US1252557A - Process and apparatus for increasing the production of oil-wells. - Google Patents

Description

. L. DUNN,

'PNocEss ANn APPARATUS EON INCREASING THE PRonucnoN or o|L wELLs.,

Patented Jan. 8,1918.`

APPLICATION FILED MAY I3. l9l6.

i siderable measure of success.

L. DUNN, OF MARIETTA, OHIO, ASSIGNOR T0 PETROLEUM PATENTS COMP,

0F CHICAGO, ILLINOIS, A CORPORATION 0F MAINE.

Specicaton of Letters Patent.

Patented dan, 8, i918.,

Application filed May 13, 1916. Serial No. 97,223.

To aZZ whom 'it may concern: Be it known that I, IRWIN L. DUNN, a citizen of the United States, residing at Marietta, in the county of Washington and State ofOhio, have invented certain new and useful Improvements in Processes and Apparatus for Increasing` the Production of Oil-l/Vells, of which the following is a specication.

Considerable areas of oil territory exlst at the present time which have been drilled with numerous oil wells, the production of which has fallen oii to such a point that the operation of the wells is of little profit and in many eases the wells have been abandoned altogether. It has been proposed to increase the productionof such oil territories by utilizing one of the wells thereon for forcing in to the oil rock a supply of compressed air, compressors beingl connected to such well for this purpose, the other wells being retained rin their usual condition and pumped by the apparatus ordinarily employed for that purpose. This process has actually been put into extensive use and in the majority of cases has met with a con- In some localities, however, the air forced into the rock instead of penetrating the full depth? and thickness thereof, and so extracting the oil from the pores of the rock and forcing i it to thepump of the wells finds an easier course through the upper layers of the rock probablybecause such rlayers contain no oil or follows the more porous open portlons of the sand and escapes from the pumping wells without fully performing its mission. It is one of the Objects of the present 1nventicn to overcome this diiiiculty by forcing the air to penetrate the lower layers and finer, less pervious portions'of 'the oil sand before it can be released at the pumping wells. c l

It is a further purpose of the invention to automatically maintain aC predetermined back pressure upon the oil and air in the rock which further assists in causing the air to penetrate throughout the sand, the denser and therefore less pervious portions as well as the coarser and more penetrable portions thereof, whereby the oil is more completely exhausted.` The advantages of my improvement, however, are notI confined great without the creation of artificial pressure.

The accompanying drawing shows diagrammatically a preferred means for carrying out my invention, Figure l representing a vertical section of an oil region equipped with apparatus for practising my invention, and Fig.' 2 a modification of one ofthe details' thereof. Referring first to Fig. l I have shown therein diagrammatically two wells, both of which penetrate through the overlying layers 3 to the oil bearing rock 4, the upper part of` which latter 4 is indicated as devoid of oil, and the lower part 4b containing oil. To the casing 5 of the well, at which the air or other gas under pressure is to be introduced is connected an air compressor pump' shown diagrammatically y face of the oil therein indicated at 8. The

space between the casing and tubing is suitably closed or packed preferably, where the well is a deep well, at or near the junction of the overlying rock and oil rock as at 9, though in case-the well is a shallow well the space may be closed at the top by the an- `nular chamber 10 shown in Fig. 2, which may be providedwith a pressure gage 11.

The lower endA of the tubing 7 may be simply left open, or perforated as at 12, and within the tubing is arranged the pump tube 13, which may be of any well known or suitable character, though preferably I place the working barrel 15 thereof at a considerable distance above the bottom of the well as shown.

In the drawing for the sake of clearness the tubing 7 is shown as of a considerably larger diameter than the pump tube 13,'but ordinarily'the diameter will be much less than shown so that the 'capacity of the annular space between the tubes will be relatively small per linear` foot. The location of the working barrel in the pump with reference to the bottom of the well varies according to the particular conditions to be met, and the back pressure which it is desired to maintain. Obviously the height of the column of oil in the tubing 7 will depend upon -the working barrel by reason of which, when the oil has been exhausted to said nipple, no

more oil is raised rby the pump until additional supplies have flowed into the tube 7. Thus there is always a back pressure automatically maintained by the column of oil4 in the tube 7, the limits of'which b'ack pressure are determined by the location of the flood nipple and the rock pressure. Thus if, for example, the rock pressure amounts to ten pounds, 1t is capableof sustaining a column of oil in the well approximately twent feet above the oil level inthe rock, and pre erably the working barrel and the liood nipple are located five or six feet below this eight, or fourteen or fifteen feet above the oil level in the well. The column of oil in the tube 7 therefore varies between fourteen or fifteen feet when the well has just been pumped, and twenty feet when the pump as been at rest for some time, andthe back pressure varies correspondingly. As the oil carries with it into the tube 7, even where the level of the oil in the rock is not reduced to that of the lower end of the tube 7, a not inconsiderable quantity of gas, in order to avoid the accumulation of gas in theupper art of the tube 7, which would increase the ack pressure perhaps to an undesirable extent, openings 16 tol the atmosphere are formed in the diaphragm in the u per end of the tube 7 to permit the escape oi) the gas. In some instances 1t has been found desirable to subject the oil in the rock to marked'variations in pressure, that is to say, to accumulate a considerable pressure therein and then suddenly release the pressure at the well. In order to effect this operation I mount thel working barrel near the bottom of thevpump tube, in which location it will nearly empty the tubing 7- at each pumping, thus relieving the back pressure or're'ducing it to a very small amount.

From the foregoing it will be'seenythat Y the improved process and apparatus is independent of the nature of the rock pressure Whether natural or artificial, and in either case conserves the rock pressure and insures its action throughout the oil stratum. This is true whether the-gas containing rock is in immediate contact with the oil rock, or

as is not unfrequently the case separated therefrom more or less by a comparatively impervious layer. l y

The tube or sleeve 7 prevents the air passing directly through the upper layers of the nsand to the well and forces it to descend to the lower layers to drive the oil therefrom. If ultimately the pressure of the air rises to such a point and the oil is so far exhausted that some of the air enters the openings 12, the rock pressure is still maintained by the weight of the column of oil.

While Iv have shown a single pumping well, it is to be understood that a considerable number of such wells may be used in conjunction with a single air forcing apparatus, or if desired more than a single well may be employed for the introduction of air. Ordinarily, however, the process is applied to a lease or area having a number of oil wells which have been bored for operation according to the previous methods, and one of the, wells is selected for the introduction of air and the others either equipped with the construction disclosed, or some of them plugged to prevent the escape of the pressure air. The equipment of the several pumping wells will ordinarily be substantially the same, but the location of the flood nipple 14 will vary according to the pressure which it is desired to maintain upon the particu-larI well to which it is applied. W'here by reason of their different distances from the point of air supp-ly, or because of peculiarities of geological formation, certain of the wells of th group are inclined to take the air at the expnse of more remote or less accessible wells, by suitably locating the working barrels and flood nipples, the relative pressures in the various wells may be so regulated that the air will be distributed evenly among them.. 1

It is sometimes desirable and is practicable to introduce the pressure air or gas into the rock through one of the pumping wells. This may be accomplished in the Well shown in Fig. 2 of the drawing by connecting up to the nipple '1 7 a compressor or other source of gas under pressure. The gas introduced at the' nipple 17 flows downwardly between the casing 5 and tubing"7 through the open lower end of the former and venters theroil rock where it is diffused in the upper part of the rock and serves to increase the pneu- Amatic'pressure therein. v

I claim: j

1. A process of operating oil wells which consists -in introducing compressedgas to the oil sand in which the wells are located, maintaining a column of oil in the well to be pumped to exert a back pressure upon the compressed gas, and pumping the oil from said wells. v

2. Apparatusfor producing oil comprising means forintroducing compressed gas means? into the oil sand, a well casing, a tubular member in said well casing, packed with respect thereto, and extending below the level of oil in the rock, and means for pumping the oil from said tubing. Y

3. Means for producing oil from oil-bearing rock, comprising means for forcing compressed gas into said rock, a well having a casing, a tube Within the casing extending down into the oil sand' below the oil levell therein, means for preventing the escape of gas between thercasing and the tubing, and an oil pump in the tubing, the Working barrel of which is located a substantial distance above the oil level in the sand.

4. Means for producing oil from oil-bearing rock,\comprising means for forcing 'compressed gas into said rock, a well having a casing, a tube Within the casing extending down into the oil sand below the oil level therein, means for preventing the escape of gas between the casing and the tubing, and an oil pum in the tubing, the working barrel of whlch is located a substantial distance above the oil level in the sand, and a Hood nipple located below the Working bar- A rel in the pump.

5. Apparatus for producing oil comprisy ing a well casing, a tubular member in said v well/casing but spaced therefrom and eX- tendin downwardly beneath the surface of the oil 1n the oil rock and an oil pump within the tubular member, the working barrel of which pump is located a substantial dis-l tance above the oil in the rock.

- IRWIN L. DUNN.

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