US2687774A

US2687774A - Method of preparing wells for production

Info

Publication number: US2687774A
Application number: US281153A
Authority: US
Inventors: James W Hodges
Original assignee: Sun Oil Co
Current assignee: Sunoco Inc
Priority date: 1949-12-20
Filing date: 1952-04-08
Publication date: 1954-08-31
Anticipated expiration: 1971-08-31

Description

Aug. 31, 1954 J. w. HODGES METHOD OF PREPARING WELLS FOR PRODUCTION Original Filed Dec. 20, 1949 INVENTOR. JAMES W. HODGES ATTORNEYS Patented Aug. 31, 1954 METHOD OF PREPARING WELLS FOR PRODUCTION James W. Hodges, Beaumont, Tex., assignor. to Sun Oil Company, Philadelphia, Pa., a corporation of New Jersey Original application D ecel nber 20, 1949, set

No. 134,011, now Patent No. 2,652,120, dated Divided and this application AprilS, 1952, Serial No. 281,153

September 15, 1953.

This invention relates to adevice adapted to be lowered into an oil well casing before the tubing is set in order to remove deposits from the well which would tend to prevent the free How of fluid into or out of a well after the tubing has been set. In particular the device is designed to effect a series of steps in cleaning out the zone of contamination which normally exists between the sand face of an oil formation and the lower end of the casing which is in communication with the oil formation. v

In the usual method for completing or preparing for production, oil, gas and salt water disposal wells, the well is of course first drilled through to the desired formation. For example, in preparing an oil well for production, the well would first be drilled to the oil formation and preferably 30 or 40 feet below the formation, in order that tools can be utilized in completing the well. After the well is drilled and the casing is positioned therewithin, the casing is set usually by cementing adjacent the sand face of the oil formation. Following this, in order toprovide communication with the oil formation, the easing is perforated by what is normally known as gun-perforation in order to provide communication with the oil formation. In drilling the well, it is necessary to circulate a drilling mud into and out of the well as it is being drilled in order to remove the drilled out material. After the casing has been set and perforated, it is necessary to remove any drilling mud remaining in the well which is usually done by circulating water, and then a tubing string, which is of smaller diameter than the diameter of the casing, is inserted in the casing and maintained in fixed position within the casing by using what is known as a pack-01f or packer which is positioned above the perforations in the casing; while the upper end of the tubing will be maintained in fixed position relative to the casing by a collar positioned around the tubing. r

In the zone adjacent the perforated area of the casing other contaminants, in addition to drilling mud, are found which tend to prevent the free flow of fluid into or out of the well tubing, such as loose cement which has beendeposited during the cementing operation, silt, and so forth. Various methods'have been resorted to in order to remove these contaminants, but apparently no very satisfactory method has heretofore been devised since it often happens that after the well has been completed it may produce for a short time and then the perforations become plugged and flow into and out of the formation is no longer possible. Methods used heretofore to re- 1 Claim. 166-44) move the contaminants are to wash them out of the well or to hail the contaminants from the well, but these methods have not been entirely eifective and are time consuming.

The present invention is directed particularly to the idea of cleaning out the zone of contami nation between the sand face of an oil orgas formation and the lower end of the casing, and

additionally to remove any contaminants deposited on the casing wall; and the operations are carried out while the rig is in place and before completion equipment is installed within the easing, for example, before the tubing, packer, etc., are positioned within the casing. The invention practically assures that the well will start producing and continue to produce since substantially no contaminants will remain in the zone adjacent the perforations in the casing or on the casing wall.

Referring to the drawings:

Figure 1 is a vertical sectional view of the device with its various elements in their first position of operation within the well casing.

Figure 2 is'a sectional View of the device with its various elements in their intermediate position of operation within the well casing.

Figure 3 is a vertical sectional view of the device with its various elements in the final position of operation within the well casing.

Sinceall of the figures are similar, each will have the various parts indicated by the same numerals and reference may be had to all of the drawings simultaneously.

Referring to the figures, It! indicates the well which has been drilled, while It indicates the casing inserted into the well having perforations 12 therein to provide communication with the producing formation which, for thepurpose of explaining the invention, will be considered an oil formation indicated at I3. The tubing string I4 isshown as having attached thereto a hollow tubular member [5, comprising one element of the cleaning device, having at its lower end a bit or drill l6, and located immediately above the bit is an apertured area made up of a plurality of ports [1. A tubular, housing or sleeve I8 is positioned about the tubular member 55 providing a space IS therewith, and adjacent its upper end the housing is provided with a plurality of friction springs 20 which contact the casing II and function to guide the device into the easing. The sleeve l8 at its lower end is provided with a resilient valve seat 2| which is apertured to permit the elongate member l5 to reciprocate therethrough. The member 15 is in effect a valve rod since when it is pulled upwardly, the bit It will function as a valve plug to close the opening in valve seat 2|. Directly below the valve ring or seat 2| is provided an inverted cup shaped member 22 which functions as a scraping element to remove, as the device is moved into the casing, any matter accumulated on the casing wall.

Directly above the valve seat 2| is provided an apertured area which is enclosed by an inflatable seal ring 23 having an enlarged groove 24 therein. Directly above the seal ring 23 are provided ports or apertures 25 through which pressure is applied to inflate the seal ring 23 to effect a seal with the casing as shown in Figures 2 and 3. The sleeve [3 at its upper end is provided with an inwardly extending flange 26 which cooperates with the joint 2'! connecting the tubing 14 and inner tubular member or valve rod 15' to force the device into the casing.

Referring to Figures 1, 2, and 3, respectively, for the operation of the device, it will be seen in Figure 1 that the device has been lowered into the casing to locate the bit l6 at apoint adjacent the casing perforations l2 and that the seal ring 23 at this time is not inflated, permitting free movement of the device into the casing and the device is guided during movement by the friction springs 2c. The inverted cup shaped member 22 has moved to a line just above the perforations and its movement into the casing has scraped any accumulated matter from the casing wall in order to prevent injury to the packing or sealing ring 23.

In Figure 2, the inner tubular member I5 has been raised upwardly to position the bit It; flush with the bottom of the valve ring 21 and also to position the apertures ll adjacent the groove 24 in the ring 23. After the bit 16 hasclosed the aperture in the valve ring 2 l, water pressure is applied to the tubing string M and the liquid passes out of the inner member l5 through the apertures ll to exert pressure through the groove 2 on the seal ring 23 to in effect inflate the ring and thereby provide a seal with the casing H. Since the valve member 21 is flexible, the pressure of the water in the tubing will also be effective to cause a more firm contact with it and the drill it, and hence assure at this time no leakage of the water into the casing. After the sealing ring has been expanded, the outer sleeve i3 is moved upwardly forcing the sealing ring 23 upwardly to cause a suction eifect and draw through the apertures I2 into the casing material from the sand face adjacent thereto. Although not shown in the drawings, it will be understood that the lower end of the casing is closed and that suction will be effected on movement upwardly of seal ring 23. The effect of raising the device is to remove all of the hydrostatic head which had existed against the sand face of the formation by virtue of the salt water or mud in the well. This creates a pressure differential which causes the formation to produce momentarily into the casing, bringing with the formation fluid any sand, cracked cement, mud, silt, and other accumulations, small enough to pass through apertures l2, which might be present in the formation adjacent the sand face.

4 Referring to Figure 3, the pump pressure on the inner tubular member l5 has been released and the bit is lowered into the accumulated matter which had been pulled into the casing. Then the pumping connections. at the surface of the well are manifolded to both the annulus and tubing so that liquid'can be admitted to the annulus for passage through the ports 25 into the outer sleeve or housing [8 and through the valve ring or seat 21 into the casing below the seal ring 23. The liquid then will intermix with the contaminants or any loose material which has been pulled into the lower end of the casing H, and enter the inner member through the apertures I"! and pass to the surface through the tubing. The liquid pressure from the annulusbetween sleeve 18 and casing H passing through outer sleeve It will maintain the seal ring expanded and cause the liquid mixture to be forced upwardly from the lower end of the casing through the apertures i1 and out of the inner tubular member 55 and well tubing it. In order to effect an agitation of the contaminants drawn into the casing the bit [5 can be rotated or reciprocated so that the contaminants in the lower end of the casing may more readily become intermixed with the circulated water. From thecondition of the mixture of the water and contaminants, it can be determined when the ac-- ournulated matter drawn into the casing has been removed and the operation can be repeated until it appears that no contaminants are being pulled into the casing from the well formation.

This application is a division of my copending application, Serial No. 134,011, filed December20, 1949, now Patent No. 2,652,120.

I claim:

Method of preparing a weil for production, after the well casing has been installed and is provided with a perforated area in its lower portion for communicating with the producing formation, which comprises the steps of scraping accumulated matter from the casing between its topandbottom and depositing it in the lower-portion, of the casing adjacent the perforated area, seaiing the lower portion of the easing from the upper portion, applying suction to the lower portion of the casing in order to draw through the perforated area loose material from the producing formation, releasing an ion and directing a stream of liquid downwardly, througli one passageway, into the lower portion of the easing to intermix with material accumulated therein and thence upwardly through a second passageway to a discharge to thereby effect removal with the stream of liquid of said accumulated matter.

References Cited in the file of this patent UNITED STATES PATENTS 2,602,516 Gray July 8, 1952