Reservoir Properties Estimation based on Pressure and Temperature Data using ES-MDA

Resumo

Well test comprises a set of planned data acquisition activities and interpretation. The acquired pressure
and temperature data are used to estimate reservoir properties and oil field performance. The pressure data have
several noise sources that may compromise the accuracy of test results. The noise may mask the transient reservoir
behavior. Therefore, estimated reservoir properties, such as permeability, porosity, and skin effects, from those
acquired field data have a high level of uncertainty.

In this work, we use an in-house flow simulator that solves the complete coupled system of equations repre-
senting the wellbore/reservoir system. The thermal energy balance equation considers the Joule-Thomson heating

and cooling, adiabatic fluid expansion/compression, conduction, and convection effects. The synthetic measured
data was obtained by adding gaussian and harmonics noises to simulate equipment and tidal effects, respectively,
to the solution of the problem for different scenarios.
Reservoir properties estimation using pressure and temperature transient data obtained from well tests is a

classical inverse problem. We use Ensemble Smoother with Multiple Data Assimilation (ES-MDA) as a non-
deterministic method to solve this inverse problem. It provides a better data matching and quantification of uncer-
tainty when compared to other methods.

The results show that the properties of a reservoir with skin are better characterized by using combined
pressure and temperature data.