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Dedicated to the art and planning of pore pressure prediction and potential drilling hazards.

Issue Number 2                                         


Greetings and warm holiday wishes for you and your family. Each year BPI sends a New Year Calendar to its select Clients. Each year we receive a few notes that the Calendar photos reminded some of a wonderful experience they had where the photograph was taken. This makes our day when we hear about the experience.

The Drillerís Geophysicistš

The Drillerís Geophysicistš shall be the new name for the BPI Newsletter, beginning with the next issue.

Update from BPI

First an update then some technical data for you, our Client: Almost everyone is interested in whatís new and whatís coming up. BPI shall do whatever it takes to maintain its technical edge in the areas of well planning and seismic pressure prognosis. What we accomplished this year:


What we are planning:

What is Hard Pressure?

Do not use the term hard pressure. The term hard pressure is a misunderstood term. The term 'hard pressure' dates back to Loucks, et al (1979), where the authors say they recognized three (3) pressure regimes, defined in terms of pressure-depth gradients:


*normal pressure (0.465 psi/ft, 8.9 PPG EMW, 1.07 kg/l),

*soft overpressure (0.465 to 0.700 psi/ft, 13.5 PPG EMW,  1.62 kg/l), and

*hard overpressure (> 0.700 psi/ft, 13.5 PPG EMW,  1.62 kg/l).


We at BPI, strongly disagree with the use of these terms. Hard pressure refers more to a short pressure transition zone where significant changes to drilling parameters are required during drilling operations. Hard pressure is not a term that BPI uses. We document transition zones and the reasons for changes and their magnitude, depth and uncertainty/certainly.


Sometimes unexpected short transition zones are encountered from geologic causes:


Geologic caused pressure transition zones are identifiable from subsurface data and seismic data.


*To convert psi/ft to PPG-EMW divide by 0.0519.

*To convert psi/ft to kg/l divide by 0.433.

PPG = pounds per gallon

EMW = equivalent mud weight


BPI Newsletter is published and freely distributed by:

Baird Petrophysical Group, Inc.

1784 W. Sam Houston Pkwy N.

Houston, Texas 77043-2723.


The results discussed herein are based on interpretation of drilling planning, geological, geophysical and other scientific data supplied to Baird Petrophysical by its various customers on a private basis.It is the Readerís responsibility to value its use.Baird Petrophysical specifically disclaims and does not warrant any of its news, comments, interpretations or opinions about the information presented here.

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