Application of Permanent Reservoir Monitoring Data (DTS* & PDG*) in a Mature Offshore Malaysian Oil Field, for Production Optimisation and Workover Control

Abstract

Abstract Permanent Downhole Reservoir Monitoring and Surveillance is becoming fundamental for optimal reservoir management, without the requirement to re-enter the well. In order to identify zonal allocation from multi layer reservoirs, DTS and zonal PDG data have been integrated to provide a cost effective alternative to conventional wireline logging (e.g. PLT), thereby mitigating oil deferment and intervention risks. This paper demonstrates the approach taken by integrating DTS and PDG data with reservoir petrophysics, to interpret reservoir inflow performance, to maximize the benefits of a successful workover, by increasing oil production and decreasing water-cut. A field case from offshore East Malaysia will be shown, demonstrating the following benefits:1. Zonal inflow profiling and trending from DTS data interpretation2. The effective use of PDG data to calibrate DTS-derived flowing BHP during zonal flow profile interpretation, has improved interpretation accuracy3. Increased oil production from the workover with zonal SSD changes, using the interpretation results of integrating DTS and PDG data, in order to reduce surface water production.4. The value of permanent DTS during initial completion pressure testing, to identify leak paths along production tubing, thus saving rig time and remedial leak-detection intervention.5. The advantages of permanent downhole monitoring against alternative of conventional PLT intervention. Throughout the DTS and PDGs deployment, the data acquired has been reliably used to assist future production strategy and reservoir management. The availability of zonal pressure and rate contributions derived from DTS and PDGs data, has allowed optimal reservoir layer drawdown, to mitigate the effects of potential sanding, which is the only well in the field that has been completed without the normal field practice of gravel pack. The retrieval of fiber-optic temperature data and PDG pressure measurements is unlimited, enabling rapid production diagnostics without the need for production deferment. Hence, a cost-effective data acquisition over the well life is achievable which has improved the analysis of zonal comingled production in multi-layer reservoirs and guided the future zonal workover control.