CA2508625A1

CA2508625A1 - Rotating flow diverter

Info

Publication number: CA2508625A1
Application number: CA002508625A
Authority: CA
Inventors: Jed M. Wood
Original assignee: HIGH ARCTIC ENERGY SERVICES Inc
Current assignee: HIGH ARCTIC ENERGY SERVICES IN
Priority date: 2005-05-30
Filing date: 2005-05-30
Publication date: 2006-11-30

Description

1 "ROTATING FLOW DIVERTER"

2

3 FIELD OF THE INVENTION

4 Embodiments of the invention relate to wellhead apparatus for well control and more particularly to apparatus used to control and divert 6 wellbore fluids, produced gas and solids during drilling and other operations.

9 In the oil and gas industry it is conventional to mount a rotating blowout preventer or rotating flow diverter at the top of a blowout preventer 11 (BOP) stack. The rotating flow diverter serves multiple purposes including 12 sealing off the Kelly and diverting fluids such as drilling mud into a 13 recirculating mud line.
14 Conventionally, at least one stripper element or seal, typically manufactured from an elastomeric, acts to seal around the Kelly and is 16 rotatable therewith inside a stationary housing. A bearing assembly is 17 supported in the stationary housing upon which the stripper element rotates. A
18 clamp secures the bearing assembly inside the housing and provides access 19 to the bearing assembly.
As disclosed in US patent 5,662,181 to Williams et al. and US
21 patnet 6,244,359 to Bridges et al. a variety of means are provide to lubricate 22 the bearing assembly. Conventionally, most lubrication means require that a 23 lubricant be injected or pumped into an annulus which houses the bearings to 24 lubricate and cool the bearings. Such lubrication means may require elaborate hydraulic mechanisms and seal arrangements to ensure adequate lubrication.

1 There is a need for a system of lubrication of the bearing 2 assembly which is simple and effective to prevent premature wear and failure 3 of the bearings.

BRIEF DESCRIPTION OF THE DRAWINGS
6 Figure 1 is a side view of a rotating flow diverter according to 7 one embodiment of the invention, an external clamp providing access to a 8 bearing assembly and being shown in one position;
9 Figure 2 is a longitudinal sectional view according to Fig. 1 and illustrating a sealed bearing assembly between a rotatable stripper element 11 and a stationary housing;
12 Figure 3 is a schematic of a kelly of a drilling or workover rig 13 engaged in an sealing element in an embodiment of a rotating flow diverter of 14 Fig. 1, the kelly being sealed by the sealing element, a stationary housing and bearing assembly being removed for illustrative purposes only;
16 Figure 4 is a schematic illustrating an embodiment of the 17 rotating flow diverter of Fig. 1, installed at a top of a blowout preventer (BOP) 18 stack below a drilling or snubbing rig;
19 Figure 5 is a schematic illustrating one embodiment of a fluid connection to the rotating flow diverter of Fig. 1;
21 Figure 6 is a schematic of an alternate embodiment of a fluid 22 connection between the rotating flow diverter of Fig. 1 and the wellhead;
and 23 Figure 7 is a schematic of an alternative embodiment of a fluid 24 connection between the rotating flow diverter of Fig 1 and a BOP stack in a drilling or snubbing rig.

2 As shown in Figs 1 and 2, a rotating flow diverter 1 comprises a 3 stationary housing 2, a sealing element 3 for forming a positive seal against a 4 tubing string such as about a kelly and a bearing assembly 4 comprising upper and lower sealed bearings 5,6. The stationary housing 2 comprises a 6 lower body portion 7 and an upper body portion 8, the sealed bearing 7 assembly 4 being housed in the upper body portion 8. A releasable clamp 9 is 8 provided for retaining the sealed bearing assembly 4 and upper body portion 9 8 to the lower body portion 7. A seal 10 is provided between the upper and lower body portions 7,8 for sealing therebetween.
11 A fluid port 11 is provided in the lower body portion 7 for 12 permitting fluids to be diverted from the wellbore (not shown) such as to a 13 recirculating drilling mud line or the like.
14 As shown in Figs 2 and 3, the sealing element 3 comprises a stripper element 12 and an energized lip seal 13 for sealing about a kelly 14 16 which passes therethrough.
17 Best seen in Fig. 4, 6 and 7, the stationary housing 2 is flanged 18 15 at a lower end 13 of the lower body portion 7 for connection to a top 14 of 19 a blowout preventer stack 16 below a rig floor 17.
Having reference again to Fig. 2, the upper and lower sealed 21 bearings 5,6 support the stripper element 12 for rotation within the stationary 22 housing 2. Unlike conventional open bearings which require complex fluidics 23 to ensure adequate lubrication during operation, the sealed bearings 5,6 of 24 the embodiments of the invention are preferably taper bearings 20 sealed 1 within a bearing race 21 and which are pre-lubricated within the race 21 2 requiring no additional lubrication for rotation or for cooling during operation.
3 The releaseable clamp 9, comprises a clamp body 30 which 4 encircles the stationary housing 2 adjacent a sealed intersection 31 of the upper and lower body portions 7,8. The clamp 9 further comprises a fastener 6 32 which can be released to remove the clamp body 30 to gain access to the 7 sealed bearings 5,6 for servicing and replacement.
8 The clamp fastener 32 can be positioned anywhere about the 9 circumference of the stationary housing and may be preferably positioned at least 90° (not shown) from the port 11 to permit easier connection of 11 apparatus A (Figs 5-7) to the port 11 and access to the bearing assembly 4 12 when the rotating flow diverter 1 is connected to other apparatus at the port 13 11.
14 In a preferred embodiment of the invention, the rotating flow diverter 1 is capable of drilling or stripping a tubing string with up to 3000 psi 16 well bore pressure and dynamic stripping and rotating pressures of about 17 1500 psi at a maximum of about 140 revolutions per minute (rpm)