Well Log Calibration

Down-hole NMR tools are routinely run during the oil and gas exploration process and provide valuable information to the reservoir engineers. The tools measure T2 distribution as a function of depth. T2 can be directly related to pore size and with the correct T2 cut-off can allow the determination of bound fluid versus free fluid in the reserve. These values can then be used to estimate recoverable reserves.

The down-hole tools must be calibrated in the laboratory by measuring the T2 cut-off of various samples. Using two basic NMR pore distributions, one on a saturated core and one on the same core that has been centrifuged, it becomes relatively easy to calculate the T2 cut-off which defines the boundary between mobile and bound fluids.