Oil Sand Characterization for Standalone Screen Design and Large-Scale Laboratory Testing for Thermal Operations

Authors: Mahdi Mahmoudi (University of Alberta) | Vahidoddin Fattahpour (University of Alberta) | Alireza Nouri (University of Alberta) | Ting Yao (University of Hong Kong) | Beatrice Anne Baudet (University of Hong Kong) | Michael Leitch (RGL Reservoir Management Inc.)

Oil sand characterization tests are essential for the selection and evaluation of sand control devices. Current approaches for screen selection and evaluation usually rely on Particle Size Distribution (PSD) and neglect the effect of important parameters such as porosity, grain shape and frictional properties. One aim of this study is to characterize oil sand’s mechanical, geometrical and size characteristics that should be considered in the completion design. Another objective is to determine if natural mixture of oil sand could be reasonably replicated with commercial sands for large-scale sand control evaluation tests.

In this paper we present the results of a comprehensive image analysis and laser sieve analysis on oil sand samples from the McMurray Formation to quantify geometrical grain characteristics (sphericity, aspect ratio, convexity and angularity) of the sand grains and establish the PSD of the samples. Direct shear tests were performed to assess the frictional characteristics of different oil sands around the liner under variable stress conditions during the SAGD well lifecycle.

Image analysis, PSD, and direct shear tests showed that natural mixture of oil sand could be successfully simulated with commercial sands in terms of size and shape of grains and mechanical properties. This conclusion is significant to those performing large-scale sand control evaluation tests that usually require large quantities of sands that are not readily available and require significant preparation.

This paper provides the first comprehensive investigation of the granular, and geomechanical characteristics of oil sand from the McMurray Formation. The paper discusses the missing parameters in the design of sand control device, and evaluates test methods that measure those parameters. The proposed testing program could be used as a benchmark for oil sand characterization in relation to the design and evaluation of sand control device.

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Prediction of heavy-oil viscosities with a simple correlation approach

Heavy-oil development is becoming increasingly important because of the continuous decline in conventional-oil production. For heavy-oil reservoirs, the oil viscosity usually varies dramatically during production processes such as in thermal processes. When producing heavy oil, the high viscosity is a major impediment to recovery. Oil viscosity is often correlated directly to the reserves estimate in heavy-oil formations and can determine the success or failure of a given enhanced-oil-recovery scheme. As a result, viscosity is an important parameter for performing numerical simulation and determining the economics of a project. In this work, a simple-to-use correlation has been developed to correlate the viscosity of heavy oil to temperature and to a simple correlating parameter that can be used for heavy-oil characterization. The reported results are the product of the analysis of heavy-oil data collected from the open literature for various heavy-oil fields around the world. The tool developed in this study can be of immense practical value for petroleum engineers, providing a method for quick assessment of the viscosity of heavy oils. In particular, petroleum and production engineers would find the proposed correlation to be user-friendly, with transparent calculations involving no complex expressions. The new proposed correlation shows consistently accurate results. This consistency could not be matched by any of the widely accepted existing correlations within the investigated range. For all conditions, the new correlation provided better results than existing correlations in the literature.

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Modelling of outflow control in Steam Assisted Gravity Drainage Process

Steam Assisted Gravity Drainage (SAGD) has been applied as a reliable oil recovery technology in the oil sand industry. In order to increase the productivity of the SAGD process, Outflow Control Devices (OCD) are used to control the injection of steam into the formation. Our work aims at the modelling of OCD with Computational Fluid Dynamics (CFD). In this paper, CFD simulation of OCD has been done based on a simplified model. The mechanism how OCD controls the flow is studied through a series of test simulations. Different models have been compared to study the effect of the setup details on the OCD flow. In the future, more accurate models will be established evolving from the results obtained currently and further investigation to be done into the problem.