US3062289A

US3062289A - Oil well heater

Info

Publication number: US3062289A
Application number: US3839A
Authority: US
Inventors: Eades John Henry
Original assignee: CHARLES E FOOTE
Current assignee: CHARLES E FOOTE
Priority date: 1960-01-21
Filing date: 1960-01-21
Publication date: 1962-11-06
Anticipated expiration: 1979-11-06

Description

J. H. EADES OIL WELL HEATER Nov. 6, 1962 2 Sheets-Sheet 1 Filed Jan. 21, 1960 JOHN HENRY EADES A TTORNE Y J. H. EADES OIL WELL HEATER Nov. 6, 1962 2 Sheets-Sheet 2 Filed Jan. 21, 1960 lllllllllllm FIG. 5. ||||l|||l JOHN HENRY EADES FIG. 6.

A TTORNE Y United States Patent *Ofiiice 3,062,289 Patented Nov. 6, 1962 3,062,289 OIL WELL HEATER John Henry Eades, Dallas, Tex., assignor of one-half to Charles E. Foote, Dallas, Tex. Filed Jan. 21, 1960, Ser. No. 3,839 1 Claim. (Cl. 166-61) This invention relates to heaters for oil wells and has reference to improvements in apparatus wherein heated fluids, for example steam or water, are circulated in a bore hole for transferring heat to a producing earth formation.

The present invention is for use in both primary and secondary recovery where paraflin or asphalt accumulate in the producing zone around the bore hole. Reducnig the viscosity of oil promotes flow and tends to separate entrained gas and water emulsions. Additionally, heat reduces the viscosity of parafiin and asphalts in the oil and promotes flow within the formation.

Heretofore, oil well heaters have been used with some degree of success but were inefiicient in their operation because considerable heat was lost in the annulus between the casing and the tubing. Another loss of heat was by conduction in the tubing itself.

An object of the invention is to increase production in oil wells by reducing the viscosity of oil in an earth formation around a bore hole.

A particular object of the invention is to heat producing formations by conduction rather than radiation and thereby effect greater eflieiency of the heater.

Another object of the invention is to provide means for at least partially insulating the heater from the well and well tubing.

Another object of the invention is to provide a well heater having direct contact means with the bore hole, yet which means may be readily removed when it becomes desirable or necessary to remove the heater from the well.

A further object of the invention is to provide means for reducing or preventing sand from entering the well tubing, together with means for repelling sand which may accumulate around the outer surface of the heater.

These and other objects will become apparent from the following description and accompanying drawings, wherein:

FIGURE 1 is a broken elevation and sectional View of a preferred form of the invention.

FIGURE 2 is a transverse sectional view taken on line 2-2 of FIGURE 1.

FIGURE 3 is a transverse sectional view taken on line 3-3 of FIGURE 1.

FIGURE 4 is a broken vertical sectional view taken approximately on line 4-4 of FIGURE 3 and additionally showing the present heater installed in a bore hole.

FIGURE 5 is a broken perspective view of an exemplary well head employed in connection with the invention.

FIGURE 6 is an elevation and broken sectional view of a modified form of the invention.

FIGURE 7 is a transverse sectional view taken on line 77 of FIGURE 6, and

FIGURE 8 is a transverse sectional view taken on line 88 of FIGURE 6.

The form of the invention shown in FIGURES 1 through 4 includes a tubular insulator 10 of a suitable thermal setting synthetic resin, such as Bakelite, overhanging upper and lower disk-like closures 11 and 12, and inner and outer

vertical connecting bars

13 and 14. A heating element in the form of a coil 15 is positioned around the inner frame bars 13 and the insulator 10, the ends of which coil have vertical extensions 16 and 17 which are connected with pipes 18 and 19 (shown only in FIGURE 5) extending to the earths surface where they are connected with means circulating hot water therethrough. The vertical extension 16 connected with the lower end of the coil 15 is herein designated as the supply lead, but circulation in either direction is effective and within the scope of the invention.

The well tubing 20 has a lower perforated extension 21 within the tubular insulator 10, and which perforated extension is connected with the well tubing by means of a collar 22 located in an opening in the upper closure 11. Similarly, the lower end of the perforated extension 21 is connected with a fitting 23 in the lower closure 12, and which fitting has a cap 24 in the lower end thereof.

The tubular insulator 10 has multiple horizontal slots 25 for admitting well fluids, and there is a screen wire strainer 26 around the insulator to prevent sand from passing through the referred to slots. It is to be understood that the slots 25 comprise the preferred construc tion but that other configurations of openings may be employed. In the upper closure 11 there is a fluid pressure supplypipe 27 which extends into the insulator 10, and the upper end of which pipe has means connecting the same with the earths surface and a supply of fluid pressure which is applied when necessary for reasons hereinafter set forth.

Other details shown include a suitable bracket 28 atop the upper closure 11 for engaging the extending portions of the supply lead 16, return portion 17 of the coil 15 and the pressure supply pipe 27. The ends of the insulator 10 are received in grooves, not numbered, in opposing faces of the closures 11 and 12 and the

vertical bars

13 and 14 are secured in their described positions by screws, not numbered. Preferably, the tubular insulator It) is asymmetrical with reference to the axis of the coil 15 so as to accommodate the lead 16 and return portion 17 so that the latter will not contact the well bore when installing or removing the described construction.

As shown in FIGURE 4, the described heater is installed in open hole of a producing formation 29 and gravel 30 is filled around the coil 15 and against the screen 26. Thus, heat from the coil 15 is transferred to the formation 29 through the gravel 30.

If sand migrates to and clogs the screen 26 fluid pressure is applied through the pressure supply pipe 27 to force the sand back and open the screen. When it becomes necessary or desirable to remove the heater from the well bore liquid pressure of considerable force is applied through the pressure supply pipe 27 forcing the gravel 30 up the well annulus, and while the gravel is suspended the heater is raised at least to a distance higher than the gravel when the latter is settled in the bore hole.

While the form of the invention illustrated in FIG- URES 1 through 4 is intended primarily for operation with heated liquid, the form of the invention illustrated in FIGURES 6 through 8 is intended for operation with steam. The latter form of the invention includes the described slots 25 therein, screen 26 therearound and perforated extension 21 connected with the lower end of the well tubing 20. Instead of the upper and lower closures 11 and 12 there are upper and

lower steam chambers

31 and 32 which are secured in spaced relation by means of vertical rods 33 connected therebetween. The heating elements are vertical tubes 34 connected in communication between the upper and

lower steam chambers

31 and 32 and outwardly of the insulator 10 and screen 26. Beneath the lower steam chamber 32 there is a sump 35 which houses steam traps 36 mounted in the bottom of said lower chamber. The steam supply line 37 is connected in communication with the upper end of the upper steam chamber 31, whereas the steam return line 38 extends from the interior of the sump 35 upwardly the insulator 10 and through the upper steam chamber 31. As in the first described form of the invention, there is a pressure supply pipe 27 in communication with the interior of the insulator 10 for removing sand from the screen 26 and for loosening the gravel 30 when removing the heater from the well. The closure at the lower end of the perforated extension 21 is a projecting boss 39 on the upper surface of the lower steam chamber 32. The operation of the last described form of the invention is substantially the same as described in connection with the first form of the invention.

The well head 40 illustrated in FIGURE 5 is exemplary and it is to be understood that various commercially available well heads may be used in conjunction with the present well heater. The well head 40 shown includes a vertical nipple 41 and a laterally connected oil flow line 42. The laterally extending fluid supply and

return lines

18 and 19, and the pressure supply line 27 have the same reference numerals as those described in the foregoing.

The invention is not limited to the constructions herein shown and described, but may be made in various ways within the scope of the appended claims.

What is claimed is:

Apparatus for heating production formations in oil wells having a string of tubing therein, said apparatus comprising a vertical perforated tube connected with the lower end of said tubing, a tubular insulator around said perforated tube, closures at the end of insulator and at the lower end of said perforated tube, means admitting the flow of fluids through the cylindrical wall of said insulator, a hollow heating element means around said insulator, means circulating heated fluid through said heating element means, and an applied permeable mass between and in contact with said heating element means and said production formation.

References Cited in the file of this patent UNITED STATES PATENTS 2,276,401 Joslyn Mar. 17, 1942 2,349,536 Bancroft May 23, 1944 2,911,047 Henderson Nov. 3, 1959