Snorre In-depth Water Diversion Using Sodium Silicate - Evaluation of Interwell Field Pilot

Declining oil production and increasing water cut in mature fields indicate the need for improved conformance control. In this paper we report on the numerical modeling performed to evaluate the in-depth water diversion pilot performed for the Snorre field, offshore Norway. For this pilot 240 000 m3 of a sodium silicate solution was injected in the period July to October 2013. The goal of the pilot was to form an in-depth flow restriction for improving the sweep. The setup, execution and measured data from response monitoring for the pilot have been presented in previous papers. As discussed therein, the operation clearly resulted in a strong in-depth flow restriction resulting in delayed tracer responses and decrease in the water cut. However, the monitoring was only limited to well observations, so to understand the spatial and temporal forming of the flow restrictions we had to rely on numerical simulation and modeling. In short, we calibrated simulation models to the observed well responses by introducing flow restrictions; i.e. using history matching techniques.

Through the reservoir modeling work we reproduce the pilot response well by introducing sound flow restrictions. This gives us clear indications on the location, timing, strength and corresponding uncertainties of the introduced flow restriction. Moreover, the modeling work supports interpretations from the response monitoring program. Finally, in addition to help evaluating the performed pilot, the learnings from the modeling work will hopefully give more accurate evaluation of potential future water diversion candidates.