Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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Transportation system for a sub-surface activity area
The present invention relates to a transportation system for evacuating
personnel
from an area of activity under a surface, comprising an ordinary transport
access
passage in addition to a separate evacuation access passage with a transport
conveyance which is dedicated to use in the event of an evacuation situation.
At present either floating or fixed installations are employed in connection
with
recovery of oil and gas at sea. Fixed installations comprise both platforms
located
on the seabed and pure seabed installations. One of the problems associated
with
recovery of oil on the Norwegian shelf on which there has been a great deal of
focus
is the risk of accidental spillage of oil, with associated pollution of the
environment.
This has been the dominant problem with regard to recovery plans in coastal
areas,
i.e. areas coinciding with or with a short drift time from areas of great
environmental value or which are important for coastal-based fishing.
In the recovery of oil in northern waters, this problem becomes even more
relevant
on account of lower temperatures and greater risk of icing amongst other
things, and
the resultant restrictions with regard to collection of oil before it reaches
land. At
the same time the environment is more vulnerable. This places greater demands
on
safety margins, and thereby an increase in recovery costs. The result is a
general
scepticism to oil recovery in the northern waters since an accident leading to
spillage, even though the chance of this happening is statistically very low,
can
entail such serious consequences for the environment. Similar evaluations also
apply in some areas off the coast of Southern and Central Norway.
An alternative to conventional floating or fixed drilling rigs could be, for
example,
to locate drilling equipment in a cavern under the surface separated from the
ocean
or the sea, and use tunnels dug in under the ocean or the sea to the cavern
where oil
and gas can be recovered. Examples of such solutions are described in the
American
patent publications US 2 331 072, US 2 989 294, US 3 486 571 and US 4 463 987.
In the last publication, US 4 463 987, a system is described for subsea
recovery of
hydrocarbons where tunnels are dug down to an underground space where the
recovery is carried out. In addition, the system comprises one or more spaces
where
hydrocarbons can be conveyed and temporarily stored in the event of an
accident.
There is also a tunnel in which personnel can escape in the event of accidents
by
walking or running. In this publication there is no indication of transport of
personnel who have to be evacuated or any transportation system for such
transport.
Since this is not a theme of the publication, it has to be assumed that the
intricate
system of tunnels of which the invention consists relates to production of
hydrocarbons from chambers located at a relatively short distance from the
surface
of the ground so that the personnel can get out by themselves.
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In connection with road tunnels, from the three German patent applications DE
102
49 252 Al, DE 102 49 267 and DE 102 49 268 it is known to provide an escape
route beside the roadway, thus enabling people to walk or run out if fire
should
break out in the tunnel. As in the case of the American publication above, the
escape routes mentioned in these publications are intended for people on foot.
There
is no mention in the documents of the possibility of providing a separate
evacuation
system with stations for boarding special, dedicated transport conveyances
located
at the stations.
In the German patent application DE 21 27 156 a closed concrete bridge is
disclosed
which in some embodiments is designed with several levels for separating
different
kinds of traffic from one another, i.e. pedestrians, cars, lorries and trains
have
different passages in the bridge. This publication in no way relates to
evacuation of
a large number of people in the event of a serious accident, such as for
example a
blow-out from an oil or gas well.
By locating the actual recovery of oil/gas in cavities under the seabed with a
supply
tunnel from land, the present invention will be able to be utilised and
possibly make
it more acceptable to start operation of the field.
Where there is a wish to develop an oil/gas field by tunnelling through to a
cavern
in an area from which oil and/or gas are recovered in the conventional manner,
it
will be necessary to work out acceptable solutions with regard to safety and
evacuation facilities for personnel in the event of an accident. An evacuation
tunnel
could be so long that it will not be practical for personnel working inside
the tunnel
to run or walk out of it. In the cases that are visualised, an operational
area of this
kind for recovery of oil/gas may be located at anything from a relatively
short
distance up to 60-70 km from a tunnel entrance.
Thus it is an object to provide a transportation system for use in production
of
oil/gas reservoirs from an underground cavity, which may be located under a
body
of water, where the safety of both personnel and environment are safeguarded.
It is a particular object of the present invention to provide a system for
rapid and
safe evacuation of personnel from an area of activity under a surface where
there is
a risk of accidents which will require a speedy evacuation of personnel from
the
said area of activity.
This is solved according to the invention as it is defined in the independent
claim.
Preferred embodiments of the invention are described in the following claims.
The present invention comprises an area of activity located under a surface,
where
activities are carried out that entail a risk of accidents which make it
necessary to
evacuate personnel working there. The activity taking place in the area of
activity
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may be recovery of hydrocarbons, i.e. oil and/or gas. It is also possible to
envisage
that such areas of activity may include other activities such as, for example,
more
general mining operations or as a depot for explosive and/or inflammable
materials
or chemical substances and possibly also radioactive materials.
In most cases, the surface under which the area of activity lies will be a
sea/ocean
bed or a land surface, but it is also conceivable for the surface to be a
water surface
and that the area of activity is then located in an isolated position in the
sea or is
placed in an isolated position on the sea/ocean bed. Where the area of
activity is
located in the sea, a structure can be built round it to keep the surrounding
water
out, and similarly the area of activity can be covered by a structure if it is
located on
the sea/ocean bed.
The area of activity will have at least one transport access passage for
transport of
personnel, goods etc. to and from the area of activity during ordinary
operation. The
transport access passage may be an ordinary tunnel extending from a point on
shore,
i.e. on an island or on the mainland through solid rock/soil to the area of
activity.
The whole or parts of the transport access passage may also be envisaged in
the
form of a sunken tunnel or a floating tunnel passing through the water. If
several
separate accesses are made to the area of activity, the different accesses may
be
designed in different ways, for example a first access may be in the form of
an
ordinary tunnel through solid rock, while a second access may be designed with
the
whole or parts of the access as a sunken tunnel.
For evacuating personnel in connection with an accident in the area of
activity,
according to the invention the transportation system comprises at least one
separate
evacuation access passage. In order to ensure that an escape route is always
ready
for immediate evacuation, the evacuation access passage is dedicated to this
purpose, and is therefore not meant to be used for transport in connection
with
ordinary operation in the area of activity.
The evacuation access passage and the transport access passage will normally
be
placed in the same bore in a common tunnel, but it is also conceivable for the
evacuation access passage and the transport access passage, wholly or partly,
to
follow different passages to the area of activity.
According to the invention, the transportation system also comprises at least
one
unit of a dedicated transport conveyance which is stationed in the evacuation
access
passage for evacuation of personnel. This transport conveyance will preferably
be a
vehicle on rails, but may also be a vehicle which does not run on rails.
In connection with the area of activity, the invention further comprises at
least one
boarding station for boarding the transport conveyance which is dedicated to
use
during evacuation. During normal operation, at least one unit of this
transport
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conveyance will always be stationed at the boarding station(s) ready for use
in the
event of an accident. The boarding station(s) is separated from the area of
activity
by means of a structure designed to withstand fire and explosions, which may
be
expected to occur in the event of an accident in the area of activity, for
long enough
to enable all personnel to be evacuated from the area. It is also possible to
place the
boarding station(s) in a separate area relatively close to, but separated from
the area
of activity by solid rock/soil with a thickness which is sufficient to
withstand the
stress of fire and explosions in the event of an accident, at least for long
enough to
enable all personnel to be evacuated. It is also possible to place the
boarding
station(s) in a separate area separated from the area of activity by solid
rock as
mentioned above combined with a fire and explosion-proof structure.
In order to reduce the chance of any dangerous gases infiltrating the
evacuation
access passage and the boarding stations in the event of an accident, the air
pressure
in the boarding station(s) and possibly in the evacuation access passage may
be
made at least as great as and preferably slightly greater than the ambient
pressure in
the area of activity and the transport access passage. Inside the transport
conveyance the pressure will be at least as great as in the boarding station,
and in
order to further increase the protection against infiltration of undesirable
gases, it
may be higher than the pressure in the boarding station. In addition, each
boarding
station has at least one access from the area of activity or the transport
access
passage which is fluid-tight when it is closed.
Where the transport access passage and the evacuation access passage are
provided
in the same bore, they are separated by a solid structure which can withstand
fire
and explosions, particularly near the area of activity where the chance of
serious
accidents is greatest, but also through the whole transport and evacuation
access
passage if the products produced in the area of activity are inflammable and
explosive and are sent out through the transport access passage. If
hydrocarbons are
involved, they will be able to be transported through one or more pipelines or
by
means of tankers, and possibly by means of both pipeline(s) and tankers. The
evacuation access passage and the transport access passage may be envisaged
located side by side in the bore or one above the other, preferably with the
evacuation access passage located below the transport access passage. At all
events
the evacuation access passage and the transport access passage must be
separated by
a solid structure as mentioned above.
The transport tunnel may advantageously be further provided with at least one
means for closing off the transport tunnel completely in connection with an
accident. The means may, for example, be in the form of a door that is rolled
or
pushed in from the side, down from the roof or up from the floor. What is
important
is that this door is solid and can withstand fire and powerful explosions. In
order to
check and/or prevent the spread of fire and undesirable gases in the transport
tunnel,
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it is advantageous to place such means at regular intervals throughout the
transport
tunnel which closes off the part of the transport tunnel where fire and/or
undesirable
gases are detected by means of sensors. Between two such closing-off means,
the
transport tunnel may comprise a fluid-tight access, either directly to the
evacuation
5 access passage, or to a boarding station for the evacuation access passage.
This or
these boarding station(s) may be of the same type as that described above and
may
also possibly comprise a stationed transport conveyance.
The present invention will now be described by means of a preferred, but not
limiting embodiment, where reference is made to the attached drawings, in
which:
Fig. 1 illustrates a map of an area where the use of the present invention may
be
envisaged.
Fig. 2 illustrates a section of a stretch of open sea and the substructure
under the sea
associated with a geographical area where the invention may be used.
Fig. 3 illustrates an area of activity with transport access passage and
evacuation
access passage viewed from the side.
Fig. 4 illustrates a section through a tunnel with the transport access
passage located
above the evacuation access passage in a common bore.
Fig. 5 illustrates a section through a tunnel with the transport access
passage located
beside the evacuation access passage in a common bore.
Fig. 6 illustrates a boarding station with an access and a transport
conveyance for
evacuation.
Fig. 7 illustrates an area of activity with transport access passage and
evacuation
access passage viewed from above.
Fig. 8 illustrates boarding stations in connection with the evacuation access
passage
outside the area of activity.
In figure 1 a map is illustrated of an area where the use of the present
invention may
be envisaged. A point 10, illustrated here located on an island, but which
naturally
may be located on the mainland, may comprise a plant for refining oil/gas. An
oilfield is also illustrated located approximately 60 km out at sea.
In figure 2 a section of the subsurface is illustrated from an area also shown
in
figure 1, where a tunnel 15 is indicated running under the seabed 14 from a
terminal
12 to an area of activity 161ocated in or near an area where there is a
deposit of
oil/gas. The terminal 12 may be a single access to the tunnel 15, but may also
comprise a plant for further refining of the oil/gas produced in and
transported from
the area of activity 16.
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Figure 3 is a schematic view of how the design of an area of activity may be
envisaged. The tunnel 15 from the terminal 12 may comprise one or more
branches
in the area where drilling for oil and/or gas is to take place. At the end of
a branch,
the tunnel 15 may be envisaged extended to an area of activity 16 which is
made
large enough to provide space for necessary production equipment. A drilling
rig 19
is depicted in the figure, but there may well be more than one drilling rig in
each
area of activity. In the figure it is also shown that the tunnel 15 is divided
into a
transport access passage 17 and an evacuation access passage 18. During normal
operation, transport of personnel, equipment etc. will be conducted through
the
transport access passage 17, while the evacuation access passage 18 will only
be
used in situations where an evacuation of personnel is imperative.
Two embodiments of the tunnel 15 are illustrated in figures 4 and 5. In figure
4 we
can see that the tunnel 15 is divided horizontally, with the transport access
passage
171ocated above the evacuation access passage 18. The transport access passage
comprises roadways 25 for vehicles such as cars, trucks and articulated
lorries.
Beside the roadways 25, pipelines 26 may be envisaged for transport of oil
and/or
gas from the area of activity 16. These pipelines may well be separated from
the
transport access passage 17 by a non-illustrated partition device. Just
beneath the
roof of the tunnel 15, ducts/pipes 27 may be placed for cables and the like or
transport of necessary fluids to/from the area of activity 16. Oil/gas
pipelines 26 and
ducts/pipes 27 may, of course be located as appropriate in other positions in
the
transport access passage 17. The evacuation access passage 18 is located under
the
roadway 25 in the transport access passage 17. The two passages are physically
separated by a solid partition structure 24 which is designed to be able to
withstand
fire and explosions in the event of an accident for long enough to give
personnel
located in the area of activity 16 and/or the transport access passage 17 a
reasonable
chance of getting out through the evacuation access passage 18. For example,
the
partition structure 24 may be designed in such a manner that it can withstand
temperatures that can be expected during a fire for one hour, or possibly for
a
longer or shorter period, before it collapses. In the same way it may be
designed in
such a manner that it can withstand explosions of maximum anticipated strength
in
the event of an accident.
In figure 5 a second embodiment is illustrated where the transport access
passage 17
and the evacuation access passage 18 are located side by side, physically
separated
by a solid partition structure 24 which is designed to be able to resist fire
and
explosions in the event of an accident in the same way as described above.
From the
figure it can be seen that the pipelines 26 for transport of oil/gas are
located above
the evacuation access passage 18 and ducts/pipes 27 are placed directly under
the
roof of the tunnel, but the location of the pipeline 26 and the ducts 27 may
of course
be implemented in a different way if so desired. The partition structure 24 is
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designed in the same way as explained above, i.e. it must be designed with a
view to
being able to withstand fire and explosions of anticipated strength for long
enough
to give personnel working in the area of activity and/or stationed in the
tunnel
enough time to get out by means of the evacuation access passage 18.
The evacuation access passage 18 has at least one boarding station 20 located
in or
near the area of activity 16. Figure 6 illustrates an embodiment of a boarding
station
located at the end of an evacuation access passage 18. At the end of the
evacuation
access passage at least one unit of a transport conveyance 21 is stationed
ready for
immediate evacuation if necessary. In the figure a transport conveyance on
rails 21
is shown, but the transport conveyance may also comprise a vehicle that does
not
run on rails. The boarding station is separated from the area of activity by a
partition structure 24 which is designed to withstand fire and explosions of
maximum anticipated strength for long enough to give personnel a reasonable
chance of being evacuated through the evacuation access passage 18. The
evacuation access passage 18 may be provided in a separate tunnel bore at the
area
of activity 16. In this case the partition structure 24 consists of bedrock,
selected in
a thickness that can withstand fire and explosions as indicated above. The
partition
structure 24 may also be constructed inside the area of activity 16,
preferably along
the edge as indicated in figure 7, in which case it may consist of, for
example,
reinforced concrete. The partition structure 24 may also be envisaged
consisting of
a combination of bedrock and a structure composed of, for example, reinforced
concrete. Other constructional materials such as steel will also be possible
and it
will be up to a skilled person to select the most suitable material or
materials. The
boarding station 20 also comprises an access 22 from the area of activity 16.
This
access is kept automatically closed by a mechanism which, for example, may
comprise a spring mechanism. The access 22 also comprises means to ensure that
it
is fluid-tight in a closed state. Inside the boarding station 20, and possibly
the
evacuation access passage 18, the air pressure is slightly higher than the
ambient
pressure in the area of activity 16 in order as far as possible to prevent
gases that
may develop in the event of fire or explosion from infiltrating the boarding
station
and/or the evacuation access passage. The boarding station also comprises an
access
23 for the transport conveyance 21 which is dedicated to evacuation of
personnel.
The air pressure in the transport conveyance 21 should be at least as great as
the
pressure in the boarding station 20, but may well be higher, thereby providing
extra
protection against infiltration of undesirable gases into the transport
conveyance 21
in the event of an accident.
In figure 7 an area of activity 16 is illustrated comprising an evacuation
access
passage 18 divided into two branches 28 at the entrance to the area of
activity 16,
with the result that in connection with this area of activity there are two
boarding
stations 20 for access to the transport conveyance 21 in a branch 28 of the
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evacuation access passage 18. The evacuation access passage may comprise as
many branches 28 as are considered necessary for a given area of activity 16.
Each
branch 28 will normally comprise one boarding station 20 with an associated
transport conveyance 21 in order to avoid "traffic problems" in the event of
evacuation. Where two branches 28 meet in a branch intersection 29, the
traffic of
transport conveyances 21 may be controlled by means of, for example, traffic
lights
that are controlled automatically by a system of sensors which detect arriving
transport conveyances 21. If the transport conveyance 21 is driverless, it may
advantageously be guided automatically through the branch intersection 29 as
explained below.
The evacuation access passage 18 may also comprise one or more boarding
stations
between the area of activity 16 and the terminal 12. In figure 8 an example is
illustrated where the evacuation access passage 18 comprises two branches 28
where each of the branches has a boarding station 20. The boarding stations
may
15 advantageously be designed in the same way in or beside an area of activity
16 as
described above. At each boarding station 20 a dedicated transport conveyance
21 is
standing ready for use in case an accident happens. The number of boarding
stations
in the tunnel 15 may be anything from zero to as many as are considered
necessary
in order to evacuate all the personnel in a secure manner.
20 The transport conveyance 21 may be designed in such a manner that it is
fluid-tight
against the environment when the access 23 to the transport conveyance is
closed,
thereby preventing any undesired gas that has leaked into the evacuation
tunnel
from infiltrating the transport conveyance 21. Furthermore, the transport
conveyance 21 may advantageously be driverless. In this case the transport
conveyance will be provided with means for starting it. This means may
naturally
be used for starting the transport conveyance on several occasions during the
journey through the evacuation tunnel if this should be necessary. The
transport
conveyance 21 also comprises an automatic control system which is capable of
guiding several transport conveyances 21 through the branch intersections 29,
for
example, according to a system where the transport conveyances are let through
a
branch intersection in the order of their arrival. Transport conveyances from
one or
more branches 28 may be given priority in a desired order. The transport
conveyances 21 also include brakes which are controlled automatically by the
same
control system. The system receives signals from sensors at the branch
intersections
together with one or more sensors which record whether another transport
conveyance 21 or other objects are located in front on the railway or roadway
in the
evacuation tunnel. On the basis of the data received from the sensors, any
braking
of the transport conveyance 21 that is required can be calculated and
implemented.
The transport conveyance 21 may of course also be arranged so that it is
operated
manually by a person. As explained above, the branch intersections 29 can then
be
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provided with traffic lights which detect arriving units of the transport
conveyance
21 and give them the green light, possibly in order of priority.
