Conformance control in heterogeneous oil reservoirs with polymer gels and nano-spheres

One of the most common methods for secondary oil recovery is waterflooding. Water is injected into a reservoir to push oil towards production wells. However, due to the natural heterogeneity of the reservoir, the sweep efficiency of the water flooding can be poor and water might break from injection towards production wells along higher permeable layers. That leads to high water cut in production wells and the process of oil extraction can become uneconomical.

The improvement of sweep efficiency can be achieved with conformance control methods. Among a variety of different methods, chemical methods (e.g. in-depth diversion and continuous injection of particle based fluids) are considered to be possible solutions. In this work we studied a crosslinking polymer and nano-spheres which represent a wide class of fluids for the improvement of sweep efficiency. The main challenges of their application in practise are associated with insufficient propagation in porous media and an early resistance factor build-up. Therefore, the idea of the work is to understand why it happens and how it can be improved. One of the main results of this work is the development of new procedures for the screening of fluids for practical applications in specific characteristics, as well as, recommendations for the development of new chemical systems for conformance control in heterogeneous oil reservoirs.