Commingled injection well modeling
Hi,
I am trying to model a commingled injection well which is a well completed through multilayers (5 layers in my model). Every layer in my model is represented by a single grid block in the Z direction. I want to model the injection well such that it is completed through 5 grid blocks. I would like to know if the following input is correct or not. I have increased the increment between the code numbers the successive elements with identical sink/source to 5.
GENER----1----*----2----*----3----*----4----*----5----*----6----*----7----*----8
A1 1inj 1 5 COM3 1.00
9 replies
-
It's correct, depending on what you are trying to do. In your case, elements "A1 1", "A1 2", "A1 3", "A1 4" and "A1 5" will inject COM3 at a rate of 1 kg/s each. Make sure that these elements are actually the ones in which you want to inject.
I usually don't really like using the parameter NAD and prefer explicitly listing all the sources.
-
Hello, I would like to ask about something. For simulating injection into a 5-layer model, is it possible to specify the lithology of the well for the five source/sink grid blocks in the Rock module to achieve well injection simulation? Additionally, the lithology of the well has permeability and porosity several orders of magnitude higher than those of the reservoir caprock. Can this be implemented? I've been having trouble with convergence while trying to achieve this, which makes me question the practicality of this approach.
-
I think it is definetely possible, as it has already been done. An example is given by Giorgis et al., Energy Conversion and Management 48 (2007) 1816–1826.
You need to assign a specific domain for the wellbore elements, basically with porosity equal to 1, very high permeability (1.E-6 m2), rock density negligible, rock specific heat negligible, rock conductivity negligible. The distance of wellbore nodes from the wellbore surface should be nearly zero.
The wellbore elements should have no PCAP. About RELP functions, for sure you should have Kr=1 when the wellbore is filled by the injected phase (I guess a CO2 rich-phase according to COM3).
Then you should inject only in the uppermost wellbore element, letting the code to evaluate which is the fluid flow rate injected into each layer.
What could be a bit cumbersome is the initial step of CO2 injection: if you start with the well filled with brine, is it likely that you can encounter some convergence problem because TOUGH2 is using Darcy's law even for the the flow across the wellbore elements, when you have two-phase conditions as the CO2 rich-phase is displacing the brine. If you are not interested into short term transients (otherwise you should use T2Well-ECO2N), you may consider to start with the wellbore already filled by CO2. In this way you neglect the initial brine displacement in the wellbore.
By the way, using the properties of the injected CO2, you can also estimate the value of wellbore vertical permeability to simulate the correct friction losses along the wellbore. This may be important only if you simulate a long wellbore section, otherwise you can neglect the pressure drops due to friction.
Regards,
Alfredo