Characterization of Multiphase Flow in Porous Media and Its Applications in Determining Reservoir Petrophysical Properties

Date
2017-11
Authors
Fan, Zhaoqi
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Publisher
Faculty of Graduate Studies and Research, University of Regina
Abstract

Characterization of multiphase flow in porous media has attracted numerous attentions since primary, secondary, and tertiary recovery methods are developed and applied in the petroleum industry. Physically, three-phase flow (i.e., oil, gas, and water) occurs in porous media during the secondary or tertiary recovery processes, e.g., water-alternatinggas (WAG) injection, while mobilized solids contribute to the flow in heavy oil reservoirs during the primary production, e.g., cold heavy oil production with sand (CHOPS). Considering the complexity of WAG injection and CHOPS processes resulted from hysteresis effect, sand failure, and foamy oil flow, it is still challenging to efficiently and accurately determine petrophysical properties which are significantly imperative to optimize the performance of those recovery processes. Therefore, it is essential to accurately characterize the multiphase flow and determine the corresponding petrophysical properties in hydrocarbon reservoirs for identifying fundamental mechanisms of various recovery processes. A modified ensemble randomized maximum likelihood (EnRML) algorithm has been developed and validated to estimate three-phase relative permeability with consideration of hysteresis effect. A recursive approach determining the damping factor has been developed to reduce the number of iterations and computational expenses of the EnRML algorithm, while a direct-restart method has been proposed to tackle the water/gas breakthrough problem. Such an improved EnRML algorithm has been validated by using a synthetic WAG displacement experiment and then extended to match laboratory experiments. The synthetic scenarios demonstrate that the recursive approach saves 33.7% of the computational expenses compared to the conventional trial and-error method when the maximum iteration is 14. Also, the consistency between the production data and model variables has been well maintained during the updating processes by using the direct-restart method, whereas the indirect-restart method fails to minimize the uncertainties associated with the model variables. As for the CHOPS process, a pressure-gradient-based (PGB) sand failure criterion has been proposed and validated to quantitatively determine the sand production and corresponding wormhole propagations. By considering pressure gradient, pseudointeraction force, and dynamic friction, the PGB sand failure criterion was derived at pore-scale by analyzing the mechanical balance around a throat and then further extended to grid-scale. Subsequently, the PGB sand failure criterion is validated by history matching production profiles and wormhole propagations of a laboratory sand production experiment collected from the literature. With the validated PGB sand failure criterion, a framework is proposed to determine the three-phase relative permeability considering the effects of the sand failure phenomenon and the foamy oil flow. It has been found that utilization of two sets of three-phase relative permeability can demonstrate the dynamic effects of sand failure and slurry flow on the production performance during various stages in CHOPS processes. In addition, the PGB sand failure criterion has been applied to determine the sand production and wormhole propagation of a CHOPS well in the Cold Lake field. Good agreements between the simulated and observed data confirm that the newly proposed wormhole growth model can represent the multiphase flow under CHOPS conditions. Furthermore, the PGB sand failure criterion can be incorporated with any numerical reservoir simulator and thus to be pragmatic for field cases since only a few parameters are required to be determined.

Description
A Thesis Submitted to the Faculty of Graduate Studies and Research In Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy in Petroleum Systems Engineering, University of Regina. xxvi, 220 p.
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