US3018828A - Prevention of water and gas coning - Google Patents

Description

Jan. 30, 1962 s. s. PRENTISS PREVENTION OF WATER AND GAS CONING 2 Sheets-Sheet 1 Filed July 15, 1957 INVENTOR. s. s. PRENTISS BY Z4 FIG.

A T TORNEYS Jan. 30, 1962 s. s. PRENTISS 3,018,328

PREVENTION OF WATER AND GAS CONING Filed July 15, 1957 2 Sheets-Sheet 2 S. S. PRENTISS ATTORNEYS 3,818,828 PREVENTION OF WATER AND GAS (ZONING Spencer S. Prentiss, Bartlesville, Ultla, assignor to Phillips Petroleum Company, a corporation of Delaware Filed July 15, 195.7, Ser. No. 671,978 10 Claims, (Cl. 166-53) This invention relates to an improved apparatus for reducing water and gas coning in an oil well to maintain maximum oil production rates.

Water coning and the production of water in oil wells where the producing formation is underlain with water is a serious problem in oil production in many areas. In the production of oil, the impermeable formations are pierced by a well hole reaching into the area of oilsaturated permeable sands. In many instances the oilsaturated permeable sands exist above a permeable sand of the same character which contains water. Thus, a water level or water table exists in the permeable sand formation wherein the oil comprises the upper area and the water comprises the lower area. As the oil is withdrawn from the oil-containing sand from a point in the closure between the water table and the top of the formation, coning of the water toward the point of withdrawal of the oil tends to result. This is particularly the situation in areas of high vertical permeability wherein the production rates are also high.

This coning of water is very undesirable since it results in the pumping or passing of water to the surface along with the produced oil. Production costs are increased due to the cost of pumping valueless water to the surface, which costs must be borne by the units of oil produced. Further-more, additional costs are incurred in separating water from the produced oil and disposal of the same. A more serious result which may be encountered due to the coning of water in the production area is that it may completely shut off the flow of oil itself.

Accordingly, it is an object of the invention to provide an arrangement of apparatus for preventing or alleviating water or gas coning in the pumping of an oil well. Another object is to provide apparatus for detecting or sensing the rise of water into the area around the intake of the pump in an oil well adjacent an oil-containing formation and forcing the water away from the pump intake. Other objects of the invention will become apparent upon consideration of the accompanying disclosure.

' The broadest aspect of the invention comprises sensing the presence of water in an area in an oil well sub-jacent the intake of the pump therein and injecting oil into the well bore and into the formation adjacent this area so as to force the water downwardly away from the pump intake area. Apparatuswise, the invention comprises means for sensing the presence or rise of water in the pumping area, a bypass conduit from the delivery side of the pump to an area in the well bore below the intake side of the pump having a valve therein and means for openingsaid valve responsive to or operated by said sensing means. The valve is normally closed and is perated whenwater is sensed in the pumping area and, in one form of the invention, closes when sufficient oil is forced into the wellbore to drive the water below the sensing means. In another form of the invention, the means responsive to the sensing means which actuates the control valve includes ameans for maintaining the valve Patented Jan. 369, 1952 one embodiment of the invention positioned in a well; FIGURE 2 is a circuit diagram of a preferred embodiment of the operating means for the control valve of FIGURE 1; FIGURE 3 is a partial section of an ele vation of another embodiment of the invention; and FIGURE 4 is an elevation of a gas sensing device suitable for use in the invention.

Referring to FIGURE 1, a casing 12 is positioned in a well bore adjacent an oil bearing formation and con tains a tubing string 14 on the end of which is a pump 15 which is operated by sucker rodlti. Pump 36 comprises a barrel 2%, a piston 22 in which is positioned a check valve 23, and a bottom closure 24 containing check valves 25. Perforations 26 in the skirt of barrel 28 below closure 24 serve as the intake for oil. At the lower end of the pump is positioned a conventional packer 28 thru which a conduit 38 extends and connects with pump barrel 28 on the delivery side of the pump. An orifice 32 is utilized to control the rate of flow of oil thru this conduit and may be positioned either in pump barrel 20, as shown, or somewhere in conduit 38 if desired. Conduit 30 and, particularly, orifice 32. therein, provides a selected small continuous rate of flow of oil back to the area below packer 28 which assists in preventing coning between operations of valve 36 in conduit 34. A second conduit 34 is positioned similarly to conduit 38 and is provided with a normally closed valve 36. A sensing device or probe 38 is positioned so that it senses the presence of water directly below packer 28 or below the pump intake 26. It is convenient to position probe 38, as shown in the drawing, extending thru packer 28. The pro-be is provided with a control box or circuit 48 which is sensitive to or actuated by the probe and operatively connected with valve 38. A line 42 connects the circuit in control box 48 with a source of current at the ground surface for operating the device. Casing 12 is perforated at 43 along a substantial section adjacent and below pump 16 to permit flow of oil into and from the casing. Dotted lines 45 indicate a water cone which occurs at intervals and actuates probe 38.

FIGURE 2 shows a circuit which is energized by the small current generated by probe 38 and utilizes current from a source 44, which may generate either an al-ternat-. ing or direct current, to operate valve 36. Probe 88 is connected to ground thru a relay 46 which operates a switch 48 which closes the relay when a current is flowing from the probe. Closing switch 48 completes the circuit from power source 44 thru line 42, solenoid 58, motor 52, switch 48, to ground 54. These grounds are formed by connections with casing 12. Power source 44, of course, is grounded at 55. Thus when a weak current is generated by probe 38, relay 46 closes switch 48 so as to energize the described circuit which actuates solenoid 50 to open valve 36. As long as current is being generated by probe 38, switch 48 remains closed and the flow of current thru the circuit in control box 40 maintains valve 36 in open position.

Whencurrent is flowing thru the circuit in control box 40, motor 52 is operated and this motor is connected thru a gear box 56 to a cam 58. Cam 58 is constructed so as to maintain switch 59 in closed position for a pre determined period such as 1 to 5 hours. The time can be predetermined by the speed of motor 52, the construction of gear box 56 and the design of cam 58. Switch 59 connects one terminal of motor 52 with ground 54 so that even though switch 48. opens when oil forces water below probe 38, the circuit remains energized because of the holding of switch 59 closed by means of cam 58 for a predetermined period.

FIGURE 3 shows another embodiment of the invention wherein two- Way valves 62 and 63 are positioned on the delivery and intake sides of the pump, respectively, and are operated by the same control box as the arrangement shown in FIGURE 2. In this arrangement of the apparatus, when probe 38 is contacted by underground water and the circuit in control box 40 is energized, valves 62 and 63 are rotated 90 counterclockwise so that operation of the pump passes oil from the tubing string 14- thru conduit 64, valve 63, pump 21, valve 62, and conduit 66 back into the borehole below packer 28 and into the formation.

FIGURE 4 shows a gas sensing device comprising a perforate box or housing 70 having inlet and outlet 72 and 74 for movement of gases and liquids into and from the box. A float 76 is positioned on a lever 77 pivoted at 78. Lever 77 is linked at 80 with lever 82 which in turn is pivoted at 84. Lever 82 closes switch 48 in the circuit of box 40 when the liquid around float 76 is displaced downwardly by gas. In this manner the gas sensing device actuates the circuit and operates valve 36.

Probe 38 is preferably constructed of magnesium but it may be made of another metal which has a substantially different contact potential from that of the surrounding steel casing so that, in the presence of an electrolyte, a small current is generated by the probe to actuate relay 46. If probe 38 is positioned below the end of the casing in a well, it may be surrounded with a perforate steel housing which is grounded, thereby creating the same effect as with casing 12 of FIGURE I. The detailed construction of one type of magnesium probe which may be utilized in the invention is fully described in the application of B. F. Wiley and H. M. Barton, Jr., Serial No. 520,470, filed July 7, 1955. Another type of probe which is applicable to the instant invention is shown in U. S. Patent 2,560,209 to Borell et al. However, a simple magnesium rod, which may be reinforced by a steel core is adequate for use in the apparatus and process of the invention.

Certain modifications of the invention will become apparent to those skilled in the art and the illustrative details disclosed are not to be construed as imposing unnecessary limitations on the invention.

I claim:

1. In a well having a tubing and a pump on the lower end of said tubing which delivers fluid to said tubing, said pump being adjacent an oil-bearing formation located above and adjacent a water-containing formation, the combination of a packer across said well below said pump; a conduit communicating at one end with the delivery side of said pump and at the opposite end with the area subjacent said packer; a valve in said conduit for opening and closing said conduit to flow; sensing means for sensing the presence of water in said area; actuating means sensitive to said sensing means connected therewith and structurally and actuatably connected with said valve to open same when water is sensed by said sensing means and close same when water recedes from said area.

2. The device of claim 1 including an open conduit communicating with the delivery side of said pump and extending below said packer, the flow capacity of said second conduit being smaller than that of first said conduit.

3. The combination of claim 1 wherein said sensing means comprises a probe which generates an electric current when in contact with water and said actuating means comprises a first circuit from said probe to ground, including a relay therein, a power source, a second circuit from said power source to ground having a switch therein actuated by said relay, and a solenoid in said second circuit mechanically connected with said valve for opening and closing same.

4. In a well having a casing extending into an oil-bearing formation overlying a water-containing formation,

said casing being perforate adjacent said oil-bearing formation above the level of the later defined packer, and a tubing having a pump on its lower end opposite said perforations which delivers fiuid to said tubing, the combination of a packer across said casing subjacent the intake end of said pump; a probe subjacent said packer for sensing water just below said packer and emitting an electric signal as long as water is sensed; a conduit connecting the delivery side of said pump with the well bore below said packer; a valve in said conduit; and electric valve operating means, including an electrical circuit, sensitive to said signal and operatively and structurally connected with said valve to position same to permit flow thru said conduit when said signal is being emitted and reversing same after said signal ceases.

5. The apparatus of claim 4 including a second conduit connecting the intake of said pump with the delivery side thereof; a second valve in said second conduit for passing liquid from said tubing to said intake when first said valve is open to flow from said pump thru first said conduit, wherein said valve operating means simultaneously operates said second valve to permit flow from said tubing to said pump.

6. The apparatus of claim 4 including means for keeping said circuit energized for a fixed period even though water recedes from said probe.

7. Apparatus for use in combination with a well tubing comprising a pump on the lower end of said tubing; a conduit leading from the discharge side of said pump to a point subjacent the intake of said pump; a valve in said conduit; a probe for sensing the presence of water below said intake and generating an electric current in response thereto; a power circuit connected by an electrical conductor with said probe and connected with operating means for said valve.

8. Apparatus for use in combination with a well tubing comprising a pump on the lower end of said tubing; a packer across the well adjacent the lower end of said pump; a conduit leading from the discharge side of said pump to a point below said packre; a valve in said conduit; a metal probe positioned below said packer, said probe being capable of generating an electric current when contacted with subterranean water; a first circuit connecting said probe thru a relay to a ground; and a second circuit including a power source, a solenoid operatively and mechanically connected with said valve, and a switch closable by said relay.

9. The apparatus of claim 8 including an open conduit leading from the discharge side of said pump to a point below the intake of said pump of lower flow capacity than said valved conduit.

10. The apparatus of claim 8 including in said second circuit a motor, the terminals of said motor being connected in said second circuit; a shaft having a cam thereon operating off the shaft of said motor; and an auxiliary circuit connecting with said motor and to ground having a second switch therein, said cam being mechanically connected with said second switch so as to close same for a selected period during each revolution of said cam, thereby keeping said second circuit closed for said selected period.

References Cited in the file of this patent UNITED STATES PATENTS 1,423,759 Doble July 25, 1922 1,587,714 Frazier June 8, 1926 1,604,763 Snyder et al. Oct. 26, 1926 2,326,804 Sigmund et al Aug. 17, 1943 2,371,339 Markwart Mar. 31, 1945 2,560,209 Borell et al. July 10, 1951 2,607,426 Rose Aug. 19, 1952 2,749,988 West June 12, 1956

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