Defining Downhole Contribution/Injection Profile in Multi-Zone Completion by Temperature and Spectral Noise Logging

Abstract

Abstract Success towards waterflood optimization requires the accessibility of downhole contribution and injection, challenging on the conventional cased-hole multi-zone completion where contribution and injection are gathering through sliding sleeve. This paper will describe the success in defining flow profile behind tubing by utilizing Temperature and Spectral Noise Logging. With response in frequency and noise power when fluid flowing through completion accessories, perforation tunnels and porous media, fluid entry points for producer and water departure point can be located by noise logging. Additionally, conventional temperature logging can usually define degree of intake and outflow along with change in fluid phase as a result of change in temperature. In combination of these implications, downhole flow contribution and injection profile can certainly be determined even though fluid moving in and out through production tubing and casing. Regarding pilot field implemtation in Sirikit field, two multi-zone-completed candidates have been selected, operations were carried-out for producer and injector according to the programs individually designed including logging across perforation intervals and station stops for multi-rate flow, transient and shut-in periods. Longer well stabilization is necessary for injector. In addition to production/injection logging interpretation by incorporating pressure, temperature, density and spinner data, the temperature simulation model is generated to determine downhole flowing/injecting contribution with parameters acquired during logging, for example, pressure and temperature. The other reservoir and fluid properties, e.g. permeability, thickness, hydrocarbon saturation, skin, heat conductivity and capacity have been analog based on available data from neighboring areas. Therefore, the historical data on production and injection including nearby well performance may be crucial to define necessary input to the model. In association with the interpretation of noise logging which is utilized in locating contributing/injecting zones, the interpretation strongly relies on acquired temperature data and outputs of temperature simulation model to match with measured temperature profile. However, limitations have been documented when dealing with multi-phase flow, especially in low flow rate condition – considered 5 BPD as a threshold. Sensitivity run with associated paramenters in the interpretation can significantly reduce the number of uncertainties to match with measured temperature profile. Temperature and Spectral Noise Logging to provide input to temperature model can definitely help accessing downhole injection profile for the injector by taking benefit of one phase injecting and having contrast between injecting fluid and geothermal temperatures. This application can significantly improve the waterflood performance and optimization particularly in high vertical heterogeneous reservoirs – thief zones can be identified and shut-off consequently. However, defining downhole contribution for low-rate oil wells producing from multi-layered depleted reservoirs especially in undersaturated condition is still a challenge.