Puffin field abandonment (Page 1 of 3) By Claudio Pellegrini, Subsea Intervention Manager; and James Ryan, Subsea Engineer, AGR Perth, 26 Aug 2015

Introduction

This article describes the planning and execution of the Puffin field abandonment which was successfully executed in 2014. The Puffin field is located in the Timor Sea about 200 km off the coast of Western Australia. The field consisted of two gas lifted production wells and five temporarily suspended wells. The article aims to give an outline of the processes, technologies and methodologies adapted in planning and executing the project. Finally, the article provides a conclusion of the main challenges and the key lessons learnt.

Well Abandonment Delivery Process

It is suggested that the key to success of any project is to follow a structured approach and apply proven processes. Abandonments of old fields are not so common, thus a proven delivery process did not exist. However, as the need for a structured approach was deemed paramount, the well delivery process was adapted and altered to serve as framework the project could follow from the onset. The resulting Well Abandonment Delivery Service charted a phased method to the project, each phase defining key steps that needed to be completed and monitored to proceed to the next phase. The project team hence had a framework which provided visibility of key factors affecting project success and how these factor interrelate. The integrated project management approach applied to the project benefited much from the established framework as it facilitated early identification of issues, aided strategic alignment of both the company and the contractors and ultimately was vital to achieving holistic management of the project.


AFT Deck. (Click here to view enlargement)

Project Scoping

The Puffin field lies in water depths of approximately 105 m. Production commenced in 2007. Both production wells required gas lift and were tied back to a floating production, storage and offload (FPSO) vessel. Production ceased in 2009.

Prior to disconnection of the FPSO, all subsea production infrastructure was purged of hydrocarbons, flushed, tested and left in-situ. The wells were shut in with approximately 1600 psi of gaslift gas left in the annulus. In 2013 it was decided to permanently plug and abandon (P&A) all the wells in the field using a semi-submersible.

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