Key Learnings from a Simulation Study of a Solvent-Assisted SAGD Pilot at Cold Lake

Abstract

ExxonMobil and Imperial Oil Resources (IOR) are conducting a Solvent Assisted - Steam Assisted Gravity Drainage (SA - SAGD) experimental pilot at Cold Lake in the Clearwater formation. In this SA-SAGD pilot, up to 20% by volume of a hydrocarbon solvent (diluent) has been injected along with dry steam in a dual horizontal well SAGD configuration. The primary objective of the pilot was to quantify the impact of solvent addition on bitumen production and steam-oil ratio (SOR). Key surveillance data collected during the pilot include production/injection rates (oil, water, and solvent), production/injection pressures, horizontal well temperatures, observation well temperatures, saturation logs, and time-lapse 3D seismic surveys. The objective of this paper is to discuss the modeling efforts that were completed in order to interpret the initial results of the pilot. Specifically, this paper will address (1) the construction of a detailed 3D geologic model and the corresponding flow simulation model and (2) the history-matching results. The geologic model incorporates information from 3D seismic surveys as well as core and log data from the pilot observation wells. Using the geologic model and the field production data, the SA-SAGD process was modeled using a thermal simulator. An acceptable match to the total hydrocarbon production rate, injection pressure, and SOR was achieved through a minor adjustment to the model permeability. The completed simulation studies are invaluable in increasing our understanding of the key parameters that control flow behavior in the SA-SAGD process. Ultimately, these learnings will be used by ExxonMobil and Imperial Oil Resources to optimize the process and make decisions related to full-field commercial deployment of the SA-SAGD recovery process.

Hot Solvent-Assisted Gravity Drainage in Naturally Fractured Heavy Oil Reservoirs: A New Model and Approach to Determine Optimal Solvent Injection Temperature

“…17 Recently, thermal solvent methods such as solvent-assisted SAGD (SA-SAGD) have been applied to real reservoirs and showed promising results. 18,19 Semianalytical models have also been developed to model this process. 20 Leyva-Gomez and Babadagli in 2017 numerically modeled heavy oil recovery from oil sands with a high-temperature solvent, and they showed that the process is highly sensitive to temperature and pressure.…”