US1634235A - Method of and apparatus for recovering oil - Google Patents

Description

v 1634235 June 28, 1927. L' RANNEY v METHOD OF AND APPARATUS FOR RECOVEBING OIL Filed Deo. '51, 1923 3 Sheets-Sheet 1 33? @mJy/ffm@ N l RANNY 1,634,235

METHOD OF AND APPARATUS FOR RECOVERING OIL Filed Dec. 51, 1925 s sheets-shut 3 I y fr@ 1I? 7 I /aa y l f/d 2/ y Patented June 28, 1927.

UNITEi) STATES PATENT OFFICE.A

LEO''RANNEY, 0F JACKSBORO, TEXAS, A-SSIGNOB T0 STANDARD DEVELOPMENT COM- PANY, A CORPORATION OF DELAWARE.

METHOD OF AND APPARATUS FOB, BECOVEBING" OIL.

Application led December 31, 1923. Serial No. 683,703.

This invention relates to the recovery of liquid natural products, such as oil, from the earth.

Mineral oil is recovered from more or less porous material, such as sand, sandstone, shale, limestone'or the like, all commonly called sand, in which it has collectedand 1s trapped or held by the characteristms and `position of neighboring strata of the earth. The oil bearing sand is found at various depths and invariably lies called the cap rock, an essential characteristie of which is its impervious nature causing vitto trap and comme beneath it in the porous sand oil, gas and Sometimes yvater. Usually the oil sand lies above a similar impervious bedrock which has prevented penetration of the oil downwardly into other strata.

Experience shows that when the cap rock is punctured by a Well tube the oil 1s caused to iiow from said tube by the pressure of free gas which may have collected above the oil, but more important, by the continuing pressure of the gas absorbed or held in the oil or trapped in the pores of the sand, and the pressure of which is applied more and more to the oil as the latter is Withdawn from the porous `material in which it lies. Anotherv force tending to cause fiow of the oil tothe surface is the hydrostatic pressure of Water beneath it. i y

The usual method of oil recovery consists in sinking a plurality of Wells (usually four to six inch casing pipes) to the cap rock above the oil bearing sand stratum, setting the casingu on the ca rock, and then drill ing a smal er hole t rough the cap rock, and into the sand. Such Wells are sunk at a number-of separated locations in the field and from each one-thereof are rst col- A lected the gas and oil caused to iow because ternal pressure is usuall beneath what is so'A According'to my invention the oil recoverable from most fields is increased considerably above What has been recovered by former methods and with a very marked decrease inthe lcost of production. The decrease in the cost is largely dueto the fact that my method of recovering oil is largely in the nature of a" mining method, doing awaywith the necessity for sinking a deep hole for each and every well, for a single shaft is sufiicient to reach the-oil bearing/ sands and the necessary pipes or holes to reach intimate contact with the oil bearing sand are ofvvery materially reduced length and can be increased in number to any desired degree to 'cover a Wide area at minimum cost.

The invention also enables air pressure, suction or vacuum or heating means, such as steam, to be economically or elicientl applied to a Well or Wells or to any desired1 portion of the oil bearing strata, and With more effective results, as will hereinafter appear.

The object of the invention is therefore to rofitably recover oils for use which heretoore have not been considered recoverable with suficient economy; to stimulate and increase the production of exhausted or dying Iields; to conserve and hold imprisoned the supply of gas in the sand until the field is exhausted; to greatly increase the iinal percentage of recovery; and to reduce the total cost per barrel for the oil recovered.

Further objects of the invention are in art obvious and in part Will appear more in etail hereinater. y

In the drawin s,Fig. l represents a sectional elevation i lustrating one embodiment of the invention; Fig. 2 is a sectional plan view on the line 2 2, Fig. l; Fig. 3 is a view similar to Fig. 1 and illustrating another embodiment of the invention; Fig. 4 is a sectional plan view on the line ir-4, Fig. 3; Fig. 5 1s a detail sectional view on the line 5 5, Fig. 2; Fig. 6 is a detail sectional view, somewhat diagrammatic, illustrating one arals` rangement for utilizing'heating means tor accentuating the oil tlowl; Fig. 7 is a similar view illustrating still another arrangement for the same purpose.

According to my invention the tirst step in installing a proper system for recovering oil consists in sinking a shaft l from the surface of the learth through the over-lying strata to the region otl the oil bearing porous material, such as sand, sand stone or the like. The depth ot' the oil bearing sands varies, but in any event the shaft is sunk according to usual methods ot' mining to a level adjacent the porous sands, either above or below the same. In the arrangement shown in Fig. l this shaft terminates above the cap rock 2. From thev bottom ot' the shaft lateral tunnels or mine galleries 3 are dug out by usual mining operations along the plane of the impervious stratum. These lateral tunnels may -extend in any direction, but Where the oil bearing stratum and more particularly the cap rock lies on an incline, as in Fig. 1, the lateral tunnels may be runv out horizontally or up the dip. It is not usually desirable to run the tunnels down .the dip, due to the desirability of utilizing gravity to the fullest extent in draining the oil issuing from the porous formation. As will be readily understood the tunnels 3 may be arranged in any desired manner With side galleries or rooms so as to honeycomb the stratum above the cap rock and cover as Wide a iield or area as is necessary or desiarble. Through the tunnels and galleries 3 are led a series of interconnected pipe lines 4; all comm'unicatimgr with a suitable pump or pumps 5 discharging through a pipe 6 into a reservoir 7 preferably above the ground. The pipe system 4- is provided to lead the oil to the pump :tor carrying it to the surface of the ground and said system is therefore provided with the necessar collectors or branch pipes into which t e oil flows from the oil bearing sands. These collectors are suitably spaced apart (usually at relatively short intervals as compared with the separation above ground of normal oil Wells) and are termed by boring an opening 8 through the cap rock and extending it a suitable short distance into the oil bearing stratum 9. To conserve the oil, avoid leakage and maintain clean and sanitary tunnels the holes 8 are preterably sealed by introducing thereinto a short nipple 10, which is packed tightly on its outer surface by a suitable packer, as at 1l, to prevent leakage of oil or gas between the nipple and the bed rock material. rlhis packer may be of any suitable forms, ot material unaffected by oil, and is inserted in any suitable manner. Each nipple l0 is directly connected to the pipe system 4i, preterably by way of a suitable valve 12. lt is desirable to drill part Way through the cap rock and seal in the nipple, as shown in the Laeaaee drawings, and then drill through into the sand. When the opening into the sand is completed, the nipple is connected with the oil collecting' system.

lV ith the arrangement. described oil flows from the oil bearing sands to and through each ot' the collecting pipes l() and thence through the pipe system et to be lifted to the reservoir 'i' by the pump or pumps 5. Production is unusually economical due to the abilit to tap a given tield at a large number of re atively close points or zones at minimum cost. Therefore, the 'tiow troni each collector or branch pipe may be so slow that it would be commercially valueless it' it is sued from a well at the ground surface1 but the total oil collected from a large number of such branch pipes in this system justilics the cost of installation.

rlhe method and apparatus therefore are suitable for use in recovering oils that otherwise are lett untouched. Flow oit the oil into the collectors and pumping system is produced by all oit the usual natural causes as in ordinary oil recovery practice. For eX- ample, in the arrangement shown, Where the tunnels andpiping system are above the cap rock, the first flow ot oil is usually produced by the pressure ot the gas trapped above or in the oil bearing sands or by internal pressure ot the gas absorbed in the oil. @il iioW may also be produced by the hydrostatic pressure oi water beneath the oil field, the water line being indicated at it-1i.. Obviously, as the Water line rises, and especially Where the cap rock is inclined, as shown, the several branch collectors l0 Will one by one be killed, but may readily be shut ott at their respective valves 12 to avoid contamination or" the product by Water. Iihe iield Will,l therefore, produce to the limit ot the area covered or until all collectors are killed, the sealed nipples and cap rock obviously preventing Water from entering the tunnel system.

ln some instances the oil tiovv may be produced or increased by artiicial supply of Water beneath the oil bearing sands, as has occurred in the Bradford field of Pennsyl- Vania, although Water floating in most instances is considered dangerous for other reasons. in addition oil flow may be increased by a pumping effect, either by a special form ot pump 5 producing' a suction effect through I"out the piping system or by the use ot one or more suction pumps producing an rtt'ec tive vacuum or suction at the collecting pipes l0, the oil thereby collected beingl raised to the surface ot the ground by additional pumps it necessary. W here dangerous gasesare found above the oil in the same sand, the main shaft may be sunlr outside ot and near the edge of the structure, avoiding gas entirely.

Fig. 3 shows another arrangement in itis) its ples 10 therein, each connected to the piping system hy its valve 12a.

`Witli this arrangement the oil flow is producing or accelerated by gravity in addition to such internal gas pressure as may be lpresent. or remain but, if gravity and gas pressure are insufficient, positive air pressure niay be supplied to the oil bearing stratum either through a pipe 15 from the surface oi the ground or by a pipe 1G run down the shaft la and thence into the oil bearing sand, or both, such .pipes being connected to an air pressure pump 17. Obviously, the wall of the shaft must be sealed or closed where it pierces the oil bearing sands, such as by a casing or jacket 18, thereby avoiding free flow of oil into the shaft or escape into the shaftof gas or air pressure existing or produced by artificial means.

When suction or vacuum is applied to increase the production of a field, either initially, due either to absence of gas pressure or high viscosity of the oil which retards its flow, or later on to a dying field it is obviously more economical and efficient in' the prese 'i ent arrangement than in prior practice, due

to the ability to locate the suction or vacuum pump or device at a level either closely approximating that ofthe oil bearing sands or, at least7 within barometric distance above the same. A. higher degree of vacuum is therefore available with less reduction from lossesin the line and with the ability to utilize vacuum where it would otherwise be ineffective.

Air pressure applied to the field by my system is also more effective because its eiwects are not diminished or, indeed, are accentuated by coarse or ultra-porous partings or streaks in the oil sand. Such parte ings or streaks are those from which the oil is first exhausted and according to the present practice in supplying air pressure to a field aiord convenient by-passes by which the air pressure is readily dispatched to remote regions of the field with loss of eftectiveness. This result is due to the attempt in prior practice to utilize the air pressure to positively drive or lift the oil to the pipe line level.. However, is delivered to a pipe line or system located at approximately the level of the oil sand and conveniently may be beneath the same. Consequently the air pressure may be applied to the field to assist gravity in driving the oil downwardly and porous streaksor in my method the oil partings in the oil sands merely distribute the pressure and make it more effective over the entire field. .i

Figs. 6 and 7 illustrate, somewhat diagrammatically, arrangements for utilizing the effect of' heat to increase oil production. For example, in Fig. 6 the horizontal tunnel 14 Communicating with the main shaft 'is located below the lower cap rock or bedrock, as in Fig. 3. The oil pipe line or system 4a has branches 10 passing upwardly through the bedrock into the oil field. In this system there will also be provided a steam pipe line 20 having branches 21, one for eac-h of the collecting pipes 10a and passing longitudinally through the same, as shown in the drawings. Such pipes may be capped at their ends, as at 22, and merely form heaters or radiators for supplying the heat of the steam to the collecting pipean neighboring portions `of the oil bearing sand. The sand adjacent to the collecting pipe is therefore kept hot and paraffin or like products will not condense or solidify adjacent the oil inlet pipe and thereby clog or prevent flow of oil thereto, or the para-Hin will be kept' liquid and iiow with other oil fractions into the oil system. In Fig. 7 the tunnel 3 is above the cap rock 2 and the steam heating pipe 22 has a return bend 23 passing into the branch collector 10 of the oil line or system 4. Steam may therefore be circulated through a. return bend with an increased heating effect.

These heating arrangements avoid any necessity for drawing the tubing and placing a small shot in the well to loosen the paraffin. Such shots are a mere temporary benefit and in the end force the paraffin into the pores, clogging them and decreasing or stopping the iow of oil. v

My heating system also avoids both contamination of the oil or oil field by water or moisture condensed from the steam because the steam is never brought into actual contact with the oil sand.

The method and apparatus described are particularly suitable for use in the recovery of heavy oils relatively free from gasoline, naphtha, kerosene and other like light fractions. Indeed, the method has been used for recovering oil so heavy that it is not recoverable by ordinary methods, due largely to its high viscosity and to the capilla action in the sand and the adhesion of oi to the grains thereof. However, it is also useful in the recovery of lighter oils, especially where gas is not present or is in quantities so low as to avoid danger. In any event the tunnels and shaft are sealed from the oil bearing stratum and oil and gas are not allowed to find their way thereinto and are clean and safely habitable for workmen.

The complete system is under exact control, far more so than the individual widely distributed wells of the ordinary oil eld. For this reason the recovery of oil is largely increased by my process from a lield underlain by water, where the hydrostatic pres- ,ure is utilized for raising oil to the pipe line level. Under such conditions careful observation oi each individual branch pipe or collector enables it to be shut oli as soon as the cone of water beneath it has produced Water flow, allowing the several individual small water cones to recede and to be followed by another oil producing period.

Other advantages will be apparent to those skilled in the art to which the invention relates. In my copending application Serial No. 14,448, filed March 10, 1925, I have claimed the sealing and heating methods and equipment described in the present application.

What I claim is:

1. Process .of recovering oil from an oil bearing stratum, and com rising forming a tunnel near the stratum 'ut spaced therefrom by material substantially impervious to iuid, providing a lurality of communications between the oil bearing stratum and a fluid-conducting system in the' tunnel and regulating production by vselectively controlling flow through a plurality of the communications, said regulation being effected near the oil bearing stratum.

2. Process of recovering oil from an oil bearing stratum, and comprising forming a tunnel generally parallel to the lane of the oil bearing lstratum but spaced t erefrom b a stratum substantially impervious to lui providing relatively closely spaced communications between the oil bearing stratum and conducting pipes in the tunnel, and individually and selectively controlling a simultaneous delivery from a plurality of said communications, said control being effected near the oil bearing stratum.

3. Process of recovering oil from an oil bearing stratum containing fluids other than oil, said process comprising sinking a mine shaft 'to a point adjacent ythe oil bearingA stratum, tunneling near the oil bearing stratum but separated therefrom by a stratum substantially impervious to fluid, forming a plurality of relatively closely spaced small openings to ail'ord communication bethe like, from an oil bearing stratum, and

comprising a tunnel adjacent said stratum, but spaced therefrom by material substantially impervious to fluids, a collecting pipe in said tunnel, a plurality of ni ples connected to said collecting pipe an sealed in said impervious material, said nipples leading from mine wells formed in the oil-bearing stratum, and each discharging into the collecting pipe and a valve on each nipple,v

whereby the iow therethrough may be 1ndividually and'selectively controlled near the oil bearing stratum to regulate the discharge of fluid.

In testimony whereof I hereby aiiix my signature.

LEO RANNEY.

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