Section A
Q1.
(a) Draw a neat diagram comparing the decay and build-up of voltage in Induced Polarization (IP) versus Resistivity – Capacitance (R - C) circuits. How are the two curves different? What are Membrane and Electrode Potential and why are they caused during IP measurements?
(b) What parameters are measured in sonic log acquisition and what major properties are derived from these parameters (one from each parameter)? Also write the standard corrections applied to sonic travel times.
(c)
The given schematics shows representative curves for oil migration in a rock. The three rock types shown have a dominant quartz mineralogy. Answer the following:
(i) What do R1 and R3 and E1 and E3 represent ? State their respective values.
(ii) If the bulk densities of the three rock types are \rhob1 = 2.0 gm/cc, \rhob2 = 2.25 gm/cc and \rhob3 = 2.5 gm/cc, calculate the porosity in rock types 1 and 3 only. Also given \rho_{\textbrine} = 1.2 gm/cc, \rho_{\textore} = 0.75 gm/cc and \rho_{\textquartz} = 2.65 gm/cc.