Page 59 - Standard Handbook Petroleum Natural Gas Engineering VOLUME2
P. 59
Basic Principles, Definitions, and Data 47
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POROS I TY, O/o
Flgure 532. Graphical comparison of relationship between formation
resistivity factor and porosity [55].
To summarize the general relationship between formation resistivity factor and
porosity (refer to Equation 5-49), the normal range for the geometric term, a,
is 0.6 to 1.4, and the range for the cementation exponent, m, is 1.7 to 2.5 for
most consolidated reservoir rocks [62]. Since the exact values depend on pore
geometry and composition of the rock, formation factors should be determined
