The overall goal of petrophysical work is the development of
interpretation methods
that allow the transformation of  measurable physical
properties of the subsurface as
they can be delivered by geophysical surface and borehole
methods into information
relevant for exploitation and reservoir management. The
first step in this process is
the identification of  that type of information which is
relevant for the
exploitation and may be hidden in the data gathered with
geophysical methods. The
second step is the design of a lab-experiment which 
simulates the conditions and
processes in nature with close control of all relevant
parameters. Such
lab-experiments provide the basis to study how the
interesting parameter or
information influences the physical properties, which are
directly measurable with
geophysical methods.  The discovered interdependencies
between the parameters of
interest and the measurable physical properties can then be
used to formulate
interpretation algorithms which still may require
calibration for different rock types.
However, the first step, like no other, requires the
communication between the
different scientific branches involved, from the field
geophysicist to the reservoir
engineer. With respect to petrophysics for geothermal
exploration and exploitation
there are still technical limitations due to the high
temperatures we have to deal
with. However, taking advantage of the achievements of 
material- and other technical
sciences we have many more options nowadays.  Using high
performance polymers it is
now possible to perform petrophysical experiments on drill cores
(4-electrode-resistivity; p- and  s-wave velocities,
permeability) with controlled
pore pressure up to 300°C in oil pressure chambers. The
investigation of rocks at
higher temperatures is possible in gas pressure systems but
requires a much higher
experimental and financial effort, therefore, these
experiments can not be performed
on a routine basis yet.  
This presentation will give an overview about the recent
scientific and technical
developments in experimental petrophysics that could be
useful for geothermal
exploration.

Telegrafenberg
14473 Potsdam