Marker-Based Long-Term Production Profiling Surveillance in Horizontal Wells in The Northern Capsian Sea

Summary Fundamentally new control tools for reservoir management are required in modern field tests for productivity estimation with high efficiency. One such tool is marker-based production logging enabling long-term production profiling surveillance. This research represents the case study of multi-phase flow profile estimation (oil, water and gas) in horizontal offshore oil wells in the North Caspian Sea. This method assumes that marker systems (marker cassettes) with unique codes are placed in the well as part of the lower completion. During further monitoring immediately after the well is put into production, formation fluid sampling is performed with a certain frequency according to a pre-formed schedule. The fluid and gas samples are analysed in the laboratory using specialised equipment. Based on the processing results, the distribution of each marker code was obtained. It shows the intensity of fluid flow from the formation into the wellbore. The results of production logging for each interval made it possible to determine the zones with low productivity, to identify how they correlate with the geological features of the area and the porosity and permeability distribution throughout the reservoir, and also to reveal the dependence of the production profile on well operation parameters. This information allows optimising the well operation and selecting the most promising development scenario to maximise hydrocarbon recovery.