Experiment on the profile control effect of different strength gel systems in heterogeneous reservoir

Abstract

Polymer gel has attracted extensive attention as an effective agent for profile control as development enters middle and late stage. However, formation heterogeneity and the unclear mechanism of gel profile with different strength severely limits the displacement effect. In this work, microstructure and viscosity of polymer gels with different concentrations were characterized. The injection behavior experiments were carried out to calculate breakout pressure and plugging rate. The core flooding experiments were performed to obtain the remaining oil saturation field and recovery rate. The results illustrated that the gel viscosity increased and the plugging ability enhanced as the polymer concentration increased; Meanwhile, type C was determined as the best strength for displacement in heterogeneous formation; From oil displacement results, the gel fluidity decreased and blocking formed in high permeability reservoir, which forcing subsequent water divert to the low permeability reservoir. As a result, the swept volume expanded and the oil recovery enhanced. The fruitful works throw light on the mechanism of gel profile control and provide strong technical support for enhanced oil recovery in heterogeneous formation.

Keywords

• Mechanism of gel profile control
• Polymer concentration
• Micropore structure
• Gel strength
• Enhance oil recovery