Drainage Strategy of Gamma Main Statfjord at the Oseberg Main Field
Abstract
One of the most important jobs of a reservoir engineer is to predict the future production and behaviour of a reservoir. In order to be able to do this job the reservoir engineer is dependent on having a sufficient reservoir model. For the quality of future predictions it is essential the reservoir model is reproducing the historical data.
History matching is the procedure of improving a reservoir model by adjusting its parameters until the simulated results replicate the observed data. This thesis presents a history match of Gamma Main Statfjord at the Oseberg Main Field in the North Sea. The Oseberg Main Petroleum Technology (PETEK) department at Statoil provided the initial reservoir model used in this thesis. History matching results are further evaluated and discussed. To match and improve the reservoir model, parameters such as aquifer strength, productivity index, permeability and pressure barriers between layers were modified until simulations reproduced the observed data.
Further, a new drainage strategy on Gamma Main Statfjord was developed through optimisation of water injection rate and investigating the possibilities of drilling a new producer and a new injector in the reservoir. For the new injector, both water injection and gas injection was examined as a new drive mechanism. The results from this thesis show that adding a new vertical producer and a new gas injector on Gamma Main Statfjord could potentially increase the total recovery factor with 23.9 %, whilst also increasing the lifetime of the Oseberg Main field.