US2368424A - Producing oil - Google Patents

Description

Jan 30 1945' y c. E. REISTLE, JR 2,368,424 y PRODUCING OIL original Filed April 15. V1959 2 sheets-sheet 1 FIG- 2..

FIGL 1 INVENTOR.

BY @iff ATTORNEY.

Jan. 30, 1945. c, E. Els'rLE, JR

PRODUCING OIL 2 Sheets-Sheet 2 Original Filed April l5, 1939 vPatented Jan. 30, 1945 PRODUCING OIL Carl E. Reistle, Jr., Houston, Tex., assigner to Standard Oil Development Company, a corporation of Delaware Original application April 1 5, 1939, Serial No. 268,089. Divided and this application July 2,

1 1942, Serial N0. 449,449

7 Claims.

The present invention is directed to the production of oil from a substratum and is particularly concerned with a method and means for sealing oi water and gas bearing formations from the oil bearing formation, and providing for selective production of any desired formation iiuid.

In the production of oil it frequently happens I that production comes to an untimely end or is made much less profitable by the coning of water from a lower sand into the producing section of the oil sand. When this happens the well may be effectively scaled off from the oil bearing formation, in which case it has to be abandoned. Another diiliculty, of course, is the leakage of water and gas from higher sands into the well either by reason of a poor cementing job or by reason of a pervious interface between the oil sandand the gas or water sand.

According to the present invention, the coning of water and gas from lower sands and the leakage of water or gas from higher sands into an oil bearing substratum is prevented by introducing into the formation, in the line of flow of such undesirable materials, a disk of cement or other impervious material, said ldisk having a width varying from about one foot to any desired number oi' feet. This is accomplished, according to the present invention, by weakening the formation at the point at'which it is desired to create the disk by underreaming, or any other suitable expedient, and then performing what is known as a squeeze job at the weakened point. Preferably, the point of weakness is created at the in terface between the oil bearing formation and its adjacent formation on'the side from which the undesirable iluid enters the bore hole. In many cases, however, it will be desirable to create the point of weakness and the subsequent disk of impervious material in the oil sand itself at a selected point somewhere near its interface with an adjacent substratum.

The present invention will be better understood from the accompanying drawings in which Fig. 1 is a vertical section through a well with most of the parts shown diagrammatically and with equipment in position for commencement of asqueeze lob to shut off a water cone;

Fig. 2 is a similar section of the same well after the completion of this squeeze job and the com,4 pletion'of a similansqueeze job to shut off a gas leak;

Fig. 3 is a vertical section through a well with most of the parts" shown diagrammatically, and with equipment in position for the commencement of a squeeze job through casing; and

(Cl. 16B-22) Fig. 4 is a similar section oi t'he same well after the completion ofthe squeeze lob.

Referring to Fig. 1, numeral I designates an oil sand into which water is tending to cone along a front indicated by curve 2, and into which gas is tending to cone along a front indicated by curve 3. The oil sand is penetrated by a bore hole I which extends to the surface and in which casing 5 is arranged and set by cement 6, the casing terminating just above or in the oil sand.

In order to prevent further coning of water according to the present-I invention, a drill' stem carrying an underreaming bit is lowered into the bore hole and an underreamed section'l is drilled. 'I'he bit is then raised and a second underreamed section 8 is drilled at a point at which it is desired to prevent further coning or leaking in of gas. The drill stemV is then withdrawn'and a pipe 9 carrying a packer l0 is lowered into the bore hole. The packer is set just above the underreamed section'l. This packer and the tube 9 are parts of conventional cementing equipment. Cement is then pumped into the well through pipe 9. The pressure on the cement creates a thrust against the horizontal faces of section 'l and spreads the formation apart along the horizontal plane of sec After the cement has set the tube and packer rare elevated to a point just above the weakened section 8 and the operation is repeated to form a disk I2 in the horizontal plane of weakened section 8. After this cement is set the tube and packer are removed and a drill bit is again introduced to drill out the cement in bore hole 4 Ibe- Itween disks Il and I2. The well is then ready for production from sand I.

It will be understood that disks I I and I2 can be produced simultaneously. The successive production of these disks, however, is preferred since this procedure insures that both disks will be formed.

In some cases, and particularly in a case where the producing formation is considerably above the bottom of the bore hole, the formation of a sealing disk may be desired at a point which is covered by casing. In this case the present in vention may be practiced by using, for the section of casing opposite the point where further sealing may be desired, a drillable metal. Drillable metal suitable for this purpose is available on the market, and is usually an alloy of aluminum. The practice of this embodiment of the present invention is illustrated in Figs. 3 and 4.

Referring to Fig. 3, numeral I3 designates the upper or surface' layer, numeral I4 designates an oil sand, and numeral I5 designates a water sand A11 of the substrata are penetrated by a bore holeV I6 in which is set a casing I1 having a section I8 .composed of drillable metal arranged opposite the point where' the oil sand was originally located. The casing is held in place by cement I9.

A drill stem carrying an underreaming bit is lowered into the casing and an underreamed section 20 is drilled. The exact point at which to drill may be located by ilrst running through the casing a gamma ray well logging device, such as that describedin copending application Serial No. 224,504, filed August 12, 1938. The drill stem is vthen removed and a packer 2| of conventional design vis set in the casing below zone 20 and above this zone is set a second packer 22 through which protrudes a tubing 23 connectedl to cementin'sr and pressure equipment at the surface. Cement is forcedpdown through tubing 23 into zone 20. As previously described, the pressure on the cement exerts a thrust on the horizontal faces of the underreamed section and spreads the formation Il and I5 at their interface permitting the cement to be squeezed between the formations,

, as shown in Fig. 4, in the form of a disk.

After the cementhas set the tubing 23 and packer 22 are withdrawn and the cement in the casing and packer 20 is drilled out. Of course, if there is no production below formation I4, only a small amount of the cement in the casing need be drilled out, enough to expose the necessary amount of formation I4, from which production is then accomplished by perforating the casing and the cement opposite this formation.

While the method of the present invention has been describedabove with reference to the use of cement as an impermeable material, it is apparent that the method can be practiced with other plastic impermeable materials that are capable of being forced intothe formation. Among such materials may be mentioned gels, such as silica gel, and gel-like muds made from clays capable of forming an impermeable filter cake, such as Bentonite, synthetic plastics, such as phenol aldehyde resins, and the like,which, incidentally, may be` produced in situ by forcing into the formation the necessary reaction mixture, it being nn-r derstood, of course, that the resins employed should be both water and oil insoluble. Natural resins may also be employed in the practice of the method of the present invention.

This application is a division of my copending applicationl Serial No. 268,089, filed April 15. 1939.

The nature and objects of the present invention having been thus described and illustrated, what is claimed as new and useful and is desired to be secured by Letters Patent is:

l. A method for preventing the ilow of undesirable fluid into the producing formation of an oil well from a different formation which comprises mechanically removing the wall of said well in a horizontal plane between said producing section and the source of said undesirable fluid to form a disc-shaped cavity having a diameter' which is a multiple of its thickness, and forcing impermeable material into the space left by the removed material at a pressure substantially higher than that produced by the liquid head of the well at the depth of said space.;

2. A method for preventing the flow of undesirable fiuid'into the producing formation of an oil well from a different formation which comprises underreaming the wall of said oil well on a horizontal plane between said producing section and the source of said undesirable fluid to form a disc-shaped cavity having a diameter which is a multiple of its thickness, and forcing impermeable material into said underreamed section at a pressure substantially higher than that produced by the liquid head of the well at said plane.

3. A method according to claim 2 in which the impermeable material is a mud made from a clay capable of forming an impermeable filter cake.

4. A method according to claim 2 in which the impermeable material is a gel.

'5. A method for preventing water coning into a producing oil sand from a lower water producing formation which comprises underreaming the oil sand at a point between the oil sand and the water producing formation to produce a discshaped cavity having a diameter which is a multiple of its thickness and squeezing cement under a high pressure into the underreamed section.

6. A method for preventing the intrusion of gas into a producing oil sand which comprises underreaming the oil sand on the side adjacent the source of the gas to produce a disc-shaped cavity having a diameter which is a multiple of its thickness and squeezing cement under a high pressure into the underreamed section.

7. A method according to claim 1 in which the pressure applied to the impermeable material is suiiicient to spread apart the horizontal faces of the space created by the removalof said material.

CARL E. REis'rLE, Jn.

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