Geological Model for Jeribe/Euphrates Formation, Tertiary Reservoir in Qaiyarah Oil Field, North of Iraq

Abstract

Visualizing the subsurface geology and modelling it have been considered one of the major foundations in developing any field and make a reliable reservoir model to forecast the future production from the field. Where it is mainly considering as the framework of the required structure to provide distribution of the Petrophysical properties. The geological model helps to understand the behavior of the fluid flow in the porous media that effected by the heterogeneity of the reservoir and it will help to calculate the initial oil in place as well as to select new well location with accuracy while applying reservoir management. In this study, a geological model is built for Qaiyarah heavy oil field, tertiary reservoir, Jeribe, Dhiban and Euphrates formations relying on the well data from 48 wells including the location of wells, well tops and contour map. The structural model is constructed for the tertiary reservoir in Qaiyarah field which is an asymmetrical anticline consist of two domes separated by a saddle, the south – east dome is considerably wide and the north – west dome is considerably small and tighter. The south – east dome is structurally higher than the north – west dome by 45 meter at the upper limit of Jeribe Formation. The three formation in the tertiary reservoir is composed to limestone and dolomitic lime stone with very thin shale rims introduced only in Dhiban formation which have the minimum thickness compare to the main other two formations those considered the main reservoir units. Upscaling from the software have been used to distribute and correlate between the log and core data which came very acceptable to be used for the distribution to the entire field. Both log analysis and core data have showed that the reservoir is clean formation, no volume of shale has considered in the STIIOP calculations.