PTA is an Exploration tool when we conduct a drill stem test (DST). DST’s are one of the first tests we can run, while drilling, thus in the open hole environment. DST’s are simple closed chamber impulse tests, dual packers, valve open, valve closed, repeat. Initial pressure, a key reservoir engineering parameter, is one noble goal. But inflow potential is what we explore and drill for in the first place: producible oil and gas hydrocarbons. DST’s can be our first glimpse into reservoir fluid composition and productivity.