# US 7,745,500 B2 · Method for reducing the viscosity of viscous fluids

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- Number: US 7,745,500 B2
- Document ID: US7745500B2
- Status: Granted
- Kind: B2
- Application number: 10/574,232
- Filed: 2004-09-27
- Published: 2007-02-22
- Granted: 2010-06-29
- Earliest claimed: 2003-10-02
- Assignees: Advanced Gel Technology Limited
- Inventors: Philip Fletcher; Michael John Crabtree; Donald Eagland; Nicholas John Crowther
- Web page: https://patentgrep.com/patent/US7745500B2

## CPC

- C10L 10/08: for improving lubricity; for reducing wear
- C09K 8/588: characterised by the use of specific polymers {(polymeric surfactants C09K8/584)}
- C09K 8/86: containing organic compounds
- C10M 145/04: containing monomers having an unsaturated radical bound to an alcohol, aldehyde, ketonic, ether, ketal or acetal radical
- C10M 145/08: Vinyl esters of a saturated carboxylic or carbonic acid
- C10M 145/40: Polysaccharides, e.g. cellulose
- C10M 161/00: Lubricating compositions characterised by the additive being a mixture of a macromolecular compound and a non-macromolecular compound, each of these compounds being essential
- C10M 177/00: Special methods of preparation of lubricating compositions; Chemical modification by after-treatment of components or of the whole of a lubricating composition, not covered by other classes
- F17D 1/17: by mixing with another liquid {, i.e. diluting}
- C10M 2201/02: Water
- C10M 2209/04: containing monomers having an unsaturated radical bound to an alcohol or ester thereof; bound to an aldehyde, ketonic, ether, ketal or acetal radical
- C10M 2209/062: Vinyl esters of saturated carboxylic or carbonic acids, e.g. vinyl acetate
- C10M 2209/10: Macromolecular compoundss obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
- C10M 2209/12: Polysaccharides, e.g. cellulose, biopolymers
- C10N 2020/00: Specified physical {or chemical properties or characteristics, i.e. function,} of component of lubricating compositions
- C10N 2020/091: {Water solubility}
- C10N 2030/02: Pour-point; Viscosity index
- Y02E 60/34: Hydrogen distribution
- Y10T 137/8593: Systems
- C10L: FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G OR C10K; LIQUIFIED PETROLEUM GAS; USE OF ADDITIVES TO FUELS OR FIRES; FIRE-LIGHTERS
- C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C10M: LUBRICATING COMPOSITIONS (well drilling compositions C09K8/02); USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION (mould release, i.e. separating, agents for metals B22C3/00, for plastics or substances in a plastic state, in general B29C33/56, for glass C03B40/02; textile lubricating compositions D06M11/00, D06M13/00, D06M15/00; immersion oils for microscopy G02B21/33)
- F17D: PIPE-LINE SYSTEMS; PIPE-LINES (pumps or compressors F04; fluid dynamics F15D; valves or the like F16K; pipes, laying pipes, supports, joints, branches, repairing, work on the entire line, accessories F16L; steam traps or the like F16T; fluid-pressure electric cables H01B9/06)
- C10N: INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A viscous fluid, such as heavy crude oil which is too viscous to enable it to be pumped from a flowing phase of a reservoir into and along a pipeline for delivery to a refinery or other storage facility, may be contacted with a formulation to reduce its viscosity. The formulation comprises a polymeric material AA which includes —O— moieties pendent form a polymeric backbone thereof and said material is optionally cross-linked. In one embodiment, the formulation may comprise polyvinyl alcohol. In an alternative embodiment, the formulation may comprise a cross-linked polymeric material, such as cross-linked polyvinyl alcohol. After the viscous composition has been transported to a desired location, it may be separated from the other components.

## Claims

### Claim 1

A method for reducing the viscosity of a viscous composition which is arranged to flow along a fluid flow path, said method comprising contacting the viscous composition in said fluid flow path with a treatment fluid formulation, said treatment fluid formulation comprising a polymeric material AA which includes —O— moieties pendent from a polymeric backbone thereof, wherein said polymeric material AA comprises polyvinyl acetate which has been 60 to 95% hydrolyzed to polyvinyl alcohol, wherein polymeric material AA is optionally cross-linked and wherein said treatment fluid formulation is initially contacted with said viscous composition in said fluid flow path at or downstream of a producing face of a subterranean formation.

### Claim 2 (depends on 1)

A method according to claim 1, wherein the viscosity of the viscous composition after contact with the treatment fluid formulation is less than 300 cP measured at 25° C. and 1000 s−1.

### Claim 3 (depends on 2)

A method according to claim 2, wherein the viscous composition, after contact with the treatment fluid formulation, exhibits shear thinning.

### Claim 4 (depends on 1)

A method according to claim 1, wherein said viscous composition is an oil.

### Claim 5 (depends on 1)

A method according to claim 1, wherein said fluid flow path is defined by a conduit means which includes a first conduit part which is arranged downstream of a production means.

### Claim 6 (depends on 1)

A method according to claim 1, wherein said fluid flow path extends between a first point, remote from the point of production of the viscous composition, and a second point closer to the point of production of the viscous composition.

### Claim 7 (depends on 1)

A method according to claim 1, wherein said fluid flow path is defined, in part, by a second conduit part which extends upwardly from below ground to above ground.

### Claim 8 (depends on 1)

A method according to claim 1, wherein said treatment fluid formulation is arranged to disperse and/or emulsify said viscous composition on contact therewith.

### Claim 9 (depends on 1)

A method according to claim 1, wherein flow is turbulent at the point of initial contact of said viscous composition with said treatment fluid formulation so that said composition is dispersed and/or emulsified on contact with said formulation.

### Claim 10 (depends on 1)

A method according to claim 1, wherein a delivery flow path is defined which is arranged to communicate with said fluid flow path wherein said treatment fluid formulation is dosed into said viscous composition in said fluid flow path via said delivery flow path.

### Claim 11 (depends on 10)

A method according to claim 10, wherein the ratio of the flow rate (in weight per unit time) of treatment fluid formulation in said delivery flow path to the flow rate (in the same units) of viscous composition in said fluid flow path is in the range 0.1 to 2.5.

### Claim 12 (depends on 11)

A method according to claim 11, wherein the amount of water in the composition in said fluid flow path immediately after contact between said viscous composition and said treatment fluid formulation is less than 70 wt %.

### Claim 13 (depends on 1)

A method according to claim 1, wherein said treatment fluid formulation has a viscosity at 25° C. and 1000 s−1 of greater than 1 cP and not greater than 50 cP.

### Claim 14 (depends on 1)

A method according to claim 1, wherein said treatment fluid formulation includes at least 70 wt % water.

### Claim 15 (depends on 14)

A method according to claim 14, wherein said treatment fluid formulation includes at least 0.2 wt % and less than 10 wt % of said polymeric material AA.

### Claim 16 (depends on 1)

A method according to claim 1, wherein said treatment fluid formulation includes 94.5 to 99.6 wt % water and 0.4 to 5.5 wt % of said polymeric material AA; and the ratio of the wt % of said treatment fluid formulation to the wt % of said viscous composition contacted in the method is in the range 0.4 to 0.9.

### Claim 17 (depends on 1)

A method according to claim 1, wherein said polymeric material AA is wholly soluble in water at 25° C.

### Claim 18 (depends on 1)

A method according to claim 1, wherein said polymeric backbone of said polymeric material AA includes carbon atoms which are part of —CH2— moieties.

### Claim 19 (depends on 2)

A method according to claim 2, wherein said polymeric backbone consists essentially of carbon atoms in the form of C—C single bonds.

### Claim 20 (depends on 4)

A method according to claim 4, wherein said polymeric material AA includes, on average, at least 10 —O— moieties pendent from the polymeric backbone thereof.

### Claim 21 (depends on 1)

A method according to claim 1, which involves selecting a said polymeric material AA; selecting a material BB which includes a functional group which is able to react in the presence of said polymeric material AA to cross-link polymeric material AA and form a polymeric material CC; and causing the formation of said polymeric material CC by a reaction involving said polymeric material AA and material BB.

### Claim 22 (depends on 21)

A method according to claim 21, wherein material BB has a general formula:
where G5 represents a direct link or a linking moiety.

### Claim 23 (depends on 21)

A method according to claim 21, wherein said material BB comprises:
(i) a first polymeric material having a repeat unit of formula
wherein A and B are the same or different, are selected from optionally-substituted aromatic and heteroaromatic groups and at least one comprises a relatively polar atom or group and R1 and R2 independently comprise relatively non-polar atoms or groups; or
(ii) a first polymeric material prepared or preparable by providing a compound of general formula
wherein A, B, R1 and R2 are as described above, in an aqueous solvent and causing the groups C═C in said compound to react with one another to form said first polymeric material.

### Claim 24 (depends on 4)

A method according to claim 4, wherein after the viscous composition has been delivered to a desired location the viscous composition is caused to separate from other components of the treatment fluid formulation.

### Claim 25 (depends on 24)

A method according to claim 24, wherein separation is achieved by reducing mixing or turbulent movement of the mixture and allowing the viscous composition to settle out from the water and optionally cross-linked polymeric material AA.

### Claim 26

A method of reducing the viscosity of a viscous petroleum which is arranged to flow along a fluid flow path, said method comprising contacting the viscous petroleum with a treatment fluid formulation, wherein:
a delivery flow path is defined which is arranged to communicate with said fluid flow path, said treatment fluid formulation being dosed into said viscous petroleum in said fluid flow path via said delivery flow path;
the treatment fluid formulation is initially contacted with said viscous composition in said fluid flow path at or downstream of a producing face of a subterranean formation;
the ratio of the flow ratio (in weight per unit time) of treatment fluid formulation in said delivery flow path to the flow rate (in the same weight per unit time units) of viscous petroleum in said fluid flow path is in the range 0.1 to 2.5;
said treatment fluid formulation includes at least 90 wt % water and at least 0.2 wt % of a polymeric material AA;
said polymeric material AA comprises polyvinyl acetate which has been 60 to 100% hydrolyzed to polyvinyl alcohol.

### Claim 27 (depends on 26)

A method according to claim 26, wherein:
said ratio of said flow rates is in the range 0.2 to 1;
said treatment fluid formulation includes at least 0.5 wt % and less than 5.5 wt % of said polymeric material AA.

### Claim 28 (depends on 26)

A method according to claim 26, wherein immediately after contact between said viscous petroleum and said treatment fluid formulation, said fluid flow path contains a composition which includes 40 to 80 wt % of material derived from said viscous petroleum and 20 to 60 wt % of material derived from said treatment fluid formulation.

### Claim 29 (depends on 28)

A method according to claim 28, wherein said polymeric material AA comprises polyvinylacetate which has been 60 to 95% hydrolysed to polyvinylalcohol.

### Claim 30

A fluid flow path positioned at or downstream of a producing face of a subterranean formation, wherein said flow path contains a fluid comprising petroleum, water and a polymeric material AA which is a polyvinyl alcohol polymer or copolymer which is not cross-linked, wherein said polymeric material AA comprises polyvinyl acetate which has been 60-100% hydrolyzed to polyvinyl alcohol.

### Claim 31 (depends on 30)

A fluid flow path according to claim 30, said fluid flow path containing a composition which includes 40 to 80 wt % of material derived from a viscous petroleum and 20 to 60 wt % of water.

### Claim 32

A method for reducing the viscosity of a viscous composition which is arranged to flow along a fluid flow path, said method comprising contacting the viscous composition in said fluid flow path with a treatment fluid formulation, said treatment fluid formulation comprising a polymeric material AA which includes —O— moieties pendent from a polymeric backbone thereof, wherein said polymeric material AA comprises polyvinylacetate which has been 60 to 95% hydrolysed to polyvinylalcohol, wherein polymeric material AA is optionally cross-linked and wherein said treatment fluid formulation is initially contacted with said viscous composition in said fluid flow path at or downstream of a producing face of a subterranean formation.