Enhanced Waterflooding in Multistage Fractured Horizontal Wells—An Integrated Design Workflow and Unique Application of Active Injection Control Devices
Waterflooding is a recovery method used to increase reservoir pressure and therefore improve the performance of producer wells in fields developed with multistage fracturing (MSF). Operators utilizing this method have been working continually to improve uneven injection, poor sweep efficiency, and the watering of producers caused by short-circuiting with injectors. Active injection control devices (ICDs) with an integrated design workflow offer the solution to address these challenges effectively. This paper gives an overview of the application method and design workflow.
Active ICDs allow wellbore segmentation with packers, injection control with nozzles, and reclosing valve flexibility for shutting off a specific segment and opening a secondary valve to optimize injection further. The technology features a slim diameter to fit into restricted completions, erosion resistance, and interchangeable nozzles with open and close positions. An integrated discipline and software technology workflow is developed by using distributed temperature sensing (DTS) for estimation of fracture injection contributions, well-centric dynamic modeling for a representative design base, and ICD design methodology for optimized nozzle sizes.
An active ICD features a reclosable multiposition valve with tungsten carbide nozzle inserts, which can be operated by a slim shifting tool deployed on coiled tubing (CT). Either swellable or hydraulically set packers can be used to achieve zonal isolation. The system can be installed in existing or newly drilled wells. During the initial injection period of the well and a subsequent shut-in, DTS data steady-state analysis provides an injection profile along the wellbore, identifying fracture heterogeneity. The process uses a thermal model that accounts for radial conductive heat lost as a function of injection rate. Integration of thermal modeling results with well-centric dynamic modeling enables development of a representative flow profile along the wellbore from each hydraulic fracture and hence, the ICD design methodology for efficient water injection equalization along the wellbore. The dynamic modeling workflow takes into account all the completion details to optimize the nozzles selected to choke back high-permeability zones while promoting injection into low-permeability zones and provides a completion design for technology implementation to meet expectations. The proposed workflow and technology have been successfully implemented in numerous low-permeability formations with positive field results, leading to significantly increased oil production in offset wells.
This unique technology application and design workflow approach is an innovative method for helping operators improve injection efficiency in MSF wells and ultimately maximize sweep efficiency. There is significant potential for increasing recovery factors in many low-permeability oil reservoirs developed with MSF by using this ICD technology implementation.