U.S. patent application number 10/491866 was filed with the patent office on 2004-12-02 for early hydrocarbon production system.
Invention is credited to Appleford, David Eric, Lane, Brian William.
Application Number | 20040238176 10/491866 |
Document ID | / |
Family ID | 9923771 |
Filed Date | 2004-12-02 |
United States Patent
Application |
20040238176 |
Kind Code |
A1 |
Appleford, David Eric ; et
al. |
December 2, 2004 |
Early hydrocarbon production system
Abstract
A subsea hydrocarbon reserve is exploited by intially drilling a
first well (4) from a floating drilling vessel (2). A tree (8) is
then installed on the well (4) and a production riser (10) is
established between the well and the vessel for transferring
production fluid from the first well (4) to the vessel (2) from
where an off-loading hose (12) conveys the production fluid to a
tanker (18). Production fluid is then extracted from the first well
(4) via the production riser (10) which is of sufficient
flexibility and length to permit the drilling vessel (2) to move
between appropriate locations to drill further wells (4', 20).
Inventors: |
Appleford, David Eric;
(Epping, GB) ; Lane, Brian William; (Essex,
GB) |
Correspondence
Address: |
Summa & Allan
11610 North Community House Road
Suite 200
Charlotte
NC
28277
US
|
Family ID: |
9923771 |
Appl. No.: |
10/491866 |
Filed: |
April 7, 2004 |
PCT Filed: |
October 11, 2002 |
PCT NO: |
PCT/GB02/04624 |
Current U.S.
Class: |
166/353 |
Current CPC
Class: |
B63B 27/34 20130101;
E21B 7/128 20130101; E21B 43/01 20130101; B63B 22/021 20130101 |
Class at
Publication: |
166/353 |
International
Class: |
E21B 007/12 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 12, 2001 |
GB |
0124610.7 |
Claims
1. A method of exploiting a subsea hydrocarbon reserve, comprising
the steps of drilling a first well (4) from a floating drilling
vessel (2), establishing a production riser (10) for transferring
production fluid from the first well (4) to the drilling vessel or
production fluid reception means (18) closely associated with the
vessel, and extracting production fluid from the first well (4)
while drilling one or more further wells (20) from the drilling
vessel (2), and characterised by the steps of: (i) processing the
production fluid with processing means (24) installed on the
drilling vessel (2); (ii) subsequently installing the processing
means (24) on the seabed; and (iii) carrying out subsea processing
of production fluid from the wells (4,4',20) by using the
processing means (24).
2. A method as claimed in claim 1, wherein the processing means
(24) is in the form of a module for installation as part of a
seabed processing system.
3. A method as claimed in claim 1, wherein the processing means
(24) separates the production fluid into different components.
4. A method as claimed in claim 1, wherein the production riser
(10) is sufficiently flexible to permit local excursions of the
drilling vessel (2) while it is drilling a said further well
(20).
5. A method as claimed in claim 1, wherein the production riser
(10) is of sufficient flexibility and length to permit the drilling
vessel (2) to move between appropriate locations for drilling
plural further wells (20) in order that output from two or more
wells (4,4') can be exploited while well drilling is still in
progress.
6. A method as claimed in claim 5, including the step of
establishing at least one further well (4') and transferring
production fluid from the first well (4) and the at least one
further well (4') to the drilling vessel (2) or the production
fluid reception means (18) closely associated with the vessel while
drilling at least one additional well (20).
7. A method as claimed in claim 6, including conveying the
production fluid from the drilling vessel (2) to an off-loading
buoy (12) for onward conveyance.
8. A method as claimed in claim 7, wherein said production fluid
reception means comprises a floating storage unit (18), and the
method includes storing production fluid for a period of time in
the buoy (12) while the floating storage unit (18) is removed for
replacement by another floating storage unit.
9. A method as claimed in claim 1, including conveying the
production fluid from the drilling vessel (2) to a pipeline leading
to a remote location via an off-loading buoy (12).
10. A method as claimed in claim 7, wherein production fluid is
conveyed from the drilling vessel (2) to the buoy (12) by means of
an off-loading hose (16) extending from the drilling vessel (2) to
the buoy (12).
11. A method as claimed in claim 10, wherein fluid is conveyed from
a said further well (4') by an additional production riser (10') to
the drilling vessel (2) or production fluid reception means
(18).
12. A method as claimed in claim 11, wherein fluid is conveyed from
a said further well (4') by interconnecting said further well (4')
with at least one other well (4) so that the combined production
flow from a number of wells (4,4') is conveyed via a common
production riser (10).
13. A method as claimed in claim 1, wherein fluid is conveyed from
a said further well (4') by installing a manifold to which the
further well or wells is/are attached and the combined production
flow is conveyed to the drilling vessel (2) or production fluid
reception means (18) via the production riser (10).
Description
[0001] The present invention relates to the development of a
hydrocarbon extraction system and more particularly to the early
stages of extraction of hydrocarbons from a subsea hydrocarbon
deposit.
[0002] When a subsea hydrocarbon deposit is to be tapped, it is
customary to drill a number of wells into the deposit, each of
which is capped by a so-called "Christmas tree" or "tree". Once a
number of wells with associated trees have been established, a tree
connecting manifold is installed on the sea bed which is linked to
a pipeline for conveying production fluid from the wells to a
floating or shore-based processing or storage facility for example.
Since it commonly takes around a month to drill a well and install
a tree on it, and a single drilling ship is used for this purpose,
wells capped with a tree often remain unproductive for some months
while the drilling ship drills other wells. Furthermore, the
installation of a manifold: while drilling is in progress may
present severe operational conflict problems. Such a manifold could
be installed before or after drilling operations or while drilling
a well some distance from, the location of the manifold.
[0003] An object of the invention is to overcome the above
problem.
[0004] Thus, according to the invention, there is provided a method
of exploiting a subsea hydrocarbon reserve comprising the steps
of:
[0005] (i) drilling a first well from a floating drilling
vessel;
[0006] (ii) establishing a production riser for transferring
production fluid from the first well to the vessel or production
fluid reception means closely associated with the vessel; and
[0007] (iii) extracting production fluid from the first well while
drilling one or more further wells from the drilling vessel.
[0008] With such an arrangement, exploitation of the first well
need not wait until all associated wells have been drilled. The
consequent early production from the well can be used to generate
revenue at an early stage, thus assisting cash flow.
[0009] Preferably, the production riser is sufficiently flexible to
permit local excursions of the drilling vessel while it is drilling
one of the further wells. More preferably, the production riser is
of sufficient flexibility and length to permit the drilling vessel
to move between appropriate locations for drilling plural further
wells in order that output from two or more wells can be exploited
while well drilling is still in progress.
[0010] Advantageously the method includes the step of establishing
at least one further well and transferring production fluid from
the first well and the at least one further well to the vessel or
the production fluid reception means while drilling at least one
additional well. Fluid may be conveyed from the further well;
[0011] (i) by an additional production riser to the vessel etc;
[0012] (ii) by `daisy chaining` or interconnecting it with at least
one other well so that the combined production flow from a number
of wells is conveyed via common production riser; or
[0013] (iii) by installing a manifold to which the further well or
wells is/are attached and the combined production flow is conveyed
to the vessel etc. via the production riser.
[0014] The method may include processing the production fluid with
processing means installed on the vessel. The method may also
include the step of subsequently installing the processing means on
the sea bed and carrying out subsea processing of production fluid
from the wells by using the processing means.
[0015] The method may include conveying the production fluid to an
off-loading buoy possibly by means of an off-loading hose extending
from the drilling vessel to the buoy.
[0016] Production fluid reaching the buoy may be conveyed to a
floating storage unit such as a tanker and may be stored for a
period of time in the buoy while one such floating storage unit is
removed for replacement by another. Alternatively, the buoy may be
connected to a pipeline (e.g. a seabed pipeline) leading to a
remote location such as a floating or shore-based storage or
production facility.
[0017] The invention will now be described by way of example only
with reference to the accompanying figures in which:--
[0018] FIG. 1 shows a first stage of the method according to the
invention; and
[0019] FIG. 2 shows a second stage of the method according to the
invention.
[0020] FIG. 1 shows a drilling vessel 2 drilling a first well 4 in
the seabed 6 with a drill string 7. Once the well 4 has been
completed, a first tree 8 is installed, on the well as shown in
FIG. 2. Such trees are well known in the art and include valves for
controlling the, flow of; production fluid from a hydrocarbon
reservoir tapped by the well 4. A first flexible production riser
10 is installed between the first tree 8 and the vessel 2. The
first flexible riser 10 may include buoyant means 11 for supporting
at least a part of the weight of the flexible riser 10. Such
flexible risers, including buoyancy means, are well known in the
art.
[0021] An off-loading buoy 12 is moored in the vicinity of the
first well 4 by means of mooring lines 14 connected to the sea bed
6. An off-loading hose 16 is installed for conveying production
fluid etc. from the drilling vessel 2 to the off-loading buoy 12
and a floating storage unit, for example a tanker 18, is connected
to the buoy 12 for receiving and storing production fluid etc.
Production fluid may alternatively be routed from the buoy 12 to a
sea bed pipeline for conveyance to a remote location.
[0022] The drilling vessel 2 then moves to an appropriate location
as shown in FIG. 2 for drilling a second well 20. When this has
been drilled, a second tree 22 (shown in broken lines) is installed
thereon.
[0023] As indicated in FIG. 2 with broken lines, plural wells 4, 4'
may be connected to the drilling vessel 2 while the drilling vessel
is drilling a further well 20. With such an arrangement, it is
possible to exploit the production from two or more wells through
the flexible production risers 10, 10' while the further well 20 is
being drilled. Alternatively, well 4' and any subsequent well may
be "daisy chained" to well 4 so that the combined production flow
from both wells is conveyed to the vessel 2 by the flexible
production riser 10. Alternatively, and not shown, a manifold may
be installed to which wells 4' and 4 and any subsequent wells are
connected and the combined production flow routed to the vessel 2
either by the flexible riser 10, or by an additional flexible
riser.
[0024] The drilling vessel 2 may have processing equipment 24
mounted thereon such as a processing module forming part of the
modular system designed by Alpha Thames Limited of Essex, United
Kingdom and named AlphaPRIME. The processing equipment may effect
separation of different components of the production fluid from
each other for separate conveyance to a remote location. The
processing equipment 24 may be in the form of a module for
installation as, part of a sea bed processing system such as that
designed by Alpha Thames Limited.
[0025] Once drilling of all associated wells has been completed,
production fluid from the wells will be routed to a remote location
(before or after processing) via an alternative route, i.e. not via
the flexible risers 10, 10' and the drilling vessel 2. Production
fluid may for example be routed to a sea bed processing unit which
separates different constituents of the production fluid for
conveyance through sea bed pipelines to a remote location.
[0026] The invention provides a method of exploiting output from
one or more wells in a field prior to or while other wells are
being drilled and other infrastructure fabricated or manufactured.
This will: enable early exploitation of the, well to occur and
assist cash flow by generating revenue at an earlier stage than has
hitherto been possible.
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