Patent ID: 9547105
Date: 2017-01-17
CPC Classifications: E21B,G01V

Claim:
1. A method, comprising: introducing a tool string into a wellbore, the wellbore at least partially lined with a first casing and a second casing concentrically overlapping a portion of the first casing, wherein a first annulus is defined between the first and second casings and filled with a first cement, and a second annulus is defined between the second casing and the wellbore and filled with a second cement; obtaining data from a pulsed neutron sensor, a noise sensor, a Doppler sensor, and a temperature sensor, all included in the tool string; determining a gas presence in a flow path located at a cement interface in the wellbore and a first distance of the flow path from the tool string using a pulsed neutron log borehole model and the data obtained from the pulsed neutron sensor; calculating a second distance of the flow path from the tool string and a first velocity of a gas flow in the flow path using a noise log borehole model and the data obtained from the noise sensor; correlating the first distance and the gas presence with the second distance and the first velocity to obtain a first calculated distance of the flow path and a first calculated velocity of the gas flow in the flow path; calculating a third distance of the flow path from the tool string and a second velocity of the gas flow in the flow path using a Doppler borehole model and the data obtained from the Doppler sensor; comparing the third distance and the second velocity with the first calculated distance and first calculated velocity, respectively, to obtain a second calculated distance of the flow path and a second calculated velocity of the gas flow in the flow path; calculating a fourth distance of the flow path from the tool string and a third velocity of the gas flow in the flow path using a temperature borehole model and the data obtained from the temperature sensor; and comparing the fourth distance and the third velocity with the second calculated distance and the second calculated velocity, respectively, to determine a width of the cement interface, a distance of the cement interface from the tool string, and a velocity of a gas flow in the cement interface.