Apparatus and method to reduce fluid pressure in a wellbore
AssigneeWeatherford/Lamb, Inc.
InventorsDavid Hosie, R. K. Bansal, Peter B. Moyes
Life of this patent
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Abstract
The present invention generally provides apparatus and methods for reducing the pressure of a circulating fluid in a wellbore. In one aspect of the invention an ECD (equivalent circulation density) reduction tool provides a means for drilling extended reach deep (ERD) wells with heavyweight drilling fluids by minimizing the effect of friction head on bottomhole pressure so that circulating density of the fluid is close to its actual density. With an ECD reduction tool located in the upper section of the well, the friction head is substantially reduced, which substantially reduces chances of fracturing a formation (see also FIG. 2 later on).
Claims17
A pump for use in a wellbore comprising:
- a motor operatively connected to a rotor, the rotor disposed in a stator, the rotor and stator defining a centrifugal pump;
- the pump disposed in a tubular string having an inner and outer diameter, the pump associated with the outer diameter and the motor associated with the inner diameter.
A method of using a drilling fluid with a relatively high viscosity in a circulating wellbore comprising:
- providing a drilling fluid with a predetermined viscosity;
- and
- providing energy to the fluid at a point in the wellbore where the fluid is traveling to the surface of the well, thereby reducing the pressure of the fluid and compensating for the relatively high viscosity.
A method of compensating for a friction head developed by a circulating fluid in a wellbore, the method comprising:
- adding energy to the fluid traveling in an annulus defined between a work string and the wellbore;
- and
- the energy reducing the friction head in the wellbore.
A method of removing cuttings from a wellbore during drilling, the method comprising:
- circulating a fluid down a work string and upwards in an annular area of the wellbore;
- and
- adding energy to the fluid in the annulus.
A pump for use in a wellbore to reduce fluid pressure therein, the pump comprising:
- a rotor portion with a plurality of outwardly extending undulations formed thereon;
- and
- a stator portion, the stator portion having a plurality of inwardly extending undulations formed thereon, the undulations of the stator having an alternating relationship with the undulations of the rotor, whereby a substantially constant passage is formed between the undulations as the rotor rotates within the stator.
A method of effecting circulating fluid in a wellbore comprising:
- using a flow of fluid in a first direction to operate a fluid motor, the motor disposed in the tubular string and the fluid traveling in the string;
- and
- using rotational force from the motor to operate a pump, the pump disposed in the string adjacent the motor and including a fluid urging member for acting on the fluid as the fluid moves in a second direction past the pump.
A pump for use in a wellbore, the pump comprising:
- a rotor, the rotor having a bore there though to permit fluid to pass through the pump in a first direction;
- an annular path around the rotor, the annular path permitting the fluid to pass through the pump in a second direction;
- and
- fluid urging members to urge the fluid in the second direction as it passes through the annular path.
A method of using a drilling fluid with a relatively high density in a circulating wellbore comprising:
- providing a drilling fluid with a predetermined density;
- and
- providing energy to the fluid at a point in the wellbore where the fluid is traveling to the surface of the well, thereby reducing the pressure of the fluid and compensating for the relatively high density.
Dependencies are inferred from the claim text.