Log Analysis: The State of the art on The Occasion of The Twentieth anniversary of the Canadian Well Logging Society

$10.00

Edgar Burge

1975

Abstract

From the earliest days of well log interpretation good practice has required the merging of all available rock descriptions with the electri- required the merging of all available rock descriptions with the electri cal log readings to minimize the amount of "guess-work" underlying the cal log readings to minimize the amount of "guess-work" underlying the analysis. That is, in even the most inspired interpretation, it is analysis. That is, in even the most inspired interpretation, it is desirable to have a high ratio of known to unknown variables. The elec- desirable to have a high ratio of known to unknown variables. The elec trical logs must be supported by careful examination of drill cuttings trical logs must be supported by careful examination of drill cuttings and cores for evidence of porosity, permeability, lithology and stain, and cores for evidence of porosity, permeability, lithology and stain, drill stem test results and regional knowledge. In more recent times, drill stem test results and regional knowledge. In more recent times, logs such as the Micrologs, Neutron Logs and Sonic Logs, gave improved logs such as the Micrologs, Neutron Logs and Sonic Logs, gave improved determinations of porosity and more exact descriptions of lithological determinations of porosity and more exact descriptions of lithological variations. Today the logging suite is very sophisticated indeed. Log variations. Today the logging suite is very sophisticated indeed. Log analysis has grown into the art of Petrophysics and the Petrophysicist analysis has grown into the art of Petrophysics and the Petrophysicist is required to deal competently with geology, reservoir engineering, is required to deal competently with geology, reservoir engineering, mineralogy, geophysics, capillarity, pore geometry, computer processing mineralogy, geophysics, capillarity, pore geometry, computer processing and mapping. The tools are available now for him to do a very worthwhile and mapping. The tools are available now for him to do a very worthwhile job. The question must be asked however, "Is he still being given full job. The question must be asked however, "Is he still being given full advantage of adequate background data?" advantage of adequate background data?" It is noticeable that as well logging becomes more expensive and more It is noticeable that as well logging becomes more expensive and more sophisticated, as more new logs read porosity or lithology almost sophisticated, as more new logs read porosity or lithology almost directly, there is a corresponding decrease in useful data supplied to directly, there is a corresponding decrease in useful data supplied to the log analyst by the geologists and engineers. There has also been an the log analyst by the geologists and engineers. There has also been an OWLS Journal Vol. 8, No. 1, December 1975 OWLS Journal Vol. 8, No. 1, December 1975 21 21 EDGAR BURGE EDGAR BURGE increasing trend of late for the log analyst to supply more detailed increasing trend of late for the log analyst to supply more detailed information to the geologists and geophysicists. This is good but there information to the geologists and geophysicists. This is good but there ,must be a two-way flow of data to and from the log analyst.