electrical properties of rocks_for posting [compatibility mode]

8/3/2019 Electrical Properties of Rocks_for Posting [Compatibility Mode]

1/55

Basic Well Logging

Electrical Properties of RocksNeal Alleyne

[email protected]


2/55

Basic Well-Logging InterpretationSequence


3/55

We are Making an Assumption

We are assuming that we know the porosityof the rock !!


4/55

Learning Outcomes


5/55

Recommended Reading

Pages 108 136 in Introduction to

Wireline Log Analysis, Baker Hughes Inc.(2002).

, - ,Measurement, and Interpretation of WellLogs by Zaki Bassiouni, SPE Textbook

Series Vol. 4 (1994).


6/55


7/55


8/55


9/55


10/55


11/55


12/55


13/55


14/55


15/55


16/55


17/55


18/55


19/55


20/55


21/55


22/55


23/55

Electrical Resistivity of Rock

Constituents Most rock forming minerals are insulators

(exceptions are: ores and graphite) Pore content gas - Pore content oil -

Shale and clay

Conclusion The electrical conductivity of porous

rocks is dependent on


24/55


25/55


26/55


27/55


28/55


29/55


30/55


31/55


32/55


33/55


34/55


35/55


36/55


37/55


38/55


39/55


40/55


41/55


42/55


43/55


44/55


45/55


46/55


47/55


48/55


49/55


50/55


51/55


52/55


53/55


54/55

Insights In clean clastic rocks, electrical resistivity is related to porosity and

water saturation or hydrocarbon saturation. Tortuosity and connected porosity have a significant impact on the

electrical resistivity of a rock Cementation, grain sorting and grain packing have a significant

influence on tortuosity and pore connectivity, and hence on electricalresistivit .

The spatial distribution of fluids (hydrocarbons and water) and theirsaturations have a significant impact on the resistivity of a rock.

The presence of clay may cause a significant change in theelectrical resistivity behaviour of a rock

Oil-wettability may cause a significant change in the electricalresistivity behaviour of a rock.

Conclusion Always question the validity, reliability and level ofcertainty Archies equations and parameters


55/55

Acknowledgements:Dr. Carlos Torres-Verdin, UT at Austin

Schlumberger

Baker Atlas

electrical properties of rocks_for posting [compatibility mode]

Documents