The Log Lithofacies Analysis Of Mesozoic Formation In JiYang Depression

With the development of well logging and computer and with the enhancement of exploration and development of oilfield, the log facies analysis technique has been one of the important means to search thinly bedded reservior, make formation evaluation and raise oil recovery ratio.The sedimentary in jiyang basin of mesozoic are mostly river facies and lacustrine facies. As the great tectonic movement, there are many planes of unconformity here. At the last stage, there was a lot of volcanic action, which leaded to the lithology here was very complicated, which inclued sedimentary rock as well as eruptive rock. On the other hand, the structure of the pore is very complicated and the cement is mutiplex. All this reasons lead to the reservoir heterogeneity is very obvious, so the logging interpretation is very difficult.The relationship between lith-facies and log parameters was described. The logging response characteristics of all kinds of rocks in this area were summarized. Using the established database of electrofacies and the lith-facies, 15 kinds of lithology were recognised. The interpretation model of reservoir parameters was established. In this paper, the type of clay was analysed according to spectral gamma-ray log data and core data of clay.On the basis of this principle, the author has programmed a software system using VC and applied it to 32 wells. The result shows it is fit to this area. This method can analyse lith-facies, interpretate reservior parameters and identify clay mineral type correctly and effectively.