and consists of a plurality of oppositely inclined vanes, which are preferably disposed in groups, generally indicated at I28 in Fig. '7. This construction is shown in greater detail in Fig. 11. Secured to the end of tube I20 is shaft I30, upon which the agitating elements are mounted. The top element consists of a sleeve I3I secured against rotation on shaft I30 by plugs I32 formed by welding. This sleeve is provided with a plurality of inclined vanes I33 extending radially almost to tubing 35 and adapted to deflect the upwardly moving oil stream. Just below sleeve I3I, there is inset into shaft I30 a layer of bearing material I34, and at this point on the shaft there is provided a rotatable sleeve I35, having a plurality of vanes I36 similar to vanes I33, but oppositely inclined. Below rotor I35 is a series of alternating stationary sleeves I3 I, attached to the shaft as described, and

rotating sleeves I35, so arranged that vanes I36 and I33 are oppositely inclined to abruptly change the direction of the upwardly moving oil stream as the stream strikes these successive vanes. Because of the inclination of vanes I36, each sleeve I 35 will be rotated by the upwardly moving oil stream. The construction of one of the rotors with its radial vanes is further illustrated in Fig. 12.

A plurality of these alternating stationary and movable elements are grouped together on a shaft I to form one of the agitating units or stages indicated at I28. In order to secure the desired degree of agitation to extract the gas from the oil, there are provided a plurality of such agitating units or stages I28, separated if desired by lengths of tubingI40.

At the bottom of the lowermost stage I28 there is secured a short shaft I4 I, having radial fins I43, as illustrated in Fig. 9, for the purpose of centering these units within tubing to the end that the units may work efiiciently and not scrape against the surrounding tubing.

At the bottom of shell 35 is attached coupling I44 to which is connected a gas anchor of any conventional type, here shown as comprising the elements generally described in connection with Fig. 2, namely, an upper length of pipe 14 perforated at ll to admit oil, a lower length of pipe I5 terminating in bull-nose 16, and an inner pipe I9 communication with bore I45 in coupling I44 to convey oil from the gas anchor into shell 35.

The operation of this form of apparatus is generally the same as that of the form illustrated in Fig. 2, except for certain differences caused by changed construction, which differences will now be explained. Agitating stages I are designed primarily to eflect a series oi! abrupt changes in the direction of oil flow, so that the oil is agitated sufllciently to release the contained gas. For this reason the vanes I03" and I20 are inclined oppositely to each. other, but it is not essential that wardly to chamber I within shell 05 and above the topmost agitating unit. This chamber is in the form 01' an annular space surrounding tubing I 20 and serves as the gas separating and collecting chamber, for the oil and gas will rise within this chamber to maintain a liquid level at some point such as I41, and the gas collected in the chamber above the liquidlevel will be discharged through ports 'I II into the space exterior to the eduction tube. Since shell 25 which forms the outer eduction tube wall also forms the wall for the gas collectionchamber, theinternal oil conveying tube in is provided, and is in tree communicationwith chamber I25; hence oil will flow downwardly through passages I22 and openings I2I into tubing I20, and will .be 'conveyed through the latter member upwardly into. tubing 20 101 delivery to the ground surface.

Although Fig. 7 illustratesasingle extraction unit comprising one separation chamber I25, yet more than one of these units may be used 11 desired. In such event, the lower separation unit would be provided with a valve section IIO, of which the oil passage I I9 would be adapted to discharge into bore I05 oi: coupling I located at the bottom end of the unit illustrated. This construction would provide two separation chambers operating in' tandem, as is iorm. illustrated in Fig. 2.

A second variational form 01 my invention is 11- the case with the lustrated in Figs; 13' and 14. As in the device last described, the" gravity separation chamber surrounds tubing I20 so that the construction of the upper end oi the apparatus in Fig. 13 is identical with the form illustrated in Fig. 7, except that a variational form of gas-discharge valve section 1 is shown. This valve section I 50 is provided with a plurality ofgas. outlets I5I, each closed by an individual ball I52 seating in the upper end 01' the outlet, which construction is illustrated in Fig. 15. The sides 01' the. valve section are slottedat I50 toprovide intermediate vertical ribs I50 that form cages toretain the balls in the valve' section. Tube I50 extends centrally oi the valve section to connect the interior of tubing I20 with orifice I00 in hard metal lining I01. Valve section I50 is secured to coupling I05 by section I51.

This form or device also includes a variational agitating meansQillustrated in Fig. 14 as attached to the end 01' shell 05 by means of a series of sections I00 attached to. oneanother. Within sections I00. are carried a plurality of separating bells IOI, generally similar to bells 50 oi Fig. 2. Each bell carries a short shaft I02 uponwhich is journaled a rotor I 03, similar to rotors 03 already described; hence a view on line 5a-5a of Fig. 14 is similar to Fig. 5. The bell receives the upwardly rising oil from below its central cavityd and discharges it through a plurality oi. passages I05 to the rotor carried above the bell. This rotor is revolved by the oil stream and mechanically'separates a portion'ot the released gas in the manner already described, so that the heavier liquid is thrown outwardly and rises in annular space I00 around the bell next above. At the upper end of each annular space I00 there is located a plurality of passages I01 which discharge the heavier oil to the rotor amounted on that bell, but to a point near the periphery of the rotor, in distinction to passages I05 which discharge to the inner end of the rotor vanes (see Fig. 17).

The agitation to release gas and the separation of that released gas by centrifuging is substantially similar to the operation as carried on in the iorm descrlbed in Fig. 2, and the operation of the present form will be understood from the foregoing description without any further explanation. However, it will" be noted that in Fig. 2 the outer column or heavier liquid rising through passages '00 is not discharged directly into each succeeding rotor, although the column sages I05 but through a central sleeve I10. After leaving bell IOIa, the oil and gas are discharged into top section I00 which constitutes the bottom 01' the gas collection andseparatlon chamber I25.

Sleeve I 10 is provided with slots I1I so that it, for any reason, tube I20 should drop it would rest upon sleeve. I10 and an outlet would still be had for the oil through'slots I1I, whereas without such slots the oil passage might become entirely closed.

After passing into. chamber I25, the released gas is separated from the oil by gravity, and the oil passes out of thechamber through passages I23 and opening I2 I into tubing I20, through which the oil rises to reach eduction tube 20 for delivery to the ground surface.

Gas will accumulate in chamber I25 above liquid level I12 and :will be discharged through passages I5I and slots I50-oi the valve section by the raising of valves I52 against the external pressure, as has already been explained.

,Fig. 14 is shown as provided with a coupling section I10 attached to the bottom section I00, said coupling being adaptedto receive a second valve section I50, in order to operate two of these devices in tandem, the oil from the lower device being charged intothe upper one through tubing I50 oi the lower valve section. However, a gas anchor may be attached at this point, in which case tubings 14 and 10 will respectively replace section I50 and tubing I50.

A comparison of Figure 2 with Figures 7 and 13 will disclose that the two forms of apparatus illustrated are generally similar excepting for a change in location 01' the gas separation chamber. In Fig. 2, shell 35, an enlarged portion of the eduction tube, serves as a housing for the in an internal pipe 50 that forms the walls of collection chamber 5|. In Figs. 7 and 13, shell again encloses the agitating and separating elements, but tube 28 has been provided with an extension I20 inside shell 35, so that the gas coltransmissive connection at their lower ends with the eduction tube, so that oil freed of its gas may' pass between chamber and tube with interference. In the form first described, chamber 5I opens directly to the eduction tubing. In the two later forms, communication is had between the gas chamber and the eduction tubing by means of vertically extending members I22, forming passages I23 communicating at their lower ends at openings I2I with portion I20 of the eduction tube.

Comparison of the two forms will further disclose that their general method of operation is identical, except for such minor changes as result from the structural change in the oil agitating elements. In Fig. 2 the oil and gas undergo a certain amount of mechanical separation prior to the gravity separation taking place in chamber 5|, while in the form of Fig. '7 this mechanical separation, although present in some degree, is not pronounced, and the largest amount of separation occurs within the gas collection chamber by means of gravity separation. The relation of the parts in both figures is such that pressure relations in the gas chamber and oil discharge tube will be the same as explained before and will operate to discharge gas through valve I52 in the same manner as it is discharged through valve 4 I.

Having disclosed various forms of my invention, it is to be understood that the foregoing description and annexed drawings are to be considered as illustrative of, rather than restrictive upon, the claims appended hereto, for there will occur to those skilled in the art various changes in arrangement and construction of the various parts that may be made without departing from the spirit and scope of the invention. For example, I am not to be limited to the particular illustrated combinations of pressure-actuated release valves, gas extraction units, and collection chambers, but any desired combination of the various forms of the parts may be used.

I claim as my invention:

1. In apparatus for repressuring oil sands flowing gas-charged oil into a well, the combination of eduction tubing adapted to conduct oil to the ground surface, means to maintain a predetermined pressure on the well liquid exterior to the tubing, agitation means to release gas from the gas-charged oil, said agitating means comprising rotors revolved by the oil stream to centrifuge the oil and separate released gas, a gas chamber communicating with the tubing, and a valve controlled outlet from the chamber to the well exterior to the tubing, the chamber being adapted to receive and collect the released gas under pressure in excess of the fluid pressure in the well at said outlet and to discharge gas through said outlet.

2. In apparatus for repressuring oil sands flowing gas-charged oil into a. well, the combine.-

tion of eduction tubing adapted to conduct oil to the ground surface, means to maintain a predetermined pressure on the well liquid exterior to the tubing, oil agitating and centrifuging means comprising a series of rotors turned-by the moving oil stream to release gas from the charged oil, a gas chamber communicating with the tubing and adapted to receive and collect released gas under pressure, and means for delivering gas from the chamber to the well exterior to the tubing.

3. In apparatus for repressuring oil sands flowing gas-charged oil into a well, the combination of eduction tubing adapted to conduct oil to the ground surface, means to maintain a predetermined pressure on the well liquid exterior to the tubing, agitation means comprising a series of oppositely inclined vanes causing turbulent oil flow to release gas from the charged oil, a gas chamber communicating with the tubing and adapted toreceive and collect the released gas under pressure, and means for delivering gas from the chamber to the well exterior to the tubing.

4. The method of operating a well flowing gas-charged oil into the eduction tube thereof that includes directing such oil against a moving element to thereby disintegrate it to release gas contained therein, separating within the well at least a portion of the gas so released, discharging such gas into the well external the eduction tube, and delivering the oil to the ground surface.

5. The method of operating a well flowing gascharged oil into the eduction tube thereof that includes agitating such oil by moving elements in the eduction tube to release gas contained therein, separating within the well at least a portion of the gas so released, discharging such gas into the well external the eduction tube, and delivering the oil to the ground surface.

6. The method of operating a well flowing gascharged oil into the eduction tube thereof that includes agitating such oil by flowing the same against reversely directed surfaces to release gas contained therein, separating within the well at least a portion of the gas so released, discharging such gas intothe well external the eduction tube, and delivering the oil to the ground surface.

7. The method of operating a well flowing gascharged oil into the eduction tube thereof that includes directing such oil against a movable element operable by such fluid flow to agitate the oil releasing gas contained therein, separating within the well at least a portion of the gas so released, discharging such gas into the well external the eduction tube, and delivering the oil to the ground surface.

8. The method of operating a well flowing gascharged oil into the eduction tube thereof that includes jetting such oil through an aperture against a movable member to release gas contained in such oil, separating within the well at least a portion of the gas so released, discharging such gas into the well external the eduction tube, and delivering the oil to the ground surface.

9. The method of operating a well flowing gascharged oil into the eduction tube thereof that includes passing such oil against a member rotated by the flow of fluid thereby to agitate and centrifuge such oil, separating at least a portion of the gas therefrom, collecting the gas so separated within the well, discharging such gas into eduction tube and delivering the fluid from the other column to the ground surface.

11. The method of operating a well flowing gas-charged oil into the eduction tube thereof that includes impinging such oil against a rotating member'provided with passages therethrough whereby gas is released and separated from such oil to pass through such passages and whereby oil on the surfaces of such memher is centrifugally discharged from the periphery thereof, collecting at least a portion of the gas so released within the well, discharging such gas into the well external the eduction tube, and delivering the oil from which such gas has been separated to the ground surface.

12. The method of operating a well flowing gas-charged oil into the eduction tube thereof that includes creating within such eduction tube an outer column of fluid of a higher average speciflc gravity and an inner column of lower average specific gravity by passing gas-charged oil through a series of agitating and centrifug ing elements for separating oil from gas, separating such columns of fluid between zones of centrifuging action, elevating both columns in the induction tube from one centrifuging zone to a higher centrifuging zone, collecting fluid from the inner column within the well and discharging it into the well external the eduction tube, and delivering the outer column of fluid to the ground surface.

'13. The method of operating a well flowing gas-charged oil, into the eduction tube thereof that includes agitating and centrifuging such oil duringits passage through such eduction tube by rotating elements spaced throughout a sufficient length of such eduction tube to create a column of gasified fluid of sufliciently long and of an average density sufliciently low that in a zone of the eduction tube during oil flow therethrough the pressure will be greater than the external well pressure at that zone, separating within the 'well at least a portion of the gas from -such oil and discharging such separated gas into the well in said zone of higher internal pressure. p I

14. In a device for controlling 'gas-oil ratios in a producing well, an eduction tube, agitator elements therein moved by the passage of fluid therethrough ,to agitate such fluid to release gaseous elements contained therein, means within the well for collecting such gaseous elements, said collecting means being provided with a port for dischargingsuch gaseous elements into the well external the eduction tube.

15. In apparatus for removing gas-charged oil from a producingwell, an eduction tube within the well and centrifuging means within the well and in the path'of oil flow for separating gas from such oil, said centrifuging means including a rotor having openings therethrough inclined to the axis of rotation.

16. A device as described in claim 15 and including surfaces between said openings against 'from a producing well, an eduction tube for conducting oil to the ground surface, and oil agitation means within the well having reversely directed surfaces against whichsaid oil is directed, adapted to release dissolved and occluded gas from the oil and to discharge such gas and oil into the eduction tube.

18. In apparatus for removing gas-charged oil from a producing well, an eduction tube conducting oil to the ground surface, oil agitation means having moving elements within and near the bottom of the eduction tube, said agitation means being adapted to release dissolved and occluded gas from the oil.

19. In apparatus for removing gas-charged oil from a producing well, an eduction tube, a series of spaced rotors in the path of oil. flow therein adapted to release and separate gas from such oil, and means between said rotors 21. In apparatus for removing gas-charged oil from a producing well, an eduction tube having means therein defining substantially separatepaths of flow therethrough, said defining means being intermittently interrupted to permit comm inication between such paths and centrifuging elements located at such interruptions adapted to receive fluid passing through such paths and to simultaneously centrifuge the same whereby the gas and oil are at least partially segregated and the streams in the separate paths become of different densities. w

22. A device according to claim 21 and including means for collecting within the well the fluid flowing through one of such paths.

23. A device according to claim 21 in which said eduction tube is provided with a port opening into the well external thereof, one of said paths being in communication with such port for and centrifuge such oil, the sections of eductiontubing therebetween having separate passages for fluid discharged from the periphery and from the central portions of said rotors. 25. A device according to claim 24 in which said rotary elements are provided with slots iiiclined relative to the axis of rotation of said elements. i

26. A device accordingto claim 24 in which said rotary elements comprise substantially cylindrical elements having'passages ther'ethrough inclined to the axis of rotation.

27. In apparatus forremoving gas-charged oil from a producing well, an eduction tube and agitating means therein, said means including rotary elements having surfaces inclined to the rotational axis thereof and stationary elements having passages therein adapted to direct the oil 28. In apparatus for removing gas-charged oil from a producing well, an eduction tube, rotary elements containing inclined passages therethrough and in the path of oil flow within said tube, and stationary elements having passages therethrough reversely inclined to the passages through the rotary elements.

29. In an apparatus for removing oil from a. well having gas-charged oil therein, the combination of: an eduction tube adapted to be extended into said well; a relatively long vertical separation chamber into which gas-charged oil of said well is received, said eduction tube being connected to said separation chamber; agitation means in the form of rotors adapted to be driven by said oil whereby said gas-charged oil is agitated prior to its reception into said separation chamber; and means for delivering the volatile constituent of said gas-charged oil into said well.

30. In an apparatus for removing oil from a well having gas-charged oil therein, the combination of an eduction tube adapted to be extended into said well; a relatively long separation chamber into which gas-charged oil of said well is received, said eduction tube being connected to said separation chamber; centrifuging means whereby said gas-charged oil is agitated prior to its reception into said separation chamber, said centrifuging means including a rotor whereby said gas-charged oil is centrifuged for throwing the oil outward and walls providing a separate passage for said volatile constituent; and means for delivering the volatile constituent of said gas-charged oil into said well.

31. In an apparatus for removing oil from a well having gas-charged oil therein, the combination of: a centrifugal separating means adapted to be placed in said well, which includes walls forming a volatile constituent passage and an oil passage, and a rotor for centrifuging said gascharged oil so as to deliver the volatile constituent to said volatile constituent passage; an eduction pipe whereby separated oil is delivered to the surface of the ground; and means connected to said volatile constituent passage for redelivering said volatile constituent into said well.

JOHN A. ZUBLIN.