Dear Propetra, we recently conducted a pressure buildup test in one of our sandstone well, the data when analyzed on ecrin software has characteristic trend that shows 2 iarfs (horizontals). We are confused between 2 layers and a radial composite behavior as possible diagnosis. How can we narrow down our interpretation?
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Hello,
Differentiating between two layer & radial composite modelling directly from the log-log plot may not be possible. We need to evaluate the structure and geology of the reservoir to make the right engineering judgement. Following are some of my views:
When referring to two layers model, first see if you have two different zones perfoated and flowing in the well. Were they accessible or open in wellbore when welltest was conducted? if that is true than two layers is most likely your model to analyze the data with.
If you dont have two different zone, evaluate the petrophysics & dynamic data such as permeability and production surveys to identify any possible channeling or heterogeneity within your single zone interval. If you can find reliable evidence for significant facies alteration within your zone that two layers is your model again to analyze.
Lastly if not geological, petrophysical or production data validate your theory of two layers model, you can evalaute structure data or seismic attriubutes to validate if radial composite reservoir might a possibility. The thing about using radial composite models in well-testing is that they can be made to fit almost all welltest surveys, due to their extensive variables and degree of freedom. But maybe, your reservoir is radial composite.
I cant provide more than general guidelines without actually having a look at the data or atleast the log-log plot. Feel free to reply with them for more help.
Thanks
Imran