NoonTalk@DIATI #26: Well testing to solve the Inverse Problem in Reservoir Engineering
ABSTRACT
Well testing provides a measurement of flow and pressure versus time whose variation is influenced by diffusion in a reservoir. Depending on the test duration and the reservoir diffusivity (a function of permeability, porosity and fluid properties), distances of several kilometres can be “seen”.
Considering the rate as the input, I, and pressure as the output, O, (or vice versa), the properties of the well and reservoir system, S, can be inferred: S = O ⁄ I
Unfortunately, the solution to this Inverse Problem is non-unique and there may be many different systems that produce the same output for a given input. In general, it is recommended to consider the simplest system that satisfies the measurements until other sources of information justify an increase in complexity.
Deconvolution is a powerful technique that allows the complex variations in flow and pressure measurements to be disentangled into a much simpler pressure response due to constant rate.
The result is a dynamic signature of the well and reservoir response usually depicted as a pressure derivative on a log-log plot against which reservoir models can be calibrated.
This noon talk will elaborate on these points and share insights from recent research at Politecnico di Torino.
Save the date for our next speaker-event, on October 3rd, at 13:00
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