EVALUATION OF GEOMECHANICAL DILATION AND ITS EFFECTS ON SAGD PERFORMANCE

• Author / Creator

  WANG, Xinkui

• An effective Steam Assisted Gravity Drainage (SAGD) process requires thermal and hydraulic communication to be established between the injection and the production wells during the start-up operation. To achieve inter-well communication, the conventional steam circulation start-up operations typically take several months. The reductions in start-up time can have a favourable impact on project economics. A strategy using fluid injection to promote geomechanical dilation of the oil sands, which enhance the inter-well permeability, has been proposed as a SAGD start-up technique. The mechanics of the fluid injection process involve complex interactions of thermal, geomechanical and multiple phase flow behaviours in the inter-well formation region. A better understanding of these interactions in establishing well-pair communication is essential for assessing the potential of deploying this dilation start-up technology and exploring improvements in the overall SAGD recovery performance.
  This study intends to examine whether a cold-water injection is sufficient to induce enhancements in effective permeability to water from geomechanical dilation mechanisms. An experimental program was first designed to quantify the geomechanical responses under dilation. The reclaimed and cleaned tailing sands from the McMurray Formation were treated to resume and maintain the initial water wettability, and were subsequently used to reconstruct synthetic core specimens. A modified sample preparation technique was developed to create reconstituted, dense, water-wet and bitumen sand specimens with varying levels of fluid saturations, but with nearly identical porosities. A set of experiments was carried out in a triaxial cell under several reservoir conditions, varying in terms of pressure, temperature, and stress state. The experimental results demonstrated that the effective permeability to water and porosity was greatly enhanced in dilated zones during cold-water injection at modest levels of stress anisotropy. Three geomechanical compression tests were also conducted to obtain the geomechanical properties of the materials.
  The triaxial compression tests and the geomechanical dilation tests were then analyzed and served as inputs for the field-scale numerical simulation models. Based on the results of the numerical simulation study, the SAGD performance did not show significant improvement through the enhanced dilation start-up operation due to cold-water injection. This could be considered as an efficient and sustainable solution to quickly establish communication between the well-pair, and to shorten the duration of the start-up phase.

• Subjects / Keywords

  • SAGD Start-up
  • Triaxial Compression
  • SAGD Performance
  • Numerical Simulation
  • Geomechanical Dilation
  • Experimental Study

• Graduation date

  Spring 2020

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/r3-gjye-c204

• License

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