Sonic data, ultrasonic data, density data, cased-hole neutron data, and open-hole neutron data of the wellbore are obtained. The sonic and ultrasonic data provides the amplitude, frequency, and phase of the altered sonic and ultrasonic waves. The far counts, near counts, and energy spectrum are obtained from density data, cased-hole (CH) neutron data, and open-hole (OH) neutron data. The amplitude, frequency, and phase provide the interface densities of the first, second, and third interfaces. The hydrogen index (HI) of the formation and the cased wellbore are obtained from the CH and OH neutron data. The widths of the second and third interfaces are obtained from the HI's and the densities of the second and third interfaces.