Abstract: Well logging in cased well is important in the development of current logging technology.The casing diameter and quality of cementation and the thickness of the cement ring are the main factors which influence neutron logging.It is showed by logging data that the effectiveness of corresponding neutron logging is good,it can not only indicate the relative variety of the hydrogenbearing quantity of layers but also be used in identifying reservoir.The emendation of 17.78cm and 24.45cm neutron logging can be processed by the way of plate emendation,oneparameter regression analytical method,multiparameters step regression method and the BP neutron network method,it is proved by real information processing that the BP neutron network emendation method has the highest precision,while other ones the approximate precision.The information got by 17.78cm neutron logging and its emendation effectiveness is better than that 24.45cm neutron logging.According to the real logging information,The corresponding emendation as followed is recommended,if there are well diameter and long and short space neutron counting rate,BP neural network method is used to correct neutron logging data of cased well,and when well diameter is not available,oneparameter regression analytical method is appropriate.

Key words: cased well, neutron logging, carbonate rock, sandstone, correcting method, effectiveness appraisement