Method and apparatus for detecting while drilling underbalanced the presence and depth of water produced from the formation
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.
1. A method for determining a downhole parameter in a drilling environment, comprising:
drilling a wellbore overbalanced;
detecting a fracture through the formation;
drilling said wellbore underbalanced;
selectively producing a mark on a first fluid flowing from the formation through said wellbore during under balanced drilled;
detecting the mark in the first fluid;
determining a depth at which said mark was detected in said first fluid; and resuming drilling overbalanced.