Reservoir, Production, and Facilities Design
Heavy oil extraction presents a number of challenges, so testing, evaluation, and planning are all essential when making decisions about operation and surface facilities.
Accurate modeling and simulation
Understanding the fluid properties and the geology of the reservoir before commencing the production process is crucial. Many heavy oil wells rely on horizontal completions and are prone to the flow control challenges inherent in this type of completion, such as the heel-to-toe effect from friction loss along the wellbore and sand production, as well as pressure, fluid mobility, and permeability contrasts in the producing section. Thermal EOR processes such as steam-assisted gravity drainage (SAGD), steam flooding, and cyclic steam stimulation (CSS) have also created some challenges for the reservoir engineer when simulating heavy oil reservoirs.
Sophisticated software is the basis for selecting the best recovery process and includes matching the right method to the unique properties of a specific heavy oil and reservoir for optimum production. Today’s simulation capability can help select a variety of project planning options. This includes all aspects of project design from well locations and patterns, to completion strategies and steam injection strategies for thermal recovery projects and everything in between.
Reservoir Modeling
From pilot project and field development planning, to monitoring the last days of a reservoir’s productive life, a reservoir model is a critical tool in optimizing recovery and financial performance. A model provides state-of-the-art visualization, analysis of oil, gas, water, and solids behaviors, as well as uncertainty analysis and optimization, so that potential recovery and artificial lift methods can be evaluated.
Production Planning
Pilot Studies
Pilot studies provide an insight into reservoir behavior enabling oil and gas companies to characterize a reservoir and manage it more effectively. By knowing more about a reservoir, the most suitable sequence of production methods can be decided, thereby enhancing overall field recovery.
An early production facility (EPF) is a flexible solution to the need for new surface facilities. EPFs enable operators to appraise their reservoir performance before they install more expensive, long-term facilities. They can also be used for small reserves that would be financially uncertain or uneconomical to produce with a permanent production facility.
EPFs allow operators to test their reservoirs quickly and with relatively little expense. Pilot studies can be fully integrated into the production process enabling production and cash flow to be brought on stream more quickly. If the asset does not perform as expected, more measurements and changes can be made without high capital expenditure. For the surface or facility engineer, EPFs also provide a method of testing options for various surface facility designs, such as specialty oil water separation techniques for possible heavy oil emulsion problems.
Caprock integrity
Geomechanical properties of the reservoir change for most heavy oil reservoirs both thermal and CHOPS production methods. Measurements, tools, and techniques are needed to acquire data and analyze, model, and monitor the recovery process and its effect on the reservoir, the caprock, and the environment to maintain caprock integrity.
Due to the temperature challenges encountered in thermal EOR, downhole fiber-optic distributed-temperature sensors (DTS) enable operators to see where steam chambers are developing along the entire length of a horizontal run, this information can be used to adjust steam rates from nearby injection wells using sliding sleeves or other forms of injection control.
