Patent ID: 8902695
Filing Date: 2014-12-02
Classification: E21B,G01V

Abstract:
1. A method for correcting downhole measurements; comprising: taking a plurality of measurements over a time period during drilling of a wellbore using a sensor; recording times of taking the plurality of measurements using a first clock at a first location in the wellbore; transmitting a synchronization signals through a fluid in the wellbore by a transmitter generated at the first location during drilling of the wellbore; recording a time of transmitting the synchronization signal using the first clock associated with the first location; receiving the synchronization signals at a second location; recording a time of receiving the synchronization signal using a second clock associated with the second location; determining a time delay for the synchronization signal using a distance between the first location and the second location and a speed of sound in the fluid in the wellbore; retrieving the measurements from the wellbore after the time period; determining a time drift relation between the first clock and the second clock using the determined time delay; and using the determined time drift relation to correct the plurality of times at which the measurements are taken over the time period.