GB2580860A - Method for enhancing scale inhibition within a hydrocarbon production system - Google Patents
Method for enhancing scale inhibition within a hydrocarbon production system Download PDFInfo
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- GB2580860A GB2580860A GB1815622.4A GB201815622A GB2580860A GB 2580860 A GB2580860 A GB 2580860A GB 201815622 A GB201815622 A GB 201815622A GB 2580860 A GB2580860 A GB 2580860A
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- scale inhibitor
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- 238000000034 method Methods 0.000 title claims abstract description 31
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 17
- 239000004215 Carbon black (E152) Substances 0.000 title claims abstract description 11
- 229930195733 hydrocarbon Natural products 0.000 title claims abstract description 11
- 150000002430 hydrocarbons Chemical class 0.000 title claims abstract description 11
- 230000002708 enhancing effect Effects 0.000 title claims abstract description 8
- 230000005764 inhibitory process Effects 0.000 title claims abstract description 7
- 239000002455 scale inhibitor Substances 0.000 claims abstract description 55
- 239000012530 fluid Substances 0.000 claims abstract description 29
- 238000011282 treatment Methods 0.000 claims abstract description 29
- 230000015572 biosynthetic process Effects 0.000 claims abstract description 26
- 239000000126 substance Substances 0.000 claims abstract description 26
- 239000000654 additive Substances 0.000 claims abstract description 19
- 230000000996 additive effect Effects 0.000 claims abstract description 15
- 230000014759 maintenance of location Effects 0.000 claims abstract description 12
- 238000011084 recovery Methods 0.000 claims abstract description 7
- 239000000203 mixture Substances 0.000 claims description 8
- 125000003277 amino group Chemical group 0.000 claims description 6
- 150000001412 amines Chemical class 0.000 claims description 5
- 229920006317 cationic polymer Polymers 0.000 claims description 5
- 125000002924 primary amino group Chemical class [H]N([H])* 0.000 claims description 2
- 125000000467 secondary amino group Chemical class [H]N([*:1])[*:2] 0.000 claims description 2
- 125000001302 tertiary amino group Chemical group 0.000 claims description 2
- 239000003623 enhancer Substances 0.000 abstract description 30
- 150000003242 quaternary ammonium salts Chemical class 0.000 abstract description 4
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 abstract description 3
- 239000011435 rock Substances 0.000 description 18
- 230000001965 increasing effect Effects 0.000 description 12
- 229920000642 polymer Polymers 0.000 description 11
- 239000013626 chemical specie Substances 0.000 description 9
- 238000002347 injection Methods 0.000 description 8
- 239000007924 injection Substances 0.000 description 8
- 239000003513 alkali Substances 0.000 description 6
- 239000003112 inhibitor Substances 0.000 description 6
- 239000004094 surface-active agent Substances 0.000 description 6
- 239000011162 core material Substances 0.000 description 5
- -1 diallyl ammonium salts Chemical class 0.000 description 5
- 230000000694 effects Effects 0.000 description 5
- 230000007246 mechanism Effects 0.000 description 5
- 238000001556 precipitation Methods 0.000 description 4
- 230000000717 retained effect Effects 0.000 description 4
- 238000001179 sorption measurement Methods 0.000 description 4
- 241000894007 species Species 0.000 description 4
- 229920002554 vinyl polymer Polymers 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- 239000002253 acid Substances 0.000 description 3
- 125000002091 cationic group Chemical group 0.000 description 3
- 150000001875 compounds Chemical class 0.000 description 3
- 229920001577 copolymer Polymers 0.000 description 3
- 229910052500 inorganic mineral Inorganic materials 0.000 description 3
- 239000000243 solution Substances 0.000 description 3
- NLXLAEXVIDQMFP-UHFFFAOYSA-N Ammonia chloride Chemical compound [NH4+].[Cl-] NLXLAEXVIDQMFP-UHFFFAOYSA-N 0.000 description 2
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 2
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 2
- 238000009472 formulation Methods 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 238000011065 in-situ storage Methods 0.000 description 2
- 230000002401 inhibitory effect Effects 0.000 description 2
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- 239000011707 mineral Substances 0.000 description 2
- 235000010755 mineral Nutrition 0.000 description 2
- 239000002105 nanoparticle Substances 0.000 description 2
- 229920002401 polyacrylamide Polymers 0.000 description 2
- 239000013535 sea water Substances 0.000 description 2
- 239000000758 substrate Substances 0.000 description 2
- 125000000391 vinyl group Chemical group [H]C([*])=C([H])[H] 0.000 description 2
- 239000003643 water by type Substances 0.000 description 2
- FEBUJFMRSBAMES-UHFFFAOYSA-N 2-[(2-{[3,5-dihydroxy-2-(hydroxymethyl)-6-phosphanyloxan-4-yl]oxy}-3,5-dihydroxy-6-({[3,4,5-trihydroxy-6-(hydroxymethyl)oxan-2-yl]oxy}methyl)oxan-4-yl)oxy]-3,5-dihydroxy-6-(hydroxymethyl)oxan-4-yl phosphinite Chemical compound OC1C(O)C(O)C(CO)OC1OCC1C(O)C(OC2C(C(OP)C(O)C(CO)O2)O)C(O)C(OC2C(C(CO)OC(P)C2O)O)O1 FEBUJFMRSBAMES-UHFFFAOYSA-N 0.000 description 1
- 229940123208 Biguanide Drugs 0.000 description 1
- 229920002907 Guar gum Polymers 0.000 description 1
- 229920000663 Hydroxyethyl cellulose Polymers 0.000 description 1
- 239000004354 Hydroxyethyl cellulose Substances 0.000 description 1
- 229920001202 Inulin Polymers 0.000 description 1
- JZTPOMIFAFKKSK-UHFFFAOYSA-N O-phosphonohydroxylamine Chemical class NOP(O)(O)=O JZTPOMIFAFKKSK-UHFFFAOYSA-N 0.000 description 1
- 229910019142 PO4 Inorganic materials 0.000 description 1
- ABLZXFCXXLZCGV-UHFFFAOYSA-N Phosphorous acid Chemical class OP(O)=O ABLZXFCXXLZCGV-UHFFFAOYSA-N 0.000 description 1
- 229920002873 Polyethylenimine Polymers 0.000 description 1
- 229920002305 Schizophyllan Polymers 0.000 description 1
- UIIMBOGNXHQVGW-DEQYMQKBSA-M Sodium bicarbonate-14C Chemical compound [Na+].O[14C]([O-])=O UIIMBOGNXHQVGW-DEQYMQKBSA-M 0.000 description 1
- 229920002125 Sokalan® Polymers 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 150000007513 acids Chemical class 0.000 description 1
- 150000003926 acrylamides Chemical class 0.000 description 1
- 229910052783 alkali metal Inorganic materials 0.000 description 1
- 235000019270 ammonium chloride Nutrition 0.000 description 1
- 125000000129 anionic group Chemical group 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 150000007514 bases Chemical class 0.000 description 1
- 150000004283 biguanides Chemical class 0.000 description 1
- 239000012267 brine Substances 0.000 description 1
- 229910000019 calcium carbonate Inorganic materials 0.000 description 1
- 239000013000 chemical inhibitor Substances 0.000 description 1
- 229920002770 condensed tannin Polymers 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
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- 150000004676 glycans Chemical class 0.000 description 1
- 235000010417 guar gum Nutrition 0.000 description 1
- 239000000665 guar gum Substances 0.000 description 1
- 229960002154 guar gum Drugs 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- BHEPBYXIRTUNPN-UHFFFAOYSA-N hydridophosphorus(.) (triplet) Chemical compound [PH] BHEPBYXIRTUNPN-UHFFFAOYSA-N 0.000 description 1
- 235000019447 hydroxyethyl cellulose Nutrition 0.000 description 1
- 229940071826 hydroxyethyl cellulose Drugs 0.000 description 1
- 150000002462 imidazolines Chemical class 0.000 description 1
- 229940029339 inulin Drugs 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000000178 monomer Substances 0.000 description 1
- 150000002894 organic compounds Chemical class 0.000 description 1
- 235000021317 phosphate Nutrition 0.000 description 1
- PTMHPRAIXMAOOB-UHFFFAOYSA-N phosphoramidic acid Chemical class NP(O)(O)=O PTMHPRAIXMAOOB-UHFFFAOYSA-N 0.000 description 1
- 150000003013 phosphoric acid derivatives Chemical class 0.000 description 1
- 150000003014 phosphoric acid esters Chemical class 0.000 description 1
- 229920001308 poly(aminoacid) Polymers 0.000 description 1
- 229920001798 poly[2-(acrylamido)-2-methyl-1-propanesulfonic acid] polymer Polymers 0.000 description 1
- 108010064470 polyaspartate Proteins 0.000 description 1
- 229920001444 polymaleic acid Polymers 0.000 description 1
- 229920001282 polysaccharide Polymers 0.000 description 1
- 239000005017 polysaccharide Substances 0.000 description 1
- 229920002451 polyvinyl alcohol Polymers 0.000 description 1
- 235000019422 polyvinyl alcohol Nutrition 0.000 description 1
- 229920000036 polyvinylpyrrolidone Polymers 0.000 description 1
- 235000013855 polyvinylpyrrolidone Nutrition 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 125000001453 quaternary ammonium group Chemical group 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 229910000029 sodium carbonate Inorganic materials 0.000 description 1
- HPALAKNZSZLMCH-UHFFFAOYSA-M sodium;chloride;hydrate Chemical compound O.[Na+].[Cl-] HPALAKNZSZLMCH-UHFFFAOYSA-M 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 125000001273 sulfonato group Chemical group [O-]S(*)(=O)=O 0.000 description 1
- BDHFUVZGWQCTTF-UHFFFAOYSA-N sulfonic acid Chemical compound OS(=O)=O BDHFUVZGWQCTTF-UHFFFAOYSA-N 0.000 description 1
- 239000000725 suspension Substances 0.000 description 1
- 229920001285 xanthan gum Polymers 0.000 description 1
- 235000010493 xanthan gum Nutrition 0.000 description 1
- 239000000230 xanthan gum Substances 0.000 description 1
- 229940082509 xanthan gum Drugs 0.000 description 1
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
- C09K8/52—Compositions for preventing, limiting or eliminating depositions, e.g. for cleaning
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B37/00—Methods or apparatus for cleaning boreholes or wells
- E21B37/06—Methods or apparatus for cleaning boreholes or wells using chemical means for preventing or limiting, e.g. eliminating, the deposition of paraffins or like substances
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F5/00—Softening water; Preventing scale; Adding scale preventatives or scale removers to water, e.g. adding sequestering agents
- C02F5/08—Treatment of water with complexing chemicals or other solubilising agents for softening, scale prevention or scale removal, e.g. adding sequestering agents
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F5/00—Softening water; Preventing scale; Adding scale preventatives or scale removers to water, e.g. adding sequestering agents
- C02F5/08—Treatment of water with complexing chemicals or other solubilising agents for softening, scale prevention or scale removal, e.g. adding sequestering agents
- C02F5/10—Treatment of water with complexing chemicals or other solubilising agents for softening, scale prevention or scale removal, e.g. adding sequestering agents using organic substances
- C02F5/12—Treatment of water with complexing chemicals or other solubilising agents for softening, scale prevention or scale removal, e.g. adding sequestering agents using organic substances containing nitrogen
-
- 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
- C09K8/528—Compositions for preventing, limiting or eliminating depositions, e.g. for cleaning inorganic depositions, e.g. sulfates or carbonates
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2303/00—Specific treatment goals
- C02F2303/22—Eliminating or preventing deposits, scale removal, scale prevention
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Chemical & Material Sciences (AREA)
- Environmental & Geological Engineering (AREA)
- Mining & Mineral Resources (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Geology (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Hydrology & Water Resources (AREA)
- Water Supply & Treatment (AREA)
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- Materials Engineering (AREA)
- Geochemistry & Mineralogy (AREA)
- Inorganic Chemistry (AREA)
- Emulsifying, Dispersing, Foam-Producing Or Wetting Agents (AREA)
Abstract
A method of enhancing scale inhibition within a hydrocarbon production system in which fluids have been injected into a reservoir formation to increase oil recovery, comprising; a) treating the reservoir formation with a chemical scale inhibitor (SI), and, b) treating the reservoir formation with a chemical additive which increases retention of the scale inhibitor (i.e. a scale lifetime enhancer or SLE). The chemical additive may be a polymeric quaternary ammonium salt and in particular may be poly(diallyldimethlammonium) chloride (polyDADMAC). The chemical additive may be applied to the formation as a pre-flush treatment prior to the application of the scale inhibitor, or an over-flush treatment after the application of the scale inhibitor. The chemical additive may also be added to the formation at the same time as the scale inhibitor.
Description
Method for Enhancing Scale Inhibition within a Hydrocarbon Production System
Field of Invention:
The invention relates to hydrocarbon production and a method to increase the effective lifetime of oilfield scale inhibitor squeeze treatments under enhanced oil recovery conditions by the application of enhancing chemical species to the reservoir formation.
Background of the Invention:
Inorganic scale formation from supersaturated waters that are produced in hydrocarbon production systems is a significant problem. Many different methods are available to mitigate the issue but the most widely used is the application of chemical formulations into the system to inhibit or disperse mineral deposits. A well-known method of deploying the chemical inhibitor is a squeeze treatment where the inhibitor formulation is pumped into the reservoir and then returns in the produced fluids. These treatments rely on the adsorption or precipitation of chemical species onto the surface of the reservoir rock which are then gradually released back into the produced fluids at a sufficient concentration to inhibit the formation of scale from a supersaturated solution. There are several possible mechanisms for the retention onto the rock but these primarily depend on the chemical functionality and electrostatic charge of both the rock surface and the inhibiting chemical species.
The regular deployment of squeeze treatments can result in very high production costs particularly in offshore oilfields. Therefore, methods to extend the effective duration of a treatment have been sought by causing more inhibitor to adsorb or precipitate to the rock and / or slowing the subsequent release.
O In this way, the effective lifetime of the squeeze treatment -the time for which the inhibitor species concentration remains greater than the minimum required to prevent scale formation -is increased.
C\I One method that has been described to achieve this is the addition of other chemical additives into the fluids used for the squeeze treatment. These additives are referred to as squeeze life enhancers (SLE). Squeeze life enhancers may be applied in any of the possible stages of a squeeze treatment such as the pre-flush, the main inhibitor injection, or the over-flush.
US5038861 and US5181567 disclose a method for prolonging the useful life of a scale inhibitor within a formation by injection of polyquaternary amines. US8101554 describes a method for increasing the life of a scale inhibitor by use of polymers formed from diallyl ammonium salts and scale inhibitors.
However in these existing methods, there is no description of the hydrocarbon production conditions in which the squeeze life enhancers are found to be effective in the field. The prior art refers only to the use of SLEs under conventional production conditions, defined as those producing conventional produced water, typically comprising formation waters and injected sea water, produced at moderate pHs in the range pH 5.0 -6.5 under downhole conditions. Additionally, it is not specified which types of scale inhibitors prove effective in combination with specific squeeze life enhancers. Therefore there remains scope for further improvement by developing methods that will extend lifetimes under a range of non-conventional production systems. Increasingly, hydrocarbon production involves using more complex techniques to increase the quantity of oil produced from the reservoir and extend the field lifetime. These approaches are referred to as enhanced oil recovery (EOR). Some of these methods involve the injection of chemical species into the reservoir with the aim of altering the surface properties of the reservoir rock and behaviour of the oil and water phases therein. Well-known components of EOR fluids include alkalis, surfactants, polymers and mixtures thereof Another EOR technique is water alternating gas (WAG) injection.
It is known, however, that use of EOR fluids can result in a challenge for scale control, particularly when using alkali fluids that result in a much increased pH and consequently greater supersaturation of minerals such as calcium carbonate. Moreover, the use of fluids designed to alter the surface properties of the rock may also have a negative effect on the retention of scale inhibitor species reducing the lifetime of squeeze treatments. The presence of the chemical additives in EOR applications considerably changes the effectiveness of scale inhibitor squeeze treatments and that of any squeeze life enhancers since many of the chemicals applied in EOR either compete with, or prevent, retention of scale inhibitors and squeeze life enhancers.
Use of CO2 as part of an EOR WAG treatment can have the effect of producing more acidic conditions and fluids, again increasing the scale control challenge.
Summary of Invention:
The object of the current invention relates to a method for enhancing scale inhibition within a hydrocarbon production system in which fluids have been injected into a reservoir formation to increase oil recovery, comprising of: the treatment of said reservoir formation with a chemical scale inhibitor; and the treatment of said reservoir formation with a chemical additive which increases retention of said scale inhibitor in the reservoir.
Alternatively, the invention relates to a method for enhancing scale inhibition within a hydrocarbon production system, in which fluids have been injected into the reservoir formation to increase oil recovery, by treatment of said reservoir formation, through co-injection with a chemical combination of scale inhibitors, chemical additives and injected fluids which control the retention and release rate of scale inhibitor from the formation The object of the current invention relates to the application of chemical species to the reservoir formation such that they increase the effective lifetime of scale inhibitor squeeze treatments under enhanced oil recovery (EOR) conditions.
It has been found that the addition of certain chemical species (squeeze life enhancers, SLE) into one or more stages of a squeeze treatment programme can increase the retention of scale-inhibiting chemicals on the reservoir rock and the resulting lifetime of the treatment. In particular, the lifetime is increased even under challenging production conditions when EOR fluids, particularly alkali-based O fluids such as alkaline surfactant (AS) or alkaline surfactant polymer (ASP), are injected into and then Nproduced from the reservoir, which is not the case with the prior art methods.
The invention also relates to use of system-specific combinations of squeeze life enhancers and scale inhibitor (SI) to obtain increased SI retention within the reservoir rock. It has been found that to obtain increased squeeze treatment lifetimes, it is necessary to select an appropriate squeeze life enhancer for application with a specific SI under particular production conditions. Use of a squeeze life enhancers that is not appropriate for use with a particular SI can result in no improvement in lifetime or, in some cases, actually have a negative effect.
The mechanism by which application of a squeeze life enhancer results in increased scale inhibitor retention, or retarded scale inhibitor release, may be but is not limited to, an adsorption mechanism, a precipitation mechanism, or a combination of both. Where the mechanism is by precipitation of a scale inhibitor and squeeze life enhancer complex, the precipitation may occur prior to injection, during injection or after injection of the fluids into the reservoir formation.
One embodiment of the current invention involves squeeze life enhancer addition to the fluids for the preflush stage of the treatment. A further embodiment involves squeeze life enhancer addition into the main stage of the treatment in the same solution as the SI. Another embodiment involves squeeze life enhancer addition into an overflush treatment following application of the scale inhibitor. A method of treatment may also be used in which fluids containing the squeeze life enhancer or scale inhibitor are alternatingly applied to the rock resulting in multiple layers of each being formed. The squeeze life enhancer species in the current invention may be applied in a molar concentration equal to that of the applied scale inhibitor or in a higher or lower concentration.
In one embodiment of the present invention the chemical species applied as a squeeze life enhancer is a cationic polymer or oligomer. Specifically an amine-containing cationic polymer, and more specifically a quaternary amine containing cationic polymer. Representative examples include polyquaternary amines, polyamino acids (e.g. polyaspartate, polyglutanic acid), cationic polysaccahrides, quaternary polyalkyleneimines, quaternary polyalkanolamines, polyvinyl ammonium chloride, polyvinylimidazoline acid salts and condensed tannins, polydimethylamine-co-epichlorohydrin and biguanides, zwitterionic betaines and imidazolines and quaternary ammonium salts. Other cationic polymers include copolymers of vinyl monomers having cationic protonated amine or quaternary ammonium functionalities. The squeeze life enhancer can also include an analyzable moiety allowing the concentration returning in the produced fluids to be monitored.
In another method of the current invention, the squeeze life enhancer is a polymeric or oligomeric amine without quaternary amine groups present. The polymer may contain primary, secondary or tertiary amine groups or a mixture thereof. A preferred example of such a polymer is polyethyleneimine in linear or branched form but more preferably in branched form.
In another method of the current invention, non-polymeric compounds may be used as the squeeze life enhancer. An example would be a non-polymeric compound with one or more quaternary amines.
In another method of the current invention, the squeeze life enhancer may consist of a suspension of microparticles or nanoparticles. An example of these may be microparticles or nanoparticles precipitated from a mixture of a scale inhibitor and co-ordinating chemical species.
The squeeze life enhancer applied in the current invention may be a single chemical species. Alternatively, in another embodiment, it may comprise a mixture of more than one chemical compound.
In an embodiment of the current invention, the pH of the EOR fluids flowing through the reservoir is between pH 7 and pH 14. Specifically the pH is between pH 8 and pH 12. More specifically, the pH is between 9 and 11.
In an embodiment of the current invention, the EOR fluid may contain a basic compound resulting in the fluids having a pH greater than 7. Examples of such compounds are sodium carbonate, sodium bicarbonate, sodium hydroxide (or other alkali metal basic salts), and organic amines.
The EOR fluid may optionally contain a surfactant. Such surfactants may be anionic, cationic mixed O ionic character or non-ionic and blends thereof.
C\I The EOR fluid may optionally contain a polymer. Examples of such polymers include acrylamides, polyacrylamides, hydrolysed polyacrylamides, polyacrylamidomethylpropane sulfonic acids, polyvinylpyrrolidones, polyvinyl alcohols, polysaccharides, hydroxyethylcellulose, xanthan gum, guar gum and scleroglucan.
The EOR fluid may contain a combination of alkaline, surfactant and polymer components.
In an embodiment of the current invention, the EOR fluids may contain dissolved gases, such as CO2, which result in the EOR fluids flowing through the reservoir having a pH between 1 and 7, more specifically between pH 3 and pH 5.
The scale inhibitor species whose squeeze lifetime may be enhanced can be any organic compound that prevents or slows the growth of inorganic mineral deposits. Such compounds include but are not limited to; phosphonates, aminophosphonates, phosphates, amino phosphates, phosphate esters, polyacrylic acids, phosphinopolyacrylates, polycarboxylic acids, polymaleic acids, polyvinyl sulphonates, vinyl sulphonated co-polymers, phosphorous tagged polymers, sulphonic acid co polymers, polyaspartates, carboxymethyl inulin.
Examples Example
Core flood tests were conducted with a standard polymeric scale inhibitor (SI A) and poly(diallyldimethylammonium) chloride (polyDADMAC), a polymeric quaternary ammonium salt, as the squeeze life enhancer. These tests consisted of two chemical application and release (post-flush) cycles on the same reservoir core plug. The first sequence was in absence of the SLE and the second cycle included the squeeze life enhancer. Figure 1 shows the absolute chemical concentration during post-flush for the two test cycles. Cycle #1 data (no additive applied) are plotted with the filled markers and Cycle #2 data (additive applied) are plotted with the open markers. Inhibitor release, or post-flush, was performed with a low-salinity seawater (TDS -10,000 mg/I) containing alkali giving an in situ pH of -9.5 representing an alkali system typically observed in an AS or ASP EOR flood.
The scale inhibitor concentrations for the second cycle (with squeeze life enhancer) remained well above the concentrations of the first cycle. This indicates that the inhibitor retained more strongly onto rock surface with the aid of the additive. This data presents a clear example where the so described squeeze life enhancer is applied in the pre-flush resulting in a prolonged core flood return. This shows a significant effect of the squeeze life enhancer under these challenging conditions.
Example 2
Similar effects of the SLEs in different rock material and under different application conditions are demonstrated here. Two core flood tests was conducted on unreactive outcrop sandstone core material. The first of these was conducted with a standard polymeric scale inhibitor (SI A) in the absence an SLE while the second test was conducted with SI A whereby the rock was pre-treated with poly(diallyldimethylammonium) chloride (polyDADMAC), a polymeric quaternary ammonium salt, as the squeeze life enhancer. Figure 2 compares the absolute chemical concentration during post-flush for both tests. Post-flush was conducted with a synthetic produced water containing alkali giving an in situ pH of 11 representing a high alkali system illustrating an example of what could be observed in an AS or ASP EOR flood.
This example shows a rapid decline in SI concentration in the flood without the SLE (cycle 1). However, in the presence of the SLE, the scale inhibitor concentration remains at a higher concentration throughout the alkaline flow back. This would indicate that the scale inhibitor retained more strongly onto the rock substrate and the presence of the SLE has also aided in a delayed release. This example shows that even in a more challenging scenario (very clean rock substrate and increased alkalinity flow back brine), this SLE still aids in improving scale inhibitor retention and subsequent release.
O Example 3
Static adsorption tests were conducted in which different combinations of SI and SLE were applied to crushed sandstone rock under different pH conditions. The percentage of SI remaining in solution after heating at 90°C for 20 hours, and hence not retained on the rock, is shown in Figure 3.
It can be seen that retention of SI A is not increased by the addition of SLE A but is significantly increased in the presence of SLE B at pH 4 and pH 6, but not at pH 10, and therefore this combination would only be suitable for conventional reservoirs, or those producing lower pH fluids potentially as a result of a WAG application. SI B shows no adsorption to the rock without an SLE present, or with the addition of SLE C. However, the presence of SLE D results in significant SI retained on the rock, in particular at pH 10, representative of alkaline EOR conditions.
This example demonstrates that it has been found that system-specific combinations of SI and SLE are required to obtain increased squeeze treatment lifetimes under specific production conditions, in particular under high pH, EOR conditions. Therefore, application of existing prior art methods would not be sufficient to obtain the desired result under these challenging conditions.
Claims (7)
- Method for Enhancing Scale Inhibition within a Hydrocarbon Production System Claims: A method for enhancing scale inhibition within a hydrocarbon production system in which fluids have been injected into a reservoir formation to increase oil recovery, comprising of: the treatment of said reservoir formation with a chemical scale inhibitor; and the treatment of said reservoir formation with a chemical additive which increases retention of said scale inhibitor in the reservoir.
- A method according to claim 1 in which the chemical additive is applied to the formation as a preflush treatment prior to application of the scale inhibitor.
- 3. A method according to claim 1 in which the chemical additive is applied to the formation as an overtlush treatment after application of the scale inhibitor.
- A method according to claim 1 in which the chemical additive is applied to the formation at the same time as the fluids containing the scale inhibitor.
- 5. A method according to claim 1 in which the chemical additive and the scale inhibitor are applied to the formation multiple times in an alternating manner.
- 6. A method according to claims 1 -5 in which the chemical additive is a cationic polymer or oligomer.CD
- 7. A method according to claims 1 -5 in which the chemical additive is a polymeric or oligomeric C\I amine containing primary, secondary or tertiary amine groups or a mixture thereof without quaternary amine groups present.O N
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB1815622.4A GB2580860A (en) | 2018-09-25 | 2018-09-25 | Method for enhancing scale inhibition within a hydrocarbon production system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB1815622.4A GB2580860A (en) | 2018-09-25 | 2018-09-25 | Method for enhancing scale inhibition within a hydrocarbon production system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB201815622D0 GB201815622D0 (en) | 2018-11-07 |
| GB2580860A true GB2580860A (en) | 2020-08-05 |
Family
ID=64024129
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB1815622.4A Withdrawn GB2580860A (en) | 2018-09-25 | 2018-09-25 | Method for enhancing scale inhibition within a hydrocarbon production system |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2580860A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US11970657B2 (en) | 2022-05-26 | 2024-04-30 | Baker Hughes Oilfield Operations Llc | Carbonate-based solvents for scale-squeeze enhancement |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5038861A (en) * | 1990-05-23 | 1991-08-13 | Chevron Research And Technology Company | Method for prolonging the useful life of scale inhibitors injected within a formation |
| US5181567A (en) * | 1990-05-23 | 1993-01-26 | Chevron Research And Technology Company | Method for prolonging the useful life of polymeric or blended scale inhibitors injected within a formation |
| WO2008020220A1 (en) * | 2006-08-17 | 2008-02-21 | Champion Technologies Ltd | Well treatment |
-
2018
- 2018-09-25 GB GB1815622.4A patent/GB2580860A/en not_active Withdrawn
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5038861A (en) * | 1990-05-23 | 1991-08-13 | Chevron Research And Technology Company | Method for prolonging the useful life of scale inhibitors injected within a formation |
| US5181567A (en) * | 1990-05-23 | 1993-01-26 | Chevron Research And Technology Company | Method for prolonging the useful life of polymeric or blended scale inhibitors injected within a formation |
| WO2008020220A1 (en) * | 2006-08-17 | 2008-02-21 | Champion Technologies Ltd | Well treatment |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US11970657B2 (en) | 2022-05-26 | 2024-04-30 | Baker Hughes Oilfield Operations Llc | Carbonate-based solvents for scale-squeeze enhancement |
Also Published As
| Publication number | Publication date |
|---|---|
| GB201815622D0 (en) | 2018-11-07 |
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| Date | Code | Title | Description |
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| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |