Wireline formation tester avoids dew point problems ///
Collecting representative, single-phase retrograde gas samples from heterogeneous fractured carbonate formations is challenging, especially for cases in which the reservoir pressure narrowly exceeds the dew point. Conventional wireline probe/packer assemblies are undesirable in this situation because their small-diameter probes increase the pressure drawdown compared with other available intake configurations. Furthermore, the likelihood of establishing hydraulic communication with an open fracture or vug is low with a ½-in. diameter probe compared to setting straddle packers spanning a 1-m formation interval.
Inflatable straddle packers can be run with pump-out test tools, but they have temperature, pressure and operational limitations. Like a straddle packer, the new Oval Pad tool is effective when testing thinly laminated and tight formations, as well as fractured or vuggy carbonates. The oval shape enables the pad to encompass a significant vertical length of the borehole while establishing a pressure seal with the formation.
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