Modeling of Water-containing Oil for Steam Injection Simulation

  • Author / Creator
    Venkatramani, Arun Venkat
  • Experimental results in the literature show that the water solubility in the oleic (L) phase can be high at reservoir conditions in thermal oil recovery processes; e.g., 24 mol% in the water/n-eicosane binary system at 41 bars and 523 K. It becomes even more significant as the L phase becomes more aromatic, which is the case with heavy oil and bitumen. Efficient and accurate representation of multiphase behavior, which consists of the L, vapor (V), and aqueous (W) phases, is crucial in reliable numerical simulation of steam injection processes. This research presents a new framework to model the multiphase behavior of water-containing reservoir oil by use of the Peng-Robinson equation of state (PR EOS) with the van der Waals mixing rules.
    The development of this framework involves two stages. In the first stage, a new characterization framework for the accurate representation of the multiphase compositional behavior of mixtures of water and reservoir oil is developed (Approach 1). The resulting product is a new set of correlations for the binary interaction parameter (BIP) between water and hydrocarbons (n-alkanes and pseudo-components). These correlations are functions of the molecular weight (MW) of the hydrocarbon.
    In the second stage, the shortcoming of Approach 1 with regard to the predicted volumetric behavior is addressed by first optimizing component-specific critical constants (TC, PC) and acentric factor (ω) of n-alkanes and water. The optimized TC, PC and ω are then employed to develop a new set of correlations for the BIP between water and hydrocarbons (Approach 2).
    Results show that both Approach 1 and Approach 2 can accurately represent the multiphase compositional behavior of binary and multicomponent, water-containing mixtures of n-alkanes and reservoir oil. In terms of density predictions, Approach 2 offers improved accuracy over Approach 1. The distinct advantage of employing the characterization framework developed in this research over prior thermodynamic models is the simultaneous obtainment of improved accuracy in phase behavior predictions and computational efficiency. The results of the numerical reservoir simulation performed for the expanding-solvent steam assisted gravity drainage using n-C5 as the solvent indicate that the dissolution of water in the L phase can significantly enhance the local displacement efficiency. Case studies show that the resulting improvement in oil drainage rate can be greater than 10%, signifying the importance of the accurate representation of phase behavior.

  • Subjects / Keywords
  • Graduation date
    Fall 2014
  • Type of Item
  • Degree
    Master of Science
  • DOI
  • License
    This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.