Enserch Garden Banks 388 Field Development Template Tie-Back of Existing Subsea Satellite Wells
Authors: Hellums J.W. , Granhaug O. 
Published: October 2008

The Flowline Jumper System (FJS) will be used by Enserch Exploration, Inc. to tie in three existing wells to the 24 well production template installed in Garden Banks Block 388. The FJS allows these existing satellite wells to be connected to the production template via standard wellbays, eliminating the need for dedicated receiver structures, or tie-in porches. Wellbays used for satellite well tie-ins are available for use as template wellsfollowing the removal of the jumper.

This paper describes the considerations that led to the selection and influenced the design of the FJS. The advantages ofverticaljumper systems are fully discussed with respect to the GB-388 Project. A description of the major components and how they interface with the template is included to provide a better understanding of the FJS. Also included is an outline of the System Integration Testing (SIT) of the FJS.

SYSTEM OVERVIEW

The GB-388 FJS is designed to perform the subsea tiebacks of three satellite wells to the template. These exploratory wells were drilled prior to the current fielddevelopment. Three jumpers span the distance between selected template wellbays and the satellite wells. The Tubing Spool (TS) assembly, installed on the existing wellhead, provides the interface for the FJS, and the subsea production tree. The key to the successful installation of the FJS, is the remote measurement of the relative positions of the termination hubs.

The main advantage of the FJS is that it utilizes standard template wellbays for satellite tree tie-ins. Although the onnectors are compatible with all of the wellbays on the template, only the wellbays in the outside rows are accessible for jumper installation. All fourteen of the GB388 template's exterior wellbays can be used for satellite tree tie-ins or standard template wells. The ability to make a tie-in to any external well-bay eliminates the need for dedicated satellite well porches while providing field development flexibility.

Another advantage of the FJS is its vertical operation. The jumper consists of two downward looking collet connectors with two flexible flowlines and a control umbilical suspended between them in the form of a catenary. The FJS can be installed from either a drilling rig or a installation barge. The FJS, with its vertical collet connectors, provides for a simple offshore installation. Horizontal connection systems, in comparison, require complex pull-in and connection tools.

The jumper terminations are comprised of a hydraulic connector assembly and softlanding pedestal for controlled landing. The template end of the jumper is made up of a Wellbay Connector Assembly (WBCA) interfacing directly to a standard wellbay. The WBCA lands on the wellbay and connects to the flowline hub, like the subsea tree. The WBCA lands and aligns to the wellbay using the well conductor housing. The satellite well end of the jumper is made up of a Tubing Spool Connector Assembly (TSCA) interfacing directly with a receiver structure on the satellite well. The TSCA lands and connects to a flowline hub on the tubing spool receiver structure guided by an alignment/softlanding post.