Layer | Fill | Outline |
---|
Map layers
Theme | Visible | Selectable | Appearance | Zoom Range (now: 0) |
---|
Fill | Stroke |
---|---|
Collaborating Authors
Results
Abstract Absolute permeability plays an important role in reservoir engineering. Reservoirs like oil sands are shallow unconsolidated formations and stress dependent. During steam-assisted drainage (SAGD) the effective stress increases as results of either increasing in temperature or pore pressure. Rock properties for instance permeability will be induced by this change to influence therefore reservoir calculations. To understand the behavior of stress-strain in unconsolidated reservoir during a SAGD, a series of drained triaxial compression tests were performed to study the shear-induced changes in absolute permeability at low stress conditions. The experimental program included stress-strain tests under two different paths: isotropic unloading and increasing of mean stress was followed by permeability tests at each levels of strain and at different confining effective stresses. Results from this study showed a substantial increase of absolute permeability in the lower case of 50 kPa of effective confining stress. This gain was up to 88%. In the higher level of effective confining stress, however, there was a decrease of absolute permeability. The aim of this project was to provide an empirical correlation linking the absolute permeability to effective confining stress and volumetric stain so that the behavior of absolute permeability at different overburden depths will be understood.
- North America > United States (1.00)
- North America > Canada > Alberta (1.00)
- Geology > Geological Subdiscipline > Geomechanics (1.00)
- Geology > Petroleum Play Type > Unconventional Play > Heavy Oil Play (0.49)
Abstract For stress-sensitive heavy oil reservoirs, geomechanical responses of the reservoir are taken into account as they play an important role in the accurate simulation of all thermal recovery techniques, such as SAGD, or steamflood. However full- field numerical simulations of multi-physics processes by any coupling strategies are technically impossible with current computer CPUs. Under these conditions, analytical methods can be used as approximate techniques instead of numerical simulators, as they are much faster and yet are useful tools for preliminary forecasting and sensitivity studies. In analytical models, inclusions of all flow variables impacts into geomechanics frameworks make the equations so complex and almost impossible to solve. This paper provides a flow-based domain decomposition workflow for performing different analytical coupling schemes in different reservoir compartments. Since the intensity and complexity of reservoir geomechanics vary over reservoir domain, one can divide the reservoir to some sub-domains and assess different geomechanical responses separately in each sub-domain. The presented analytical proxy, suggest decomposition of the whole domain in into two parts of "heated zone" and "wetted zone", for rapid assessment of geomechanics. The heat flow equation was combined with mass and momentum convective transport equations to obtain an exact approach that correlates the saturation front of injected hot water to temperature front. The frontal velocities are dynamic interfaces for compartmentalization of the domain. In the heated zone, the total induced stresses, were considered due to both temperature and pressure increase, and in the wetted (saturated) zone beyond the temperature front, at each instance the total stress induced is only a function of pressure increase, and accordingly stress and strain induced are due to isotropic unloading. This technique provides a rapid estimate of geomechanical responses (stress and strain profile) in each part of the reservoir (near field and far field). A numerical model was built and implemented in CMG-STARS for steam-flood case to show the robustness and applicability range of the model. The results were analyzed for synthetic case single-domain model and the model sensitivity on some reservoir parameters were checked, and at the same time geomechanical responses were not neglected anywhere (near-filed and far field) in the reservoir.
- Geology > Petroleum Play Type > Unconventional Play > Heavy Oil Play (1.00)
- Geology > Geological Subdiscipline > Geomechanics (1.00)
- Well Drilling > Wellbore Design > Wellbore integrity (1.00)
- Reservoir Description and Dynamics > Unconventional and Complex Reservoirs > Oil sand, oil shale, bitumen (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Reservoir geomechanics (1.00)
- Reservoir Description and Dynamics > Improved and Enhanced Recovery > Thermal methods (1.00)
Abstract Steam-assisted gravity drainage (SAGD) is the method of choice to extract bitumen from Athabasca oil sand reservoirs in Western Canada. Bitumen at reservoir condition is immobile due to high viscosity and its saturation is typically large that limits the injectivity of a steam at in-situ condition. In a current industry practice, steam is circulated within injection and production wells. Operators keep the steam circulation till mobile bitumen breaks through the producer and communication is established between the injector and the producer. The "start-up" (or "circulation") phase is ranging between three to several months. A variety of processes are used to minimize time of start-up phase such as: electro-magnetic (EM) heating either induction (medium frequency) or radio frequency (RF) ranges. Knowing the hot-zone size formed by steam circulation and benefit of simultaneous EM-heating techniques help better understand the start-up process and how to minimize the start-up duration. The aim of the present work is to introduce an analytical model to predict start-up duration for only steam circulation and also for with EM-heating. The results obtained from this study reveal that induction slightly decrease start-up time for frequencies smaller than 10 kHz, and it can reduce start-up time to 30% of original steam circulation for 100 kHz frequency.
- North America > United States (1.00)
- North America > Canada > Alberta > Athabasca Oil Sands (0.48)
- North America > Canada > Alberta > Western Canada Sedimentary Basin > Alberta Basin > Bluesky Formation (0.99)
- North America > Canada > Alberta > Athabasca Oil Sands > Western Canada Sedimentary Basin > Alberta Basin > North Steepbank Mine (0.99)
- North America > Canada > Alberta > Athabasca Oil Sands > Western Canada Sedimentary Basin > Alberta Basin > McMurray Formation (0.99)
- (2 more...)
- Reservoir Description and Dynamics > Unconventional and Complex Reservoirs > Oil sand, oil shale, bitumen (1.00)
- Reservoir Description and Dynamics > Improved and Enhanced Recovery > Thermal methods (1.00)
- Facilities Design, Construction and Operation > Unconventional Production Facilities > Oil sand/shale/bitumen (1.00)
Abstract Steam-assisted gravity drainage (SAGD) is one successful thermal recovery technique applied in the Albertan oil sand reservoirs. When considering in situ production from bitumen reservoirs, bitumen viscosity must be reduced to achieve the mobility required to flow toward the production well. Steam injection is currently the most promising thermal recovery method. While steam flooding techniques have proved to be commercially viable methods to extract bitumen from bitumen reservoirs, caprock integrity and the risk of losing steam containment can be a challenging operational problem. Since permeability is low in Albertan thermal project caprock formations the water trapped in pores undergo large pressure increases during heating. In addition, water undergoes a large volume increase as it flashes to steam and the resultant pore pressure causing profound effective stress reduction. Once this condition is established, pore pressure increases can lead to shear failure of the caprock, and to subsequent caprock integrity failure or casing failure. It is typically believed that low permeability caprocks impede the transmission of pore pressure from the reservoir, making them more resistant to shear failure (Collins, 2005, 2007). In cases of "thermo-hydro-mechanical pressurization", low permeability caprocks are not always more resistant. As the steam chamber rises into the caprock, the heated pore fluids may flash to steam. Consequently, there is a vapour region between the steam chamber interface penetrated into the caprock and water region within the caprock which is still at subcritical state. This study develops the fluid mass and thermal energy conservation equations and presents analytical solution to evaluate the thermo-hydro-mechanical pressurization in low permeability caprocks and flow of steam and water after initiation of steam injection in SAGD process. Both short-term and long-term response are calculated. The evaluated thermal pressurization is compared for shallow and deep oil sand reservoirs, for similar transport properties. These results showed that the thermo-hydro-mechanical pressurization is larger in deep reservoirs; SAGD application can cause high pore-pressure and potential shear with the caprock resulting steam releases to surface and casing failures.
- North America > United States (1.00)
- North America > Canada > Alberta (1.00)
- Geology > Petroleum Play Type > Unconventional Play > Heavy Oil Play (1.00)
- Geology > Geological Subdiscipline > Geomechanics (1.00)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Sandstone (0.68)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock > Shale (0.48)
- North America > Canada > Alberta > Western Canada Sedimentary Basin > Alberta Basin > Cold Lake Field > Clearwater Formation > 995053 2D Cold Lake 2-10-63-2 Well (0.99)
- North America > Canada > Alberta > Western Canada Sedimentary Basin > Alberta Basin > Clearwater Formation (0.99)
- North America > United States > New Mexico > Permian Basin > Caprock Field > Queen Formation (0.98)
- (2 more...)
Abstract Most recent studies on hydro-mechanical simulation of underground CO2 storage in saline aquifers have been focused either on the early reservoir life and short term migration of CO2 plume, or on near field scenarios in the vicinity of injection well. The main reason is the crucial computational cost that current coupling schemes and simulators carry out. Particularly, realistic inclusion of geomechanics into fluid flow processes is a bottle neck in hydro-mechanical coupling of large heterogeneous models of stress sensitive reservoirs with complex fluid flow and geomechanical physics. This work introduces a new coupling scheme between fluid flow and rock deformation, for rapid hydro-mechanical simulation of large heterogeneous reservoirs with elastic geomechanical constitutive behaviors. The technique is mainly about using of streamline simulations for hydro-mechanical coupling purposes. To assess the efficiency of the technique in terms of speed and accuracy, a large reservoir-cap rock system with relatively large number of grid-blocks was made. The speed and robustness of streamline-based hydromechanical coupling was investigated versus finite volume based flow-geomechanical simulations for the same model with the same geometry and physics. The concept of effective stress was applied in characterizing the stress state. The governing geomechanical and fluid flow equations were implemented based on mass and momentum balance equation for linear elastic materials. Forward flow streamline simulation was performed with 3DSL, which is developed on the FORTRAN platform. This paper first investigated the feasibility of inclusion of geomechanics in streamline simulation, and in the next step compared the efficiency and accuracy of the developed scheme to one of the conventional finite-volume based fluid flow-geomechanical simulations. The FV-FEA tool was developed based on Box-method (subdomain collocated finite-volume finite-element technique) to couple fluid flow and geomechanics to be compared with the so called SL-based hydromechanical coupling. The simulation results and comparative studies between two appraoches, demonstrated that the introduced technique is robust and increases the model efficiency and decreases the computational costs significantly. The approach also demonstrated to be helpful in hydromechanical coupling of CO2 storage, particularly for large domains and during the injection period.
- Europe (0.93)
- North America > Canada > Alberta (0.28)
- North America > United States > Texas (0.28)
- North America > Canada > Saskatchewan (0.28)
- North America > Canada > Saskatchewan > Williston Basin > Weyburn Field > Mission Canyon Formation (0.99)
- North America > Canada > Saskatchewan > Williston Basin > Weyburn Field > Madison Formation (0.99)
- North America > Canada > Saskatchewan > Williston Basin > Weyburn Field > Forbisher Formation (0.99)
- (2 more...)
- Reservoir Description and Dynamics > Storage Reservoir Engineering > CO2 capture and sequestration (1.00)
- Reservoir Description and Dynamics > Reservoir Simulation > Streamline simulation (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Exploration, development, structural geology (1.00)
- (3 more...)
- Information Technology > Modeling & Simulation (1.00)
- Information Technology > Software (0.93)