Well Log Analysis

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The Log Analysis application estimates reservoir shale volume, effective porosity and water saturation.

Shale Volume is estimated using any of the following correlations. The correlation can be specified in the "Common Data Panel".



Effective Porosity is estimated from the shale volume, density porosity and neutron porosity with the following equations:



Water Saturation is calculated using a Simandoux shaley sand model by the following equations:



Variables

Ira
GR Gamma ray reading average in the zone if interest, API gamma ray units
GRclean
GRshale
Vsh Shale volume
PorDcorr % of bulk volume
PorD % of bulk volume
PorDshale % of bulk volume
PorNcorr % of bulk volume
PorN % of bulk volume
PorNshale % of bulk volume
PorE Effective Porosity % of bulk volume
Sw Water Saturation
Rw Water Resistivity is the resistivity of the formation water at the downhole temperature and pressure. This can be estimated from water analysis, spontaneous potential (SP) log curve response or can be calculated from a clean water sand. ohm-m
Rshale Shale Resistivity is the resistivity reading in a shale interval. This resistivity will most likely be determined at the same depth that the GR shale value occurs. ohm-m
Rt True Resistivity is the average resistivity of the formation in the interval of interest. True resistivity assumes the log resistivity readings have been corrected for fluid invasion and is usually approximated by the resistivity reading with the deepest radius of investigation. ohm-m



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Last updated 8 October 2006