Use of Classification Technique to Characterize Porous Carbonate Reservoir in Machukhy Field, Onshore Ukraine

Classification technique are increasingly used during seismic reservoir characterization work. Particularly, discriminant analysis allows to obtain probability of assignment into facies from which can be derived a most likely facies cube. Additional properties such as porosity can be characterized depending on the predicted facies. Here the work is performed on the Machukhy field, focusing on the evaluation of Carboniferous carbonate reservoir in the Ukrainian Dniepr-Donetsk Basin. The objective consists in performing reservoir characterization, following surface seismic inversion, in order to provide key elements to help predicting inter-well reservoir location, thickness and properties behavior. A two-pass discriminant analysis is performed in order to isolate massive carbonate facies and predict porous carbonate facies. Then, effective porosity cube is derived from the inverted Pimpedance cube using a polynomial relationship within the massive carbonate facies. It shows that both massive and porous carbonate, as well as effective porosity, predictions are reliable as demonstrated by well based QCs. Based on results, surfaces have been tracked to accurately isolate massive and porous carbonate facies. Thereafter, in order to consider both results, a porous thickness map is computed providing an insight on the prospectivity of the area, characterized by higher reservoir facies thickness and higher effective porosity.