1. A method of storing CO2 in a geological formation, said method comprising:
(i) Injecting a first composition comprising CO2 into said formation; and
(ii) Injecting a second composition comprising CO2 and at least one CO2 soluble polymer into said formation,
wherein steps (i) and (ii) are performed separately and in any order and wherein said first and second compositions are different.
2. A method as claimed in claim 1, wherein the first composition andor the second composition are injected at or near supercritical conditions.
3. A method as claimed in claim 1 or 2, wherein the first composition is injected in a gas-like supercritical phase and the second composition is injected in a liquid-like supercritical phase.
4. A method as claimed in any of claims 1 to 3, wherein the method comprises cycling alternately between step (i) and step (ii).
5. A method as claimed in claim 4, wherein the method comprises at least 2 cycles.
6. A method as claimed in any of claims 1 to 5, wherein each of steps (i) and (ii) are carried out for a time period of between one month and one year.
7. A method as claimed in any of claims 1 to 6, wherein step (i) is carried out for a time period of two months and step (ii) is carried out for a time period of one month.
8. A method as claimed in any of claims 1 to 7, wherein the at least one CO2 soluble polymer has a weight average molecular weight of at least 10,000 gmol.
9. A method as claimed in any of claims 1 to 8, wherein the at least one CO2 soluble polymer is selected from the group consisting of polyolefins such as polyethylene, polypropylene, polybutene, polydecene-1 and polyisobutylene; polyurethanes; polyvinyl esters; polyvinyl ethers; silicon-containing polymers such as polysiloxanes, including polydimethyl siloxane; fluoropolymers such as fluoroalkyl polymers, fluoroethers, polyperfluoroether and fluoroacrylates; perfluorocarbons; and polyalkylene glycols such as polyethylene glycol and polypropylene glycol.
10. A method as claimed in any of claims 1 to 9, wherein the second composition comprises 0.1 to 50 wt % of the at least one CO2 soluble polymer.
11. A method as claimed in any of claims 1 to 10, wherein the second composition comprises 50-99.9 wt % of CO2.
12. A method as claimed in any of claims 1 to 11, wherein the first composition consists of CO2 and any unavoidable impurities.
13. A method as claimed in any of claims 1 to 12, wherein the viscosity of the second composition is 2-200 fold greater than that of the first composition.
14. A method of monitoring CO2 storage in a geological formation, said method comprising:
(i) Injecting a first composition comprising CO2 into said formation;
(ii) Injecting a second composition comprising CO2 and at least one CO2 soluble polymer into said formation;
wherein steps (i) and (ii) are performed separately and in any order and
wherein said first and second compositions are different and are as defined in any of claims 1 to 13; and
(iii) Monitoring the stored CO2.
15. A method for at least one of the following optimising storage, controlling of CO2 and monitoring CO2 storage in geological formations, wherein a CO2 containing composition is mixed with at least one CO2 soluble polymer containing composition prior to injection of the composition into the formation.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A process for preparing silylated mixed anhydride of formula II:
which comprises reacting the compound of formula III or a salt thereof:
with ethyl chloroformate of formula IV:
to obtain mixed an hydride of formula V:
then silylating the mixed anhydride of formula V obtained above with N,O-bis(trimethylsilyl)acetamide to obtain the compound of formula II.
2. The process according to claim 1, wherein the mixed anhydride of formula V is prepared by reacting R-(Z)-4-hydroxy-\u03b1-(3-methoxy-1-methyl-3-oxo-1-propenyl)aminobenzeneacetic acid, mono potassium salt (amoxydane salt) with ethyl chloroformate in a chlorinated solvent.
3. The process according to claim 2, wherein the chlorinated solvent is methylene chloride.
4. The process according to claim 2, wherein the reaction is carried out in the presence of dimethylformamide along with the said chlorinated solvent.
5. The process according to claim 2, wherein the catalytic quantities of N-methyl morpholine and methanesulfonic acid are used.
6. The process according to claim 1, wherein the reaction between the compound of formula III or salt thereof and ethyl chloroformate is carried out below about \u221220\xb0 C.
7. The process according to claim 6, wherein the reaction is carried out below \u221240\xb0 C.
8. The process according to claim 1, wherein the silylation of the mixed anhydride is carried out in a chlorinated solvent.
9. The process according to claim 8, wherein the chlorinated solvent is methylene chloride.
10. The process according to claim 3, wherein the catalytic quantities of N- methyl morpholine and methanesulfonic acid are used.
11. The process according to claim 4, wherein the catalytic quantities of N-methyl morpholine and methanesulfonic acid are used.