Subsea wellbore drilling system for reducing bottom hole pressure
First Claim
1. A method of controlling bottomhole pressure during drilling of a wellbore with a drill string having a bottomhole assembly at an end of a tubing and wherein a drilling fluid supplied under pressure during drilling to the tubing returns to the surface (“
- the return fluid”
), said method comprising;
(a) providing a pump in the return fluid;
(b) determining a parameter relating to the drilling fluid; and
(c) controlling the speed of the pump in the return fluid in response to the determined parameter to control the bottomhole pressure.
2 Assignments
0 Petitions
Accused Products
Abstract
The present invention provides drilling systems for drilling subsea wellbores. The drilling system includes a tubing that passes through a sea bottom wellhead and carries a drill bit. A drilling fluid system continuously supplies drilling fluid into the tubing, which discharges at the drill bit bottom and returns to the wellhead through an annulus between the tubing and the wellbore carrying the drill cuttings. A fluid return line extending from the wellhead equipment to the drilling vessel transports the returning fluid to the surface. In a riserless arrangement, the return fluid line is separate and spaced apart from the tubing. In a system using a riser, the return fluid line may be the riser or a separate line carried by the riser. The tubing may be coiled tubing with a drilling motor in the bottom hole assembly driving the drill bit. A suction pump coupled to the annulus is used to control the bottom hole pressure during drilling operations, making it possible to use heavier drilling muds and drill to greater depths than would be possible without the suction pump. An optional delivery system continuously injects a flowable material, whose fluid density is less than the density of the drilling fluid, into the returning fluid at one or more suitable locations the rate of such lighter material can be controlled to provide supplementary regulation of the pressure. Various pressure, temperature, flow rate and kick sensors included in the drilling system provide signals to a controller that controls the suction pump, the surface mud pump, a number of flow control devices, and the optional delivery system.
135 Citations
72 Claims
-
1. A method of controlling bottomhole pressure during drilling of a wellbore with a drill string having a bottomhole assembly at an end of a tubing and wherein a drilling fluid supplied under pressure during drilling to the tubing returns to the surface (“
- the return fluid”
), said method comprising;(a) providing a pump in the return fluid;
(b) determining a parameter relating to the drilling fluid; and
(c) controlling the speed of the pump in the return fluid in response to the determined parameter to control the bottomhole pressure. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
- the return fluid”
-
13. A wellbore system for controlling bottomhole pressure comprising:
-
(a) a drill string having a bottomhole assembly at an end thereof in the wellbore;
(b) a fluid system supplying fluid under pressure to a fluid circulation system, said fluid returning via a return path carrying cuttings (“
the return fluid”
);
(c) a sensor for measuring a selected parameter of the fluid;
(d) a pump associated with the return fluid; and
(e) a controller controlling the speed of the pump in response to the selected parameter to control the bottomhole pressure at a desired value. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
-
-
24. A method of controlling bottomhole pressure during drilling of a wellbore with a drill string having a bottomhole assembly at an end of a tubing and wherein a drilling fluid supplied under pressure during drilling to the tubing returns to the surface (“
- the return fluid”
), said method comprising;(a) providing a pump in the wellbore for pumping the return fluid toward surface and to control the bottomhole pressure at a desired pressure during drilling of the wellbore;
(b) determining bottomhole pressure during drilling of the wellbore;
(c) controlling the pump in response to the determined bottomhole pressure to control the bottomhole pressure at the desired pressure. - View Dependent Claims (25, 26, 27)
- the return fluid”
-
28. A method of controlling pressure in a wellbore during drilling of the wellbore with a drill string having a bottomhole assembly at an end of a drill string and wherein a drilling fluid supplied to a circulation system returns via a return path (“
- the return fluid”
), the method comprising;(a) providing a pump in the wellbore;
(b) determining a parameter of interest; and
(c) controlling the pump in response to the determined parameter to control the bottomhole pressure. - View Dependent Claims (29, 30, 31, 32, 33, 34, 35)
- the return fluid”
-
36. A wellbore system for controlling bottomhole pressure comprising:
-
(a) a drill string having a bottomhole assembly at an end thereof in a wellbore;
(b) a fluid system supplying fluid under pressure to the wellbore, said fluid returning via a return path (“
the return fluid”
);
(c) a pump positioned in the wellbore;
(d) a sensor for measuring a selected parameter; and
(e) a controller controlling the pump in response to the selected parameter to control the bottomhole pressure. - View Dependent Claims (37, 38, 39)
-
-
40. A method of controlling bottomhole pressure during drilling of a wellbore with a drill string having a bottomhole assembly at an end of a tubing and wherein a drilling fluid supplied to a circulation system returns via a return path (“
- the return fluid”
), the method comprising;(a) providing a pump in the return fluid;
(b) operating the pump during drilling of the wellbore;
(c) determining a parameter of interest; and
(d) controlling the pump during drilling of the wellbore in response to the determined parameter to control the bottomhole pressure. - View Dependent Claims (41, 42, 43, 44, 45, 46, 47, 48)
- the return fluid”
-
49. A wellbore system for controlling bottomhole pressure comprising:
-
(a) a drill string having a bottomhole assembly at an end thereof in the wellbore;
(b) a fluid system supplying fluid under pressure to the wellbore, said fluid returning via a return path carrying cuttings (“
the return fluid”
);
(c) a sensor for measuring a selected parameter of interest;
(d) a pump positioned in the return fluid, the pump operating during drilling of the wellbore; and
(e) a controller controlling the pumb during drilling of the wellbore in response to the selected parameter to control the bottomhole pressure. - View Dependent Claims (50, 51, 52, 53, 54, 55)
-
-
56. A method of controlling bottomhole pressure during drilling of a wellbore with a drill string having a bottomhole assembly at an end of a tubing and wherein a drilling fluid supplied under pressure during drilling to the tubing returns to the surface (“
- the return fluid”
), said method comprising;(a) providing a pump in the return fluid;
(b) selecting a desired bottomhole pressure;
(c) determining a selected parameter of interest; and
(d) controlling the flow rate of the pump in the return fluid in response to the determined parameter to control the bottomhole pressure at the desired pressure. - View Dependent Claims (57, 58, 59, 60, 61, 62, 63, 64)
- the return fluid”
-
65. A wellbore system for controlling bottomhole pressure comprising:
-
(a) a drill string having a bottomhole assembly at an end thereof in the wellbore;
(b) a fluid system supplying fluid under pressure to the tubing, said fluid returning to the surface carrying cuttings (“
the return fluid”
);
(c) a sensor for measuring a selected parameter of interest;
(d) a pump associated with the return fluid; and
(e) a controller controlling the flow rate of the pump in response to the selected parameter to control the bottomhole pressure at a desired value. - View Dependent Claims (66, 67, 68, 69, 70, 71, 72)
-
Specification