US Patent 9238960 System and method for formation detection and evaluation

A method for using markers with a drilling plan uses a first log file of a first well in order to identify and store one or more markers that have a name, a true vertical depth (TVD) and a waveform. Second well log data generated while a second well is being drilled is monitored in real time. The second well log data is compared to the one or more markers to located a match to at least one marker in a predetermined TVD range. An estimated TVD value and an uncertainty range value are assigned to each of the at least one planned marker. When a matching marker is located for one of the one or more markers in the predetermined TVD range a report is generated.