Acoustic property of heavy oil - measured data

Summary Heavy oils are viscous fluid having three phases: fluid, quasi-solid and glass solid depended on temperature. We have measured ultrasonic velocities on 10 heavy oil samples at different phases. Measured data suggest that heavy oil properties are similar to the light oil properties if temperatures are higher than the liquid point. With temperature decreases below the liquid point, heavy oil transfers from liquid phase to a quasi-solid phase with drastic increase of viscosity, S-wave velocity appears measurable and P-wave velocity deviated up from the light oil trend. P- and S-wave velocities of heavy oils show a systematic relation to API gravity, temperature, pressure, GOR, and appear dispersive as heavy oil in the quasi-solid state. densities, gas-oil ratios and bubble points may not apply well to heavy oils. Heavy oil at high temperatures can be characterized similar as light oil. However, at low temperatures, viscosity of heavy oils increases drastically and properties of heavy oils are significantly different. We need study properties of heavy oil thoroughly in order to build a proper rock physics model for heavy oil reservoirs.