Patent ID: 7260985
Filing Date: 2007-08-28
Classification: E21B,G01N

Abstract:
1. A downhole apparatus comprising: a drill collar having an outer surface for interaction with an earth formation; an extendable sample device having a bore and recessed beneath said outer surface in a first position to extend beyond said outer surface to a second position; a first draw down chamber slidably retaining a first draw down piston, said first draw down piston actuatable between a first position and a second position and said first draw down chamber in fluid communication with said extendable sample device; a flow line between said extendable sample device and said first draw down chamber, said bore and said flow line to receive at least formation fluid from the earth formation; and a second draw down chamber slidably retaining a second draw down piston, said second draw down chamber in fluid series with said first draw down chamber and said extendable sample device.