WO2004104367A1 - Sludge control in crude oil - Google Patents

Sludge control in crude oil Download PDF

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Publication number
WO2004104367A1
WO2004104367A1 PCT/GB2004/002197 GB2004002197W WO2004104367A1 WO 2004104367 A1 WO2004104367 A1 WO 2004104367A1 GB 2004002197 W GB2004002197 W GB 2004002197W WO 2004104367 A1 WO2004104367 A1 WO 2004104367A1
Authority
WO
WIPO (PCT)
Prior art keywords
tetrakis
hydroxymethyl
stimulation
organophosphorus species
phosphonium
Prior art date
Application number
PCT/GB2004/002197
Other languages
French (fr)
Inventor
Christopher Raymond Jones
Robert S. Taylor
Original Assignee
Rhodia Consumer Specialties Limited
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Rhodia Consumer Specialties Limited filed Critical Rhodia Consumer Specialties Limited
Publication of WO2004104367A1 publication Critical patent/WO2004104367A1/en

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K8/00—Compositions for drilling of boreholes or wells; Compositions for treating boreholes or wells, e.g. for completion or for remedial operations
    • C09K8/54—Compositions for in situ inhibition of corrosion in boreholes or wells
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K8/00—Compositions for drilling of boreholes or wells; Compositions for treating boreholes or wells, e.g. for completion or for remedial operations
    • C09K8/52—Compositions for preventing, limiting or eliminating depositions, e.g. for cleaning
    • C09K8/524—Compositions for preventing, limiting or eliminating depositions, e.g. for cleaning organic depositions, e.g. paraffins or asphaltenes

Definitions

  • This invention relates to a method for controlling, and preferably substantially preventing, the formation of ferric-ion-induced sludge in a process for the extraction of crude oil and to the use of organophosphorus species to break down already formed sludge.
  • stimulation fluids which include acids (especially hydrochloric acid) are frequently used.
  • acids especially hydrochloric acid
  • the action of the acid on pipelines and reservoir rock causes dissolution of iron (as ferric ions) into the fluids.
  • ferric ions cross-link high molecular weight organic molecules, such as asphaltenic and naphthenate molecules present in the oil, causing a thick sludge to be formed.
  • the present invention provides a method for controlling the formation of ferric-ion-induced sludge in a process for the extraction of crude oil under acidic stimulation conditions, said method comprising the addition to the stimulation fluid or to the formation fluids of an effective amount of an organophosphorus species.
  • formation fluids takes the standard meaning known in the art of oil, water, gas or emulsion thereof.
  • the method substantially prevents the formation of the ferric- ion- induced sludge.
  • the organophosphorus species may be an alkyl-substituted phosphine oxide, for example tris(hydroxymethyl) phosphine oxide (THPO).
  • THPO tris(hydroxymethyl) phosphine oxide
  • the THPO may be pre-formed or generated (by means known per se) in situ in the oil extraction system.
  • the organophosphorus species may be a tetrakis(hydroxyalkyl) ⁇ hos ⁇ honium salt (THPX) , for example tetrakis(hydroxyalkyl)phosphonium sulphate (THPS) or tetrakis(hydroxymethyl) ⁇ hos ⁇ honium chloride (THPC) or the phosphate, acetate or oxalate equivalent forms.
  • TTPX tetrakis(hydroxyalkyl) ⁇ hos ⁇ honium salt
  • THPS tetrakis(hydroxyalkyl)phosphonium sulphate
  • THPC tetrakis(hydroxymethyl) ⁇ hos ⁇ honium chloride
  • the stimulation fluid includes up to 28% by weight of an inorganic acid, for example hydrochloric acid.
  • an inorganic acid for example hydrochloric acid.
  • Other components will include corrosion inhibitors, surfactants and other specialist additives.
  • the pH of the stimulation fluid is preferably 4 or less.
  • the organophosphorus species is preferably added to the stimulation fluid or to the formation fluids in an amount of from 0.01% to 10% (by weight) , preferably from 0.1 to 1.0%.
  • organophosphorus species is THPO
  • it may be added to the stimulation fluid or to the formation fluids at any stage in the extraction process. It has been found that the formation of ferric-ion-induced sludge is substantially prevented, even when the THPO is pre-mixed with the stimulation fluid already containing ferric ions, resulting in rapid phase- separation of fluid and oil.
  • organophosphorus species is THPX, THPS or THPC
  • THPX THPX
  • THPS THPS
  • THPC THPC
  • THPO THPO
  • THPS THPC
  • THPC can break down already-formed sludge in crude oil.
  • the present invention also provides the use of an organophosphorus species to break down already-formed, ferric-ion-induced sludge in crude oil.
  • the organophosphorus species may be, for example, THPO, THPS or THPC.
  • the already-formed sludge may be exposed to the organophosphorus species for a soaking period, e.g. of between 6-96 hours.
  • a typical North Sea crude oil was treated with a stimulation fluid comprising 15% hydrochloric acid and containing about 5000 ppm ferric ions. To this mixture was added 0.1% THPO (by weight of the oil) .

Abstract

A method is provided for controlling the formation of ferric-ion-induced sludge in a process for the extraction of crude oil under acidic stimulation conditions. The method comprises the addition to the stimulation fluid or the formulation fluids of an effective amount of an organophosphorus species. The organophosphorus species may be a tetrakis(hydroxyalkyl)phosphonium salt.

Description

SLUDGE CONTROL IN CRUDE OIL
This invention relates to a method for controlling, and preferably substantially preventing, the formation of ferric-ion-induced sludge in a process for the extraction of crude oil and to the use of organophosphorus species to break down already formed sludge.
In the extraction of crude oil, stimulation fluids which include acids (especially hydrochloric acid) are frequently used. The action of the acid on pipelines and reservoir rock causes dissolution of iron (as ferric ions) into the fluids. Under acidic conditions, the ferric ions cross-link high molecular weight organic molecules, such as asphaltenic and naphthenate molecules present in the oil, causing a thick sludge to be formed.
It has been proposed to prevent such cross-linking by the addition of chelating agents to the stimulation fluids. However, most of the commonly-available chelating agents are anionic in nature and therefore ineffective at low pH values, e.g. below pH4.
It has also been proposed to add reducing agents to the stimulation fluids, to reduce ferric ions to ferrous ions. While such a treatment would avoid sludge formation (ferrous ions would not cross-link the asphaltenic molecules) it leads to the deposit of ferrous sulphide, with consequent formation of scale and eventual blockage.
We have now unexpectedly found that the addition to an oil-extraction system of an organophosphorus species results in the substantial prevention of sludge formation in the crude oil.
We have also found that certain organophosphorus species can cause the breakdown of already-formed sludge in crude oil. Accordingly, the present invention provides a method for controlling the formation of ferric-ion-induced sludge in a process for the extraction of crude oil under acidic stimulation conditions, said method comprising the addition to the stimulation fluid or to the formation fluids of an effective amount of an organophosphorus species.
In the context of the present invention the phrase "formation fluids" takes the standard meaning known in the art of oil, water, gas or emulsion thereof.
Preferably the method substantially prevents the formation of the ferric- ion- induced sludge.
The organophosphorus species may be an alkyl-substituted phosphine oxide, for example tris(hydroxymethyl) phosphine oxide (THPO). The THPO may be pre-formed or generated (by means known per se) in situ in the oil extraction system.
Alternatively, the organophosphorus species may be a tetrakis(hydroxyalkyl)ρhosρhonium salt (THPX) , for example tetrakis(hydroxyalkyl)phosphonium sulphate (THPS) or tetrakis(hydroxymethyl)ρhosρhonium chloride (THPC) or the phosphate, acetate or oxalate equivalent forms.
Suitably, the stimulation fluid includes up to 28% by weight of an inorganic acid, for example hydrochloric acid. Other components will include corrosion inhibitors, surfactants and other specialist additives.
The pH of the stimulation fluid is preferably 4 or less. The organophosphorus species is preferably added to the stimulation fluid or to the formation fluids in an amount of from 0.01% to 10% (by weight) , preferably from 0.1 to 1.0%.
Where the organophosphorus species is THPO, it may be added to the stimulation fluid or to the formation fluids at any stage in the extraction process. It has been found that the formation of ferric-ion-induced sludge is substantially prevented, even when the THPO is pre-mixed with the stimulation fluid already containing ferric ions, resulting in rapid phase- separation of fluid and oil.
It has further been found that the addition to the extraction system of 0.2% THPO (by weight of oil) will control at least 5000 ppm of ferric ion and that the addition of 1% THPO (by weight of oil) will control at least 10000 ppm of ferric ion.
Where the organophosphorus species is THPX, THPS or THPC, it is contacted with the oil before contact with the stimulation fluid containing ferric ions. It has been found that this results in the substantial prevention of sludge-formation, with rapid phase-separation of fluid and oil.
It has further been found that the addition to the formation fluids or oil of 1% THPS or THPC (by weight of oil) will control at least 10000 ppm of ferric ion.
Further, it has been found that THPO, THPS and THPC can break down already-formed sludge in crude oil. Thus, the present invention also provides the use of an organophosphorus species to break down already-formed, ferric-ion-induced sludge in crude oil.
The organophosphorus species may be, for example, THPO, THPS or THPC.
The already-formed sludge may be exposed to the organophosphorus species for a soaking period, e.g. of between 6-96 hours.
The present invention will be illustrated by way of the following Example.
Example
A typical North Sea crude oil was treated with a stimulation fluid comprising 15% hydrochloric acid and containing about 5000 ppm ferric ions. To this mixture was added 0.1% THPO (by weight of the oil) .
Immediate phase- separation of oil and acid occurred and no sludge was produced. This is shown in Figure 1 of the accompanying illustrations.
A control (where no THPO was added) resulted in a solid sludge, as shown in Figure 2 of the accompanying illustrations.

Claims

1. A method for controlling the formation of ferric-ion-induced sludge in a process for the extraction of crude oil under acidic stimulation conditions, said method comprising the addition to the stimulation fluid or to the formation fluids of an effective amount of an organophosphorus species.
2. A method according to Claim 1, in which the organophosphorus species is an alkyl-substituted phosphine oxide.
3. A method according to Claim 1 or 2, in which the organophosphorus species is tris(hydroxymethyl)phosphine oxide (THPO).
4. A method according to Claim 1, in which the organophosphorus species is a tetrakis(hydroxyalkyl)phosphonium salt (THPX).
5. A method according to Claim 1 or 4, in which the organophosphorus species is tetrakis (hydroxymethyl)phosphonium sulphate (THPS), tetrakis (hydroxymethyl)phosphonium chloride (THPC), tetrakis (hydroxymethyl)phosphonium acetate , tetrakis(hydroxymethyl)phosphonium phosphate or tetrakis (hydroxymethyl)phosphonium oxalate .
6. A method according to any one of the preceding claims, in which the stimulation fluid includes up to 28% by weight of an inorganic acid.
7. A method according to Claim 6, in which the inorganic acid is hydrochloric acid.
8. A method according to any one of the preceding claims, in which the pH of the stimulation fluid is 4 or less.
9. A method according to Claim 3 (and to any one of Claims 6 to 8 when dependent upon Claim 3), in which the THPO is added to the stimulation fluid at any stage in the stimulation process.
10. A method according to Claim 3 (and to any one of Claims 6 to 8 when dependent upon Claim 3), in which the THPO is added to the formation fluids at any stage in the stimulation or extraction process.
11. A method according to Claims 4 or 5 (and to any one of Claims 6 to 8 when dependent upon Claim 4 or 5) , in which the tetrakis (hydroxymethyl)phosphonium salt is contacted with the formation fluids before contact with the stimulation fluid.
12. A method according to any one of the preceding claims, in which the organophosphorus species is added to the stimulation fluid or to the formation fluids in an amount of from 0.01% to 10% (by weight), preferably 0.1% to 1%.
13. A method for controlling the formation of ferric-ion-induced sludge in a process for the extraction of crude oil, substantially as hereinbefore described with reference to the Example.
14. The use of an organophosphorus species to break down already- formed, ferric-ion-induced sludge in crude oil.
15. Use according to Claim 14, in which the organophosphorus species is THPO, THPS, THPC or the acetate, phosphate or oxalate forms of a tetrakis(hydroxalkyl)phosphonium salt.
16. Use according to Claim 14 or 15, in which the sludge is exposed to the organophosphorus species for a soaking period of between 6 to 96 hours.
PCT/GB2004/002197 2003-05-24 2004-05-21 Sludge control in crude oil WO2004104367A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB0312017A GB0312017D0 (en) 2003-05-24 2003-05-24 Sludge control in crude oil
GB0312017.7 2003-05-24

Publications (1)

Publication Number Publication Date
WO2004104367A1 true WO2004104367A1 (en) 2004-12-02

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GB (1) GB0312017D0 (en)
WO (1) WO2004104367A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2423099A (en) * 2005-02-10 2006-08-16 Rhodia Uk Ltd Phosphorus containing species in sludge control

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0198225A2 (en) * 1985-03-30 1986-10-22 Akzo GmbH Means against the precipitation and sedimentation of asphaltenes and the like
US4698168A (en) * 1986-08-29 1987-10-06 Hughes Tool Company Corrosion inhibitor for well acidizing treatments
US5130473A (en) * 1986-05-15 1992-07-14 Petrolite Corporation Dithiocarbamate compounds
US6204420B1 (en) * 1998-06-25 2001-03-20 Clariant Gmbh Synergistic mixtures of phosphoric esters with carboxylic acids or carboxylic acid derivatives as asphaltene dispersants

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0198225A2 (en) * 1985-03-30 1986-10-22 Akzo GmbH Means against the precipitation and sedimentation of asphaltenes and the like
US5130473A (en) * 1986-05-15 1992-07-14 Petrolite Corporation Dithiocarbamate compounds
US4698168A (en) * 1986-08-29 1987-10-06 Hughes Tool Company Corrosion inhibitor for well acidizing treatments
US6204420B1 (en) * 1998-06-25 2001-03-20 Clariant Gmbh Synergistic mixtures of phosphoric esters with carboxylic acids or carboxylic acid derivatives as asphaltene dispersants

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2423099A (en) * 2005-02-10 2006-08-16 Rhodia Uk Ltd Phosphorus containing species in sludge control
WO2006084662A1 (en) * 2005-02-10 2006-08-17 Rhodia Uk Limited Phosphorous-containing species for use in sludge control

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Publication number Publication date
GB0312017D0 (en) 2003-07-02

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