Cold Production from a Fractured Carbonate Heavy Oil Reservoir in Iran - Case Study

Abstract

A successful case study on a carbonate heavy/extra-heavy oil field is presented and the techniques and challenges behind the production from highly fractured carbonate Bangestan reservoirs are discussed in this study. The field consists of two fractured carbonate reservoir with about 3.6 billions barrels of initial oil in place of 7.5-18o API heavy/extra heavy oil. The oil viscosity at reservoir temperature (139.3 oF) is around 700-800 cp. The pressure is 927 psi at 1119 mdd but heavy oil does not naturally flow to the surface. Based on field conditions and reservoir characterization, it was decided to implement initially cold production by two experimental methods of lifting with no injection but only swabbing and use of PCP (Progressing Cavity Pumps). simulation showed a good match with the further field data when the cold production scenario was employed. The challenges and techniques employed on field pilot including various techniques of production are summarized and optimized production methods of cheaper lifting procedures of heavy oil to surface is described. Consequently lifting heavy and extra heavy oil to surface using PCP is applicable for this field in stage of cold production prior to any expensive and complicated thermal method implementation in future phases of production.