US1760420A - Oil recovery method and apparatus - Google Patents

Description

`May 27, 1930. w. A. LooMls OIL RECOVERY METHOD AND APPARATUS Filed April 21. 1926 w w y, Z M A III VA WAVJ Patented May 27; 1930 WALTER A. LOOMIS, 0F LONG BEACH, CALIFORNIA -01212' RECOVERY METHOD AND APPARATUS Application med April 21,

This invention relates to a method of oil recovery and apparatus therefor.

In oil well production is usually occurs that the flow of oil from a well is accompanied by a flow of gas, and it often happens that the How of gas is so excessive that proper control of the well is prevented, with the result that a considerable amount of both oil and gas is wasted. 1o It is common practice to provide'a structure known .as a bean, through which the oil and gasfiow from the well. in' an attempt to mechanically controlthe How. This device is provided with a constricted orifice which tends to check the iow of both fluids and to prevent an excessive escape of the lighter fractions of oil and gas. T his method has not proven to be an entire success, and it is the principal object of the present inlvention to provide a'method of oil recovery and an apparatus therefor, of the type generally shown in my Patent No.' 1,554,444, entitled System for the recovery of mineral oils, which will utilize the pressure of the lighter hydrocarbon fractions within the well to prevent unrestricted flow of gas from the well, and at the same time to control and stimulate 'the How fromthe well in an automat-ic operation.

Further and extensive practice of the invention set forth in my mentioned patent, in which hydrocarbon gases capable of solution in oils or of undergoing a change of phase, are utiiized for a'lifting effect, under the condit-ions of operation, has shown not only that intelligent application 'of the various principles, and methods therein set forth is capable of greatly increasing oil production, but that the technique and installation may be widely varied and materially modified; and also that it is, in general, worthwhile to provide each well in connection' .with which my invention is used, not only with means permitting a practically continu'ou's observation and control of pressure therein, but also with means, including an il inlet or tail pipe which extends practically to the bottom of the well, whereby any water or sand entering the same may be reliably withdrawn in the oil stream,

1926. Serial No. 103,448.

and whereby the well may be substantiallyy prevented from flowing withoutcontrol.

The present invention contemplates provision of an apparatus in a well casing which will establish oil and gas columns and will cause the pressure of the lighter hydrocarbon fractions to act against and with the column of oil to prevent violent action of the oil and the gas and to produce a lifting action of the column of oil by the hydrocarbon fractions under certain optimum conditions; the invention contemplating the beneficial use of light hydrocarbon fractions which liquefy under the pressure of an excessive hydrostatic head and will gasify and aerate a column of liquid when released in the bottom thereof to effect an upward movement of said liquid column, saidqgas being accelerated by the heat energy present inan oil well of considerable depth.

IThe invention is illustrated by way oi example in the accompanying drawing, in which:

Fig. l is a fragmentary view in central vertical section through the apparatus with which the present invention is concerned and with parts broken away for the sake of convenicnce.

Fig. 2 is a fragmentary view' in central Ivertical section through a modified form of S0 the apparatus with which the tion is concerned.'

Referring more particularly to Fig. .1 of the drawing, 10 indicates a well casing. This n casing is of a desired length, and consists of a S" plurality of lengths of imperforate casing 11,v and lengths of perforate casing 12, disposed therebeneath and in continuation thereof.. Mounted upon the upper end of the casing 10 is a closure cap 13 fitted with a pipe 14 carry- 99 ing a valve l5. The pipe communicates with the interior of the casing and the valve permits the introduction of a gas into the casing, or the escape of a gas therefrom, as may ,J be desired. A 95 The cap 13 has a central opening therethrough to reeive a string of tubing 16. This string of ltubing extends longitudinally and centrally of the casing.

A suitable packing collar securesk and seals 10 present invender lesser preures.

the tubing to the cap. An outlet delivery pipe 18 is connected with the upper end of the tubing 16 and permits thewithdrawal of. oil which is elevated within the tubin in the manner to be hereinafter described. e tubing extends downwardly within the casing to a desired depth and is fitted at; its lower end with a slip oint 19, whlc'h recelves the upper end of a gas jacket 20. The gas jacket 1s a cylindrical tube of substantially the same sectional dimensions as the tubing 16, and forms a continuation thereof. Ex tending through the slip joint is an inner oil tube 21 fastened in position by a packing nut 22, which engages the slip joint. It will thus be seen that the slip joint separates the string of tubing 16 from the gas jacket 20 and that communication to the interior of the string of tubing 16 is then afforded through the inner oil tube 21.

The lower end of the gas jacket 20' is threaded into a coupling` 23 which also receives the upper end of a tail pipe 24, which pipe is in longitudinal alignment with7 the string of tubing 16 and forms a downward continuation thereof. The coupling also has a threaded bore receiving amixer 25. This mixer has a Vent ri passageway through it, extending longitudinally of the pipe structure and estabhshing communication between the tail pipe 24 andthe inner oil tube 21. At points around the mixer, and slightly above the point of constriction in the Venturi pas,- sageway, a plurality of outwardly and downwardly extending ducts 26 are formed through the lwall of the mixer and communicate with the chamber 27, formed between the outer wall of the mixer and the circumscribin' inner wall of the gas jacket 20. The tall pipe 24 ma extend any desired distance below the coup ing 22. In some linstances it has been satisfactorily extended fora distancey of one thousand feet below this coupling.

The lower end of the-tail pipe is formed with perforations 28, which permit an inow of oil to the tail pipe. Interposedat a desired point in the lenh of the tail pipe is a Venturi throat mem r 39, which produces a constricted orifice through which fluids must flow inpassing upwardly through the tail pipe. v Disposed within this orifice-is an Aupturned nozzle 30, in communication withA a central feed pipe 31. This pipe extends centrally and upwardly through thetail pipe 24, the mixer 25, the inner oil tube 21 and the string of tubing`16, beingY thereafter suitably connected with an oil fractionator and a compressor by which it may be supplied with light hydrocarbon fractions, such as propane, which have the characteristic of liquelying under excessive pressures and gasifying un- These hydrocarbon fractions also have the characteristic of being absrbed by hydrocarbon oils under heavy Vpressure and of being liberated under progressive conditions of partial pressure. The

liquefied hydrocarbons may be delivered under pressure to the central feed pipe 31, or

means may be provided toinsure that theyI will be constantly supplied thereto while permitting the hydrostatic'head of the well to produce the pressure In a well of a depth of substantially four t ousand feet it is found that a typical pressure is approximately 2500 rality of( gas open1ngs'24L whichv extendthrough the wall of the jacket at a point adjacent and beneath the slip joint 19, thus establishing communication between the casing 10 and the interior of the gas jacket 20.

In the form of the invention shown in Fig. 2 of the drawing, the parts are substantially identical to those indicated in Fig. 1 of the drawing, with the exception that the positions of the mixer ducts 26 and the gas inlet ducts 36am reversed and the mixer is thus disposed above the positionat which the gas inlet ducts are formed through the gas jacket 20. In this structure it will also be noted that the mixer communicates directly at its upper end with the string of tubing 16, and that at its lower endl it communicates directly with the tail pipe 24, which extends downwardly through the slip joint 19. In the 4structure shown in Fig. 2, it will, therefore, be evident that the inner oil tube 21 has been eliminated and that in the reversal of parts, the tail pipe 16 has been connected to the mixer at the point originally provided for the inner oil tube when the mixer was inA its reversed position. v

It will also be noted that in both forms of. the invention, the inlet ducts 26 incline upwardly and inwardly through the wall of the mixer and. communicate with the Venturi throat at a therein. Y

In some installations it may -be desirable to connect the casings lof structures similar to those shown in Figs. 1 and 2, so that a flowof gas may7 be effected from one casing to the other.

in Fig. 1 of the drawing, it will be assumed point above the constriction is may `beiaccomplishedy by connecting pipe 37, controlled by valves'38 that the -well casing and the tail pipe extend-l into a productiveoil bearing stratum, in which event the oil and gas will percolate into the lowerv end ofthe casing 10, through -theopenings inthe perforated section 12; it

'its Way through the openings 28 in the tail` pipe 24. By this arrangement, it will, thereore,

l pipe will'be oil substantially \free from gas and that the fluid outside of the tail pipe and confined' within the casing willbe a mixture of gas and oil.' rl`he mixed fluids within the caslng will, therefore, be of-lighter specific gravity than the liquid Within the tail pipe and the levels assumed by the liquid in the tail pipe and the fluids within the casing will be materially different when the two columns are in hydrostatic balance.

An investigation of conditions in a particular Well Will determine this variation in level between the two columns and will make 'it possible to determine the point at which the gas inlet openings 36 occur, as well as the `point at'which thegmixer 25 may be placed.

. The level o the column of oil under the operating conditions of specific gravity pres` ent should substantially intersect the operiings 26 leading from the compartment 27 through the side walls of the mixer 25; this level being indicated at b in Fig. 1. The level of the fluid mixture as indicated vat a should be maintained due to the pressure of the gas within the casing 10, above the level of the 'mixture and as coniined by the casing cap 13. This pressure may be'relieved by the manipulation of the valve 15, or it may' be increased by introducing light hydrocarbon fractions, such as propane, into the upper end of the casing, by the valve 14 and through the pipe 15.

lt is to be understood that the gas within the compartment 4formed by vthe wall of the casingand the Atubing string 16, and defined at the top by the casingcap 13 and by the level of the fluid mixture as indicated at a, is preferably. a propane .hydrocarbon fraction which will `liquefy under pressure and may be absorbed by the oil into which it is injectedthereafter changing its physical state to a gas under conditions of reduced pressure to perform the beneicial work herein contemplated.

The gas under pressure will pass through be evident that the fluid within the tail? 27 to the openings 2 6 through theV mixer.

This. gas will then encounter the liquid with in the mixer and will tend to force itself' upwardly through the liquid in an eiort t0 l escape. If the pressure 1sV excessive, it

liquefy and move upwardly under the res-f -sure until it. has opportunity to expan at which time it will begin to gasify accompanied by ebullitin and the prodiiction o` a froth formed by the mixture of the oil andV the gas, as it aerates the fluid particles and velevates them upwardly through the delivery pipe l8.` If the pressure of the gas above the level a of the mixture of gas and oil should sulii'ciently reduce, itis evident that the' mixture of gas and oil in the casing a would rise to a' new level, generally' indicated by dottedlines at a; for it'is to be understood that it is only the counter-pressure of the gas above the level a of the mixed fluids which holds the mixture of gas and oil to the level j a below the gas inlet openings 24. The` level of the mixture of gas and oil in the column will not recede to a point `where the'gas vinlet openings 24 are uncovered, untilsuf cient gas has been liberated from the mix` ture to create an adequate counterpressure upon the mixture and again force 1t downdii.

ward to the level a o r therebelow. Under these varying conditions of gas pressure, it is obvious that the pumping of oil would be intermittent, and it is vintended that the appar'atus shall be designed so that this pumping shall be substantially continuous. This is practically insured, due to the friction 'head which is produced Within the gas jacket 20 between the gas inlet openings 24 and the mixer 25, which will act to maintain the column of gas and oilvvithin the casing, and the column of oil Within the oil tube and tail pipe, with substantially uniform levels with relation to the conduits in which they are contained and with relation to each other'. This eliminates the necessity of the use of so-called beans having a constricted orifice through which the Huids may iiow and cause the weil to operate under substantially constant dowing conditions after equilibrium has once been established. t

lin order to increase the production of a vwell after the foregoing desirable conditions of operation have been established, light hylili) drocarbon fractions, such as propane, are delivered to the central feed pipe 31 and conveyed to the nozzle 30 positioned Within the Venturi throat 29; The relative position of this nozzle and throat to the mixer is dependent upon the degree of latent heat existing 'gravity of the column, and at the same time to lift the column through the mixer 25 and upwardly by the aidof thegas under pressure in the casing above the level of the mixture of gas and oil to the outlet delivery pipe 18 of the well.

In the form of the invention shown in Fig. 2 of the drawing, the characteristic of the appiratus is such that the pum ing action will intermittent and the liuidls) pumped from the well will be emitted in alternate quanti- `ties of oil and gas, thus the pumping action Will be interrupted during a period of accumulation of oil within the tail pipe 24 and the tubing 16, after which a sufficient pressure of gas above the level of the mixture of oil and gas in the casing will act to force the oil downwardly until the level of the mixture of gas and oil is below the level of the openings 36, ratpwhich time the gas under this excessive ressure will rush upwardly within the gas Jacket 20 and through the opening ducts 26 1n the mixer 25 to encounter av slug of oil standing within the mixer and within the tail pipe 16 to raise the slug of oil until the pressure is suliciently relieved within the casing to rmit the mixture of gas and oil to rise an cover the gas' inlet openings 36, to a distance determined by the relative specific gravities of the mixture of gas and oil within the casinff and the column of oil extending upwardly through the tail pipe 24; this, of course, being also dependent upon the gas pressure wit in the casing above the mixture as an additional factor. p It is to be understood that in the operation of this variation of the invention, the central feed pipe will operate to deliver the light hydrocarbon fractions to the lower end of the oil column, as previously described.

' It will be understood that the greater the dilerence .between the levels of the. mixer openings 26 and of the gas inlet openings 36,

the greater will be the. luctuationsin gas pressure withinthe casing. -This will also cause a greater interval between surges of oil and will cause the quantity of oil emitted at anyone surge to be eater.

v Itwill thus be seen that-,by the method and apparatus here disclosed, asubstantially constant or fluctuating equilibrium may be established between' a column of oil and a ycolumn of mixed gas and oil,in a manner to cause the pressure of a gas forming one fraction of the -vate the oil therein in a manner to avoid waste oil to act to elevate the oil and to prevent the premature and useless exhaustion of the energy, and it will further 'be evident t at without use of external pumpin means the products of the well may be uti ed to eleof gas and danger of early sanding-up of the wells, and ina manner to permit the fluid pressure within the well to be at all times suitably controlled in proper relation to the successive stages of its development.

While I have shown the preferred method of carrying out my invention and preferred embodiments of apparatus therefore, it will be understood that various changes might be made in the steps of the method and the construction of the a aratus without departing from the spirit ofptrhe invention as claimed.

I claim:

1. In means for causing and controlling the ow of an oil well, a tubin string for the upward delivery of oil, a tall pipe therebelow, extending substanti-ally'to the bottom of a l well, an intermediate organization comprising a mixer surrounded b a shell, said mixer and shell being aperture at different levels, means for supplying pressure fluid to the mixer, and a pipe for the downward and interior delivery of a light hydrocarbon to a level below said mixer. l

2. A method of oil production in which a light hydrocarbon mixture, kept in liquid phase by high pressure, is fed into a column of heavier oil near the bottom thereof, and in which a gas containing a lighter hydroarblon is admitted to said column at a higher eve . 3. A method of oil production in which a light Ahydrocarbon mixture, kept in liquid phase by high pressure, is fed into a column of heavier oil near the bottom thereof, and in which a gas containing a lighter hydrocarbon isl admitted to said column at a higher level, internal and external pressures at the last mentioned level being substantially the same. l

4. In .the elevation of oil from a well, maintaining an accumulated columnfof oil therein in communication, at an intermediate level and at a low level, with a derived column of oil provided with an outlet at the top of the well, periodically building up upon said accumulated column a gas pressure suiicient to elevate a slug of oil in said derived column above said intermediate level of communication while incidentally lowering the level of said accumulated column suiciently to deliver gas, at said intermediate level only, into said derived column, said gas being'initially 125 delivered thereto at vsubstantially the same pressure as then exists at the same level within said derived column to create an upward; surge in said derived column, and effecting a reduction in the gas pressure upon said acumulated column to intermittently cut off said gas delivery.

5. A method of the ned in claim 4, in which said accumulated column and said derived column both extend substantially to the bottom of said Well.

6. A method of the general character delined in' claim 4, in which thementioned up- Ward surge is supplemented by the separate introduction of a light hydrocarbon below said intermediate level.

7. In the elevation of oil vfrom a Well, producing a surging ilow with slugs of oil from an oil Well by maintaining communication at two levels between a derived column and an accumulated column of oil therein, and so periodically varying a gas pressure upon the lsaid accumulated column as to produce differences in the height of said columns and to admit gas intermittently to said derived column at said intermediate level.

8. A method ofelevating oil from a Well which consists in creating a column of heavy gravity oil and a column ofy lighter gravity hydrocarbons comprising a mixture of said o1l and gaseous fractions thereof, thereafter causing the pressure of gaseous fractions' liberated from the mixture to force said gas into the column of oil to elevate the same and then projectin a stream of light hydrocarbon fractions into the bottom of the column of oil i in liquid phase toV cause elevation of said column of oil as said light hydrocarbon fractions change Afrom a liquid to a gaseous state.

In testimony whereof, I have hereunto set my hand at Los Angeles, California, this 15th day of April, 1926. y

WALTER A. LOOMIS.

eneral character deu

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