US2346248A - Means for flowing liquid from wells - Google Patents

Description

April 11, 1944. w. BRAUER 2,346,248

MEANS FOR FLOWING LIQUID FROM WELLS Filed May 29. 1941 wflzarflmar INVENTOR I ATTORNEY Patented Apr. 11, 1944 um'rso SW55 PATENT OFFICE MEANS FGR FLOWING LIQUID FRGM WELLS Walter Brauer, Oklahoma City, Okla.

Application 29, 1941, Serial No. 395,742

(01.. lil3-232) 4' Claims.

This invention relates to the means shutting off water and other extraneous fluid in oil wells, and more particularly but not by way of limitation, comprises means for separating the salt water from the oil by a bottom hole packer or plug, and allowing the oil packed off to flow into ,the eduction tubing at a volume complementary to the bottom hole or sand pressure of the well.

The invasion of salt water into oil yielding sands and more particularly the shot hole of an oil well is detrimental in the production of the well in that the salt water causes corrosion of the equipment, and more particularly creates a pumping or production media comprising a large amount of water rather than the oil. Many attempts have been made to shut off or separate the salt water by the use of plugs, packers and the like, as well as the use of chemicals for retarding the flow of salt water into the shot hole by sealing pores in the rock layer formation. Obviously the greater retarding of the salt water will provide an increase in the oil to be pumped which i a desideratum.

This invention has for a particular object to prevent a rise of the water pressure gradient or hydrostatic. head of salt water greater than the oil pressure created by the sand pressure of the well.

Another object of this invention is to assure -the maintenance of oil on top of the separated salt water by allowing ficw of oil into the eduction tubing in volumes complementary with the sand pressure discharging the oil into the tubing.

And still another object of this invention is to displace oil from the eduction tubing of a well at predetermined intervals in synergetic relationship with the back pressure of the well while simultaneously preventing dissipation of the oil from the shot hole in great volumes than that discharged into the shot hole so as to maintain the oil on top of the Water and prevent any increase in the water pressure gradient.

Other objects and advantages of the invention will be evident from the following detailed description read in conjunction with the accompanying drawing which illustrates one form of my invention.

In the drawing:

Fig. 1 is a fragmentary elevational view partly in section showing the arrangement of the production apparatus disposed in a well hole.

Fig. 2 is a detail view of one of the choke valves.

Referring to the drawing in detail and more particularly to Fig. 1, reference character 2 represents the casing of an oil well hole. A string of tubing is disposed in spaced relation to the casing 2 and has arranged therein at a point in proximity of the shot hole an oil lifting device 6 of any conventional type, but preferably a lifting apparatus actuated by motive fluid pressure, and of the automatic intermitting type.

A packing unit 8 is disposed between the casing 2 and the tubing t at a point below the lifting apparatus 8. The lowermost portion of the. tubing 4 is provided with a collar Ill having diametrically opposed outward projections 12 provided with threaded apertures M for receiving a valve iii of the ball type. Inthe present instance two valves are preferably used, however it will be understood that any number of apertures l4 and valves may be utilized. The valves I6 act as inlet valves for the oil into the tubing as will be hereinafter set forth.

The valves are identical in structure, and referring to Fig. 2 showing the valves in detail, each one comprises an external threaded cylinder t8 formed with a small bore 20 communicating with a large bore 22. A ball 24 is disposed in bore 22 and allows flow of oil or fluid from the shot hole of the well into the tubing. The valve acts as a check to prevent emission of thefluid from the tubing by the ball seating against one end of the smaller bore Zii. A single rib or baflie 26 retains the ball 24 in bore 22. The tubing extends from the collar H] to a point in the shot hole where it is closed off by a conventional bull plug 28 threaded to the lower end thereof.

In locating the oil lifting apparatus in the tubing of a well so as to maintain a substantially constant pool of oil on top of the salt water it is necessary to position the packing unit at a point in proximity of the shot hole. The bottom hole or sand pressure of an oil well is determined by the hydrostatic head of fluid disposed in the well hole since it is common knowledge that one pound of well pressureordinarily will lift oil and water approximately two feet. Consequently from the height of fluid standing in a well the bottom hole pressure can be readily determined, assuming the depth of the well is known.

Furthermore, where the ratio of production between the oil and water is known, e. g., 10 barrels of oil to barrels of water relative to a determined hydrostatic head of fluid, in order to separate the water and oil, the packing unit 8 must be set in position to prevent a column or hydrostatic head of salt water greater than the pressure created by the sand pressure. It will be apparent that if the packer is disposed in a position to allow a column or head of fluid to rise in the well hole greater than the back or sand pressure of the well, such fluid head would cut off the flow of oil from the sand into the shot hole and a substantially continuous salt water pond would be present. In this condition the water-oil ratio would be increased to such an extent that the production fluid would be substantially salt water in lieu of oil and gas.

Upon determination of the bottom hole pressure of a particular well, the packing unit 8 is always set so as to maintain the oil pressure greater than the pressure gradient of the salt water. With the packer positioned relative to the bottom hole pressure, the oil from the rock and sand formation will discharge into the shot hole and due to its lighter gravity will rise to the top of the salt water. In this condition the oil is separated and disposed on top of the water and will remain as such as long as there is sufiicient pressure to prevent any increase in the water gradient.

The choke valves it only allow a flow of oil and gas therethrough at a volume commensurate with that of the sand pressure. It will be apparent that the proper sized choke valves can be utilized in order to prevent discharge of the oil into the eduction tubing in amounts greater than the oil being replaced in the shot hole by the back or sand pressure. In use with an intermittent lifting apparatus, the size of the choke valves can be determined so that the valves I 6 will allow a discharge of oil into the eduction tubing 6 to always provide a column of fluid in the tubin to be lifted at predetermined timed intervals. With the oil lifted from the tubing, oil is nevertheless maintained on top of the salt water below the packer 8 and valves 1 6 since the flow through th valves i6 is never greater than that produced by the oil bearing strata.

In wells producing large volumes of gas intermingled with oil, it will be apparent that the size of the bores in valves 16 can be varied to compensate for the gas.

From the foregoing it will be apparent that the packer is set to prevent any possibility of oreating a hydrostatic head in the well greater than the back pressure of the well thereby always maintaining oil on top of the salt water, and furthermore, the valves act as chokes for choking off the flow of oil into the eduction tubing to prevent any greater flow of oil from the shot hole in volume than that which will be replaced by the sand or back pressure of the well. It will likewise be apparent that the apparatus can be utilized in wells having perforated casings in lieu of shot holes or'the like, as long as the packer is set in proper position commensurate with the pressure of the oil bearing strata. Furthermore, it is to be understood that the invention is not limited to any particular lifting apparatus.

Changes may be made in the combination and arrangement of parts as heretofore set forth in the specification and shown in the drawing, it being understood that any modification in the precise embodiment of the invention may be made within the scope of the following claims without departing from the spirit of the invention.

What I claim is:

1. In an apparatus for lifting fluids from wells comprising a casing, a string oi eduction tubing disposed in the casing, a packer arranged between the tubing and casing in the lowermost portion of the well, choke valves arranged in the tubing below the packer and adapted to choke the flow of the separated oil in quantities commensurate with the discharge of oil from the production strata, and means above the packer for lifting the choked oil, at timed intervals in synergetic relation with the time for discharging oil from the production strata.

2. In an apparatus for lifting fluids from wells comprising a casing, a string of eduction tubing disposed in the casing, packing means arrangedv in the lowermost portion of the well and adapted to retard the salt water gradient of the well to provide separation of oil from the water, means arranged below the packer for choking the flow of the separated oil from the well commensurate with the discharge of oil into the well by the oil bearin strata, and means above the packing means for lifting the choked oil, at timed intervals in synergetic relation with the time for the discharging of oil from the oil bearing strata.

3. An apparatus of the class described, comprising an oil wel1 casing, an eduction tube extending through the casing, a packer arranged adjacent to the lower end of the tube for packing off the space between the eduction tube and the casing, means closing the lower end of the eduction tube, passageways interposed in the eduction tube between its closed bottom and the packer, said passageways being inclined upwardly toward the axis of the tube, a check valve arranged in each passageway, and means above the packer for introducing gas into the eduction tube for lifting oil therethrough.

4. An apparatus of the class described, comprising an oil well casing, an eduction tube extending through the casing, a packer arranged adjacent the lower end of the tube and packing off the space between the eduction tube and the casing, means closing the lower end portion of the induction tube, a passagewa interposed in the eduction tube between its closed lower end portion and the packer, a check valve in the passageway for controlling the admission of well liquid into the eduction tube from the space below the packer and between the tube and casing, and means above the packer for introducing gas into the eduction tube for lifting oil therethrough.

WALTER BRAUER.

Images