In a crude oil–water mixture (as encountered in desalting and production systems), bulk electrical conductivity depends on which parameters?

Introduction:
Electrical desalters and production separators rely on the electrical properties of crude–water emulsions. Understanding which variables influence conductivity helps operators optimize electric field strength, mixing, and chemical dosage for effective coalescence and salt removal.

Given Data / Assumptions:

• A two-phase crude oil–brine system is considered.
• We examine macroscopic conductivity relevant to electrostatic coalescence.
• Parameters of interest: pH, water percentage, temperature.

Concept / Approach:
Conductivity is carried primarily by the aqueous phase (brine droplets). Higher water cut increases conductive pathways. Temperature affects ion mobility and viscosity, generally raising conductivity as temperature increases. pH can influence interfacial films and dissociation equilibria, subtly impacting effective conductivity and emulsion stability.

Step-by-Step Solution:
1) Identify the carrier of conductivity: the brine phase in the emulsion.2) Water percentage: more brine → more continuous/connected conductive paths → higher measured conductivity.3) Temperature: higher T → increased ion mobility and reduced viscosity → higher conductivity.4) pH: affects surface-active species and ionic equilibria, influencing interfacial behavior and effective conductivity.

Verification / Alternative check:
Operational guidelines for electrical desalters link setpoints and field strengths to water cut and temperature; lab measurements show temperature coefficients for brine conductivity and pH effects on emulsion films.

Why Other Options Are Wrong:
Any single-factor choice ignores the multi-parameter nature of conductivity in emulsions.“Only salinity” is incomplete; while salinity is important, water cut, T, and pH also matter.

Common Pitfalls:
Assuming crude oil alone conducts; in practice, the aqueous phase dominates conductivity, and emulsions show strong dependence on water percentage and temperature.

Final Answer:
All (a), (b) and (c)