The Dalia Development Challenges and Achievements
Authors: Picard D. , Thebault J. , Goncalves F.J. , Costa R. 
Published: October 2008

This paper sets the scene for a full suite of papers which will summarise the main challenges and achievements of the Dalia Development, which was managed by an integrated project team. An overview of the development will be presented in this paper, which will be complemented by a further six papers providing details covering:Subsurface, Drilling and Well CompletionsSystem Design and Flow AssuranceSubsea Production SystemFlowlines, Risers and UmbilicalsFPSOOil Offloading Export System Spanning from pre-award to first oil, this paper will highlight some of the many challenges faced, describe the major technological innovations adopted (including some "world firsts". It will also comment on how lessons learned from Girassol development were incorporated, and comment on HSE management, the development schedule and contracting strategy. Finally the integration of the project into Angola including the new industrial bases, training and environmental commitment will be described.

Introduction

Setting the Scene

Building on the success of Girassol, Total have continued, together with the Concessionaire and Partners, to push the boundaries of deep water technology in the Dalia development, by using innovative technology to execute this multi-well heavy oil development. The development has been performed in accordance with the Company HSE and Quality Charters.

The field is located 210 km north west of Luanda, about 140 km from shore (Figure 1). It was the second major discovery out of 15 made in the prolific Block 17 (Figure 2).

Figure 1 - Block 17 Geographical Location and Reservoirs(available in full paper)

The project chronology has been marked by some significant dates:1997: Field discovery1999: Declaration of commercial discovery2003: Project launch2005: Commencement of drilling campaign2006: Offshore installation13th December 2006: First Oil Dalia is a large and complex field by many measures:Dalia is estimated to contain close to 1 billion barrels of recoverable oil in a reservoir extending some 230 km2 only 800 metres below sea bed in water depths of between 1,200 to 1,400 metresHeavy oil at 21° API compared to 32° API on GirassolThe development scheme is based on 71 subsea completed wells: 37 producers, 31 water injectors and 3 gas injectors.The production wells are set in clusters around nine manifolds on four pipe in pipe production flow loops. Each manifold is capable of connecting up to six wellsThe water injection wells connect to four water injection lines via inline teesThe gas injection wells connect to two gas injection lines via inline teesThe subsea network links to the FPSO via flexible risersThe FPSO is a large new build vessel with an oil processing capacity of an average 240,000 barrels per day, water injection of 405,000 barrels per day and gas compression capacity of 8 million standard cubic metres per day. The FPSO oil storage capacity is two million barrelsOil export is performed via an offloading buoy

Integrated Teams

In order to bring such a large field on stream in deep waters, it has been necessary to develop and qualify new technologies, new equipment and address a number of key issues such as reservoir uncertainties and flow assurance.