US2186035A - Method of and apparatus for flowing wells - Google Patents

Description

ATTORN EY Jan. 9, 1940. w. E. NlLEs METHOD 0F AND APPARATUS FOR FLOWING WELLS Filed June 30, 1938 INVENTOR VVI'/ m E. /V/es 'patetica Jan. 9, 1940 PATENT OFFICE METHOD oF AND APPARATUS Fon. FLowiNG WELLS William E. Niles, Kansas City, Mo. Application June 30, 1938, Serial No. 216,728

8 Claims.

the fluid levels in the formation or clogging of the producing sands with paraflin and asphalt. In some instances the hydrocarbons may become or are so viscous that they will not flow through the containing sands into the well. In cases where the natural pressures become depleted or are insuflicient to lift the liquid that flows into the well, it is necessary to provide mechanical means to lift the fluid 'that does collect in the bottom of the well but due to the extreme depth of the present day wells, crooked well holes and various mechanical imperfections in the pumping apparat-us, pumping` rods, pump valves, etc., such methods are diicult and a constant source of trouble. Even lthough a well has been successfully pumped there comes a time when the fluid level subsides because of clogging of the formation with paraffin and asphalt with the result that much of the hydrocarbons cannot reach the pump and the well is abandoned.

It is, therefore, the principal object of the present invention to provide a method and apparatus for effectively extracting oil from formations wherein the oil cannot ordinarily be recovered by present methods.

Other important objects of the invention are to effect flow of the oil that is ordinarily too viscous to flow through the producing formation; and to continue iiow of wells after depletion of the natural pressure, thereby avoiding the usual pumping difficulties above noted.

It is also an important objectl of the present invention to keep the formation clean, and free of substances that ordinarily tend to clog the iiow passages of the producing formation.

In accomplishing these and other objects of the invention, I have provided an improved apparatus, the preferred form of which is illustrated in the accompanying drawing, wherein:

Fig. 1 is a vertical section through a Well equipped with a well flowing apparatus constructed in accordance with the present inven-4 tion.

Fig. 2 is an enlarged horizontal section through the well on the line 2-2 of Fig. 1, particularly (Cl. IBG-21) illustrating support of the electrical conductors by the well tubing.

Fig. 3 is an enlarged horizontal .cross-section through the heater whereby the producing formation is heated to effect suflicient vaporization of the fluid contained in the formation'thereby artificially generating sufficient pressure to effect iioW of the well.

Fig. 4 is a vertical section through the heater.

Fig. 5 is an enlarged detail perspective view lo of the heater showing a part of the heater casing in section.

Referring more in detail to the drawing:

I designates the bore hole of an oil well that is drilled from the surface of the earth into the oil producing formation 2. The bore hole is cased by the ordinary casing 3 that is supported on theI cap-rock 4 above the producing formation, as in conventional practice. Located within the casing and extending from the top to the bottom of the well isa tubing 5, through which oil flows to the top of the weil under control of a master valve 6 into a lateral flow line 1 leading to a storage tank, pipe line or other source of disposal.

When a well is first completed the oil will 25 usually iiow through the producing sand and accumulate within the shot-hole 8 by reason of difference in the natural pressure existing in the formation and the space within the well. The oil will continue to enter the well and the fluid will so rise in the tubing until the iiuid pressure is equivalent to the natural formation pressure. Usually this pressure is sufficient to force the oil to the top of the well and the well will flow naturally, but eventually the formation pressure subs 4sides so that it is necessary to provide mechanical .means in lifting the oil or to supplement the formation pressure with an artificial pressure medium to continue the flow. It has been found that when artificial mediums are injected into the well m they interfere with the natural flow of oil from the formation into the shot-hole of the well. When the fluid is lifted by a pump or the like difliculty is encountered because of breakage of the rods, leakage of pump valves, crooked Well holes, and many other reasons. I have, therefore, provided an improved method and apparatus for reestablishing a substantially natural formation pressure whereby the iiow is continued in substantially the same manner as when conducted 50 under the natural formation pressures.

In carrying out the invention, I have provided means for heating the producing formation at a point directly below the cap-rock 4 so that the accumulated heat travels 'back through the formation and eifects suiiicient vaporization of the fluids remaining in the upper portion thereof to generate pressure which effects flow of oil downwardly through the formation and in the direction of the well hole so that the oil is again co1- lected in the well pocket and caused to rise in the tubing as the pressures reestablished. As the pressure in the formation gradually builds up it soon becomes suflicient to again start flow of the well in substantially all essentials the same as when lunder its original, natural now. I am aware that heaters have been provided to melt paranin, asphalt and like materials tending to clog the flow channels in the surfaces of the shot-hole and to keep the screen free from such accumulations, but in all instances it has been necessary to equip the well with conventional pumping-apparatus to lift the oil to the top of the well. I have found that by locating the heater at a certain position in the well relatively to the depth of the formation the heat therefrom is eective in generating pressure which is sufficient to establish natural flow without the use of mechanically operated pumps and the like, as now to be described.

Located in the tubing at spaced elevations are check valves 9, each including a coupling I that is inserted between adjacent joints of tubing and have ports II provided with valve yseats I2 that are normally closed by gravity operated valves I3. the valves I3 being retained in valving position within cages I4 formed as a part of the coupling and adapted to extend upwardly within the tubing. The tubing is sealed from the casing at a point above the cap-rock by means of spaced packers I5 and I6 so as to prevent escape of accumulated pressure between the tubing and casing sothat the generated pressure is effective in causing ow of oil through the tubing.

Fixed to the lower section of the tubing, at a point directly below the cap-rock, is a heater I1 comprising a cylindrical outer casing I8 of suitable diameter to be inserted into the well through the well casing and which is of sufllcient length to house the required size resistance element to produce the desired heat. Located within the casing I8 are concentrically arranged cylindrical partitions I9 and 28, the partition I9 conforming in diameter to that of the tubing so as to form a flow channel 2I through which theoil fluid is passed through the heater. 'I'he outer partition is spaced from the partition I9 to form an annular insulating space 22 surrounding the ow channel 2I so that the heat generated by theresistance elements is insulated from the well flow moving through the channel 2I. The insulating space may be exhausted of air or the space may be filled with .suitable insulating material as desired. The partition 20 cooperates with the outer wall of the casing to form an annular chamber 23 for accommodatingk the heating element 24. 'I'he ends of the casing are closed by heads 25 and 26 having internally threaded collars 21 and 28 to respectively connect the heater with a lower joint of tubing and with the threaded neck 29 of a conventional screen 30, such as used in ordinary pumping equipment. The screen 38 may extend to the bottom of the formation or may be supported at the desired elevation on a conventional stand of pipe, as in regular practice. It is important, however,'that the heater be located above the screenso that the pressure is generated above the fiow'passageways to the screen, and a liquid seal is maintained relatively to the interior of the tubing.

aieaoao The heating element may be of any desired form and is supplied with a suitable current through conductors 3| and 32 that lead from the top of the well through a conduit 33. The conduit is supported from the tubing 5 by clamping bands 34 located at spaced intervals along the length thereof as shown in Fig. 2. The conductors 3| and 32 are connected with the terminals of a generator 35 that is shown in diagram in Fig. 1 and which is driven by a prime mover such as a motor 36, having its terminals connected by conductors 31 and 38 with service lines 39 and 40. The field coils 4I of the generator are supplied with an exciting current from any slutable source such as the service lines 39 and 48, through conductors 42 and 43, one of the conductors being connected with a rheostat 44 for regulating voltage of the current flowing through the neld coils so that the current output of the generator may be regulated to provide the desired voltage to produce the heat required in maintaining iiow from the producing formation without overheating and cracking of theoil.

In operating a well flowing apparatus, as above described, the master valve 6 may be initially closed and the current supply established to the heating elements of the heater. As the heat builds up within the upper portion of the shothole the walls of the pocket are heated to vaporize any vaporizable nuids that are contained in -the upper portion of the producing formation.

The heat gradually accumulates in the formation and is carried by conduction in all radial directions from the well hole to effect vaporization of any volatile fluids remaining in the upper portion of the formation until finally the pressure is -suflicient to cause movement of liquid petroleum When suilicient pressure has been built up the master valve is opened to cause the accumulated oil to be ejected from the tubing through the lateral flow line l. The now will then continue as long as the articially generated pressure is suilicient. Escape of the gases through the tubing may, perhaps, cause a drop in pressure and theV flow may stop until sufllcient pressure has again built up. Thus the well may possibly flow in heads, that is periods of flow alternate with brief periods of quiescence while suiilcient hydrocarbons are being vaporized to reestablish the required pressure. The generated gas that does escape moves through the column of oil in the tubing in the form of bubbles to assist flow of the well liquids.

From the foregoing it is apparent that I have provided an improved method and apparatus for producing and maintaining flow of oil fromaip'roQ-j ducing formation after the natural pressure'fhas subsided. It is also obvious that the heatv being conducted through the upper portion of the formation reduces the viscosity of any hydrocarbons remaining in the lower level and causes their now in the direction of the well hole so that the major portion of the hydrocarbons in the formation are extracted and caused to ow to the top of the well.

What I claim and desire to secure by Letters Patent is:

1. An apparatus for owing wells drilled into a producing formation including a tubing in the well extending into said formation, a packer in the well for retaining pressure in said formation, a heater carried by the tubing in the upper portion of the formation for heating a certain portion of the formation to generate pressure on the petroleum contained in the lower portion of the formation and to effect flow of said petroleum through the formation and through the tubing to the top of the well, means insulating the heater from the ow moving through said tubing, check means in the tubing for trapping the flow at selected points in the tubing upon drop of pressure in said formation, and a master4 valve at the upper end of the tubing for controlling said flow to retain the generated pressure.

2. The method of recovering petroleum by way of a well drilled through a cap-rock into a producingformation including vaporizing a portion of the petroleum contained in the formation directly under said cap-rock by application of extraneous heat to establish a high pressure area in the formation, and creating a low pressure area at a selected point in the formation below said high pressure area to cause flow of petroleum from the high pressure area to said selected point and to the top of the well without increase in temperature of said petroleum when passing said heated area.

3. The method of recovering petroleum by way of a well drilled through a cap-rock into a producing formation including vaporizing a portion of the petroleum contained in the formation under said cap-rock by application of extraneous heat to establish a high pressure area in the formation, creating a low pressure area at a selected point in the formation below said high pressure area to cause flow of petroleum from said highpressure area to said selected point and for effecting flow of the petroleum from said low pressure area to the top of the well responsive to the pressure acting in said high pressure area without increase in temperature of said petroleum when passing said heated area, and trapping iaid flow at a series of points above said torina- 4. The method of recovering petroleum from petroleum producing formations including heating a portion of the formation to establish a high pressure area in said formation, creating a low pressure area at a selected point in the formation below the high pressure area to cause flow of petroleum upwardly in saidlow pressure area and through said heating zone without susbtantial increase in temperature, and releasing pressure from the low pressure area to effect flow of said petroleum and to retain said high pressure.

5. The method of recovering petroleum from petroleum producing formations including heating a portion of the formation to establish a high pressure area in said formation, creating a low pressure area at a selected point below the high pressure area to cause flow of petroleum to said low pressure area, releasing pressure from the low pressure area to effect flow of said petroleum upwardly through said heating zone without additional increase in temperature, and trapping the flow at a series of points above said formation.

6. An apparatus for flowing wells drilled into a producing formation including a tubing in the well extending into said formation, a packer in said well to retain pressure in said formation, a heater carried by the tubing in the upper portion of the formation for heating said portion of the formation to generate pressure on the petroleum contained in the lower portion of the formation and to effect ow of said petroleum through the formation and through the tubing to the top of the well, and means insulating the heater from the flow moving through said tubing.

7. An apparatus for flowing wells drilled into a producing formation including a tubing in the well extending into said formation, a packer in said well to retain pressure in said formation, a

heater carried bythe tubing in the upper portion of the formation for heating said portion of the formation to generate pressure on the petroleum contained in the lower portion of the formation and to effect flow of said petroleum through the formation and through the tubing to the top of the well, means insulating the heater from the flow moving through said tubing, and check means in the tubing for trapping the flow at selected points in the tubing upon drop of pressure in said formation.

8. An apparatus for flowing wells drilled into a producing formation including a tubing in the well extendingl into said formation, a packer in said well to retain pressure in said formation, a heater carried by the tubing in the upper portion 0f the formation for heating said portion of the formation to generate pressure on the petroleum contained in the lower portion of the formation and to eiect iiow of said petroleum through the formation and through the tubing to the top of the well, means insulating the heater from said tubing, means in the tubing for trapping the flow at selected points in the tubing, and a master valve at the upper end of the tubing for controlling said flow to retain said generated pressure.

4 WILLIAM E. NILES.

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