CAP (Capacitance Logging Tool)

Applications

• Assessing borehole multiphase flow components

Sample Logs

Tool Schematic

Mathematical Model

where 

$//<![CDATA[ \begin{array}{l}\{ s_w, \ s_o, \ s_g \}\end{array} //]]>$ – volumetric fractions of water, oil and gas phase ( $//<![CDATA[ \begin{array}{l}s_w + s_o + s_g = 1\end{array} //]]>$), 

$//<![CDATA[ \begin{array}{l}\{ Y_w , \ Y_o , \ Y_g \}\end{array} //]]>$ – are reference values for capacitance of water, oil and gas at given temperature and pressure,

$//<![CDATA[ \begin{array}{l}\mathring{Y}_w\end{array} //]]>$ fresh water capacitance at NTP,

$//<![CDATA[ \begin{array}{l}F_{\rm cap}\end{array} //]]>$ – non-near function specific to each tool.