EQUATION-OF-STATE MEASUREMENTS FOR CRUDE OILS AT PRESSURES UP TO 1-GPA

Equation-of-state measurements of two crude oils with different compos itions and viscosity were performed at room temperature in the pressur e range 0 < P < 1.0 GPa. We found large compressibilities and a strong dependence of the compressibility on oil content and viscosity. The b ulk modulus changed with pressure from 2.0 to 12.1 GPa for one oil and from 1.3 to 9.5 GPa for the other. We discuss the possibility of dete cting phase transitions in the region under investigation. The Tait an d Murnaghan equations of state were fitted to the data, and residuals are presented.