ABSTRACT
By their very nature, hydrocarbon-bearing rocks rely on pore-space and permeability for the possibility of having recoverable reserves that can be produced at a well. The necessary entrapment beneath a shale-sealed anticline or by the juxtaposed impermeable layer caused by fortuitous faulting, are two basic scenarios for the presentday existence of the reserve. The necessary migration of the hydrocarbons from source rocks into potential entrapment structures, without escape to the atmosphere, adds to the adverse statistics of hydrocarbon exploration. Too close to the surface the sealing properties of shale, salt or clay-smear in faults, may have been compromised by lack of plasticity and too high permeability. Too deep, the pore space and permeability of the reservoir may be compromised, giving a reduced reserve and the need for permeability enhancement and gradient enhancement, or a decision for non-development.
