Field Application of Nano Polymer Microspheres Profile Control: A Pilot Test in Ultra-Low Permeability Oil Reservoir

Abstract During the development of low permeability oil reservoirs, the problems of rapid breakthrough of water, non-uniform water-absorbing of injection well and the low efficiency of water flooding are usual facing. The application of polymer microspheres (PMs) for in-depth profile control is considered to be an effective method to solve these problems. This paper systematically reports a field application case of nanoscale PMs for in-depth profile control in the ultralow permeability oil reservoir. In the paper, the characteristics of static geological and dynamic production of Block A in Changing oilfield are analyzed in detail. Meanwhile, the production history and facing problems of the Block A are clarified. According to the analysis results, the pilot test area for the application of PMs in-depth profile control is selected, and its characteristics are described. Then, a detailed implementation scheme is made for the pilot test area. Finally, according to the evaluation parameters of production wells and injection wells, the performance of PMs in the pilot test area is evaluated. The performance evaluation results show that the application of PMs in the pilot test area is very successful, and the PMs can be used for in-depth profile control in the ultralow permeability oil reservoir. More specifically, the average injection pressure of single well increased by 1.1 MPa, and the average thickness of water absorption layer increased by 1.2 m after PMs injection. The success ratio of in-depth profile control was 37.3%, and the total oil production increment of production wells was 4609.2 t. In addition, comparing the performance of well groups that use the PMs with different calibration diameter, it indicates that the application of PMs with appropriate particle size and the reasonable implementation schemes are critical to the success of in-depth profile control. For the pilot test area, the PMs with the calibration diameter as 300 nm is more suitable.