Reservoir Pathway Identification in a Fractured Carbonate Heavy Oil Reservoir

Abstract

AbstractThe first production log in heavy oil in Egypt through y-tool, using a high capacity ESP pump, in an open hole completion was performed recently by Scimitar Production Company in Issaran heavy oil field. The objective of the job was to identify the source of water, evaluate the contributions from the different open hole zones and determine whether or not there is cross flow in this fractured heavy oil carbonate reservoir. These wells had originally not been completed with y-tool. Therefore a special y-tool with high capacity ESP was designed especially for Scimitar by Zenith to be able to log the wells under special dynamic conditions. This was the first application world wide of this y-tool, which was used as a temporary completion in the wells.Production logging (PL) was successfully carried out in 3 Issaran wells at different rates, to identify the high permeability (super-K) layers dominating production and calculate their pressure/PI. Likewise flow profiles were determined and high water producing layers identified. Shut in surveys were successful in detecting cross flowing layers. Calculated flow profile results matched well with surface measured rates.PL results had a significant effect upon the Issaran field development plan. Water was found to be produced from layers having resistivity up to 30 ohm-m. This led to an increase in the resistivity cutoff for hydrocarbon production and a reduction in water cut. Hydrocarbon producing zones were better identified and Scimitar decided to abandon open hole completions in future wells and go in for cased hole completions, in order both to control the water production as well as avoid breakthrough of injected steam.This paper describes the field and gives details on job planning, operations, results and way forward for field re-development.