Fuel and related compositions – Solidified liquid – Liquid hydrocarbon base
Reexamination Certificate
2000-07-03
2002-05-14
Badio, Barbara P. (Department: 1616)
Fuel and related compositions
Solidified liquid
Liquid hydrocarbon base
C507S238000, C507S239000, C507S246000, C507S269000, C507S271000, C507S922000
Reexamination Certificate
active
06387137
ABSTRACT:
FIELD OF THE INVENTION
Generally, the present invention is directed to the improved gellation of hydrocarbons liquids for a variety of applications. The present invention is specifically directed to an enhancer for improving the gelling of hydrocarbon liquids when treated with phosphate esters and crosslinking agents.
BACKGROUND OF THE INVENTION
In order to maximize the amount of oil derived from an oil well a process known as hydraulic pressure stimulation or, more commonly, formation fracturing is often employed. Generally, a fluid is pumped under high pressure down the wellbore through a steel pipe having small perforations in order to create or perpetuate cracks in the adjacent rock. The fluid employed must be able withstand exceptionally high shear forces. Gelled liquids, particularly gelled hydrocarbons, are often employed. In gelling the hydrocarbon on-site it is also preferred that gellation occur as quickly as possible.
Rapid gellation of hydrocarbon liquids is also required when tanks or vessels containing such liquids are damaged during transit to avoid or reduce spillage and the resultant damage to the environment.
A variety of other applications exist which require the rapid gellation of hydrocarbon liquids. Therefore, several means for gelling hydrocarbon liquids are disclosed in the prior art.
U.S. Pat. No. 5,417,287 to Smith et al. is directed to a method for fracturing a subterranean formation which involves adding to a hydrocarbon liquid (a) an organic phosphate of the formula HPO
4
RR′ where R is an alkyl or alkaryl group having from 6 to 18 carbon atoms and R′ is hydrogen or an aryl, alkaryl, or alkyl group having from 1 to 18 carbon atoms; and (b) a ferric salt.
European Patent Application No. 551021A1 to McCabe et al. is directed to gelling a hydrocarbon liquid by adding thereto an at least partially neutralized alkyl orthophosphate acid ester, a C
8
-C
18
surface active amine and a C
2
-C
4
monohydric alcohol. The surface active amine employed includes alkyl and alkanol amines having from about 8-18 carbon atoms, N-heterocyclic amines, alkyl substituted derivatives of such heterocyclics and mixtures thereof. Amines having more than one nitrogen group are preferred and imidazoline such as that prepared from the reaction of a tall oil fatty acid with diethylenetriamine is most preferred.
U.S. Pat. No. 4,316,810 to Burnham is directed to a fracturing composition which is an aluminum salt of an oxaalkyl phosphate in an oil base liquid. Surface active agents are not disclosed.
U.S. Pat. No. 4,153,649 to Griffin is directed to the reaction product of a hydroxy ether and a pentavalent phosphorus compound and an alcohol. The hydroxy ether has the formula ROR
1
OH wherein R is a C
1
to C
6
alkyl group, R
1
is a C
2
or C
3
alkylene group and the total carbon atoms of R
1
and R range from 3 to about 8. The disclosed reaction product may be employed in the gelling of hydrocarbon liquids when used with a compound containing a multivalent metal cation.
U.S. Pat. No. 5,271,464 to McCabe is directed to a method of plugging or sealing a subterranean formation by introducing a rapidly gelling hydrocarbon thereto. To the hydrocarbon is added a first component which is an at least partially neutralized alkyl orthophosphate ester and a second component which is the reaction product of an aqueous source of aluminum or ferric ions and a C
8
-C
18
surface active amine in the presence of a water miscible organic solvent. The surface active amine is as defined above for European Patent Application No. 551021A1, also to McCabe. The water miscible organic solvent is generally a monohydric alcohol.
U.S. Pat. No. 3,494,949 to Monroe et al. is directed to an additive for improving the viscosity of motor oils which is generally an aluminum salt of an alkyl orthophosphate.
U.S. Pat. No. 2,983,678 to Pellegrini et al. is directed to an additive for lubricating oils which is generally a rare earth metal salt of a diester phosphate.
While a variety of systems are available for gelling hydrocarbon liquids for the applications discussed above, there exists a clear need in the art for a means of improving the known systems to achieve decreased gelling times and improved viscosity.
SUMMARY OF THE INVENTION
Therefore, it is one object of the present invention to provide such a means for improving known gellation systems.
It is a further object of the present invention to provide a novel gellation system exhibiting decreased gelling times and improved viscosity.
It is yet another object of the present invention to provide a composition for decreasing gelling time and improving viscosity for use in conventional methods of gelling hydrocarbon liquids.
These as well as other objects are achieved by providing an enhancer for improving the gelling of hydrocarbon liquids with phosphate esters and crosslinking agents, said enhancer comprising an oxyalkylated amine.
Such objects are also achieved by providing a method of gelling hydrocarbon liquids which involves adding to a hydrocarbon liquid (a) a phosphate ester; (b) a crosslinking agent; and (c) an enhancer comprising an oxyalkylated amine.
Such objects are further achieved by providing a method of gelling hydrocarbon liquids which involves adding to a hydrocarbon liquid (a) an ether phosphate ester; (b) a crosslinking agent; and (c) an enhancer which is a C
2
-C
22
amine.
Such objects are still further achieved by providing an enhancer for improving the gelling of hydrocarbon liquids with ether phosphate esters and crosslinking agents, said enhancer comprising a C
2
-C
22
amine.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Generally, the present invention is related to an enhancer for use in the gelling of hydrocarbon liquids when such a liquid is treated with a phosphate ester and a crosslinking agent. Specifically, the present invention is directed to the gel which results from adding to a hydrocarbon liquid a phosphate ester, a crosslinking agent and an enhancer.
Hydrocarbon liquids which are appropriate for use in accordance with the present invention include kerosene, diesel oil and crude oil, gasoline and other aliphatic and aromatic hydrocarbons such as octane, heptane, paraffinic oils and lubricating oils. Generally, kerosene is the preferred; but, the hydrocarbon liquid chosen for use in accordance with the present invention will depend on the end-use application.
The crosslinking agent or activator employed is generally the salt of a multivalent cation, preferably the salt of a multivalent metal cation. Although a wide variety of metal salts, such as aluminum salts and rare earth metal salts, are within the scope of the present invention, ferric salts are generally preferred. Preferred ferric salts include ferric nitrate and ferric sulfate.
The phosphate ester of the present invention is generally the reaction product of a pentavalent phosphorus compound and an alcohol. It is preferred that an oxyalkene such as oxyethylene, oxypropylene or oxybutylene is also present as a reactant in order to yield an ether phosphate ester. Accordingly, the term “phosphate ester” as used herein includes ether phosphate esters such as described below. The phosphate ester of the present invention will thus contain one or more of the following structures:
wherein R, R
1
, and R
2
are independently C
1
-C
18
alkyl, C
6
aryl, C
1
-C
12
alkyl or dialkyl C
6
aryl, C
1
-C
18
alkyl ether, C
6
aryl ether, or C
1
-C
18
alkyl or dialkyl C
6
aryl ether where any R, R
1
, or R
2
C
1
-C
18
alkyl ether or C
6
aryl ether group has the following structures, respectively:
C
1
-C
18
alkyl —(OCH
2
CHR′)
n
— and C
6
aryl —(OCH
2
CHR′)
n
wherein R′ is hydrogen, methyl or ethyl and n is an integer from 1 to 100.
Generally, it is preferred that the phosphate ester of the present invention is non-neutralized. However, depending on the enhancer employed, it is also within the scope of the invention to at least partially neutralize the phosphate ester.
The enhancer of the present invention is generally an amine and is preferably a
Angres Isaac A.
Badio Barbara P.
Ethox Chemicals LLC
Petraglia Susan P.
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