Nanocellulose as additives are used in the field of enhanced oil and gas recovery and specific additives

The application of nanocellulose in the field of Enhanced Oil Recovery (EOR) is mainly to improve the efficiency of the recovery process by utilizing its surfactivity, rheology regulation capabilities and nanoscale characteristics. By introducing nanocellulose into the injected fluid (such as water or polymer solution), the wettability of the oil layer, the interfacial tension and the fluid viscosity can be improved, thereby improving the recovery of oil and gas. Here are some use cases and typical addition ranges:

1. Used to regulate rheological performance

Nanocellulose can significantly improve the rheology performance of injected fluids, making it more suitable for oil displacement. This helps increase the viscosity of the fluid, thereby improving the fluid's displacement capability.

• Case : Adding **0.05% to 0.5%** cellulose nanofibers (CNF) to water-based EOR can increase the viscosity and shear thinning properties of the fluid, enhance the displacement effect, and allow more crude oil to be pushed to Production well.

2. Improve wetting and interface tension

The surface modification of nanocellulose can adjust the wettability of the oil layer (from hydrophobic to hydrophilic) and help release oil droplets attached to the rock surface. In addition, nanocellulose can also reduce water-oil interface tension and increase oil flowability.

• Case : In carbonate reservoirs, adding 0.1% to 0.3% carboxylated nanocellulose (CNC) can change the wettability of the rock surface and allow more oil to flow out of the pores. This improves the recovery rate.

3. Improve the stability of injected fluid

Nanocellulose can improve the stability of polymer flooding and keep the polymer solution stable under high temperature and high salt reservoir conditions. Its nanoscale dimensions allow it to enter subtle rock pores and improve the harvesting effect.

• Case : Adding 0.05% to 0.2%** TEMPO oxidized cellulose nanofibers to the polymer flooding can enhance the stability of the solution, prevent polymer degradation and decomposition, thereby improving EOR efficiency.

4. Used for foam and nanofluid transport

Nanocellulose is used in combination with foaming agents to increase the stability and viscosity of the foam, making it last longer during the oil dispersion process. In addition, nanocellulose can also be used to prepare nanofluids to further enhance the permeability and recovery of the oil layer.

• Case : Adding **0.1% to 0.5%** nanocellulose to the foam oil flooding significantly improves the stability and volume of the foam, enhances the water blocking ability of the foam, and allows more oil to be harvested.

Summary of the addition quantity

The typical addition amount of nanocellulose in enhanced oil and gas recovery applications ranges from 0.05% to 0.5% (mass fraction), and the specific addition amount depends on the different EOR methods:

• Water-based EOR rheology regulation : 0.05% to 0.5%。

• Wetting regulation and interface tension reduction : 0.1% to 0.3%。

• Enhanced stability of polymer flooding : 0.05% to 0.2%。

• Foam or nanofluid transport : 0.1% to 0.5%。

Through appropriate modification and adjustment of the amount of addition, nanocellulose can effectively improve the recovery efficiency in different EOR methods and is a promising enhanced oil and gas recovery additive.