Unformatted text preview: 05 by Ali Ghalambor & Boyun Guo 63 1. Detection Methods
There have been larger number of techniques
developed to detect and quantify abnormal
pressures, See page No.2 for detail.
2.Penetration Rate Charge
This is one of primary indicators for abnormal
pressures because of its ease in observation.
Maximum penetration rates can be attained when
the mud hydrostatic pressure is approximately
equal to the formation pressure. The relationship
can be seen in Fig.1 where the differential
pressures is the difference between the mud
hydrostatic pressure and the formation fluid
pressure. Fig.1 Effect of differential pressure on drilling rate Copyright(c) 2005 by Ali Ghalambor & Boyun Guo 128 64 3. Shale Density Charge: The porosity in abnormally pressured
zones will be greater than normal, the density of the shale will
be less than normal due to the high water content in the
porosity. Any deviation from a normal shale density increase
will indicate abnormal porosities which detect abnormal
4. Mud Chloride Change: Also a result of the high rock...
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- Fall '14
- Boyun Guo, Ali Ghalambor