Reservoir simulation and near-well bore modelling to aid scale management in a subsea Gulf of Mexico field

This paper presents the findings of a study into the impact of reservoir flow behavior on both the scaling risk at production wells, and the options for managing this scaling risk, for a deepwater sandstone reservoir in the Gulf of Mexico. One significant feature in this field is that flow takes place through isolated formation layers, and choices made regarding the seawater injection wells have a great impact, not only on the BaSO₄ scaling tendency, but also on the placement of scale inhibitor squeeze treatments in the producers. In addition to seawater injection, oil production is supported by the aquifer. The formation brines contain barium, and the injection water is full of sulfate seawater, and the relative proportion of each brine, the water production rate, pressure and temperature conditions all determine the scaling risk. This changes with time as water cut and water composition changes. Furthermore, by varying the amount of seawater injected into each of the formation layers, the pressures in the layers are affected. This provides an opportunity to manage the injection wells via intelligent completions, not only to improve sweep efficiency, but also to balance reservoir pressures and make squeeze treatments more efficient.