US 4,231,617 A · Consolidation of in-situ retort

Abstract

Shale oil is recovered from an underground oil shale deposit by in-situ retorting of rubblized shale in a retort formed in the deposit. Oil shale in a volume in the range of ten to fifty percent of the volume of the retort is mined from the deposit and delivered to the surface to provide void space for the expansion of the shale that occurs on rubblization to form the in-situ retort. The oil shale delivered to the surface is retorted at the surface. After completion of the in-situ retorting, boreholes are drilled downwardly through the retorted shale and a pipe lowered through the borehole to a level near the bottom of the retort. Spent shale from the surface retorting operation is slurried and pumped into the lower end of the in-situ retort. Pumping is continued to squeeze the slurry into the fissures between blocks of spent shale. The slurry is delivered into successively higher levels of the retort and the pumping and squeezing operation repeated at each level. In a preferred operation, slurry discharged into the retort is allowed to set before discharging slurry into the retort at a higher level to avoid excessive hydrostatic pressures on the retort.

Claims19

Dependent claims

A method of consolidating a rubblized in-situ oil shale retort, after in-situ retorting of the shale is completed comprising:

(a) retorting oil shale at the ground surface;
(b) preparing an aqueous slurry of spent shale from the surface retorting;
and
(c) pumping the slurry into the in-situ retort;
wherein the pumping of step (c) is accomplished by discharging the slurry into the in-situ retort at successively higher levels in the retort and squeezing the slurry into fissures between blocks of in-situ retorted rubblized spent shale at each level to fill void space in the in-situ retorted shale, the squeezing of the slurry being accomplished at high pressures adapted to apply a pressure on walls of the retort below the fracturing pressure of the oil shale formation.

2 more elements

A method of recovering oil from underground deposits of oil shale comprising:

(a) mining a quantity of shale in the zone of a desired underground retort ranging from 10 to 50 percent of the volume of the retort and lifting the mined shale to the surface;
(b) blasting the shale in the zone of the retort to form a permeable rubblized mass of shale in the retort;
(c) retorting the rubblized shale to liberate shale oil therefrom and lifting the produced shale oil to the surface;
(d) retorting the mined shale delivered to the surface at the surface;
(e) after retorting of the rubblized shale in the in-situ retort is completed, discharging a slurry of spent shale from the surface retorting from a pipe opening into the in-situ retort near the lower end thereof and squeezing the slurry at a pressure approaching the pressure required to fracture the shale formation to fill voids between blocks of rubblized spent shale in the retort;
and
(f) repeating the step of discharging the slurry of spent surface retorted shale at successively higher levels in the in-situ retort and squeezing the cement at each level to fill void space in the retort from the bottom of the retort substantially to the top.

4 more elements

Dependencies are inferred from the claim text.

Consolidation of in-situ retort

Life of this patent

Consolidation of in-situ retort

Life of this patent

Abstract

Claims19