''Formation testers'' are a class of wireline tools used to measure the downhole pressure of formations. Stationary measurements of formation pressure in an open hole are made at any number of depths during a single trip into the hole. These pressure measurements are useful in determining
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''Formation testers'' are a class of wireline tools used to measure the downhole pressure of formations. Stationary measurements of formation pressure in an open hole are made at any number of depths during a single [[trip]] into the hole. These pressure measurements are useful in determining
# variations in pressure among various formations,
# variations in pressure among various formations,