Development and application of proxy models for predicting the shale barrier size using reservoir parameters and SAGD production data

Abstract

The modelling of an interbedded shale barrier in heterogeneous oil sands reservoirs has high uncertainty, which has a critical impact on the steam-assisted gravity drainage (SAGD) performance. Generally, an interpretation of 4D seismic data is the most widely used method for understanding the uncertainty of the shale barrier size.In a shale interbedded oil sands reservoir, the SAGD production data, such as the oil rate and steam-oil ratio (SOR), increase to a peak point and decrease to a trough point; the point intermediate between these two points is called the inflection point (IP).In this study, proxy models were developed to predict the shale barrier size using reservoir parameters and the IP of the SAGD production data without utilizing a 4D seismic data interpretation. In addition, a field application was carried out to test the developed proxy models using the data from Suncor's Firebag SAGD project, Alberta, Canada.The proxy models for predicting the shale width (WD), shale length (LN), and vertical location of the shale (VL) were developed using the statistical analysis of the reservoir parameters, shale size and location, and IP from production data. As a verification procedure, homogeneous 3-D simulations were performed to reconstruct the predicted WD, LN, and VL, and the oil production profiles of the SAGD field were compared with the simulation results. The oil production profiles showed a similar trend between the simulation results of the reconstructed model and the field SAGD production data. Therefore, the developed proxy models may use to predict the shale barrier size properly, and might be useful for field applications.