US1851446A

US1851446A - Oil recharging and recovery method and apparatus

Info

Publication number: US1851446A
Application number: US336857A
Authority: US
Inventors: Ranney Leo
Original assignee: Standard Oil Development Co
Current assignee: Standard Oil Development Co
Priority date: 1929-02-01
Filing date: 1929-02-01
Publication date: 1932-03-29
Anticipated expiration: 1949-03-29

Description

arch 29, 1932. RANNEY 1,851,446

OIL RECHARGING AND RECOVERY METHOD AND APPARATUS Filed Feb. 1, 1929 3 Sheets-Sheet 1 33% M S ated/mug March 29, 1932. RANNEY 1,851,446

OIL RECHARGING AND RECOVERY METHOD AND APPARATUS Filed Feb. 1, 1929 3 Sheets-Sheet 2 o o O O- 9 0 o o o o o 0 o o o 0 O O o o 0 avwemboz WMQMMWWH March 29, 1932. RANNEY 1,851,446

OIL RECHARGING AND RECOVERY METHOD AND APPARATUS Filed Feb. 1, 1929 3 Sheets-Sheet (5 j gvwemtoz Patented Mar. 29, 1932 UNITED STATES PATENT. orator:

LEO BANNEY, 01 NEW YORK, N. Y ASSIGNOR TO STANDARD OIL DEVELOPMENT COM- PANY, A CORPORATION OF DELAWARE OIL BECHABGIN'G AND RECOVERY METHOD AND APPARATUS Application filed February 1, 1929. Serial No. 336,857.

invention is to recharge the oil with gas, thereby enlivening the oil or increasing its tendency to flow. In the method described herein gas is not primarily caused to form a moving barrier which drives oil before it. On the.

contrary, the oil is directly modified by the gas so that flow without applied pressure is ossible. This application is a continuation 1n part of my co-pending applications Serial No. 127,233, filed August 6, 1926, and Serial N 0. 160,793, filed January 13, 1927.

The invention will be fully understood from the following description, read in connection with the accompanyingdrawings, in which Fig. 1 is a diagrammatic vertical section showing a portion of a mine gallery and illustrating the first stage of the recharging operation;

Fig. 2 is a similar view showing the second stage of that operation;

Fig. 3 is a similar view showing the oil collecting stage Fig. 4 is a diagrammatic plan showing a preferred arrangement of the mine galleries;

Fig. 5 is a vertical section through a control valve arranged in a mine well; and

Fig. 6 is a similar view showing an alternative form of valve.

Referring first to Figs. 1 to 4 of the drawings, 1 denotes amine gallery driven in a lower can rock 2 underlying an oil sand 3. which contains shale partings 4. or the like. An upper cap rock 5 covers the oil san'd. Conduits 6 and 6' are set in holes 7, drilled upwardly into the lower can rock, but preferably not through into the oil sand. The holes may be drilled vertically as shown. or at an angle. The lower part of each holeis enlarged to receive a sealing material 8. (cement, lead wool, or the like) which makes a fluid-tight seal between the can rock 2 and the 'conduits 6, 6'. Openings 9. drilled through the conduits as extensions of holes 7, tap the oil sand and form what I term mine wells. Openings 9 are preferably enlarged at their ends by reaming or blasting to form fluid distributing or collecting areas 10.

Conduits 6 are connected to a pipe 11 which is in turn connected to a source of gas or air under pressure, and conduits 6 are connected to an oil collecting pipe line 12. Control valves 13, preferably of the gate type, are installed in each conduit.

While the described method of tapping the oil sand is preferred, it will be .understood that any method may be adopted which permits gas under pressure to be injected into the sand at or near the bottom. Instead of working from below as illustrated, it is evident that an equivalent result may be obtained by drilling from above, provided of course that the opening through the sand is cased or cemented so that gas cannot escape into the sand except near its bottom.

For best results the mine gallery should be formed about the margin of the tract to be worked, for example as shown in Fig. 4, which represents a square 40 acre tract encompassed by a gallery from which numerous mine wells 9 are drilled into the sand.

In the preferred operation of my method, a gas under pressure is passed into the oil sand through conduits 6. I prefer natural gas for this purpose, though air, mixtures of air and natural gas, etc., may be used. In the first stage of he recharging operation, as illustrated in Fig. 1, the pressure is kept relatively low (10 to 50 lbs. per square inch for sands of average porosity). This is to insure the formation of a gas layer throughout the bottom area of the sand.

If high pressure is initially applied, there is a tendency for the gas to break through,

as between the shale partings 4, and spread Y throughout the upper region of the sand, leaving the lower part untouched. Gas tends to pass laterally more readily than vertically through the oil sand, and if the initial pres sure is not too high, a good distribution of gas can be obtained throughout the whole lower area.

When this has been accomplished the pressure is increased, say to about to 150 lbs. per square inch. The gas enters the charged lower layer and ascends through the sand.

This condition is illustrated in Fig. 2. During the rechar ing operation the gas moves outwardl an upwardly from the intake wells and gradually. rises toward the to of the sand. In so doing it charges the 011 with gas.

I do not wishto be limited to the particular pressures specified, as these will naturally vary in accordance with porosity of the sand, the initial gas content of the oil, and other conditions. The pressure in the preliminary charging stage will ordinarily be within the range of 10 to 50 lbs. per square inch and for the second sta e between 50 and 300 lbs. per square inch. Iore than two stages of pressure may, of course, be applied where conditions necessitate pressure increase.

In some cases it is desirable to remove a portion of the oil from the bottom layers of sand before entering the stage of hi her pressure, the purpose being to make the bottom layers 0 sand more permeable to the gas during the second stage. This partial extraction of oil from the sand bottom is accomplished by removing the applied pressure and allowing the occluded gas in the bottom oil to expand and drive the oil to the nearest producing well. Once the bottom layers of sand are partially cleared of oil, the gas, when a ain applied under pressure, spreads rapi y throughout the sand bottom The time required for recharging will vary greatly. In porous sands, for example, distributlon of gas throughout the lower area may be obtained by holding pressure on a 40 acre tract for three or four weeks. A similar period will be required for charging the upper areas at higher pressure. In tight sands much" longer application of pressure is required. The gas may be heated and in special cases unexcavated drainage tunne1s may be formed, as described in my applications referred to above.

During the recharging period all of the oil outlets are preferably closed. When the oil in the sand has been recharged substantially throughout, the gas is shut oil and the oil collecting conduits 6' are opened to permit flow of oil into line 12. If desired the gas line 11 may also be utilized for the collection of oil. Suitable pumps, separators, etc., are provided for forwarding the oil and gas to the earths surface, for example as shown in m' In some cases it is permissible to withdraw oil during the recharging stage. In general, however, I prefer to complete this stage before any oil is withdrawn. In the present method I do not, in any case, use the initial charging gas as a moving barrier to expel oil. Although it is not generally necessary, I may aid in theexpulsion of the charged oil by more gradual applying fluid pressure (water, gas, etc.) or by applying suction.

Recovery of oil through mine wells as described isnormally most convenient, but other means are also suitable, For instance, in many fields which are no longer producing oil. because of gas depletion, there are aba'n doned surface wells-which can be used for oil recove after the oil has been enlivened as described. When recovery of oil is through mine wells, the valves therein may be operated to control flow of oil so as to prevent too great an escape ofgas through oil collecting outlets, or to prevent other undesirable results. When mine-wells are producin oil it is sometimes desirable to keep an oil sea above the valve to retain free gas, but at other times it is desirable to allow the gas to flow freely-at various intervals to create a diflerential'of pressure within. the sand, the lowest pressure being at the producing well. This sudden release of pressure enables the occluded gas to expand and to push the oil to the producing well. The periodic venting may be by manual operation ofvalves, or pressure responsivedevices, float controlled valves, or the like, may be used to vent gas automatically when required. In Fig. 5 a pressure responsive valve is illustrated. This comprises a valve head 13 and a valve seat 14 in the form of an annulus mounted in the pipe 15. A centrally erforated plate 16 is adjustably arranged elow the valve seat in the pipe. A coil spring 17 is secured to the valve head and encircles a valve stem 18 which plate 16. The spring is supported by the latter plate, which may be adjusted to regulate the tension on the spring so as to cause the valve to open at the desired pressure. After the pressure is relieved, the valve closes. Fig. 6 shows a float operated valve. comprises a'valve head 19 and a valve seat 20. The orifice in this should be beveled downwardly to prevent sand grains from collecting and keeping the valve open. A float 21 is attached to a stem 22 secured to'the valve head, preferably by adjustable means. When the level of oil in the mine well reaches a predetermined level, the valve opens to permit. temporary outflow into the collecting line 12. c

The valves in the gas injection conduits 6 may be selectively regulated to control the Y'tdt' f .Ith' th d't'- U. S. Patent 1,660,818, granted February 28, m m uc Ion 0 gas 18 way 8 1s m 1928.

may be obtained by test devices such as are shown in my United States Patent 'No. 1,667,269, granted April 24, 1928.

y invention is to be distinguished from prior methods in which gas is forced into an runs through seat 14 and oil sand without insuring that it shall enterm less resistance to the entry of the gas.

at the bottom. If the gas has free access to the upper portion of the sand, it will preferentially fill that portion of it, since the upper part is relatively oil-free and therefore Ofi'Flll'S e barrier of gas thus formed above the oil can be used to force it out to a substantial extent, but will not serve effectively to recharge the oil with gas. The latter result is obtained by the present method. Oil properly recharged with gas flows freely and can be readily withdrawn from the sand, irrespective of applied pressure, which in some cases is ineffective due to interposed shale barriers or other obstructions in the sand. Recharged oil contains its own expulsive agent (occluded gas) and this becomes operative whenever the pressure is released, even in part.

The methods described above are preferred, but it will be understood that various changes and alternative procedures may be adopted within the scope of the appended claims in which it is my intention to claim all novelty inherent in the invention as broadly as the prior art permits.

I claim:

1. Method of recovering oil from an oil bearing stratum, comprising passing gas into the stratum from near the bottom only and below the level of oil in the stratum, and withdrawing oil charged with gas.

2. Method of recovering oil from an oilbearing stratum, comprising passing gas at relatively low pressure into the stratum from near the bottom only and below the level of oil in the stratum, selectively regulating the introduction of the gas, and withdrawing oil charged with gas.

3. Method of recovering oil from an oilbearing stratum, comprising introducing gas first under relatively low pressure and then under higher pressure into the stratum from near the bottom only and below the level of oil in the stratum, and withdrawing oil charged with gas.

r 4. Method of recovering oil from an oilbearing stratum, comprising introducing gas under relatively low pressure into the stratum from near the bottom only and below the level of oil in the stratum, until the lower area of the stratum is substantially filled wlth gas, then introducing gas under a higher pressure so as to cause the upper portion of the stratum to be substantially filled with gas, and withdrawing oil charged with gas from the stratum.

5. Method of recovering oil from an oilbearing stratum, comprising passing gas at relatively low pressure into the stratum from near the bottom only and below the level of oil in the stratum, then injecting gas at a.

higher pressure from below the level of oil in the stratum, selectively regulating the introduction of the gas, and withdrawing oil cl charged with gas.

6. Method of recovering oil from an oil sand in which the oil is relatively free of gas, comprising introducing gas into the sand below the level of oil from about the margin of the tract to be worked until oil in the sand is substantially charged with it, and thereafter opening oil outlets so that the oil charged with gas may flow from the sand.

7. Method of recharging oil within the pores of an oil sand in a natural earth stratum, comprising the introduction of gas under pressure at a point near the bottom of the sand and below the level of oil in the sand, so that the gas moving outwardly and upwardly from the intake may gradually rise toward the top of the sand, recharging the oil in its path.

8. Method of recharging oil within an oil sand, comprising the introduction of gas under relatively low pressure near the bottom of the sand and below the level of oil in the sand, withdrawing the oil so charged, and filling such partially drained area with gas under higher pressure for movement outwardly and upwardly through the remainder of the sand body.

9. In an installation for working an oil sand from a mine gallery located adjacent the sand but spaced therefrom, the improvement which comprises gas inlets opening near the bottom only of the sand, means for passing gas through the openings to recharge the oil with gas, and means for withdrawing oil.

10. The method of charging oil in a tract of natural earth stratum with gas, which comprises injecting the gas into the stratum below the level of the oil in the stratum from the outer horizontal edges of the tract.

11. The method of charging oil in a natural earth stratum with gas, which comprises injecting the gas into the stratum below the level of the oil in the stratum under progressively increasing pressures to cause the gas to flow laterally into the oil impregnated stratum and upwardly through the oil carrying portion of the stratum.

12. The method of charging oil in natural earth stratum with gas, which comprises injecting the gas into the stratum below the level of the. oil in the stratum at slightly greater than atmospheric pressures to cause the gas to flow laterally through the stratum, and elevating the pressure of the gas whereby the gas flows upwardly through the stratum.

' LEO RANNEY.