Abstract
Wireline Formation Testers are used to obtain formation fluid samples and to produce profiles of high precision pressure measurements versus depth. In addition, pressure transients are interpreted to estimate permeability in the region near the probe. Test attempts must confront a number of problems that previously have restricted the practical operating domain to a small fraction of candidate wells. Well- known fluid sampling problems include filtrate invasion, difficulty establishing and maintaining a probe seal, and pressure drawdown below bubblepoint.