Apparatus and method for conducting offshore well operations

• US 4,286,665 A
• Filed: 10/17/1979
• Issued: 09/01/1981
• Est. Priority Date: 04/24/1979
• Status: Expired due to Term

• Current Assignee: Fluor Corporation
• Original Assignee: Deep Oil Technology Incorporated
• Inventors: Walker, Raymond W.
• Primary Examiner(s): Pate, III, William F.
• Application Number:
  US06/085,340
• Time in Patent Office: 685 Days
• Field of Search: 166/349, 166/366, 166/360, 166/362, 166/363, 166/368, 166/339, 166/343, 175/7, 175/10, 179/342
• US Class Current: 166/339
• CPC Class Codes: E21B 41/08 Underwater guide bases, e.g. drilling templates; Levelling thereof
• CPC Class Codes: E21B 41/10 Guide posts, e.g. releasable; Attaching guide lines to underwater guide bases
• CPC Class Codes: E21B 43/017 Production satellite stations, i.e. underwater installations comprising a plurality of satellite well heads connected to a central station

Abstract

An apparatus and method for offshore well operations in which a tension leg platform, a multiwell template means, and a riser system are arranged to provide: effective use of the advantages of a tension leg platform, a simplified riser design, and a novel template design which minimizes orientation problems of well equipment at the sea floor. A multiwell template means in which the template frame includes a latch ring member for each well to cooperate with a retrievable guide line base frame having releasable latch members whereby angular or radial orientation of the guide line base frame is not required with respect to the template frame. A retrievable guide line base frame having alignment means thereon and guide posts with guide lines attached thereto.

Claims

1. In combination:

a sea floor template frame means for one or more wells each having a well axis including

a latch ring member provided with an annular engagement face on said template means arranged coaxial to each well axis;

a retrievable guide line base frame adapted to be lowered in coaxial relation with a selected well axis and freely movable around said selected well axis relative to said ring member for random positioning in any angular relation to said ring member;

and latch means on said guide line base frame cooperably engageable with said annular engagement face on said latch ring member on said template frame means in any random angular position of said guide line base frame about said well axis relative to said ring member.

2. A combination as stated in claim 1 wherein said guide line base frame includes

a cylindrical member receivable within said latch ring member for coaxially guiding and aligning said guide line base frame with said axis;

said latch means being radially outwardly of said cylindrical member.

3. In combination:

a sea floor template frame means for one or more wells including

a latch ring member on said template frame means arranged relative to a well axis;

a guide line base frame adapted to be lowered in coaxial relation with said well axis and freely movable around said axis relative to said ring member;

and latch means on said guide line base frame cooperably engageable with said latch ring member on said template frame means in any angular position of said guide line base frame about said axis relative to said ring member;

said latch means on said guide line base frame including;

a pivoted release means on said base frame for disengagement of said guide line base frame from said latch ring member on said template frame means.

4. A combination as stated in claim 3 wherein

said pivoted release means includes a pivot axis, a latch element inboard of said pivot axis, and a pressure contact element outboard of said axis;

and

a release tool means movable along guide lines of said guide line base frame for pressure contact with said outboard element of said release means for said latch means for disengagement of said latch means with said latch ring member.

5. A sea floor template means for subsea drilling and production operations including:

a template frame means for one or more wells;

a guide funnel means on said template frame means for providing a well axis;

and an open ring member provided with an annular engagement face concentric with said well axis and for receiving therewithin, locating, and releasably securing a component well part in any angular and coaxial relation to said well axis.

6. A sea floor template means as stated in claim 5 wherein

said annular engagement face on said ring member is continuous around said axis and is provided on the bottom edge face of said ring member.

7. A retrievable guide line base frame means for well operations to be conducted over a single well having a well axis comprising:

a polygonal base frame provided with guide post means at corners thereof having guide line means attached thereto;

said base frame having an open-ended cylindrical guide member within said base frame;

said cylindrical member having an axis positionable in coaxial relation with said well axis;

said base frame having latch means radially outwardly of said cylindrical guide member and adapted to releasably engage a ring member outwardly thereof on a template frame and having an axis coaxial with said well axis in any angular position of the frame relative to the ring member.

8. In a method of conducting offshore well operations in which a well template means is located on a sea floor, said well template means having a well hole guide funnel for each well and a latch ring member coaxial with each guide funnel, the steps of:

lowering a well hole selector and stabbing guide means into temporary engagement with a selected well hole guide funnel;

lowering along the stabbing guide means a retrievable guide line base frame having a guide line attached thereto;

latching said retrievable base frame onto said latch ring in any non-oriented angular relationship with the axis of the guide funnel;

said step of lowering the retrievable guide line base frame including

releasably attaching a running guide frame to said base frame.

9. A method as claimed in claim 8 including

releasing said stabbing guide means from said well hole guide funnel and retrieving said stabbing guide means and running guide frame.

10. In a method as stated in claim 8 including the steps of suspending production pipe in the well hole with safety valve block means at the well template frame;

and providing a protective cage for said safety valve block means.

11. In a method as stated in claim 10 including the steps of lowering and connecting riser pipe to said safety valve block means by guiding said riser pipe along said guide line;

and retrieving said guide line base frame means.

12. In a method of conducting offshore well operations in which a well template means is located on a sea floor, said well template means having a well hole guide funnel for each well and a latch ring member coaxial with each guide funnel, the steps of:

lowering a well hole selector means into temporary engagement with a selected well hole guide funnel;

lowering along the selector means a retrievable guide line base frame having a guide line attached thereto for engagement and release of the base frame with said well template means;

latching said retrievable guide line base frame onto said latch ring member in any angular position relative to the latch ring member and to said axis;

and releasing said guide line base frame from said well template means after a well operation,

said step of releasing said base frame including the step of lowering a running guide frame into contact with said base frame to unlatch said guide line base frame.

13. In an offshore production well installation, the combination of:

a tension leg platform having a plurality of tension legs connected to anchor means at the sea floor for minimizing heave of said platform;

a multi-well template means located on the sea floor beneath said tension leg platform;

said template means including a guide funnel for each well hole;

a wellhead at the template means for supporting production tubing and well casing below the sea floor at an associated well hole;

means for primary control of production fluid of said well at the sea floor including safety valve block means connected to said production tubing at said template means;

a plurality of production risers each including a riser connector at said safety valve block means, each of said risers extending to said platform;

riser tensioning means of relatively short travel connected to each of said risers at said platform; and

means for secondary control of production fluids of said wells at said platform and including wellhead means for each production riser.

14. In an offshore well installation as claimed in claim 13 wherein

each of said production risers have a tapered riser portion extending from said safety valve block means.

15. In an offshore well installation as claimed in claim 13 wherein

said template means includes at each guide funnel a latch ring member adapted to cooperate in non-oriented relation with a guide line base frame lowered from said platform.

16. In an offshore well installation as claimed in claim 13 including

a latch ring member on said template means at each well hole;

a guide line base frame adapted to be lowered from said platform for latching engagement with said latch ring member of a selected well hole for conducting a well operation;

and a running frame means adapted to be lowered from said platform to unlatch said guide line base frame for retrieval thereof.

17. In an offshore well installation as claimed in claim 13 including

a cage means surrounding and protecting said safety valve block means.

18. In an offshore well installation as claimed in claim 17 including

riser connector means within said cage means for connecting said wellhead at said template means to an associated riser.

19. In combination:

a sea floor template frame means for one or more wells including

a latch ring member provided with an annular engagement face on said template frame means arranged coaxial to a well axis;

a retrievable guide line base frame adapted to be lowered in coaxial relation with the said well axis and freely movable around said axis relative to said ring member for positioning in any angular relation to said ring member;

and latch means on said guide line base frame cooperably engageable with said annular engagement face on said latch ring member on said template frame means in any angular position of said guide line base frame about said axis relative to said ring member;

said latch means including a pivoted latch element biased in a radial outward direction with respect to said well axis and engageable with said annular engagement face on said latch ring member.

20. In combination:

a sea floor template means including a plurality of well hole guide funnels each funnel having a well axis and each funnel encircled by a latch ring having an axis common to the axis of its associated well funnel;

a guide line base frame including a cylindrical member adapted to be lowered along said well axis for positioning within said latch ring in coaxial non-radially oriented relation;

and latch means on said base frame engageable with said latch ring in any non-radially oriented position of said frame and cylindrical member at said template means.