US2307557A - Apparatus for elevating fluids in wells - Google Patents

Description

i Jan. 5, 1943. H. D. woODMANsEx-z APPARATUS FOR ELEVATING FLUIDS IN WELLS www WMM am Filed May '7, 1940 Patented Jan. 5, 1943 A OFFICE y APPARATUS Fon ELEVATING FLUms IN WELLS Hollis D. Woodmansee, Cypress, Calif.

Application May 7, 1940, Serial No. 333,736

3 Claims.

This invention relates to wellv equipment and relates more particularly to apparatus for elevating liquids in wells where the gas pressure is insuiiicient to cause the well to owand for increasing'the production of flowing wells. A general object of the invention is to provide a simple, eiective and economical apparatus of this character.

Another object of the invention is to provide a uid elevating apparatus of the character referred to embodying one or more gas lifts or separators constructed and arranged to most eniciently utilize the fluid pressure or gas pressure to successively elevate the liquid.

Another object of this invention is to provide an apparatus of the character referred to in which a minimum number of separators or lift units is required.

Another object of thisinvention is to provide an apparatus of the' character referred to in which the separators or lift units are related and located to take full advantage of the natural tendency for the gas to elevate the liquid before it separates from the liquid at given levels and the elevating units serve to rem-ix the gas with i y the oil or other liquid at or below each natural level of separation to provide for the successive stages of lifting action.

Another object of this invention is to provide an apparatus of the character referred to that is simple and doesl not require valves or other parts liable to Wear or fail.

Another object of this invention is to provide an apparatus of the character referred to embodying a pump for receiving the fluid after it leaves the uppermost lift unit or separator and before the gas is allowed to again separate from the liquid, the pump operating to discharge the fluid from the top of the well, assuring a substantially constant maximum production with a minimum expenditure of power.

A further object of the invention is to provide an apparatus of the character referred to that is effective in increasing the production of owing wells. When the apparatus is employed in a flowing well the separator or lift units serve to reduce the separation of the gas from the oil and operate to remix the gas with the liquid or oil so that Ythere is a greater proportion of o oil produced.

The various objects and features of my invention will be fully understood from the following detailed description of a typical, preferred form and application of the invention, throughout which description reference is made to the accompanying drawing, in which:

Fig. 1 is a diagrammatic view of the upper portion of the apparatus arranged in a well with the body parts and tubing in longitudinal cross section. Fig. 2 is a view similar to Fig. l showing the lower portion of the apparatus in c well. Fig. 3 is an enlarged longitudinal detailed sectional view of the upper portion of one of the separators and Fig. 4 is a view similar to Fig. 3 showing the lower portion of the separator, certain parts appearing in side elevation in Figs. 3 and 4. i

The apparatus of the present invention as employed in a non-flowing well may be said to comprise, generally, a tubular well string or production string I0 arranged in a well, one or more gas lift units II connected in the string I0 and a pump I2 for elevating the fluid after it leaves the uppermost lift unit I I.

`The tubular string I 0 extends into the well from the ground surface to pass through the well casing C with suitable clearance. The casing C is suspended from the usual casing head and the tubing ,string I0 is suspended from a suitable tubing head. Casing heads and tubing heads are conventional in the various forms of well production' equipment and as the present invention is not, primarily concerned with the details of thesestructures the heads have been yomitted from the present disclosure. Itis to be understood, however, that the casing head and the tubing head are provided with the usual iiuid connections, etc. The string I0 of tubing extends downwardly in the well to have its lower end in receiving relation to the producing sands or productive zone of the Well. In most cases there will be a column of fluid standing in the Well and extending upwardly into the well casing C and the string I0 may extend a considerable distance into this fluid column. In accordance with the usual practice the string IU may be made up of lengths of pipe or tubing I3 connected by suitable threaded couplings. i

The separators or gas lift units II are interposed in the string I0 to utilize the elevating action of the gas under pressure lfor the successive elevation of the oil or liquid. The number of units II employed, depends upon numerous factors such as the depth of the well, the gas pressure, the ratio of gas and oil, etc. It is a feature of the invention that a large number of separators or units II is not required. The lowermost separatoror, unit II is positioned only a short distance below the plane where the gas would normally separate from the fluid flowing up in the string I0 and, in most cases, 'this lowermost unit I I isspaced from the well bottom a distance equal from one-third to' one-half the depth of kthe well. The second to the lowermost separator or lift unit I I is located slightly below the plane where the gas would again separate from the oil or liquid iiowing up through the string I0 from the first or lowermost unit II. In

- many cases the second to the lowermost unit II the well although where the well is very deep the second to the lowermost unit II may be a substantial distance from the ground surface in which case a third or even a fourth unit II may be required. It is important to note that the separators or gas lift units II are only required at points below the planes of normal separation of the gas from the liquid flowing up in the string II! and that these points are usually a substantial distance apart so that the minimum number of units II is required.

Each separator or lift unit II comprises a barrel or body I4. The bodies I4 of the units II may be lengths of tubing similar to the lengths of tubing I3. A coupling l is provided at each end of each body I4. The couplings I5 are screw threaded to the tubing sections I3 at I6 and are screw threaded to the bodies I4 at I1. Transverse webs or partitions I`8 are provided in the couplings I 5 and form the upper and lower walls of the bodies I4. The webs or partitions I8 may be integral parts of the couplings I5 or may be otherwise formed. A central vertical opening I9 is provided in each partition I8.

The separators or lift units I I each further include an inlet tube extending upwardly from its lower partition I8. The lower ends of the inlet tubes 20 are screw threaded or otherwise fixed in the openings I9 of the lower partitions I8. The inlet tubes 20 extend upwardly a substantial distance in their respective bodies I4 to have their upper ends a shortkdistance below the upper partitions I 8. The tubes 20 are preferably .quite small in diameter and fluid capacity and are received inthe bodies I4 with substantial clearance. The upper ends 2| of the tubes 28 are open to discharge into the bodiesI4.

Each separator or lift unit II further includes an outlet tube 22 arranged to conduct the fluid from the body I4. The outlet tubes 22 extend downwardly from the upper partitions I8 having their upper ends screw threaded or otherwise xed in the openings I9 in the upper partitions. The outlet tubes 22 are quite small in diameter and are of substantial length to have their lower ends spaced a short distance from the lower partitions I8. The tubes 20 and 22, arranged and proportioned as described, overlap or extend for a considerable distance in side by side relation. The tubes i20 and 22 are secured in the central openings I9 of the partitions I8 and, therefore, may engage one against the other but as the tubes are quite small in diameter and quite limber they readily lean in opposite directions as illustrated in the drawing so that this interference or engagement is of no consequence. The

centralized attachment of the ends of the tubes 20 and 22 to their respective partitions I 8 is desirable for obvious reasons.

The lower portions of the outlet tubes 22 are formed lto receive the iluid from the lower portions of the bodies I4 and, in accordance with the invention, are constructed to effectively mix the gas with the oil or liquid when suicient volumes of gas have accumulated in the bodies I4 to discharge through the tubes 22.l Closures or plugs 23 may close the lower ends of the outlet tubes 22. The lower portion of each outlet tube 22'is provided with a plurality of slots 24 for admitting fluid from the bodies I4 to the interiors of the tubes. The slots 24 are narrow and are formed to effectively scrub the gas into the oil or liquid when the conditions are such that oil and gas both enter the tubes 22. The size and a substantially constant ow from the well andv relieves the lift units II of a dampening or choking pressure that might otherwise develop. In accordance with the invention any suitable or selected form of well pump may be employed. The pump I2 is arranged in the string I0 above the uppermost lift unit II and in accordance with the invention is arranged slightly below the plane where the gas would normally separate from the oil or liquid after leaving the uppermost unit Il. This uppermost plane of gas and liquid separation may be a substantial distance above the uppermost unit I I and may be only a. short distance from the top of the well. Accordingly, the pump I2 may not be required to lift the fluid a great expenditure of power.

In the diagrammatically illustrated apparatus the pump I2 is of the standing plunger and working barrel type having a plunger 25 suitably anchored in the string I0 and having a barrel 28 reciprocating down over the plunger. The barrel 26 is operated by a pump rod 21 extending to the ground surface and the pump embodies the usual standing and working valves. The inlet 28 of the pump I2 directly receives the fluid from the interior of the string I0 below the pump. The pump I2 may operate to elevate the fluid through the upper portion of the string I0 or, if desired, a second or inner string may be employed to conduct the pump fluid upwardly from the pump to the ground surface.

In use or operation the apparatus is installed as above described to have the lowermost lift unit I'I slightly below the plane of separation of the gas from the uid owing through the string I0 and the second to the lowermostunit II is likewise arranged a short distance below the plane of natural separation of the gas from the oil or liquid passing upwardly through the string I 0 after leaving the lowermost unit II. Where more than two units II are employed the units are, in each case, arranged a short distance below the plane of natural separation of the gas from the liquid flowing upwardly through the string I0. Because of this positioning of the units II the full natural lifting action of the entrained gas is utilized and a maximum delivery of liquid to the units is assured. With the lowermost unit Il positioned a substantial distance from the bottom of the well or the production -zone the fluid is free to flow upwardly through the string I0 to said unit I I and there is no choking action or retarding action due to the installation of lifts or separators in the lower part of the string I0.

'I'he gas is delivered to the units II while still mixed or entrained with the oil or liquid and separates from the liquid only upon the discharge of the fluid into the bodies I4. This separation of the gas from the oil or liquid is not, of course, necessarily complete and a substantial proportion of the gas may remain mixed with the oil which falls into. the lower portions of the bodies I4. The liquid discharging from the upper ends of the inlet tubes 20 falls into the lower portions of the bodies I4, which are closed byl the lower partitions I8. A substantial body of liquid soon accumulates in the lower portion of each body I4 and this liquid rises above the lower end of the outlet tube 22 and its slots 24.

The gas under pressure accumulates in the upper portions of the bodies I4. The liquid accumulating in the lower portions of the body I4 is forced through the perforations or slots 24 and upwardlyr through the outlet tubes 22 by the gas 'pressure accumulating in the upper portions of the body I4. In practice, there may be a substantial prolonged delivery of oil or liquid from a unit II by the action just described. The gas, delivered to the units II with the liquid, accumulates in the upper portions of the bodies I4 and the accumulations of the gas increase. In time the lower level of an accumulation of gas in a body I4 reaches the slots 24 so that gas as well as liquid is delivered to the related outlet tube 22. The slots 24 are narrow so that this gas is thoroughly mixed with the liquid leaving the unit II. Thus the gas that separates from the liquid in the units Il is remixed with the liquid to assist in the stage elevation or successive lifting of the liquid through the string I0. The liquid and gas levels in the units I I may iluctuate from time to time as the ratio oi' gas and oil changes. However, it will be apparent that the gas separating from the oil or liquid as it passes through the units II is ultimately substantially entirely remixed 'with the oil or liquid for the next lifting stage.

The pump I2 may be in continuous operation and serves to elevate the iluld through the upper portion of the well. As above described, the pump I2 is located a short distance below the plane of natural separation of the gas from the liquid that has been lifted from the uppermost unit II and there is little or no free gas delivered to the pump I2. Accordingly, the pump I 2 operates without a gas lock condition developing. The pump I2 operating to pump away uid delivered to it by the uppermost unit II greatly assists the units II in their stage elevation of the fluid.

In applying the invention to a ilowing well the pump I2 is not necessary. When a well is owing from natural causes there is usually a marked tendency for the gas to separate from the liquid or oil so that the well produces liquid and free gas. When'the apparatus of the present invention is utilized in a ilowing well the gas is held in the oil and there is a much greater proportion of oil produced than there would be if the well was allowed to iiow naturally. In the case where theapparatus is installed in a ilowing well the separators or units II are installed and located as above described, that is, they are positioned adjacent and slightly below the planes where the separation of the gas would normally occur. The 'gas that separates from the liquid accumulates in the upper portions oi the bodies-I4 and the pressure of the gas in the bodies builds up and operates, as above described, to assist in elevating the liquid through the string I0. Further, the gas pressure thus maintained in the units II keeps the fluid underV a substantial pressure and prevents, or at least greatly reduces, the separation of the gas from the oil. The gas leaving the bodies I4 remixes with the liquid or oil when the fluids pass through the slots 24, this action being described above. The uid is produced from the well with a minimum of gas separation and the production is proportionately increased.

Having described only a typical preferred form and application ot my invention, I do not wish to be limited or restricted to the specific details herein set forth, but wish to reserve to myself any variations or modifications that may appear to those skilled in the art or fall within the scope of the following claims.

Having described my invention, I claim:

1. Apparatus for elevating iluid in a well producing liquid andy gas under pressure comprising a tubular string extending into the well to conduct the fluids therefrom, a plurality of vertically spaced fluid lift units interposed in the string, the lowermost unit being adjacent and below the plane of separation of the gas from the liquid rising in the lower portion of the string, the other units being adjacent and below the planes of separation of the gas from the liquid rising in the string from the units ynext below them, and a pump adjacent and below the plane of separation of the gas from the liquid rising from the uppermost unit for elevating the iluid to the ground surface.

2. Apparatus for elevating uid in a well producing liquid and gas under pressure comprising a tubular string extending into the well to conduct the uids therefrom,'a iluid lift unit interposed in the string adjacent and below the plane of separation of the gas from the liquid vrising through the lower portion of the string and operable to elevate the liquid through the string by the pressure of the accumulating freed gas, and a `iluid liftunit 'interposed in the string adjacent and below the plane of separation of the gas from the liquid rising from the rst named lift unit and operable to further elevate the liquid in the string by the pressure of the accumulating freed gas, the portion of the string between the units being free and-unrestricted, each of said units including a body having a chamber, an inlet tube for carrying the fluid upwardly from the portion of the string below the body to the upper portion of the chamber, and an outlet tube for carrying the fluid upwardly from the lower portion of the body to the part of the string above the body.

3. Apparatus for elevating uid inv a well producing liquid and gas under pressure comprising a tubular string extending-into the well to conduct the fluids therefrom, a uid lift unit interposed in the string adjacent and below the plane of separation o! the gas from the liquid rising through the lower portion o! the string and operable to elevate the liquid through the string by the pressure of the accumulatingireed gas, and a iluid lift unit interposed in the string adjacent and below the plane of separation oi.' the sas from the liquid rising from the nrst named lii't unit and operable to further elevate the liquid in the string by the pressure ot the accumulating freed gas. the portion of the string between the umts being free and unrestricted, each of said units including a body having a chamber. an inlet tube for carrying the duid upwardly from the portion of the string below the body to the upper portion of the chamber. and an outlet tube for carrying the iluid upwardly from the lower portionv oi' the body to the part 'of the string above the body. the lower portion of the outlet tube havlng slots for admitting the fluid from the body and serving to mix the gas with the liquid as the fluids enter the outlet tube.

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