NORMALIZATION OF CASED-HOLE NEUTRON LOGS, SLAUGHTER-FIELD, COCHRAN, AND HOCKLEY COUNTIES, TX

Currently accepted methods of normalizing cased hole neutron logs to p orosity were determined to be unusable under conditions encountered du ring a reservoir study of the Texaco Bob Slaughter Block and nearby le ases in Slaughter Field, Cochran, and Hockley Counties, TX. A new meth od for normalizing a large number of neutron logs was developed that i s applicable in a wide range of situations. The method uses statistica l parameters derived from available con and modern log suites to trans form dependably the neutron log response. Unlike earlier techniques, a linear transform equation is developed for each log being normalized. The method calculates the slope of the transform equation by comparin g the standard deviation of the neutron values to a reference log with similar characteristics over a specified depth interval. The intercep t of the transform line is then calculated from average porosity value s for a specific interval, but not necessarily the same interval used to calculate the standard deviation. The technique eliminates inaccura cies in the normalization process created by tool differences, scale f actors, and hole size. The effect of changes in lithology and formatio n fluid on the resulting porosity values are also minimized.