Production Characteristics and Reservoir Quality at the Ivanić Oil Field (Croatia) Predicted by Machine Learning System

Abstract

At the Ivanić oil field, hydrocarbons are accumulated in fine tomedium grained litharenits of the Ivanić-Grad Formation (Iva-sandstones member) of Upper Miocene age. Reservoir rocks are dividedinlo eight depositional (production) units (i1- i8). Deposits of eachunit are characterized by their own reservoir quality parameters(porosity, horizontal permeability, net pay ... ). Production characteristicsof 30 wells have been studied by a simple slatistical method. Twomajor production well categorics ("good producers" and " bad producers")have been found. The contribution of each depositional unit to the total production of an individual well was studied by using a machine learning system which can serve as an expert system shell.The results have shown that:1) the most important factors affecting the total hydrocarbon productionof each well are horizontal permeability and net pay thickness of the depositional units i5, i4 i3.2) after 20 wells had been drilled during the primary recovery period it was possible to predict the production category of a well to be drilled in the future with a reliability of 80%.