The adsorption properties of a novel ether nanofluid for gas wetting of tight sandstone reservoir

Abstract

At present, the most effective means of releasing the ‘water blocking damage’ in the near-well zone is to change the wettability of the rock surface from liquid wetting to gas wetting. Previous studies were limited to rock wettability and liquid phase relative seepage capacity changes, while systematic study on the adsorption properties of chemical agents on rock surfaces was relatively insufficient. In this paper, the wettability of the reservoir rock, the core taken from the tight sandstone of the 105X well in Dibei, was modified to gas wetting using the ether surfactant nano-solution CNDAD1#, and the static and dynamic macroscopic adsorption properties, microscopic adsorption properties, improvement in liquid phase percolation capacity and erosion resistance was systematically evaluated. The results show that the CNDAD1# nano-solution changes the sandstone wettability from liquid wetting to gas wetting. Chemical has a good static adsorption and dynamic adsorption on the surface of rock. SEM microscopic imaging and EDX elemental analysis shows the nano-solution of ether surfactant has good micro-adsorption properties on the surface of rock powder, and the surface roughness of sandstone is invariable, which makes its different from the principle of fluorine-containing gas wetting agent.

Keywords:

• tight gas reservoir
• wettability alteration
• gas wetting
• macroscopic adsorption
• microscopic adsorption
• endpoint relative permeability

Acknowledgments

The authors would also like to acknowledge the editor and reviewers from FPE for their time and effort on improving the quality of this article.

Conflicts of interest

The authors declare no financial conflicts of interest regarding the publication of this paper.

Additional information

Funding

This work was financially supported by the Foundation of State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum at Beijing (No. PRP/indep-4-1314), and Science Foundations of China University of Petroleum at Beijing (No. 462014YJRC015) and National Science and Technology major project (No.2015ZX05051003).