Abstract

Two-Rate Flow Test method has been used in Langkat Field Pertamina Unit EP–1, to estimate the average reservoir pressure, formation permeability and skin-factor. The required pressure data were obtained by observation of the transient bottom-hole pressure behavior after the stabilized producing rate of the well was changed to another lower rate.

Other parameters required for the analysis of Two-Rate Flow Test were similar to those used for the conventional pressure build-up analysis.

The advantage of applying this new method was that the extended shut in periods experienced with conventional build-ups because of long, low rate after production periods were eliminated by flow tests.

In 1983, Langkat Field carried out 17 Two-Rate Flow Test measurements, which could avoid a total production loss of about 201 m³.

The analysis of flowing bottom hole pressure data gave the same value of P* (P extrapolation) as pressure build-up test, except in oil producing wells with high water cut (water cut >50 %).

It was also found that the application of Two-Rate Flow Test could indicate the effect of a fault.