Low volatile phosphorous gelling agent
Liquid hydrocarbons are gelled by the introduction of a phosphate ester and a crosslinking agent for use in oil recovery. Generally a proppant, delayed gel breaker and other modifiers are added to the gelled hydrocarbon to improve the oil recovery process. The phosphate ester used in this method and composition for oil recovery has low volatility and good stability during hydrocarbon distillation resulting in improved distillation efficiency in a refinery.
1. A method of fracturing a subterranean formation comprising the steps of:
(a) preparing a gelled liquid hydrocarbon fracturing fluid having a low content of volatile phosphorus comprising a hydrocarbon liquid, a ferric iron or aluminum polyvalent metal salt of a mixture of phosphoric acid esters having the formulae:
proppant material, water and an amount of a delayed gel breaker effective to break said gelled hydrocarbon fracturing fluid; and
(b) contacting said subterranean formation with said gelled hydrocarbon fracturing fluid having a low content of volatile phosphorus under conditions effective to create at least one fracture in said subterranean formation.
2. The method of claim 1 wherein said hydrocarbon liquid is selected from the group consisting of olefins, kerosene, diesel oil, gas oil, fuel oil, petroleum distillate and crude oil.
3. The method of claim 1 wherein said polyvalent metal salt of a phosphoric acid ester is produced by reacting said phosphoric acid ester with a ferric iron compound.
4. The method of claim 1 wherein said polyvalent metal salt of a phosphoric acid ester is produced by reacting said phosphoric acid ester with an aluminum compound.
5. The method of claim 1 wherein said ferric iron or aluminum polyvalent metal, salt of a phosphoric acid ester is present in said hydrocarbon liquid in an amount in the range of from about 0.1% to about 2.5% by weight of said hydrocarbon liquid.
6. The method of claim 1 wherein said delayed gel breaker is selected from the group consisting of magnesium oxide, alkali metal carbonates, alkali metal bicarbonates, alkali metal acetates, alkali metal hydroxides, amines and weak acids which are slowly water soluble or are encapsulated with a slowly water soluble encapsulating material.
7. The method of claim 1 wherein said delayed gel breaker is slowly water soluble hard burned magnesium oxide.
8. The method of claim 3 wherein said delayed gel breaker is a reducing agent that reduces ferric iron to ferrous iron.
9. The method of claim 1 wherein said gel breaker is present in said gelled hydrocarbon liquid in an amount in the range of from about 0.01% to about 3% by weight of said hydrocarbon liquid.
10. A method of preparing a gelled liquid hydrocarbon fracturing fluid having a low content of volatile phosphorus comprising adding a mixture of phosphoric acid esters to a hydrocarbon liquid, the phosphoric acid esters having the formulae:
at least a stoichiometric amount of a polyvalent metal source selected from ferric iron salts and aluminum compounds which reacts with said mixtures of phosphoric acid esters to form a ferric iron or aluminum polyvalent metal salt thereof, water and an amount of a delayed gel breaker effective to break said gelled hydrocarbon fracturing fluid.
11. The method of claim 10 wherein said hydrocarbon liquid is selected from the group consisting of olefins, kerosene, diesel oil, gas oil, fuel oil, petroleum distillate, and crude oil.
12. The method of claim 10 wherein said ferric iron or aluminum polyvalent metal salt of said phosphoric acid ester formed in said hydrocarbon liquid is present therein in an amount in the range of from about 0.1% to about 2.5% by weight of said hydrocarbon liquid.
13. The method of claim 10 wherein said delayed gel breaker is selected from the group consisting of magnesium oxide, alkali metal carbonates, alkali metal bicarbonates, alkali metal acetates, alkali metal hydroxides, amines and weak acids which are slowly water soluble or are encapsulated with a slowly water soluble encapsulating material.
14. The method of claim 10 wherein said delayed gel breaker is slowly water soluble hard burned magnesium oxide.
15. The method of claim 10 wherein said delayed gel breaker is a reducing agent that reduces ferric iron to ferrous iron.
16. The method of claim 10 wherein said gel breaker is present in said gelled hydrocarbon liquid in an amount in the range of from about 0.01% to about 3% by weight of said hydrocarbon liquid.
17. A gelled liquid hydrocarbon fluid composition having a low content of volatile phosphorus comprising:
(a) a hydrocarbon liquid;
(b) a gelling agent comprising a polyvalent metal salt of a mixture of phosphoric acid esters produced from a mixture of phosphoric acid esters and a ferric iron salt or an aluminum compound, said phosphoric acid esters having the formulae:
(c) water; and
(d) a delayed gel breaker present in an amount effective to break the gel formed by said gelling agent and said hydrocarbon liquid.
18. The composition of claim 17 wherein R is an alkyl group having from 8 to 10 carbon atoms.
19. The composition of claim 17 wherein said hydrocarbon liquid is selected from the group consisting of olefins, kerosene, diesel oil, gas oil, fuel oil, petroleum distillate, and crude oil.
20. The composition of claim 17 wherein said ferric iron salt is selected from the group consisting of ferric sulfate and ferric chloride.
21. The composition of claim 17 wherein said aluminum compound is selected from the group consisting of aluminum chloride, aluminum sulfate and aluminum isopropoxide.
22. The composition of claim 17 wherein said ferric iron or aluminum polyvalent metal salt of said phosphoric acid ester is present in said hydrocarbon liquid in an amount in the range of from about 0.1% to about 2.5% by weight of said hydrocarbon liquid.
23. The composition of claim 17 wherein said delayed gel breaker is selected from the group consisting of magnesium oxide, alkali metal carbonates, alkali metal bicarbonates, alkali metal acetates, alkali metal hydroxides, amines and weak acids which are slowly water soluble or are encapsulated with a slowly water soluble encapsulating material.
24. The composition of claim 17 wherein said delayed gel breaker is slowly water soluble, hard burned magnesium oxide.
25. The composition of claim 17 wherein said delayed gel, breaker is a reducing agent that reduces ferric iron to ferrous iron encapsulated with a slowly water soluble encapsulating material.
26. The composition of claim 25 wherein said gel breaker is present in said gelled hydrocarbon liquid in an amount in the range of from about 0.01% to about 3% by weight of said hydrocarbon liquid.