Abstract
This paper describes the chemistry and treatment design of the first field application of a recently developed, organically crosslinked polymer (OCP) system for water shutoff. The candidate for which this treatment was designed is a production well in the North Sea that was completed in naturally fractured chalk. Each of the completed intervals were acid fractured to further open the existing natural fractures and increase production.
The recommended treatment volume calculations took into account the leak-off considerations and the acid fracture volume. The method by which the leak-off requirements were calculated is described.
The placement and shut-in temperatures of the recommended treatment volume were then calculated as a function of time. These simulations used a production - operation wellbore simulator in combination with an advanced processes reservoir simulator. The fractures in the target zone were defined in the grid-block system that was used in these temperature simulations.
The results of these temperature calculations were used to formulate the chemical compositions of the stages of the OCP treatment and to calculate gel times and shut-in times. The calculations of these gel times and how they correspond to the gel times during the actual treatment are also described.
