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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