WetMod is a Danish Hydrocarbon Research and Technology Centre (DHRTC) project granted to Nico Bovet which is running from 1st October 2017 to 31st December 2017 and is a follow-up of the SPRINT project SurfChem.
Title: Wettability Modification of Chalk
One method for enhancing oil recovery is by advanced water flooding, where water composition is optimized. The processes that control oil production are influenced by nanoscale phenomena at the interface between the pore surfaces and the oil and water mixture. However, little is known about the chemical mechanisms that make oil stick to surfaces and what parameters can trigger the release of organic molecules from pore surfaces when the composition of the water flood is changed. Recent theoretical studies have shown that incorporation of ions in and on calcite surfaces can change wettability dramatically [1,2].
To study experimentally the adsorption and incorporation of selected ions on calcite surfaces as a model for chalk. We want to link the theoretical, molecular scale information to data obtained with a technique that can see at the nanometer scale, X-ray photoelectron spectroscopy (XPS) and to macroscopic measurements of contact angle. We will investigate Mg, which is predicted to make the calcite surface more water wet and to enhance oil recovery in laboratory tests, and Sr, which is predicted to sorb easily in and on calcite and render its surface less water wet.
In parallel, we will follow the adsorption of the same ions on real chalk samples, using cryogenic XPS. This technique allows us to study the ionic composition at the fluid-mineral interface, in the 10 nm of solid and adsorbed solution. We will explore the surface-fluid composition on pure calcite and on chalk surfaces. We will get direct access to the electric double layer composition and identify the potential determining ions near the surface, parameters which control surface tension, electrostatic interaction, adhesion of oil and wetting properties.