Patent ID: 9593571
Date: 2017-03-14
CPC Classifications: E21B

Claim:
1. A method comprising: accepting as input to a computer measurements of a characteristic of a subsurface formation made at a plurality of spaced apart positions along a pipe string moved along a wellbore; accepting as input to the computer measurements of pipe string depth in the wellbore made at the Earth's surface, the measurements of pipe string depth including measurements of apparent depth of each of the spaced apart locations; in the computer, identifying the subsurface formation from the measurements of the characteristic; in the computer determining a true depth of the subsurface formation using the measurements of pipe string depth and apparent depth of the formation from each of the spaced apart positions; and generating a record of measurements of the characteristic with respect to depth corrected for changes in length of the pipe string caused by axial forces along the pipe string.