A process of stimulating hydrocarbon recovery is described and claimed. This process includes introducing a gas, a liquified gas or a vaporized liquified gas, into an underground formation containing hydrocarbons such as crude oil and gas, permitting said gas to be absorbed by said hydrocarbons, and withdrawing said hydrocarbons containing the gas therein, wherein a pill of Hydrocarbon Recovery Fluid comprising surface functionalized nanoparticles is inserted into the underground formation containing hydrocarbons before, during or after the introduction of the gas, liquified gas or a vaporized liquified gas.