Early hydrocarbon production system

• US 20040238176A1
• Filed: 04/07/2004
• Published: 12/02/2004
• Est. Priority Date: 10/12/2001
• Status: Abandoned Application

• Current Assignee: Alpha Thames Limited
• Original Assignee: Alpha Thames Limited
• Inventors: Appleford, David Eric, Lane, Brian William
• Application Number:
  US10/491,866
• Publication Number:
  US 20040238176A1
• Time in Patent Office: Days
• US Class Current: 166/353
• CPC Class Codes: B63B 22/021 and for transferring fluids, e.g. liquids container type buoys having means to selectively release contents, not adapted for mooring a vessel B63B22/26
• CPC Class Codes: B63B 27/34 using pipe-lines anchoring arrangements for special vessels with mooring turrets B63B21/507; buoys specially adapted for mooring a vessel and for transferring fluids, e.g. liquids B63B22/021
• CPC Class Codes: E21B 43/01 specially adapted for obtaining from underwater installations
• CPC Class Codes: E21B 7/128 from floating support with independent underwater anchored guide base

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).

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).