Method of obtaining oil from oil shale deposits

A process for extracting oil and/or gas from an oil shale formation having at least one generally horizontally extending layer of predominantly kerogen phase continuous oil-rich shale having a grade of at least 25 gallons of oil per ton, with most of the rest of said formation being of a lesser grade, comprising:

• excavating one or more of said layers of oil-rich shale from said shale oil formation, said oil-rich shale having an oil content of at least 25 gallons of oil per ton;
• explosively fragmenting a portion of the remaining oil shale into the resulting excavation to form a rubblized mass of oil shale having no regions having substantial volumes of kerogen phase continuous oil shale which could compress and block air flow;
• retorting said excavated oil-rich shale above ground;
• and
• retorting said rubblized oil shale in situ.

A process for extracting oil and/or gas from oil shale comprising:

• excavating oil-rich shale from a shale oil deposit, said oil-rich shale having an oil content of at least 25 gallons of oil per ton, and being formed of predominantly kerogen phase continuous shale, said excavating including the step of mining specially spaced horizontal layers of kerogen phase continuous oil shale to prelude the presence in the rubblized retort volume of any substantial contiguous volumes of kerogen phase continuous oil shale which could otherwise compact and block the retorting process;
• explosively fragmenting a portion of the remaining oil shale into the resulting excavation to form a rubblized mass of oil shale;
• retorting said excavated oil-rich shale aboveground;
• and
• retorting said rubblized oil shale in situ.

A process for extracting oil and/or gas from an oil shale formation which is made up principally of oil shale having phase continuous inorganic material, and having at least two spaced substantially horizontally extending layers or strata of kerogen phase continuous oil shale, comprising the steps of:

• excavating oil-rich shale from a shale oil deposit, said oil-rich shale having an oil content of at least 25 gallons of oil per ton, said excavating including the step of mining said spaced substantially horizontal layers of kerogen phase continuous oil shale, to preclude the presence in the rubblized retort volume of any substantial contiguous volumes of kerogen phase continuous oil shale which could otherwise compact and block the retorting process;
• leaving pillars to support said formation, with the pillars constituting less than thirty-five per cent of the volume of each of the excavated layers;
• explosively fragmenting said pillars and a portion of the remaining oil shale formation into the resulting excavation to form a rubblized mass of oil shale;
• and
• retorting said rubblized oil shale in situ.

A process for extracting oil and/or gas from an oil shale formation having at least one generally horizontally extending layer of oil-rich shale having a grade of at least 25 gallons of oil per ton, and being predominantly formed of kerogen phase continuous oil shale, with most of the rest of said formation being of a lesser grade, comprising the steps of:

• excavating more than sixty-five percent of said generally horizontally extending layer of oil-rich shale;
• excavating a second generally horizontally extending layer of oil shale in general vertical alignment with said first section;
• leaving pillars to support said formation, with the pillars comprising less than thirty-five percent of the volume of each of said layers;
• explosively rubblizing the oil shale in said pillars and between said two sections;
• so that there are no regions within the rubblized mass having substantial volumes of kerogen phase continuous oil shale which could compress and block gas flow, and
• retorting the rubblized oil shale in situ to obtain oil therefrom.

A process for extracting oil and/or gas from an oil shale formation having at least one generally horizontally extending layer of oil-rich shale having a grade of at least 25 gallons of oil per ton, and being predominantly formed of kerogen phase continuous oil shale, with most of the rest of said formation being of a lesser grade, comprising the steps of:

• excavating more than sixty-five percent of said generally horizontally extending layer of oil-rich shale;
• excavating more than sixty-five percent of a second generally horizontally extending layer of oil shale in general vertical alignment with said first section, said second section also including substantial quantities of kerogen phase continuous oil shale;
• leaving pillars to support said formation, with the pillars comprising less than thirty-five percent of the volume of each of said layers;
• explosively rubblizing the oil shale in said pillars and between said two sections;
• so that there are no regions within the rubblized mass having substantial volumes of kerogen phase continuous oil shale which could compress and block gas flow, and
• retorting the rubblized oil shale in situ to obtain oil therefrom.