Device and method of measuring depth and azimuth

1. A method of measuring depth and/or azimuth of logging data, the logging data being related to at least one property of a zone surrounding a wellbore and being measured by at least one sensor array, the method comprising the steps of:

acquiring and storing a first logging data frame corresponding to a first position of the sensor array, and

acquiring and storing a second logging data frame corresponding to a second position of the sensor array,

wherein the first and second position are such that the second logging data frame overlaps at least partially the first logging data frame, and

wherein the method further comprises the steps of:

comparing the first and second logging data frame with a computer, and

determining a relative change in the depth and/or azimuth of logging data measured by the sensor array between the first and second logging data frame.

2. A method of measuring depth and/or azimuth according to claim 1 , wherein the method further comprises the step of calculating an actual depth value and/or an actual azimuth value of logging data based on the relative change in the depth and/or azimuth of logging data and a prior estimation of the depth and/or azimuth of logging data.

3. A method of measuring depth and/or azimuth according to claim 1 , wherein the step of comparing the first and second logging data frame includes determining an overlapping area, between both logging data frames.

4. A method of measuring depth and/or azimuth according to claim 3 , wherein the step of determining the overlapping area includes evaluating the coherence of the logging data frames by applying a correlation method on both logging data frames.

5. A method of measuring depth and/or azimuth according to claim 3 , wherein the step of determining the overlapping area includes evaluating the similarity of the logging data frames by applying a semblance method on both logging data frames.

6. A method of measuring depth and/or azimuth according to claim 1 , wherein the method further comprises correcting the prior estimation of the depth and/or the prior estimation of the azimuth of logging data based on a measurement made by a surface depth measuring system or a weight on tool measuring system.

7. A method of measuring depth and/or azimuth according to claim 1 , wherein the logging data are mechanical, electromagnetic, nuclear, acoustic or ultrasonic measurements.

8. A method of measuring depth and/or azimuth according to claim 1 , wherein the first and second logging data frames are 1D images or 2D images.

9. The method according to claim 1 , wherein the measuring is carried out by a non-transitory computer readable medium containing computer instructions stored therein for causing a computer processor to perform a program for a depth and/or azimuth measuring device arranged to be deployed into a wellbore, the program comprising a set of instructions that, when loaded into a program memory of the depth and/or azimuth measuring device, causes the depth and/or azimuth measuring device to carry out the steps of the method of measuring depth and/or azimuth of logging data.

10. A device for measuring depth and/or azimuth of logging data, the device being coupled to at least a sensor array for measuring logging data related to at least one property of a zone surrounding a wellbore, and comprising a memory buffer and at least one processing module, wherein the processing module of the depth and/or azimuth measuring device is arranged to:

acquire and store into the memory buffer a first logging data frame corresponding to a first position of the sensor array and a second logging data frame corresponding to a second position of the sensor array, the second logging data frame overlapping at least partially the first logging data frame,

compare the first and second logging data frame, and

calculate a relative change in the depth and/or azimuth of logging data between the first and second logging data frame.

11. A device for measuring depth and/or azimuth according to claim 9 , wherein the processing module of the depth and/or azimuth measuring device is further arranged to calculate an actual depth value and/or an actual azimuth value of logging data based on the relative change in the depth and/or azimuth of logging data and a prior estimation of the depth and/or azimuth of logging data.

12. A device for measuring depth and/or azimuth according to claim 9 , wherein the sensor array is a 1D sensor array or a 2D sensor array.

13. A device according to claim 9 , wherein the device is part of one of a drilling assembly and a logging tool.