Abstract

This paper reports on the successful application of Pressure Transient Analysis (PTA) providing theoretical background to support the hydraulic fracturing of several reservoirs in the Brazilian Northeast, thus leading to a huge hike in oil production.

We describe how PTA has helped shed light on the fact such reservoir should not be viewed as a conventional system, but rather as an unconventional one. Based on our findings, we conjecture that it could be regarded as a fracture network surrounded by a porous matrix.

That being said, a hydraulic fracture would readily connect the wellbore with the fracture network, bypassing the less permeable matrix, and, as a result, cause an increase in oil production. The gain in oil flow rate, in our examples, has averaged a tenfold increase. Not only did PTA help increase oil production, it also helped shed light on how best to read the dynamic behavior of a mature reservoir.

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