Patent ID: 8151884
Filing Date: 2012-04-10
Classification: E21B,Y02C

Abstract:
1. A method for producing hydrocarbons from subsurface formations at different depths, comprising: heating organic-rich rock comprising oil shale to a pyrolysis temperature, in situ, within a subsurface formation at a first depth, thereby pyrolyzing at least a portion of the organic-rich rock into hydrocarbon fluids; providing at least one substantially unheated zone within the subsurface formation of the first depth, thereby leaving the organic-rich rock in the at least one substantially unheated zone below a pyrolysis temperature, wherein the substantially unheated zone comprises a substantially unheated vertical pillar interior to and surrounded laterally by the heated portion of the organic-rich rock at the first depth; drilling at least one production well through the at least one substantially unheated vertical pillar at the first depth, and completing the at least one production well in a subsurface formation at a second depth that is deeper than the first depth, wherein the subsurface formation at the second depth is a tight gas formation and the at least one production well is substantially vertical in orientation as the at least one production well passes through the substantially unheated vertical pillar at the first depth; and producing hydrocarbon fluids comprising natural gas from the tight gas formation through the at least one production well.