1. A method comprising: forming a micro-scale beam from kerogen-rich reservoir rock, the micro-scale beam comprising reservoir rock and kerogen having polymeric properties, wherein a maximum dimension of the micro-scale beam is at most 1000 micrometer (μm); performing a mechanical experiment on the micro-scale beam, wherein the mechanical experiment comprises a tension test or a compression test; imaging the mechanical experiment using a scanning electron microscope (SEM) or a transmission electron microscope (TEM); determining a material parameter of the kerogen in the micro-scale beam based on results of the mechanical experiment and images obtained responsive to the imaging; before forming the micro-scale beam, treating the kerogen-rich reservoir rock with a fluid configured to break down kerogen in the reservoir rock; and determining an effect of the fluid on the kerogen in the reservoir rock based on the material parameter of the kerogen in the micro-scale beam.