# US 5,702,205 A · Steel catenary riser system for marine platform

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- Number: US 5,702,205 A
- Document ID: US5702205A
- Status: Granted
- Kind: A
- Application number: 08/566,807
- Filed: 1995-12-04
- Granted: 1997-12-30
- Earliest claimed: 1995-12-04
- Assignees: Mobil Oil Corporation
- Inventors: William C. Mahone; Bruce D. Chandler; Joseph P. Killeen; David L. Garrett
- Web page: https://patentgrep.com/patent/US5702205A

## CPC

- E21B 15/02: specially adapted for underwater drilling (E21B15/04 takes precedence)
- E21B 17/015: {Non-vertical risers, e.g. articulated or catenary-type}
- E21B 43/01: specially adapted for obtaining from underwater installations
- E21B: EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS

## Abstract

A marine riser system for a bottom-supported platform which can be installed by divers without the use of J-tubes or I-tubes. A flowline, e.g. steel pipeline, is laid between a subsea well or the like, and a jacket of a bottom-supported platform. The free end of the flowline is curved upwardly in a catenary amd is attached to the jacket at a depth which is below the turbulence zone but is one which is substantially above the marine bottom; preferably at a depth at which divers can safely work. After the flowline is structurally attached to the jacket, the free end of the flowline is fluidly connected (e.g. by divers) to a substantially vertical riser section which is clamped within the jacket and which extends through the turbulence zone to the surface.

## Claims

### Claim 1

A marine riser system comprising:
a platform jacket positioned onto the marine bottom of a body of water;
a tie-in structure mounted on said jacket and lying at a depth below the turbulence zone of said body of water but at a depth which is substantially above said marine bottom, wherein said tie-in structure comprises:
a frame attached to said jacket at said depth;
a receptacle on said frame, said receptable comprising:
a plate having a slot therein;
at least one flowline on said marine bottom having one end curving upward through a catenary from the marine bottom to said tie-in structure; and wherein said one end of said at least one flowline includes:
a tapered joint forming the terminus of said one end of said at least one flowline;
a connecting flange on the end of said tapered joint; and
an anchor flange on said tapered joint positioned below said connecting flange; and
means for structurally connecting said one end of said at least one flowline within said slot in said plate of said tie-in structure.

### Claim 2 (depends on 1)

The marine riser system of claim 1 wherein said at least one flowline comprises a steel pipeline.

### Claim 3 (depends on 1)

The marine riser system of claim 1 wherein said depth is a depth at which divers can safely work.

### Claim 4 (depends on 1)

The marine riser system of claim 1 including:
a substantially vertical riser section on said jacket and extending substantially from said depth to the surface of said body of water; and
means for fluidly connecting said at least one flowline to said riser portion.

### Claim 5 (depends on 1)

The marine riser system of claim 1 wherein said means for connecting said one end of said at least one flowline to said tie-in structure comprises:
means for connecting said anchor flange on said tapered joint to said plate of said receptacle.

### Claim 6 (depends on 5)

The marine riser system of claim 5 wherein said means for connecting said one end of said at least one flowline to said tie-in structure comprises:
a retainer plate positioned onto said anchoring flange; and
means for connecting said retainer plate to said plate of said receptacle.

### Claim 7 (depends on 1)

The marine riser system of claim 1 wherein said tie-in structure is mounted onto the jacket before said jacket is positioned in said body of water.

### Claim 8 (depends on 1)

The marine riser system of claim 1 wherein said tie-in structure is mounted onto the jacket after said jacket is positioned in said body of water.