Oil exploration of Jiyang depression has recently been proved that Mesozoic

formations are favorable to hydrocarbon accumulation

and some oil reservoirs heve

therefore

been discovered. Based on well loge and. other imformation .available

the authors systematically studied the mineral composition

physical .pro-perties and distribution of reservoirs of petrologically complicated

Mesozoic in present region

and have developed a new .method. of log interpretation supported by an computer program. This method is based on geophysical inversion theory using optimization.method for calculation. It covers a log interpretation model established for lithologically complicated formation

and may be used for analyzing errors of well logs

correcting influence of various environmental factors for logs and checking geological parameters calculated. Geological results obtained by this. method in. processing log data on .Mesozoic formations of Jiyang depression are obviously.better than that by coventional digital processing method.