Method and Apparatus for Detecting while Drilling Underbalanced The Presence and Depth of Water Produced from The Formation and for Measuring Parameters Related Thereto

摘要

The invention relates to methods and apparatus for determining a downhole parameter in an underbalanced drilling environment which include: selectively activating a first fluid flowing from the formation through a wellbore while under balanced drilled; detecting the activated first fluid, and determining a depth at which said fluid enters the wellbore.