Annular flow restrictor for electrical submersible pump
AssigneeBaker Hughes Incorporated
InventorsSteve E. Hester, Michael Gary Gagner, Ernesto Alejandro Vilcinskas
Life of this patent
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Abstract
A method of pumping well fluid from a well having casing with perforations includes connecting an electrical motor to a lower end of a pump and securing the pump to tubing. A restrictor is mounted to the tubing above the pump, the restrictor having a restrictor passage. The well annulus contains a well fluid with a static level under static conditions. When the motor is started to cause the pump to operate, downward flow of well fluid contained in the well annulus flows through the restrictor passage. This reduces the amount of downward flow to increase well fluid flow through the perforations.
Claims30
A method of pumping well fluid from a well having casing with perforations by using a pump assembly that includes a pump having an intake defining a flowpath from the perforations to the intake, the pump being coupled to a downhole motor that is suspended in the flowpath upstream of the intake of the pump, the pump assembly being suspended on and discharging well fluid into a string of tubing, the string of tubing and the pump assembly being surrounded by a well annulus, the method comprising:
- (a) shutting off the motor and allowing well fluid from the perforations to rise in the well annulus to a static level;
- (b) starting the motor to cause the pump to operate;
- then
- (c) reducing downward flow of the well fluid in the well annulus to the intake by an amount sufficient to increase well fluid flow through the perforations past the motor for cooling the motor during initial starting of the pump.
A method of pumping well fluid from a well having casing with perforations by using a pump assembly that includes a pump coupled to a downhole motor, the pump assembly being suspended on and discharging well fluid into a string of tubing, the string of tubing and the pump assembly being surrounded by a well annulus that contains well fluid under static conditions when the pump is not operating, the method comprising:
- (a) starting the motor to cause the pump to operate;
- then
- (b) restricting downward flow of well fluid in the well annulus by an amount sufficient to increase well fluid flow through the perforations during initial starting of the pump;
- and
- wherein step (b) comprises placing a blocking member in the well annulus above an intake of the pump, the blocking member having a lower end with a gas pocket portion elevated above a well fluid portion, the blocking member having a well fluid passage through the well fluid portion and a gas flow passage through the gas pocket portion, the method comprising causing at least some of the well fluid flowing downward through the well annulus to flow through the well fluid passage, and causing gas flowing in from the perforations to flow to the gas pocket portion and upward through the gas flow tube.
A method of pumping well fluid from a well having casing with perforations by using a pump assembly that includes a pump coupled to a downhole motor, the pump assembly being suspended on and discharging well fluid into a string of tubing, the string of tubing and the pump assembly being surrounded by a well annulus that contains well fluid under static conditions when the pump is not operating, the method comprising:
- (a) starting the motor to cause the pump to operate;
- then
- (b) restricting downward flow of well fluid in the well annulus by an amount sufficient to increase well fluid flow through the perforations during initial starting of the pump;
- and
- wherein step (b) comprises placing a blocking member in the well annulus above an intake of the pump, the blocking member having a passage therethrough for allowing the downward flow of the well fluid, and a pressure responsive variable orifice valve in the passage of the blocking member, the method comprising decreasing the flow area through the passage in the blocking member with the valve in response to an increase in pressure differential across the blocking member.
A method of pumping well fluid from a well having casing with perforations, comprising:
- (a) connecting an electrical motor to a lower end of a pump;
- (b) securing the pump to tubing;
- (c) mounting a restrictor to the tubing above an intake of the pump, the restrictor having a restrictor passage therethrough in communication with a well annulus above and below the restrictor;
- (d) lowering the tubing, restrictor, and pump into the well, the well annulus containing a well fluid that has flowed from the perforations to a static level above the restrictor under static conditions;
- (e) starting the motor to cause the pump to operate;
- then
- (f) restricting downward flow of the well fluid contained in the well annulus above the restrictor by causing at least some of the well fluid to flow through the restrictor passage to the pump to increase well fluid flow through the perforations.
A method of pumping well fluid from a well having casing with perforations, comprising:
- (a) connecting an electrical motor to a lower end of a pump;
- (b) securing the pump to tubing;
- (c) mounting a restrictor to the tubing above an intake of the pump, the restrictor having a restrictor passage therethrough;
- (d) lowering the tubing, restrictor, and pump into the well, defining a well annulus that contains a well fluid with a static level under static conditions;
- (e) starting the motor to cause the pump to operate;
- then
- (f) restricting downward flow of well fluid contained in the well annulus by causing at least some of the well fluid to flow through the restrictor passage to increase well fluid flow through the perforations;
- and
- wherein step (c) comprises providing the restrictor with a lower end that has a gas pocket portion spaced above a well fluid portion, the restrictor passage extending upward from the well fluid portion of the lower end, the restrictor further having a gas flow passage that extends through the restrictor from the gas pocket portion, the method further comprising causing gas flowing through the perforations to collect in the gas pocket portion and flow upward through the gas tube.
A method of pumping well fluid from a well having casing with perforations, comprising:
- (a) connecting an electrical motor to a lower end of a pump;
- (b) securing the pump to tubing;
- (c) mounting a restrictor to the tubing above an intake of the pump, the restrictor having a restrictor passage therethrough;
- (d) lowering the tubing, restrictor, and pump into the well, defining a well annulus that contains a well fluid with a static level under static conditions;
- (e) starting the motor to cause the pump to operate;
- then
- (f) restricting downward flow of well fluid contained in the well annulus by causing at least some of the well fluid to flow through the restrictor passage to increase well fluid flow through the perforations;
- and
- wherein step (c) comprises providing the restrictor with a pressure responsive variable orifice valve, the method further comprising reducing the flow area in the restrictor passage in response to an increase in the differential pressure across the restrictor.
In a well having a casing with a set of perforations in communication with an earth formation and a string of tubing suspended in the casing, an apparatus for pumping well fluid from the well, comprising:
- a pump assembly that includes a downhole motor located below a pump having an intake, the pump assembly being suspended on the tubing, the tubing and the pump assembly defining a well annulus, the motor being located upstream from the intake of the pump in a flowpath leading from the perforations to the intake;
- a well fluid in the well annulus that originates in the earth formation and rises to a static level under static conditions due to internal pressure in the earth formation;
- and
- a restrictor located in the well annulus above the intake of the pump and below the static level of the well fluid under static conditions, the restrictor partially blocking downward flow of the well fluid from the well annulus to the intake to increase well fluid flow through the perforations and past the motor during initial starting of the pump assembly.
In a well having a casing with a set of perforations and a string of tubing suspended in the casing, an apparatus for pumping well fluid from the well, comprising:
- a pump assembly that includes a downhole motor located below a pump, the pump assembly being suspended on the tubing, the tubing and the pump assembly defining a well annulus that contains well fluid under static conditions when the pump assembly is not operating;
- a restrictor located in the well annulus above an intake of the pump for restricting downward flow of well fluid from the well annulus to increase well fluid flow through the perforations and past the motor during initial starting of the pump assembly;
- and
- wherein the restrictor comprises a blocking member mounted to the string of tubing, the blocking member having a lower end with a gas pocket portion elevated above a well fluid portion, the blocking member having a well fluid passage through the well fluid portion for allowing downward flow of the well fluid, and a gas flow passage through the gas pocket portion for collecting and facilitating upward flow of gas.
Dependencies are inferred from the claim text.