Parameter Based SCAL - Analysing Relative Permeability for Full Field Application

Einar Ebeltoft, Frode Lomeland, Amund Brautaset and Åsmund Haugen
Statoil ASA, Stavanger, Norway

This paper was prepared for presentation at the International Symposium of the Society of Core
Analysts held in Avignon, France, 8-11 September, 2014

Abstract:
A method is proposed where the flow properties from SCAL experiments are parameterized and implemented into saturation functions for full field applications. Parameterization of the flow properties facilitates analysis of end point saturations and curve shapes individually for each SCAL experiment, and storing the parameters in a SCAL database. A number of these parameterized SCAL experiments are subsequently combined to generate representative saturation functions for full field application that are consistent with wettability as well as rock properties.

The method starts by verifying each SCAL experiment by simulation followed by parameterization of the appropriate flow properties, including residual oil saturation (S_orw or S_org), end point relative permeabilities (k_rw(S_orw) or k_rg(S_org)) and the shape parameters of the curves. These flow parameters are then stored in a SCAL database and interrelated with plug specific data, including experimental conditions and geo-references. Each flow parameter is analysed individually as functions of initial water saturation, porosity and permeability and supported by wettability consistent trend models. The trend models for each flow parameter have been developed based on the underlying theory of wettability, reservoir physics and observed behaviour of a large set of SCAL data from the Norwegian Continental Shelf. The trend models and application are presented in this paper.

The advantage of parameterization, using trend models and possible analogues from the database, are smooth and well defined saturation functions that are consistent with wettability. The resulting relative permeability is determined as a base case with optimistic and pessimistic bounds. These are easily implemented as saturation functions in full field reservoir simulators for sensitivity and field performance analyses. This approach is demonstrated for a real field case from the Norwegian Continental Shelf, taking the underlying theory behind trend models, rock quality and wettability into consideration.

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