US2133730A - Oil production apparatus - Google Patents

Description

W. J. BRUNDRED OIL PRODUCTION APPARATUS Oct. 18, 1938.

Filed A ril 22, 1956 1N ENTOR. 50% J M ATTORNEY.

Patented Oct. 18, 1938 JUNITED STATES OIL PRODUCTION APPARATUS William J. Brundred, Oil City, Pa., assignor Brundred Oil Corporation, Oil City, Pa., a corporation of Pennsylvania Application April 22, 1936, Serial No. 75,700

9 Claims."

This invention relates to process and apparatus for the recovery of oil from a plurality of wells piercing a plurality of oil bearing strata which have diflerent characteristics of permeability and porosity.

In the case of oil flelds where the production of the individual wells is limited, it has been proposed to introduce a flooding fluid, such as air, gas or water, under pressure into one or more wells of a group, to drive the oil through the different strata into another well or wells of the group from which the oil is withdrawn.

Hereinafter the wells into which the flooding fluid is introduced are termed the pressure wells, while the wells from which the oil is withdraw are termed the producing wells.

It is to the solution of the problem of increasing the production of such oil flelds that the present invention is directed.

One suggested method of eflecting the desired result comprises drilling a group of wells in accordance with a symmetrical arrangement and employing certain wells for the introduction of fluid under pressure into the strata while other wells were to be used as the producing wells.

While such a system may be advantageously applied in some instances when a new oil fleld is being developed or an old field redrilled, such arrangement is not essential to my invention.

Moreover, in the same stratum or in like strata the permeability to the flow of the flooding fluid may vary over the area of the stratum or strata, and thus relative distance between the wells or their relative arrangement is not the controlling 35 factor, but the controlling factor is the relative permeability.

For instance a given stratum may have areas of diiferent permeability which are pierced by different wells, and thus different pressures of the flooding fluid are required to force the oil to the producing well or wells.

, The different sands which a well pierces are usually composed of a plurality of strata having different permeability and thus the flooding pres- 45 sures for a single well must be varied for different levels to drive the oil from these several strata to the producing well or wells.

In my invention all these factors are taken into sand or sands pierced by a given well the flooding fluid at the proper pressure to suit the permeability of the said stratum, or to suit the permeability of the particular area of said stratum which is pierced by the said well.

I accomplish these results as follows:-

I first determine the relative elevation of th various strata in each sand, which is pierced by the well, by taking samples thereof, as by core boring or other well known methods; and I test these samples for permeability and porosity. The porosity determines the oil-holding capacity of the individual strata and their permeability determines the resistance and therefore the pressure of the flooding fluid required to drive out the oil.

I then introduce into the well a tubing of sumciently less diameter than that of the well to permit the tubing to be packed off with the wall of the well between the strata of each of several oilbearing sands. Thus I prevent leakage of pressure from one stratum to another.

For this purpose I prefer to use an inflatable packer which is expanded into sealing engagement with the well wall, and particularly the character of packer hereinafter described but which is per se the subject matter of Patent 2,098,484 of November 9, 1937.

I introduce down through the bore of the tubing aplurality of pipes of smaller diameter, and connect each of these pipes, through pressure tight openings in the wall of the tubing, with the interior of the well between adjacent packers, or in other words with the individual strata of the several sands.

To the upper ends of the several pipes means are connected to supply to the individual pipes the flooding fluid at the several pressures required. In case two or more strata require the same pressure of the flooding fluid, these strata may be supplied from the same pipe.

The flooding fluid may be supplied from the same source, such as a pump or a battery of pumps, and the pressure of the flooding fluid in the individual pipes is regulated as by pressurecontrol valves.

In the case of the producing wells the arrangement of packers and pipes connected individually with the oil-bearing strata is substantially the same as that described, but instead of introducing pressure through such pipes,'the latter are employed to withdraw the oil either by flowing or pumping.

Thus these pipes function as flow strings for the escape of oil in front of the flooding fluid.

In instances where these pipes are connected to strata of relatively high permeability and wherein the flow of the flooding fluid is excessive compared to the production of oil, it is advisable to throttle this flow, as by partially closing valves in the pipe lines at the surface, thereby building up the fluid pressure in the strata and thus permitting the oil to have an opportunity to proceed the flow of the flooding fluid toward the producing well. I am therefore able to control the ratio of oil production to the flow of the flooding fluid. v

If the flow of the fluid persists at the producing well it may be readily traced to the strata fed by an individual pipe in the pressure well. The valve in the pipe string may be partially closed simultaneously with the control valve at the producing well, thereby gaining complete control of the flow of the flooding fluid through that particular strata.

Again where a given stratum ceases to yield oil in economically recoverable amounts, such stratum may be sealed or otherwise packed off at the pressure well or wells and thus waste of the flooding fluid may be avoided.

Other novel characteristics and features will appear from the following description.

In the accompanying drawing, wherein I show a practical embodiment of the principles of my invention,

Fig. 1 is a diagrammatic view illustrating in vertical section a well driven down through the strata of a plurality of oil sands, and arranged and equipped, either as a pressure well or as a producing well, in accordance with my invention.

Fig. 2 is a sectional detail on larger scale showing a portion of the Well, the tubing, one of the packers and three of the pipes for the supply of flooding fluid or the withdrawal of oil.

Fig. 3 is an enlarged sectional view showing a modified structure for plugging the lower end of the tubing in a well.

Referring to the drawing, i represents a portion of the well which is shown as extending down through a plurality of strata in the oil. bearing sands, said strata being respectively indicated at 2 to Ill, inclusive, the intervening layers of shale or other non-oil bearing material or of material having very low vertical perme ability being indicated at El.

I2 represents a tubing which extends down into the well and whose bore is closed adjacent its lower end by the plug l3 which may be welded or otherwise held in position to seai the lower end of the tubing it. The lengths of tub ing which compose the tubing i2 are connected together by the usual couplings such as indicated at H in Fig. 2.

Between adjacent strata which it is desired to seal from each other, because of their difference in permeability, I provide a packer 55 carried by the tubing and engaging the wall of the well.

I prefer to use the type of packer shown, and which in general comprises a central tubular stem l6 which has substantially the same interior bore as the tubing and forms a part of the same, being connected up at its ends in the tubing string by the couplings I4. IT and I8 represent the upper and lower cap members which are slidable on the stem l6 and have the slidable collars i9 interposed between them and the couplings Hi. The opposed ends of the cap members ll and IB are cup-shaped to receive the upper and lower ends of the inflatable packing member 20 formed of rubber or like mattrial and having its intermediate portion vulcanized or otherwise secured to the stem I6. The ends of the packing member are also secured to the caps. The packing member is provided with an internal annular chamber 2| which is connected to the interior of the stem l by the radially disposed nipples 22, so that fluid pressure entering from the tubing I! will inflate the packing element and thus seal the well against the escape of flooding pressure from one stratum to an adjoining stratum.

' Extending down from the top of the well are the pipes, indicated at 23, 24 and 25, which in a pressure well are employed to introduce the flooding fluid and in a producing well are used .for the recovery of the oil.

These pipes are sufllcient in number to provide the different pressures required for the various strata, and are connected through the wall of the tubing I! to the space between the packers l5 which seal the corresponding stratum from above and below. This connection is preferably formed by bending the end or the pipe in a long or gradual curve and welding its extremity in a port in the tubing wall as shown at 26. No pressure should be allowed to escape through these ports except through the pipes.

Where two or more strata are known to require the same flooding pressure, as for instance the strata 6, 8 and I 0, the space between the packers with which the pipe 23, extending from the top of the well, communicates, is connected by a pipe 23a with the space between the packers above and below the stratum 8, while the latter space is connected by the pipe 23b with the space below the packer just above the stratum ill. The pipes 23a and 231) are within the tubing l2 and have their curved extremities flxed in ports in the wall of said tubing. A like pipe 25:: is shown as connecting strata and 9, the pipe 25 supplying flooding pressure to the stratum I.

In the operation of my method the packing elements 20 are all inflated to seal against the wall of the well and prevent the escape of pressure past the packer. I may effect this in any convenient manner. Thus I may introduce air under pressure through the tubing 12 and the stems I5 into the chambers 2i and maintain the pressure, or I may first flll the tubing with liquid and then impose air pressure on the column of liquid. Any other suitable method of maintaining an inflation pressure in the packing elements, higher than the flooding pressures, may be used.

If air be used as the flooding fluid, I may use water with air pressure imposed thereon to inhate the packers, but if the flooding fluid is water, I prefer to use a liquid having a higher specific gravity for packing purposes, such for instance as mud in suspension.

After the packers are inflated, I introduce the flooding fluid through the pipes 23, 24 and 25, employing in each pipe the proper pressure dictated by the relative permeability of the stratum or strata into which the flooding fluid is to be introduced through said pipe.

The result is to supply to each stratum the proper flooding pressure to drive the oil toward the producing well or wells.

In the case of the producing well or wells, the oil enters the well from the individual strata, and therefore enters a like arrangement of pipes as that already described. The oil then passes up and out of the well either by the flooding pressure behind it or by pumping.

, It is evident from the foregoing that by means of my invention the production of oil from a given stratum or strata is greatly increased, as the different areas of the same stratum and of the different strata are supplied with the. necessary flooding fluid at the different pressures respectively required.

Should the same pressure be supplied to all the various areas or strata the flooding fluid would take the easiest course or courses toward the producing well or wells, and thus the oil would be driven from the areas and strata having the higher permeability. while the oil in the areas and strata having lower permeability would not recover or would'be recovered to a less degree;

Again I may introduce the same pressure into all the strata at the pressure well'or wells and relatively throttle the withdrawal pipes in the producing well or wells so that the withdrawal of oil from the more permeable stratum or strata will be more or less reduced, and thus the flow of oil through the different strata will be substantially the same and the effect of the pressures in the different strata will be rendered uniform.- Thus the oil will be recovered from all the strata pierced by the wells.

Referring to the modification shown in Fig. 3, 21 represents a stufllng box positioned within the tubing l2 and adjacent the lower end thereof in place of the plug I 3. The stuiling box comprises the shell 28 arranged to be flxedwithin the tubing l2 to prevent the passage of fluid therebetween and provided with internal threads 29 at the ends thereof. 30 represents upper and lower gland members having exterior threads which are arranged to be screwed into the ends of the shell 28 and compress the packing ll therebetween.

Each gland member is provided with an axial bore arranged to slidably receive the inner concentric pipe 32 which forms the lower end of a pipe string extending to the surface. This pipe 32 is similar to the pipes 23, 24 and 25, but owing to the fact that it must be capable of movement relative to the stuiling box 21 it may be connected directly to the strata below the stuffing box 21 at the bottom of the well. The extremity of the pipe 32 is provided with the cap member 33 enclosing the same. The pipe 32 is vented as at 34. This vent is spaced from the cap 33 a distance greater than the over-all length of the stufllng box 21 to permit the pipe 32 to work the lowermost stratum in the well. In the case of a pressure well this pipe string would be employed to conduct the flooding fluid to the bottom of the well and in the case of a producing well this pipe string would be employed to withdraw or flow oil from the well.

If water or water with mud in suspension -or other suitable liquids were employed to inflate the packers on the tubing string i2 and it was found necessary to withdraw this string and the packers from the well it would be necessary to withdraw this liquid to deflate the packers. This may be accomplished by lifting the pipe string 32 within the stumng box until the cap 33 engages the under surface of the lower packing gland 30 as shown in dotted lines in Fig. 3. In this position the vent 34 extends above the stumng box in tubing string l2. The pipe string 32 may then be employed for forcing air or steam into the bottom of the tubing string l2 and thereby forcing the inflating liquid therefrom to'the topof the well. With this arrangement the packers I5 may be deflated and withdrawn from the well.

Again the lower end of a pipe similar to that of 23b may be provided with a left hand threaded coupling member which could be uncoupled from the surface of the well to accomplish the same purpose. However, such an arrangement would permit some of the inflating liquid to escape into the well hole after the pipe is disengaged and when the liquid is being forced from the tubing l2. In the case of a producing well, the same may be packed and the oil withdrawn from the various strata by means of the pipes, or the packers may be omitted from the producing well and the oil pumped therefrom in the usual manner.

When a well is drilled to and into a productive horizon or sand body and a core or cross section of the sand body is taken, it will be found that the sand'body is not one uniform stratumbut rather is composed of several strata of different permeability and at times separated one from the other by a difference in the material cementing or ioiningthe sand grains; or strata are frequently separated by thin shale seams often no thicker than a pencil lead. If flooding fluid is applied to the entire sand wall at uniform pressure the more permeable strata absorb most of the volume at the expense of the less permeable strata. If therefore one desires to introduce an equal volume into all parts of the sand it is necessary to separate by means of packers strata of differing permeability.

One sand body might contain ten or twelve strata, some of which may be of approximately equal permeability but separated one from the other by intervening strata of higher or lower permeability. In such a case ten or twelve packers might be set and certain strata of approximately equal permeability can be served by the same pressure .line. The different pressure lines then carry difl'erent pressures, pressure control being by means of control valves at the ground level.

I claim:---

1. In apparatus for producing oil, the combination of a tubing extending downwardly in an oil well, a plurality of packers mounted circumferentially of said tubing and arranged to isolate the various strata pierced by the well from each other, and a plurality of pipes extendng downwardly within the tubing and having their lower ends in communication through the wall of the tubing with strata having varying characteristics of permeability. l

2. In apparatus for producing oil, the combination of a tubing extending downwardly in an oil well, a plurality of packers mounted circumferentially of said tubing 'and arranged to isolate the various strata pierced by the well from each other, a plurality of pipes extending downwardly within the tubing and having their lower ends in communication through the wall of the tubing with strata having varying characteristics of permeability, and other pipes within the tubing connecting strata of substantially the same permeability.

3. In apparatus for producing oil. the combination of a casing extending downwardly in an oil well, a plurality of inflatable packers mounted circumferentially of the casing and arranged to isolate the various strata pierced by the well from each other, pipes within the casing communicating with the various strata through the wall of the casing, and means for inflating said packers through the interior of the tubing.

4. In apparatus for producing oil, the combination of a tubing extending downwardly in an oil well, a plurality of inflatable packers mounted circumferentially of the tubing and arranged to isolate the various strata pierced by the well from each other, pipes within the tubing communicating with the various strata. through the wall of the tubing, means for inflating said packers through the interior of the tubing, and means for controlling the ratio of the production of oil with respect to the flow of flooding fluid.

5. In apparatus for producing oil, the combination of a tubing extending downwardly in a well, a plurality of inflatable packers mounted circumferentially of the tubing and arranged to isolate the various strata pierced by the well from each other, a plurality of pipes within the tubing communicating with the various strata through the wall of the tubing, and means including a fluid within said tubing for inflating said packers.

6. In apparatus for producing oil, the combination of a tubing extending downwardly in a well, a plurality of inflatable packers mounted circumferentially of the tubing and arranged to isolate the various strata pierced by the well from each other, a plurality of pipes within the tubing communicating with the various strata through the wall of the tubing, and means including a liquid within said tubing supplemented with a fluid under pressure thereon for inflating said packers.

'Z. In apparatus for producing oil, the combination of a tubing extending downwardly in a well, a plurality of inflatable packers mounted circumferentially of the tubing and arranged to isolate the various strata pierced by the well from each other, pipes within the tubing communicating with the various strata through the wall of the tubing, means including a liquid within said tubing for inflating said packers, and valvular means in the bottom of said well for operating the lowermost strata thereof when in one position and for discharging the packer inflating liquid when in the other position.

8. In a well, the combination of a tubing extending downwardly to the bottom thereof, a closure member on the bottom of said tubing, a pipe movable longitudinally through said tubing and said closure member, said pipe being closed at the bottom thereof, means defining a passageway through the wall of said pipe adjacent its lower end for operating the bottom of the well when below said closure member, and for discharging fluid from said tubing when above said closure member, said pipe being closed to the tubing and the bottom of the well when said passageway reposes within the closure member.

9. In a well, the combination of a tubing extending downwardly within the well, packing means in the bottom of said tubing, a pipe in said tubing extending through said packing, and means defining a port in said pipe which when below said packing connects the bottom of the well with said pipe and when above said packing connects said pipe with the interior of the tubing said pipe forming a seal with said packing means for closing the bottom of the tubing when in either position.

WILLIAM J. BRUNDRED.

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