HR: 0800h
AN: GP31C-04 [Abstracts]
TI: Magnetic Properties of Drill Cutting from an Oil Well at Golfo San Jorge Basin, Argentina. Their
Correlation with Several Conventional Logs
AU: * Mena, M
EM: mena@gl.fcen.uba.ar
AF: University of Buenos Aires and CONICET, Department of Geological Sciences. FCEN.
Ciudad Universitaria Pab II, Buenos Aires, BA 1425, Argentina
AU: Orgeira, M J
EM: orgeira@gl.fcen.uba.ar
AF: University of Buenos Aires and CONICET, Department of Geological Sciences. FCEN.
Ciudad Universitaria Pab II, Buenos Aires, BA 1425, Argentina
AB:
The Golfo San Jorge Basin is one of the most important hydrocarbon-producing basins in Argentina. It is
characterized by good source rock, favourable structural complexity and multiple thin tuffaceous sandstones as
reservoirs. A study of magnetic properties performed over drill cutting take at different depth levels from an oil well
drilled in this basin was carried out. The cutting samples correspond to the upper terms of the Pozo D-129
Formation, main source rock of the basin.
Magnetic susceptibility measurements and rock-magnetic studies were performed to define the magnetic
mineralogy. Concentration indexes of the different magnetic minerals were determined on the base of isothermal
remanent magnetization (IRM) acquisition curves.
A correlation analysis between the magnetic properties and conventional well logs (sonic, neutronic, density,
induction, resisitivity and spontaneous potential) was performed. Several kinds of correlations were found:
significantly positive correlation between magnetic properties and porosities, and significantly negative
correlation between the concentration indexes of some magnetic species (titanomagnetite and pirrotite) and the
resistivity. The positive correlation between magnetic properties and porosities is especially good with the
porosity calculated from the neutronic log.
The presence of hydrocarbons in cutting is associated with the frequency dependence of susceptibility factor,
showing different relationship with oil and gas.
DE: 1512 Environmental magnetism
SC: Geomagnetism and Paleomagnetism [GP]
MN: 2007 Joint Assembly