# US 10,370,914 B2 · Choke and kill system

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- Number: US 10,370,914 B2
- Document ID: US10370914B2
- Status: Granted
- Kind: B2
- Application number: 15/712,766
- Filed: 2017-09-22
- Published: 2018-01-11
- Granted: 2019-08-06
- Earliest claimed: 2015-05-01
- Assignees: Kinetic Pressure Control Ltd.
- Applicants: Kinetic Pressure Control, Ltd.
- Inventors: Steven Anthony Angstmann; Bobby James Gallagher
- Web page: https://patentgrep.com/patent/US10370914B2

## CPC

- E21B 21/08: Controlling or monitoring pressure or flow of drilling fluid, e.g. automatic filling of boreholes, automatic control of bottom pressure (valve arrangements therefor E21B21/10)
- E21B 33/0355: {Control systems, e.g. hydraulic, pneumatic, electric, acoustic, for submerged well heads}
- E21B 33/038: Connectors used on well heads, e.g. for connecting blow-out preventer and riser
- E21B: EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS

## Abstract

A choke and kill system, and a method of adapting a low pressure drilling rig for use in a high pressure application are described. The system has a low pressure stack and a high pressure blowout preventer stack fluidly connected to the low pressure stack. A choke is fluidly connected to a low pressure choke line of the low pressure stack and is connected to a high pressure choke line of the high pressure blowout preventer stack. The choke is adapted to reduce the pressure from the high pressure choke line to the low pressure choke line.

## Claims

### Claim 1

A choke and kill system for a deep water drilling rig, the choke and kill system comprising:
a low pressure stack of the deep water drilling rig, the low pressure stack comprising pipe rams;
a high pressure blowout preventer stack of the deep water drilling rig fluidly connected to the low pressure stack, the high pressure blowout preventer stack connected to a wellhead, the high pressure blowout preventer stack comprising components rated to a higher pressure than components of the low pressure stack;
a choke fluidly connected to a low pressure choke line of the low pressure stack, the low pressure choke line connected to the low pressure stack below the pipe rams, the choke fluidly connected to a high pressure choke line of the high pressure blowout preventer stack, the high pressure choke line connected below the high pressure blowout preventer stack and above the wellhead, the high pressure choke line rated to a higher pressure than the low pressure choke line, the choke adapted to reduce the pressure from the high pressure choke line to the low pressure choke line.

### Claim 2 (depends on 1)

The choke and kill system of claim 1 , further comprising a high pressure kill line fluidly connected to the high pressure blow out preventer stack.

### Claim 3 (depends on 2)

The choke and kill system of claim 2, wherein the high pressure kill line is adapted to convey drilling fluid to the high pressure blow out preventer stack.

### Claim 4 (depends on 3)

The choke and kill system of claim 3, wherein the high pressure kill line extends to a surface vessel, the surface vessel comprising a pump adapted to supply drilling fluid to the high pressure kill line.

### Claim 5 (depends on 2)

The choke and kill system of claim 2, further comprising a subsea pump that is adapted to pump drilling fluid into the high pressure kill line.

### Claim 6 (depends on 5)

The choke and kill system of claim 5, wherein the subsea pump is adapted to receive drilling fluid from a low pressure kill line of the drilling riser.

### Claim 7 (depends on 6)

The choke and kill system of claim 6, wherein the subsea pump increases the pressure of the drilling fluid from the low pressure kill line to the high pressure kill line.

### Claim 8 (depends on 5)

The choke and kill system of claim 5, wherein the subsea pump is adapted to receive drilling fluid from a low pressure auxiliary line of the drilling riser.

### Claim 9 (depends on 8)

The choke and kill system of claim 8, wherein the subsea pump increases the pressure of the drilling fluid from the low pressure auxiliary line to the high pressure kill line.

### Claim 10 (depends on 5)

The choke and kill system of any one of claim 5, wherein the subsea pump is driven hydraulically.

### Claim 11 (depends on 10)

The choke and kill system of claim 10, wherein the subsea pump is driven by at least one radial hydraulic piston motor.

### Claim 12 (depends on 10)

The choke and kill system of claim 10, wherein hydraulic fluid to drive the subsea pump is supplied by a riser auxiliary line of the drilling riser.

### Claim 13 (depends on 12)

The choke and kill system of claim 12, wherein the hydraulic fluid is seawater.

### Claim 14 (depends on 12)

The choke and kill system of claim 12, wherein once the hydraulic fluid has been used to drive the subsea pump, the hydraulic fluid is discharged to the sea.

### Claim 15 (depends on 5)

The choke and kill system of claim 5, wherein the subsea pump comprises ceramic bearings.

### Claim 16 (depends on 5)

The choke and kill system of claim 5, wherein the subsea pump uses seawater for lubrication.

### Claim 17 (depends on 15)

The choke and kill system of claim 15, wherein the subsea pump is located at or near the high pressure blow out preventer stack.

### Claim 18 (depends on 17)

The choke and kill system of claim 17, wherein the subsea pump is mounted to the high pressure blow out preventer stack.

### Claim 19 (depends on 1)

The choke and kill system of claim 1, wherein the choke uses a control system from the low pressure stack.

### Claim 20 (depends on 19)

The choke and kill system of claim 19, wherein the control system is a hydraulic control system.

### Claim 21 (depends on 19)

The choke and kill system of claim 19, wherein the choke is adapted to utilise a multiplexer control system from the low pressure stack.

### Claim 22 (depends on 1)

The choke and kill system of claim 1, wherein the choke is located proximate the high pressure blow out preventer stack.

### Claim 23 (depends on 22)

The choke and kill system of claim 22, wherein the choke is mounted to the high pressure blow out preventer stack.

### Claim 24 (depends on 1)

The choke and kill system of claim 1, further comprising a plurality of chokes.

### Claim 25 (depends on 24)

The choke and kill system of claim 24, wherein the plurality of chokes is located in a single body.

### Claim 26 (depends on 1)

The choke and kill system of claim 1, wherein the low pressure stack includes at least one low pressure blowout preventer.

### Claim 27 (depends on 1)

The choke and kill system of claim 1, wherein the high pressure blow out preventer stack comprises a plurality of high pressure blowout preventers.

### Claim 28 (depends on 27)

The choke and kill system of claim 27, wherein the high pressure blowout preventer stack comprises a wellhead connector to connect to a well.

### Claim 29 (depends on 1)

The choke and kill system of claim 1, wherein the high pressure blowout preventer stack comprises a mandrel located toward an upper end of the high pressure blowout preventer stack to which the low pressure stack connects.

### Claim 30 (depends on 1)

The choke and kill system of claim 1, further comprising at least one of pressure and temperature sensors to adjust the choke.

### Claim 31 (depends on 1)

The choke and kill system of claim 1, wherein the low pressure stack is rated at at most 15,000 pounds per square inch and the high pressure stack is rated at at least 25,000 pounds per square inch.

### Claim 32

A method for adapting a low pressure drilling rig for use in a high pressure application, the method comprising:
connecting a high pressure blowout preventer stack to a low pressure stack of the low pressure drilling rig, the high pressure blowout preventer stack connected to a wellhead and rated to a higher pressure than the low pressure stack;
fluidly connecting a choke to a low pressure choke line of the low pressure stack; and
fluidly connecting the choke to a high pressure choke line of the high pressure blowout preventer stack, the high pressure choke line connected below the high pressure blowout preventer stack and above a wellhead, the high pressure choke line rated to a higher pressure than the low pressure choke line, wherein the choke is adapted to reduce the pressure from the high pressure choke line to the low pressure choke line.

### Claim 33 (depends on 32)

The method of claim 32, further comprising of fluidly connecting a high pressure kill line to the high pressure blowout preventer stack.

### Claim 34 (depends on 33)

The method of claim 33, wherein the fluidly connecting the high pressure kill line to the high pressure blowout preventer stack includes fluidly connecting a low pressure kill line of the low pressure stack to a subsea pump and fluidly connecting the subsea pump to the high pressure kill line such that the subsea pump can pump fluid from the low pressure kill line to the high pressure kill line, increasing the pressure of the fluid from the low pressure kill line to the high pressure kill line.