Standard Oil Company (Indiana)

Chevron U.s.a. Inc.

Amoco Corporation

The Standard Oil Company

Gulf Oil Corporation

George R Hoekstra

John M Forgac

Product yield and quality is increased during in situ retorting of oil shale by pulsed combustion in which the flow of feed gas to the flame front is intermittently stopped while continuously retorting the oil shale. In the process, a water purge is injected into the retort between pulses of feed gas to enhance transfer of sensible heat from the combustion zone to the retorting zone and enlarge the separation between the combustion zone and the advancing front of the retorting zone. Retort water produced during retorting can be used as part of the water purge and/or feed gas for process economy and efficiency.

In situ retorting of oil shale with pulsed water purge

Greater product yield and quality and continuous upgrading of shale oil with hydrogen-rich, purge mode off gases is attained by pulsing in situ retorts at different phases and intervals. In the process, flow of feed gases to the flame fronts of underground retorts are sequentially stopped and purged while continuously retorting the oil shale to enhance transfer of sensible heat from the combustion zones to the retorting zones and enlarge the separation between the combustion zones and the advancing fronts of the retorting zones. The flame fronts can be purged with steam, water, carbon dioxide, nitrogen, hydrogen, combustion mode off gases, purge mode off gases, reactor off gases, or combinations thereof. The combustion mode off gases and/or purge mode off gases can also be used as part of the feed gas or fuel gas.

Pulsed in situ retorting in an array of oil shale retorts

One or more in situ oil shale retorts are alternately operated in a combustion mode and a purge mode with a steam or water purge to produce a greater yield of shale oil. Hydrogen-rich off gases emitted during purging are mixed with the shale oil in a reactor in the presence of a catalyst, after being stripped of carbon dioxide, to produce a high quality shale oil. The reactor off gases, purge mode off gases, and/or hydrogen gases can also be used as the purge gas.

Pulsed retorting with continuous shale oil upgrading

A process is provided for determining retorting conditions in an in situ oil shale retort. In the process, the thickness of the hot shale zone is determined by monitoring the off gases in response to changing the feed conditions, such as the temperature or flow rate, of the feed gas. The location and depth of the hot shale zone can be determined by monitoring the response time and temperature of the off gases when the proportion of steam and air in the feed gas is changed. The depth of the mineral decomposition zone can be monitored by monitoring the amount of carbon dioxide produced when the air content of the feed gas is substantially reduced. The depth of the kerogen decomposition zone can be determined by monitoring the amount of hydrogen saturated gases produced when the inflow of air in the feed gas is stopped.

Growing community of inventors

Wheaton, IL, United States of America

George R Hoekstra