Patent ID: 7500517

Claim:
A method for extracting a kerogen-based product from a subsurface shale formation comprising subsurface shale, the method comprising the steps of: a) increasing accessibility of kerogen in subsurface shale to a fluid, wherein the subsurface shale comprises an inorganic component in addition to the kerogen, and wherein the step of increasing accessibility comprises the sub-step of: i) drilling a cased injection well into the subsurface shale formation comprising the subsurface shale; ii) delivering a slurry to the injection well, the slurry comprising liquid CO 2 and solid CO 2 ; iii) pressurizing the well by permitting the liquid CO 2 and solid CO 2 inside the well to form supercritical CO 2 , thereby forming a pressurized well; and iv) depressurizing the pressurized well to reach a steady state reduced pressure, whereby an associated adiabatic expansion of the CO 2 cools the subsurface shale formation and causes thermal and mechanical stresses within the formation which in turn lead to fracturing of said formation, b) contacting the kerogen in the subsurface shale with a reactive fluid to create a mobile kerogen-based product; and c) transporting the mobile kerogen-based product out of the subsurface shale formation to yield an extracted kerogen-based product.