This PhD thesis presents the case of the Norwegian Sea continental margin, intending to reconstruct the evolution of depositional environments during the syn-rift and post-rift stages. However, the syn-rift to post-rift transition is still a matter of debate. Stratigraphic rift-basin successions have promoted a tremendous amount of tectonostratigraphic studies during the last decades. The methodology for applying 4D seismic has been reported extensively in the literature as has the sensitivity of the acoustic impedance to changing reservoir saturations and reservoir pressure.There are few reservoir analogies to Draugen, however, the closest ones are perhaps those situated on the Norwegian shelf with 4D studies having been reported for Statfjord, Gullfaks and Troll.Some studies have reported the results obtained by integrating 4D interpretations with numerical simulation for improved reservoir characterization.Others have suggested improved workflow procedures for integrating 4D results into the reservoir management process.
#Draugen achievements full
Reservoir management for Draugen utilizes a Full Field reservoir simulation Model (FFM) based on a geological model with numerous faults.Replicating the dynamic communication across several non-neighbour connections (NNC's) with hundreds of on-lap connections between the different reservoirs in the simulation model poses significant challenges.ĤD seismic interpretation of the water influx is important for establishing fault communication and modifying the geological model for a viable history-match.Iterations of geologic modelling, reservoir simulation and seismic forward modelling are generally recommended for consistency between dynamic model and 4D seismic in accordance with current "best practice" methodology. The Draugen Field is located 100 km offshore Norway.The field has excellent reservoir characteristics that have enabled a field development with a minimal number of appraisal and development wells given the areal size of the field.The lack of well control for the structural mapping has resulted in a relatively high degree of uncertainty for both the top reservoir structure and the in-place volume.Therefore, interpretation of the field structure is largely dependant upon 3D seismic surveys conducted in 1990, 1998, 20 and the associated seismic time to depth conversion work.The latter three surveys included 4D seismic interpretations of the water encroachment into the reservoir the most recent survey was acquired as a combined high-resolution and 4D survey.
4D seismic interpretation plays a key role in the reservoir management of the Draugen Field, situated offshore Norway.Time lapse seismic surveys of exceptional quality conducted in 1990, 1998, 20 have all shown outstanding areal and vertical definition of the water movement towards the producing wells.Įxcellent reservoir properties with relatively few high rate wells and an expected recovery factor exceeding 60 percent make Draugen one of the best performing fields offshore Norway.The field has a simple geology, however, the reservoir structure is relatively uncertain due to the low number of well penetrations for calibrating the structure.Fortunately, the 4D seismic interpretations have largely compensated for this shortcoming by providing improved lateral control for refining the reservoir simulation models.Īll of the 4D interpretations conducted so far have indicated the need for simulation model changes such as modified reservoir volumes in certain areas, revised fault transmissibilities, and the need for improved relative permeability characteristics.Integration of the 4D interpretation results has greatly improved the various Draugen reservoir simulation models enabling improved forecast and reserve estimates as well as better business decisions.Effects on the field reservoir management have included revising the water injection strategy, converting a producer to injector, re-positioning a development well and drilling an appraisal well.
0 kommentar(er)
