Satellite Field Development Using Diverless Flowline Connections for Rigid and Flexible Pipe
Authors: Adamek F.G. , Johnson Ready , Galle G.L. 
Published: October 2008

Utilization of novel remotely operated connectors on offshore pipeline and subsea flow line is currently expediting completion of a satellite field development program in the North Sea. The development of the diverless metal to metal sealing connector used state of the art 3D solid modeling and parametric computer techniques to achieve three different sizes with inherently similar design features. These sizes were integrated with an advanced connection tool to remotely connect water injection, production, and methanol lines previously laid to a distant existing North Sea platform. The design methodology will be reviewed, the remote subsea clamp connector design features explained and the prototype test results highlighted. The significance of this achievement will be assessed and recommendations made for applications contemplating use of this subsea diverless connection approach.

INTRODUCTION

The technique of remotely connecting multiple 2-112" through 12" bore rigid pipelines to flexible flowlines that have been previously laid represents a challenge and allows the potential for cost savings in field developments such as those in the North Sea.

Figure 1 Remotely Operated Connector(available in full paper)

In the recent past, flow line connectors and their associated tools have been bulky, complex devices in order to handle the requirements of pipeline pull-in and alignment as well as the connection and sealing loads generated by high pressure fluids. The complexity of the connector either limited the number of connections from a cost or a reliability standpoint. Therefore, it would be considered quite an achievement if the complex operations inherent in this operation could be segregated from the more proven and reliable techniques. Satellite field development necessitates the need for numerous manifolds and interconnecting piping systems to adequately produce the reservoir. These systems direct the product to nearby platforms capable of processing and transporting the product through existing export lines. This generally entails the need for flexible and rigid flowlines, and requires proven joint and metal seal technology for reliable long term performance. The need for multiple connections must further address the inherent cost of the connectors and weigh the advantages of applying the more costly functions to the single Flange Up Tool (FUT) as opposed to the multitude of permanently installed remotely operated connectors. This original concept was jointly pursued jointly in study agreement T-46070.1 The resultant subsea remotely operated clamp-type connector presented addresses the task of segregating the tasks and applying their functions to either the FUT or the remote connector. The FUT is typically deployed for the initial assembly or future maintenance and then subsequently retrieved leaving only the remote connector itself to perform it's long term connection and sealing functions.

DESIGN REQUIREMENTS

The remotely operated connector had to comply the following customer requested and situation necessitated prerequisites:The connector must comply with existing hub profiles on the installed pipelines.The flow line seal must be metal to metal and based on proven technology.The connector, with the aid of a tool, must be capable of being installed, tested, and retrieved completely diverlessly.Due to the high cost of vessel time, the installation and retrieval must be as simple and reliable as possible.