GB2032489A - Creation of Inventions and Patents with Artificial Intelligence

GB2032489A – Blow Out Arrestor
– Google Patents

GB2032489A – Blow Out Arrestor
– Google Patents
Blow Out Arrestor

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Publication number
GB2032489A

GB2032489A
GB7834281A
GB7834281A
GB2032489A
GB 2032489 A
GB2032489 A
GB 2032489A
GB 7834281 A
GB7834281 A
GB 7834281A
GB 7834281 A
GB7834281 A
GB 7834281A
GB 2032489 A
GB2032489 A
GB 2032489A
Authority
GB
United Kingdom
Prior art keywords
slides
arrestor
drill
drill shaft
blowout
Prior art date
1978-08-23
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)

Withdrawn

Application number
GB7834281A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)

Durham Drilling & Eng Co Ltd

Original Assignee
Durham Drilling & Eng Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
1978-08-23
Filing date
1978-08-23
Publication date
1980-05-08

1978-08-23
Application filed by Durham Drilling & Eng Co Ltd
filed
Critical
Durham Drilling & Eng Co Ltd

1978-08-23
Priority to GB7834281A
priority
Critical
patent/GB2032489A/en

1980-05-08
Publication of GB2032489A
publication
Critical
patent/GB2032489A/en

Status
Withdrawn
legal-status
Critical
Current

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Classifications

E—FIXED CONSTRUCTIONS

E21—EARTH DRILLING; MINING

E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS

E21B33/00—Sealing or packing boreholes or wells

E21B33/02—Surface sealing or packing

E21B33/03—Well heads; Setting-up thereof

E21B33/06—Blow-out preventers, i.e. apparatus closing around a drill pipe, e.g. annular blow-out preventers

E21B33/061—Ram-type blow-out preventers, e.g. with pivoting rams

E21B33/062—Ram-type blow-out preventers, e.g. with pivoting rams with sliding rams

Abstract

A blow out arrestor, of limited axial extent comprises a box-shaped casing with a passage therethrough for drill tubing 29, and slides 27, 28 in the box movable perpendicularly to seal the drill shaft, the slides being actuated by remotely controlled rams 32, 32a. The slides are faced with neoprene to give a gas tight compression seal when the slides are forced together about the drill tubing 29. The casing may have water inlets so that debris can be flushed out before operation of the slides.

Description

SPECIFICATION
Improved Drilling Rig Blowout Arrestor
This invention relates to a blowout arrestor for use with drilling rigs. In the course of exploratory drilling for surveying geological strata, and proving suspected oil or gas fields, it is possible for a drill to release gas (or oil) under pressure, up through the bore hole, when the drill penetrates domed impervious strata.
Such a release is known as a “blow out” in the case of gas, and the gas is frequently ignited leading to an explosion followed by a fire, in which an entire drilling rig, valued at 50,000- 100,000 can be lost or severely damaged, quite apart from the risk to the operating crew.
It is known to employ blowout arrestors for the purpose of checking blowouts before a large volume of gas can escape and present a major hazard. However existing designs of arrestor are over one metre in length. The blowout arrestor is usually fitted on the head of a bore liner, and below a drilling platform used for connecting up drill sections.
In the case of mobile rigs designed to be transported by a lorry-sized vehicle, within the limits imposed by vehicle tonnage regulations, however, the drilling platform is effectively the loading platform of the vehicle, and there is insufficient space between the underside of the loading piafform und the head of the bore liner, for insertion of such a known blowout arrestor, as the clearance is usually from 50 to 60 mm between the head and the platform; clearly this is insufficient for insertion of a part at least twice as high as the clearance.
It is therefore an object of this invention to provide a blowout arrestor which can be provided in dimentions enabling it to be used with a vehicle mounted transportable rig.
In accordance with the invention, a blow out arrestor comprises a casing for fitting around a drill shaft and on top of a bore liner, and defining a passage surrounding the drill shaft, the arrestor having slides with pressure tight seals, movable into sealing engagement with the drill shaft in a plane perpendicular to the axis of the drill shaft.
Since the sealing-off of the space around the drill shaft is effected by horizontal movement of slides, the casing need only be large enough for a robust construction capable of mechanically withstanding the pressures involved and together with connecting flanges, the arrestor can have dimensions axially of the drill shaft from 30 to 40 mm i.e. sufficiently compact to be locatable below a vehicle chassis.
The slides are preferrably actuated by hydraulic rams controlled from a remote (e.g.
more than 1 5 metres removed) control location.
Sealing within the casing and around the surfaces of the slide may be affected by way of neoprene seats, dimensioned so that the seals are compressed when closed.
Preferrably, means are provided for flushing debris from the bore out of the space between the slides, as the slides close. This may be ettectea Dy water inlets directed into the space entering from the casing sides between the slides.
A preferred embodiment of the invention will now be described with reference to the accompanying drawings wherein: Fig. 1 is a perspective view of the blowout arrestor.
Fig. 2 is a vertical sectional view on line Il-Il of Fig. 1.
Fig. 3 is a horizontal sectional view on line 111- 111 of Fig. 2 and Fig. 4 is a fragmentary enlargement of part of
Fig. 3.
Referring to the drawings, a blowout arrestor according to the invention comprises a casing made up of top and bottom plates 11 and 12, side plates 13 and 14, and end plates 15 and 16, secured by nut and bolt assembles such as 18 to form a substantially sealed box.
Top plate 11, and bottom plate 1 2 each respectively carry a union 1 9, 20 consisting of a tubular part 21,22 and a securing flange 23,24 respectively. As shown in Fig. 1 the flange 24 of union 20 on the bottom plate 12 is secured to a flange of a bore liner pipe 25, by nuts and bolts. In
Fig. 2 the flange 23 of union 1 9 is additionally shown thus secured to a flange of a continuation pipe 26 which is continuous to the drilling platform (not shown).
The casing encloses a space in which is contained a pair of opposed slides 27, 28 mounted on opposite sides of a region aligned with the unions 19, 20 and through which a tubular drill section 29 extends axially. Each slide 27, 28 is carried by a piston 30, 31 of a respective ram 32, 32a operable by fluid connectors 33, 34 and 35, 36. The opposed faces of the slides 27, 28 each have a semi-cylindrical recess 37, 38 of a diameter such as to accommodate the drill section 29, and the faces are covered with a layer 39, 40 of resilient neoprene, of dimensions such as to form a tight seal when the slides are forced together, between the neoprene covered faces of the slides 27, 28 and with the drill section 29. This is achieved by making the neoprene parts 39, 40 marginally oversized.
As is best seen in Fig. 3 the space between the slides 27, 28 when they are retracted is of a rectangular shape, with corners within which debris can coliect. Following usual drilling practice, liquid mud is pumped down the interior of drill 29, to act as a coolant and remove debris from the drill bit. The return stream rises outside the drill tube 29, in the direction of arrows A, and such mud with any rock debris can accumulate on the corner ledges of the space.
However, for the slides 27, 28 to be able to close, any such debris must be removed, and this is carried out by injecting a stream of water at each side of the casing through respective pipes 41,42. The water is sprayed as effectively as possible using nozzles 43, 44 in the side plates 13, 14 which have a plurality of passages directed to each side, and in line with the axis of the nozzle. These jets may be operated continuously or only immediately prior to operation of the slides 27, 28.
The fluid connections 33, 34, 35 and 36 are connected to a control valve which is located at a distance of at least 1 5 metres from the bore, and may be operated manually. When an imminent blowout is detected e.g. by a surge in the returning mud, the arrestor can be manually operated. The distance of 1 5 metres is required to ensure that the arrestor can be operated in reasonable safety when a blowout has already occurred and an explosion or fire is likely or has started.
When a blowout is imminent, or has in fact occurred, the control valve is operated to close the slides 27, 28 at the same time the water through nozzles 43, 44 being set to flush out the ledges.
The rams 32, 32a then force the slides together, effecting a firm seal with each other and the tube 29, by reason of the oversized neoprene facings 39, 40. As shown in Fig. 4 the sealing around pipe 29 is enhanced by provision of a corner part 42 on each cusp of each facing 39, 40 at the corners of the recesses 37, 38 which
provides a protruding sealing lip.
At the same time additional valves at the head
of the drill tube (usually at the rig top) may be
operated to seal off this further escape route for
gas.
It will be appreciated that because the slides 27, 28 and their rams 32, 32a are operated in a plane perpendicular to the drill shaft, it is possible to reduce the height or axial extent of the blowout arrestor to a minimum compatible with robustness of contraction, and thus provide an arrestor suitable for use with mobile, vehicle carried transportable light rigs which cannot use the known arrestors with their excessive height.

Claims (5)

Claims

1. A blowout arrestor comprising a sealed casing for location near the top of a drill shaft, defining a passage surrounding the drill shaft, the arrestor having slides with pressure tight seals movable into sealing engagement with the drill shaft in a plane perpendicular to the axis of the drill shaft.

2. An arrestor according to Claim 1, wherein the slides are actuated by hydraulic rams controlled remotely.

3. An arrestor according to Claim 1 or 2 wherein water inlets are provided to enable jets of water to be deployed to flush debris from the interior of the casing so that such debris does not interfere with the operation of the slides.

4. An arrestor according to any preceding claim wherein the contacting surfaces of the slides are faced with neoprene which is dimensioned to be comprsssed when the slides are closed.

5. A blowout arrestor, substantially as hereinbefore described, with reference to and as illustrated in the accompanying drawings.

GB7834281A
1978-08-23
1978-08-23
Blow Out Arrestor

Withdrawn

GB2032489A
(en)

Priority Applications (1)

Application Number
Priority Date
Filing Date
Title

GB7834281A

GB2032489A
(en)

1978-08-23
1978-08-23
Blow Out Arrestor

Applications Claiming Priority (1)

Application Number
Priority Date
Filing Date
Title

GB7834281A

GB2032489A
(en)

1978-08-23
1978-08-23
Blow Out Arrestor

Publications (1)

Publication Number
Publication Date

GB2032489A
true

GB2032489A
(en)

1980-05-08

Family
ID=10499222
Family Applications (1)

Application Number
Title
Priority Date
Filing Date

GB7834281A
Withdrawn

GB2032489A
(en)

1978-08-23
1978-08-23
Blow Out Arrestor

Country Status (1)

Country
Link

GB
(1)

GB2032489A
(en)

1978

1978-08-23
GB
GB7834281A
patent/GB2032489A/en
not_active
Withdrawn

Contact information