Case01 Injection and Production
Contents
The primary goal of this example is to demonstrate the usage of well elements in an illustrative THM injection and production faulted model.
The files for the project are in directory: ParaGeo Examples\General Examples\Ex_008\Case01. Only the key data associated with usage of well elements, contact property and transient time step growth solution data will be described here. A tutorial on how to generate the geometry for this Case01 example using Gmsh is available in Gmsh_002, albeit with slightly different mesh refinement from that presented here.
Note that the injection and production wells are not 'active' until stage 4 and 5 respectively, however, it is recommended that the wells are defined in stage 1 with the well points 'shut' and then updated to 'open' when they come online in the later stages. This enables the user to visualize and track the wells throughout the simulation.
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Model and Mesh Definition |
Key contact property data (.contact)
•Note that the thermal normal contact conductivities for the fault are defined the same as the layer material grain thermal conductivities. •A one metre damage zone is defined for the fault Contact_width.
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Key data for well definition in Stage 1
Well_definition #1 (Injection well)
Well_definition #2 (Production well) •Notice that Well_temperature is not defined for the production well as it only makes sense to define this data for the injected well fluid.
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| Key data for well definition in Stage 4 injection and Stage 5 production |
Once the wells come online, the well data previously defined in stage 1 still applies and the re-definition well data need only consist of the name of the well, the status distribution (and well loading time curve if different from previously defined).
Well_definition #1 (Injection well)
Well_definition #2 (Production well)
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| Key data for solution control in Stage 6 injection and production flow over 14 years duration |
It is not uncommon in reservoir injection and production simulations which take place over a long duration (e.g. 14 years) that steady-state flow occurs where the pore pressure in the injected/depleted reservoir remains constant. Under these conditions, the model simulation does not require small time steps to capture the change in pore pressure as there is little/no pore pressure change, hence the simulation can be performed using large time step increments. To achieve this, a transient time step growth factor in the solution control data can be defined.
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| Results |
The result files for the project are in directory: ParaGeo Examples\General Examples\Ex_008\Case01\Results.
The results below show the initial condition of the model with depth-dependent spatial temperature gradient from 10°C at the surface to 71°C at the base of the model and hydrostatic pore pressure for the whole model. Injected well temperature is at 30°C.
Initial Condition: Depth-dependent spatial temperature gradient and hydrostatic pore pressure
Below shows the plots of temperature and pore pressure distribution through the simulation time at four history points located in the injected/depleted reservoir layer. Notice that the pore pressure is near constant after 60 days with maximum over-pressure of 4.4MPa in the vicinity of the injected 'open' well. The heat transfer of the well injected temperature of 30°C from west to east progresses slowly through time with the fault hanging wall only 'seeing' the injected fluid temperature after 3000 days.
History points in injected/depleted reservoir layer and the temperature and pore pressure distribution at these points over simulated model time
Over-pressure in both reservoir layers can be seen in the plots below with maximum over-pressure of 4.4MPa in the injected reservoir in the vicinity of the 'open' injection well and 3MPa in the top reservoir layer.
Over-pressure in the two reservoir layers at various times
The plots below show the flow velocity vectors moving across and up from the injected/depleted reservoir layer to the top reservoir layer in the early stages of injection/depletion. Over time, the flow vectors is predominantly moving across from injection to depletion wells, crossing the fault.
Flow vectors in the two reservoir layers at various times
The plots of change in temperature in the injected/depleted reservoir layer shows heat transfer of the injected well fluid (30°C) mainly from advection flow progressing slowly over the simulated time from injection well to production well.
Change in temperature highlighting heat transfer predominantly via advection flow in the injected/depleted reservoir layer at various times
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