Field development of a marginal oil field on the Norwegian Continental Shelf

Abstract

A small model oil field Tesla has been created based on assumptions and data from an existing field. With a lifetime of 8 years and expected total production of 8 million Sm3 oil, it is a marginal development, where the development concept influence the net present value (NPV), which decides whether this field is going to be developed or not. The made assumptions are thoroughly described, and used for inputs in Acona Cost Estimation Software (ACES).The assumptions mainly apply to the subsea system, process concept and platform. Production profiles are also calculated, and these are important for dimensioning the process facilities. These assumptions were applied to 8 platform concepts and by using ACES the results in form of technical-, cost- and NPV reports were calculated. These results provided insight in e.g. which components on a production platform required great amount of structural material, the different amount of vessel days required for different marine operations, the basis for NPV calculations and how different platform concepts affected the NPV. The major differences between concepts and their NPV was that wet trees with subsea system is more expensive than dry trees, and drilling facilities are costly investments for a small field with a small amount of wells. The option of leasing production facilities gave a larger positive NPV than purchasing the facilities, and tie-back of close-by discoveries can extend lifetime and provide a higher NPV. The discussion summarizes what other factors can have an effect on the decided concept, and it is concluded that a jacket platform with dry trees is the most suitable development concept for the model field, due to its high NPV of 2955 million NOK, at an oil price of 75,76 USD/bbl.