The paper presents methodology and implementation results for a complex well test survey to evaluate displacement efficiency and relative permeability in-situ. Test procedure includes several “injection-production” cycles with brines of different salinity. Dynamic well data are supplemented by periodical water saturation measurements by pulse neutron logging methods and analyses of produced water composition.
The principles of well test design are discussed. Technical solutions are validated for controllable brine injection in conditions of low well injectivity. A complex interpretation procedure is developed for the set of measured logging, geochemical and dynamic flow data. Numerical multiphase flow simulations and optimal control (adjoint) methods are used for solution of the inverse problem to evaluate reservoir properties and relative permeability.
The test survey was implemented on an oil well in conditions of arctic climate and full autonomy. The obtained experience and results made it possible to evaluate in-situ displacement efficiency and relative permeability dynamics, as well as to tryout and improve the methodology of the well test. Unconventional effects in two-phase reservoir flow processes were revealed.
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