Diverless Hard-Pipe Connection Systems for Subsea Pipelines and Flowlines (1996)

Abstract Hard-pipe tie-in jumpers, for diverles. subsea connections between production manifolds and export pipelines (or satellite wells), are an economical alternative to additional diverless connection methods like deflection and pull-in: and also to flexible pipe jumpers. A systems level approach to the design of the jumpers. which takes into consideration performance requirements, measurement methods, fabrication and installation constraints, as well as code requirements, is essential to making these connections economical and reliable. A dependable, ROV-friendly measurement stem is key to making these connections possible. The parameter affecting the design of hard-pipe jumpers, and the relationship between these, are discussed in the context of minimizing cost while maintaining reliability. The applicability (Ifpipeline cedes to the design of hard-pipe jumpers is examined. The design construction and installation of the how Liuhua 11-1 pipeline tie-in jumpers are presented as a case study for applying these concepts. Introduction There are numerous advantages to tying in a production facility to an expect pipeline by means of a jumper spool piece. The advantage over a lay-away system is that using the jumper system, two vessels need not be on location at the same time. The cost associated with the lay-away method is particularly high when multiple connections have to be made. Deflection and pull-m method have been used as an alternative to the lay-away method The deflection method requires a large ?sweep' area for deflecting the pipeline terminations to the production manifold and requires a large vessel or stem capable of generating the loads required to deflect the pipeline, The pull-in method has the disadvantage of transferring the pull-in loads on to the production manifold and often requires the use of complex tooling In many instances. particularly when the trend is for small, light weight manifolds, this method is unacceptable Amoco function Company, as part of the development of their generic Deepwater Subsea Production System (DSPS) (Ref. 1), conducted a study in collaboration with Oceaneering Intention engineering (formerly Oil Industry Engineering, inc.) and others to develop the concept of using hard-pipe jumpers to connect a subsea production manifold to both the individual wells and to the export pipeline. The jumpers were to be designed such that they could be constructed on, and installed from, a drilling or production vessel. The ?short- jumpers connecting the wells to adjacent wells and wells to the gathering manifold were designed to be measured and installed using a high precision measurement tool known as the Measurement, Installation and Retrieval (MIR) rod. Another simpler ROV operable measurement tool was also developed as part of this system. This tool, called the Pre- Measurement Tool (PMT), is a mechanical measurement tool which can be operated with ROV hydraulics. The primary purpose of this tool is to make linear and angular measurements for constructing the hard-pipe tie-in spools ('long' jumpers) between the central manifold and the export pipelines.