Process for simultaneously extracting and upgrading by controlled extraction a heavy hydrocarbon mixture
View Patent ↗The present invention provides a process for simultaneously extracting and upgrading a heavy hydrocarbon mixture, said process comprising: i) injecting supercritical or near-supercritical CO 2 at a temperature of around the critical temperature and a pressure of from around the critical pressure into a heavy hydrocarbon deposit; and ii) removing a stream of CO 2 from the deposit, which stream is charged with a hydrocarbon mixture having a lower average molecular weight than that of the heavy hydrocarbon deposit, wherein the removed CO 2 is optionally recovered and either recycled for subsequent re-injection or injected for long-term sub-surface storage.
1. A process for simultaneously extracting and upgrading by controlled extraction a heavy hydrocarbon mixture, said process comprising:
i) injecting supercritical or near-supercritical CO 2 , in the absence of H 2 , at a temperature of around the critical temperature and a pressure of around the critical pressure into an initial heavy hydrocarbon deposit;
ii) removing a stream of CO 2 from the deposit, said stream being charged with a recovered hydrocarbon mixture, which is separated from said initial heavy hydrocarbon deposit, having a lower average molecular weight than that of the initial heavy hydrocarbon deposit and leaving a residual hydrocarbon mixture in said deposit having a higher average molecular weight than that of the initial heavy hydrocarbon deposit; and
iii) separating the recovered hydrocarbon mixture from the CO 2 stream,
wherein said recovered hydrocarbon mixture is separated in essentially a single fraction, and
wherein the removed CO 2 is optionally recovered and either recycled for subsequent re-injection or injected for long-term sub-surface storage.
2. The process of claim 1 , wherein said initial heavy hydrocarbon deposit is a submarine deposit and wherein the injection site for said supercritical CO 2 is an off-shore injection site.
3. The process of claim 1 , wherein the initial heavy hydrocarbon mixture has an API gravity of between about 8 and about 25 degrees.
4. The process of claim 1 , wherein the CO 2 is injected at a temperature of between about 25 and about 100° C.
5. The process of claim 1 , wherein the supercritical CO 2 is injected at a pressure of between 7.4 and 30 MPa.
6. The process of claim 1 , wherein said recovered hydrocarbon mixture contains an increased proportion of C 2-24 hydrocarbons and a decreased proportion of C 25+ hydrocarbons relative to the initial heavy hydrocarbon deposit.
7. The process of claim 1 wherein the upgraded hydrocarbon product is a pumpable crude oil having an API gravity of greater than 25 degrees.
8. A method of optimising production of hydrocarbon from a heavy hydrocarbon deposit, said method comprising monitoring a process as claimed in claim 1 and altering the injection conditions of CO 2 into said deposit and/or altering the depth from which the heavy hydrocarbon is extracted such that the characteristics of the hydrocarbon produced is kept as constant as possible.
9. A pumpable crude oil producible by a process as claimed in claim 1 .
10. The process of claim 4 , wherein the CO 2 is injected at a temperature of greater than 25° C. and less than 40° C.
11. The process of claim 5 , wherein the CO 2 is injected at a pressure of between 10 and 25 mPa.
12. The process of claim 1 , wherein in situ conditions of said deposit are a temperature of between 25° C. and 120° C. and a pressure of between 7.4 and 30 mPa.