CA1295120C - Aqueous polysaccharide compositions - Google Patents
Aqueous polysaccharide compositionsInfo
- Publication number
- CA1295120C CA1295120C CA000545750A CA545750A CA1295120C CA 1295120 C CA1295120 C CA 1295120C CA 000545750 A CA000545750 A CA 000545750A CA 545750 A CA545750 A CA 545750A CA 1295120 C CA1295120 C CA 1295120C
- Authority
- CA
- Canada
- Prior art keywords
- composition according
- formate
- polysaccharide
- salt
- water
- Prior art date
- Legal status (The legal status 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 status listed.)
- Expired - Lifetime
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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
- C09K8/02—Well-drilling compositions
- C09K8/04—Aqueous well-drilling compositions
- C09K8/06—Clay-free compositions
- C09K8/08—Clay-free compositions containing natural organic compounds, e.g. polysaccharides, or derivatives thereof
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K3/00—Use of inorganic substances as compounding ingredients
- C08K3/16—Halogen-containing compounds
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K5/00—Use of organic ingredients
- C08K5/04—Oxygen-containing compounds
- C08K5/09—Carboxylic acids; Metal salts thereof; Anhydrides thereof
- C08K5/098—Metal salts of carboxylic acids
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S507/00—Earth boring, well treating, and oil field chemistry
- Y10S507/925—Completion or workover fluid
Abstract
ABSTRACT
AQUEOUS POLYSACCHARIDE COMPOSITIONS
The invention provides aqueous polysaccharide compositions comprising 0.03 to 5% w/v of a water-soluble polysaccharide, 5 to 80% w/v of at least one salt of at least one mono- or divalent cation, wherein at least 0.05% w/v, based on the composition, of the at least one salt is formate, the balance of the at least one salt, if any, being at least one halide, a process for preparing the compositions, and their use in well-drilling operations.
AQUEOUS POLYSACCHARIDE COMPOSITIONS
The invention provides aqueous polysaccharide compositions comprising 0.03 to 5% w/v of a water-soluble polysaccharide, 5 to 80% w/v of at least one salt of at least one mono- or divalent cation, wherein at least 0.05% w/v, based on the composition, of the at least one salt is formate, the balance of the at least one salt, if any, being at least one halide, a process for preparing the compositions, and their use in well-drilling operations.
Description
AQUEOUS POLYSACCHARIDE CoMPOSITIONS
I~his invention relates to aqueous polysacch æide compositions, their prepæ ation and their use in well-drillLng operations.
It is known to use aqueous polysaccharide compositions in well-drilling operations, e.g. in oil and gas wells. Examples of polysaccharides include cellulose derivatives, such as cæboxyethylc~llulose, c æboxymethylcellulose, carboxymethylhydroxyethylcellulose, aLkylhydroxyalkylcelluloses, alkylcelluloses, alkylcarboxyaLkylcelluloses and hydroxyalkylcelluloses (particulæ ly hydroxyeth~lcellulose); and microbial polysaccharides such as Succinoglycan polysaccharides, Scleroglucan polysaccharides and Xanthan polysaccharides.
Succinoglycan polysaccharides comprise glucose, and, for each 7 mols of glucose, 0.9 to 1.2 mols of galactose, 0.65 to 1.1 mols pyruvate, 0 to 2 mols succinate and 0 to 2 mols of acetate, and are pro~uced by cultivating a slime-forming species of Pseudomonas, Rhizobium, Alcaligenes or Agrobacterium, e.g.
____ _ _ Pseudomonas sp. NCIB 11264, Pseudomonas sp. NCIB 11592 or Agrobacterium radiobacter NCIB 11883, or mutants thereof, as described, for example, in EP-A-40445 (Applicants ref K 1480) or EP-A-138255 (Applicants ref. K 1924), Scleroglucan polysaccharides comprise linear chairls of PS04.001 z~
I~his invention relates to aqueous polysacch æide compositions, their prepæ ation and their use in well-drillLng operations.
It is known to use aqueous polysaccharide compositions in well-drilling operations, e.g. in oil and gas wells. Examples of polysaccharides include cellulose derivatives, such as cæboxyethylc~llulose, c æboxymethylcellulose, carboxymethylhydroxyethylcellulose, aLkylhydroxyalkylcelluloses, alkylcelluloses, alkylcarboxyaLkylcelluloses and hydroxyalkylcelluloses (particulæ ly hydroxyeth~lcellulose); and microbial polysaccharides such as Succinoglycan polysaccharides, Scleroglucan polysaccharides and Xanthan polysaccharides.
Succinoglycan polysaccharides comprise glucose, and, for each 7 mols of glucose, 0.9 to 1.2 mols of galactose, 0.65 to 1.1 mols pyruvate, 0 to 2 mols succinate and 0 to 2 mols of acetate, and are pro~uced by cultivating a slime-forming species of Pseudomonas, Rhizobium, Alcaligenes or Agrobacterium, e.g.
____ _ _ Pseudomonas sp. NCIB 11264, Pseudomonas sp. NCIB 11592 or Agrobacterium radiobacter NCIB 11883, or mutants thereof, as described, for example, in EP-A-40445 (Applicants ref K 1480) or EP-A-138255 (Applicants ref. K 1924), Scleroglucan polysaccharides comprise linear chairls of PS04.001 z~
-D-(1~3) - linked glucose residues with single glucose side chains in @-D~ 6~ linkages, and are produced by fungii of the genus sclerotium.
Xanthan polysaccharides typically contain mannose, glucose, glucuronic acid, O-acetyl radicals and acetal-linked pyruvic acid in molar ratio 2:2~ 0.5, and are produced by cultivating a species of Xanthomonas bacteria, preferably Xanthcmonas campestris e.g. NRRL B-1459, as descxiked, for example, in US
Patent No. 4,299,825, or Xanthomonas campestris NCIB 11854, as described in EP-A-130647 (Applicants ref. K 1882).
In order to achieve suitable density for use in well-drilling oEerations, it is conventional for the known aqueous polysaccharide campositions to include water soluble salts, e.g. as described in VK Patent No. 1,549,734. These salts are typically halide salts (e.g. chlorides and bromides) of mono- or divalent cations, such as sodium, potassium, calcium and zinc, e.g. sodium chloride, potassium chloride, calcium bramide or zinc bxomide.
One problem faced in drilling operations relates to thexmal stability of completion fluids, work-over fluids and drilling fluids. Temperatures in subsurface formations generally rise approx:imately 1C per hundred feet (30 metres) depth. Any aqueous polysaccharide composition has its own characteristic temperature above which it undergoes severe chemical degradation with undesirable reduction of viscosity, thus imposing limitations upon its use in drilling operations below a corresponding depth.
Additives, for example blends of polymeric aIkaline materials such as that sold by International Drilling Fluids (l~) Ltd., ~der the trade mark "PTS 200", have been used to improve thermal stability of a~leous polysaccharide compositions.
It has now surprisingly been found that the thermal stability of aqueous polysaccharide solutions can be PS04.001 2~
significantly enhanced by incorporation therein of certain formate salts.
According to the present invention therefore there is provided an aqueous polysaccharide composition camprising 0.03 to 5% w/v of a water-soluble polysaccharide, 5 to 120~ w/v of at least one salt of at least one mono- or divalent cation, wherein at least 0.05% w/v, based on the composition, of the at least one salt is formate, the balance of the at least one salt, if any, being at least ~ne halide.
The halide is ~ost conveniently selected frcm chloride and bromide.
It is preferred for the at least one cation to be selected fram the group consisting of ammonium, barium, caesium, calcium, lead, lithium, magne~ium, manganese, potassium, rubidium, silver, sodium, strontium, thallium c~n~ zinc. Calcium, potassium, sodium and zinc are very convenient cations.
me water-soluble polysaccharide may be a cellulose derivative, such as hydroxyethyl cellulose, or it may be a microbial polysaccharide, such as a Succinoglycan polysaccharide, a Scleroglucan polysaccharide, or a Xanthan polysaccharide. Particularly good results have been achieved using Xanth~l polysaccharides in campositions of the inventionO
Preferably the water-soluble polysaccharide is present in an amount fram 0.1 to 2% w/v, ~ore preferably 0.25 to 0.75% w/v.
It is preferred for the at least one salt to be present in an amount of at least 9% w/v, and the formate to be present in an amount of at least 2% w/v. A~valTtageously the formate is present in an amount of at least 10% w/v. If desired substantially all of the at least one salt may be formate.
Those skilled in the art will appreciate that 1~ w/v corresponds to a concentration of 10 kg m 3 ~10 g/1) of composition.
It will be apparent to those skilled in th~ art that incidental ~uantitites of other salts, such as sulphates, nitrates cmd bicarbonates, may also be present in cc~ositions PS~ . 001 ~.f~
of the invention, and inevitably will be present in compositions where sea water, or other naturally occuring brine, is used in preparing the c~p~sition in order to provide at least some of the halide salt (whexe present).
If desired the composition may also contain an antioxidant, e.g. 2~mercaptobenzothiazole. When 2-mercaptobenzothiazole is used it may conveniently be incorporated in the sam~ proportion, w/v, as the water soluble polysaccharide.
It is advantageous fcr the pH of the composition to be greater than 7, preferably at least 9, for reasons of stability and reduced corrosiveness of the composition. m e pH may be controlled by addition of suitable reagents, e.g. sodium hydroxide or sodium carbonate. me presence of a magnesium salt, e.g. magnesium chloride, in the composition can enable a suitable buffering effect to be achieved.
The invention also provides a process for preparing an aqueous polysaccharide composition of the invention, which process comprises dissolving the at least 0.05% w/v of the formate salt in an aqueous composition containing the water-soluble polysaccharide, wi-th, when present, the at least one halide. Those skilled in the art will appreciate that the order of incorporation of components in the composition is primarily a matter of convenience.
Further in accordance with the invention there is provided the use of a cGmposition of the invention as a completion fluid, a work-over fluid or drilling fluid in a well-drilling operation.
The invention will be further understood from the following illustrative Examples.
~
To solutions of "SHELLFL0-XA" (trade mark) biopolymer ~Xanthan biopolymer) (2.85 kg m 3 active polymer) in synthetic sea water the following were added: 2-mercapto~enzothiazole 2.85 kg m 3; magnesium chloride 9.5 kg m 3; sodi~n hydroxide to pH 10.0 ~25C) ti.e. until a precipitate of Mg(OH)2 begins to PS04.001 ~~3 appear~. Sodium formate was added to five samples of this solution in the following amounts: 0, 14.3, 28.5, 57.1 c~nd 142.7 kg m 3 final solution.
Synthetic sea water was water containing the following components:-Kg m_ Sodium chloride 24.5 Magnesium chloride 5.2 Sodium sulphate 4.09 Calcium chloride 1.16 Potassium chloride 0.695 Sodium bicarbonate 0.201 Potassium bromide OolOl Boric acid 0.027 Strontium chloride 0.025 Sodium fluoride 0.003 Barium nitrate 99.4 milligrams m 3 Manganese nitrate 34 milligrams m 3 Lead nitrate 66 milligrams m 3 Silver nitrate 0.49 milligrams m 3 Each of the five solutions was sealed in a glass bottle and the bottles were placed in gas-tight pressure pots. The pots were rolled in an oven at 140~C for 16 hours. The viscosity of each solution WrdS measured at 30C and lOs 1 sheæ rate, using a Haake Viscometer (CV 100) before ~nd after hot rolling to determine the retained viscosity. Results are shcwn in Table 1.
PS04.001 L2~D
Table 1 Exa~ple Concentration of % of initial Number sodi~n formate (k~ m 3) viscosity retained 1 14.3 40 2 28.5 58 3 57.1 70 4 1~2.7 98 Comparative A 0 8.5 Examples 5 t_ 8 Solutions in distilled water were prepared ocmprising the following: "S~E~IEIC-XA" (trade mark) biopolymer 12.53 kg m 3 active polymer); 2-mercaptobenzothiazole 2.53 kg m 3; magnesium chloride 9.5 kg m 3; 270 kg m of a mixture of sodium chloride and sodium formate; sodium hydroxide to pH 10.0 (25C). m e ratio of sodium formate to sodium chloride was varied to give seven samples ranging 0 to 101 kg m 3 sodium formate. Solutions were sealed in glass bottles inside gas-tight pressure pots and hot-rolled in an oven at 150C for 16 hours. Viscosities before and after rolling were determined at 30C and 10 s 1 shear rate as in ExaNples 1 to 4. Results are shown in Table 2.
Table 2 Example Concentration of ~ of initial Number sodium fonnate (kg m 3) viscosity retained 0.68 52 6 6.8 60 7 20.~ 80 8 101.0 87 Co~parative B 0 17 Example 9 "SHELLFLC-XA" (trade mark) biopolymer was used to thicken bw~ drilling fluids of different composition, but with the same density at 20C (1.23 kg m 3). Comparative Fluid C comprised:
"SHELLFI0-XA" (7.1 kg m 3 active polymer); "PTS 200" (trade PS04.001 mark) stabiliser 11.4 kg m 3 ("PTS 200" stabiliser is a blend of polymeric alkaline materials and is sold by International Drilling Fluids (UK) Ltd.); calci~n chloride 300 kg m 3.
Example 9 Fluid compxised: S~E~IEI~-X~ (7.1 kg m 3 active polymer); 2-mercapto-benzothiazole 7~1 kg m 3; magnesium chloride 9.5 kg m 3/ potassi~n formate 460 kg m 3; sodium hydroxide to pH lO.0 (25C). Each fluid was sealed in a glass bottle inside a gas-tight pressure pot and hot rolled in an oven at 153C. Viscosities were measured at 30C and 10 s 1 shear rate before and after rolling. Results are shown in Table 3.
Table 3 Example % of initial Number Time at 153C (hours) viscosity retained Comparative C 16 2.4 Examples 10 to 12 Solutions in distilled water were prepared canprising the following: 2.53 kg m 3 of "KELZAN XC" (trade mark) biopolymer, "KELZAN XCD" (trade mark) biopolymer or "SHELLFIO-XA" (trade mark) biopolymer (all Xanthan biopolymers);
2-mercaptobenzothia~ole 2.53 kg m 3; magnesium chloride 9.5 kg m 3; potassium formate 500 kg m 3; sodium hydroxide to pH 10.0 (25C). me solutions were then sealed in glass bottles inside gas-tight pressure pots and hot-rolled in an oven for 16 hours at either 130C, 150C or 160C. Viscosities before and after rolling were determined at 30C and 10 s 1 shear rate as in Examples 1 to 4. Results are shown in T~ble 4, where Example 10 gives the results for "KELZ~N XC" biopolymer; Example 11 gives the results for "KELZAN XCD" biopolymer and Example 12 gives the results for "SHELLFLO-XA" biopolymer.
PS04.001 ! 2~
Table 4 Example% of initial viscoslty retained at Number 130C 150C 160C
Exc~mples 13 and 14 Solutions were prepared of "SHEILFI0-S" (trade mark) biopolymer (succinoglycan biopolymer) (2.53 kg m 3 active polymer) in distilled water containing 2-mercap~obenzothiazole 2.53 kg m 3; magnesium chloride 9.5 kg m 3; sodium hydroxide to pH 10.0 (25C). Potassium formate was added to samples of this solution in the following amounts: 100, 200 kg m 3 final solution. Comparative D contains no potassium formate.
Solutions were sealed in glass bottles inside gas-tight pressure pots and hot-rolled in an oven for 16 hours at 85C.
Viscosities before and after rolling were determined at 30C and 10 s 1 shear rate as in EXamples 1 to 4. Results were shcwn in Table 5.
Table 5 Concentration of ~ of initial Examplepotassium formate viscosity Number (kg m~3) retained .
13 100. 48 14 200. 48 Comparative D 0. 0 xan~les 15 and 16 Solutions in distilled water were prepared comprising the following: "SHELLFL0-XA" (trade mark) biopolymer ~2.53 kg m 3 active polymer); magnesium chloride 9.5 kg m 3; sodium hydroxide to pH 10.0 (25C). Potassium formate was added to sclmples of this solution in the following amounts: 400 and ~00 kg m 3 final solution. Comparative solutions E and E' were prepared with the san~ ccmposition except that potassium formate was replaced by potassium acetate. ~he solutions were then sealed PS04.001 in glass b~ttles inside gas-ti.ght pressure pots and hot-rolled in an oven for 16 hours at 165C. Viscosities before and after rolling ~ere deternuned at 30C and 10 s 1 shear rate as in Exan~les 1 to 4. Results are shown in Table 6.
Table 6 Conc ntration of % of initial Examplepotassium formate viscosity Number (kg m 3) retained 400. 79 10Ccmparative E 400. 13 i6 600. 93 Comparative F600. 20 PS04.001
Xanthan polysaccharides typically contain mannose, glucose, glucuronic acid, O-acetyl radicals and acetal-linked pyruvic acid in molar ratio 2:2~ 0.5, and are produced by cultivating a species of Xanthomonas bacteria, preferably Xanthcmonas campestris e.g. NRRL B-1459, as descxiked, for example, in US
Patent No. 4,299,825, or Xanthomonas campestris NCIB 11854, as described in EP-A-130647 (Applicants ref. K 1882).
In order to achieve suitable density for use in well-drilling oEerations, it is conventional for the known aqueous polysaccharide campositions to include water soluble salts, e.g. as described in VK Patent No. 1,549,734. These salts are typically halide salts (e.g. chlorides and bromides) of mono- or divalent cations, such as sodium, potassium, calcium and zinc, e.g. sodium chloride, potassium chloride, calcium bramide or zinc bxomide.
One problem faced in drilling operations relates to thexmal stability of completion fluids, work-over fluids and drilling fluids. Temperatures in subsurface formations generally rise approx:imately 1C per hundred feet (30 metres) depth. Any aqueous polysaccharide composition has its own characteristic temperature above which it undergoes severe chemical degradation with undesirable reduction of viscosity, thus imposing limitations upon its use in drilling operations below a corresponding depth.
Additives, for example blends of polymeric aIkaline materials such as that sold by International Drilling Fluids (l~) Ltd., ~der the trade mark "PTS 200", have been used to improve thermal stability of a~leous polysaccharide compositions.
It has now surprisingly been found that the thermal stability of aqueous polysaccharide solutions can be PS04.001 2~
significantly enhanced by incorporation therein of certain formate salts.
According to the present invention therefore there is provided an aqueous polysaccharide composition camprising 0.03 to 5% w/v of a water-soluble polysaccharide, 5 to 120~ w/v of at least one salt of at least one mono- or divalent cation, wherein at least 0.05% w/v, based on the composition, of the at least one salt is formate, the balance of the at least one salt, if any, being at least ~ne halide.
The halide is ~ost conveniently selected frcm chloride and bromide.
It is preferred for the at least one cation to be selected fram the group consisting of ammonium, barium, caesium, calcium, lead, lithium, magne~ium, manganese, potassium, rubidium, silver, sodium, strontium, thallium c~n~ zinc. Calcium, potassium, sodium and zinc are very convenient cations.
me water-soluble polysaccharide may be a cellulose derivative, such as hydroxyethyl cellulose, or it may be a microbial polysaccharide, such as a Succinoglycan polysaccharide, a Scleroglucan polysaccharide, or a Xanthan polysaccharide. Particularly good results have been achieved using Xanth~l polysaccharides in campositions of the inventionO
Preferably the water-soluble polysaccharide is present in an amount fram 0.1 to 2% w/v, ~ore preferably 0.25 to 0.75% w/v.
It is preferred for the at least one salt to be present in an amount of at least 9% w/v, and the formate to be present in an amount of at least 2% w/v. A~valTtageously the formate is present in an amount of at least 10% w/v. If desired substantially all of the at least one salt may be formate.
Those skilled in the art will appreciate that 1~ w/v corresponds to a concentration of 10 kg m 3 ~10 g/1) of composition.
It will be apparent to those skilled in th~ art that incidental ~uantitites of other salts, such as sulphates, nitrates cmd bicarbonates, may also be present in cc~ositions PS~ . 001 ~.f~
of the invention, and inevitably will be present in compositions where sea water, or other naturally occuring brine, is used in preparing the c~p~sition in order to provide at least some of the halide salt (whexe present).
If desired the composition may also contain an antioxidant, e.g. 2~mercaptobenzothiazole. When 2-mercaptobenzothiazole is used it may conveniently be incorporated in the sam~ proportion, w/v, as the water soluble polysaccharide.
It is advantageous fcr the pH of the composition to be greater than 7, preferably at least 9, for reasons of stability and reduced corrosiveness of the composition. m e pH may be controlled by addition of suitable reagents, e.g. sodium hydroxide or sodium carbonate. me presence of a magnesium salt, e.g. magnesium chloride, in the composition can enable a suitable buffering effect to be achieved.
The invention also provides a process for preparing an aqueous polysaccharide composition of the invention, which process comprises dissolving the at least 0.05% w/v of the formate salt in an aqueous composition containing the water-soluble polysaccharide, wi-th, when present, the at least one halide. Those skilled in the art will appreciate that the order of incorporation of components in the composition is primarily a matter of convenience.
Further in accordance with the invention there is provided the use of a cGmposition of the invention as a completion fluid, a work-over fluid or drilling fluid in a well-drilling operation.
The invention will be further understood from the following illustrative Examples.
~
To solutions of "SHELLFL0-XA" (trade mark) biopolymer ~Xanthan biopolymer) (2.85 kg m 3 active polymer) in synthetic sea water the following were added: 2-mercapto~enzothiazole 2.85 kg m 3; magnesium chloride 9.5 kg m 3; sodi~n hydroxide to pH 10.0 ~25C) ti.e. until a precipitate of Mg(OH)2 begins to PS04.001 ~~3 appear~. Sodium formate was added to five samples of this solution in the following amounts: 0, 14.3, 28.5, 57.1 c~nd 142.7 kg m 3 final solution.
Synthetic sea water was water containing the following components:-Kg m_ Sodium chloride 24.5 Magnesium chloride 5.2 Sodium sulphate 4.09 Calcium chloride 1.16 Potassium chloride 0.695 Sodium bicarbonate 0.201 Potassium bromide OolOl Boric acid 0.027 Strontium chloride 0.025 Sodium fluoride 0.003 Barium nitrate 99.4 milligrams m 3 Manganese nitrate 34 milligrams m 3 Lead nitrate 66 milligrams m 3 Silver nitrate 0.49 milligrams m 3 Each of the five solutions was sealed in a glass bottle and the bottles were placed in gas-tight pressure pots. The pots were rolled in an oven at 140~C for 16 hours. The viscosity of each solution WrdS measured at 30C and lOs 1 sheæ rate, using a Haake Viscometer (CV 100) before ~nd after hot rolling to determine the retained viscosity. Results are shcwn in Table 1.
PS04.001 L2~D
Table 1 Exa~ple Concentration of % of initial Number sodi~n formate (k~ m 3) viscosity retained 1 14.3 40 2 28.5 58 3 57.1 70 4 1~2.7 98 Comparative A 0 8.5 Examples 5 t_ 8 Solutions in distilled water were prepared ocmprising the following: "S~E~IEIC-XA" (trade mark) biopolymer 12.53 kg m 3 active polymer); 2-mercaptobenzothiazole 2.53 kg m 3; magnesium chloride 9.5 kg m 3; 270 kg m of a mixture of sodium chloride and sodium formate; sodium hydroxide to pH 10.0 (25C). m e ratio of sodium formate to sodium chloride was varied to give seven samples ranging 0 to 101 kg m 3 sodium formate. Solutions were sealed in glass bottles inside gas-tight pressure pots and hot-rolled in an oven at 150C for 16 hours. Viscosities before and after rolling were determined at 30C and 10 s 1 shear rate as in ExaNples 1 to 4. Results are shown in Table 2.
Table 2 Example Concentration of ~ of initial Number sodium fonnate (kg m 3) viscosity retained 0.68 52 6 6.8 60 7 20.~ 80 8 101.0 87 Co~parative B 0 17 Example 9 "SHELLFLC-XA" (trade mark) biopolymer was used to thicken bw~ drilling fluids of different composition, but with the same density at 20C (1.23 kg m 3). Comparative Fluid C comprised:
"SHELLFI0-XA" (7.1 kg m 3 active polymer); "PTS 200" (trade PS04.001 mark) stabiliser 11.4 kg m 3 ("PTS 200" stabiliser is a blend of polymeric alkaline materials and is sold by International Drilling Fluids (UK) Ltd.); calci~n chloride 300 kg m 3.
Example 9 Fluid compxised: S~E~IEI~-X~ (7.1 kg m 3 active polymer); 2-mercapto-benzothiazole 7~1 kg m 3; magnesium chloride 9.5 kg m 3/ potassi~n formate 460 kg m 3; sodium hydroxide to pH lO.0 (25C). Each fluid was sealed in a glass bottle inside a gas-tight pressure pot and hot rolled in an oven at 153C. Viscosities were measured at 30C and 10 s 1 shear rate before and after rolling. Results are shown in Table 3.
Table 3 Example % of initial Number Time at 153C (hours) viscosity retained Comparative C 16 2.4 Examples 10 to 12 Solutions in distilled water were prepared canprising the following: 2.53 kg m 3 of "KELZAN XC" (trade mark) biopolymer, "KELZAN XCD" (trade mark) biopolymer or "SHELLFIO-XA" (trade mark) biopolymer (all Xanthan biopolymers);
2-mercaptobenzothia~ole 2.53 kg m 3; magnesium chloride 9.5 kg m 3; potassium formate 500 kg m 3; sodium hydroxide to pH 10.0 (25C). me solutions were then sealed in glass bottles inside gas-tight pressure pots and hot-rolled in an oven for 16 hours at either 130C, 150C or 160C. Viscosities before and after rolling were determined at 30C and 10 s 1 shear rate as in Examples 1 to 4. Results are shown in T~ble 4, where Example 10 gives the results for "KELZ~N XC" biopolymer; Example 11 gives the results for "KELZAN XCD" biopolymer and Example 12 gives the results for "SHELLFLO-XA" biopolymer.
PS04.001 ! 2~
Table 4 Example% of initial viscoslty retained at Number 130C 150C 160C
Exc~mples 13 and 14 Solutions were prepared of "SHEILFI0-S" (trade mark) biopolymer (succinoglycan biopolymer) (2.53 kg m 3 active polymer) in distilled water containing 2-mercap~obenzothiazole 2.53 kg m 3; magnesium chloride 9.5 kg m 3; sodium hydroxide to pH 10.0 (25C). Potassium formate was added to samples of this solution in the following amounts: 100, 200 kg m 3 final solution. Comparative D contains no potassium formate.
Solutions were sealed in glass bottles inside gas-tight pressure pots and hot-rolled in an oven for 16 hours at 85C.
Viscosities before and after rolling were determined at 30C and 10 s 1 shear rate as in EXamples 1 to 4. Results were shcwn in Table 5.
Table 5 Concentration of ~ of initial Examplepotassium formate viscosity Number (kg m~3) retained .
13 100. 48 14 200. 48 Comparative D 0. 0 xan~les 15 and 16 Solutions in distilled water were prepared comprising the following: "SHELLFL0-XA" (trade mark) biopolymer ~2.53 kg m 3 active polymer); magnesium chloride 9.5 kg m 3; sodium hydroxide to pH 10.0 (25C). Potassium formate was added to sclmples of this solution in the following amounts: 400 and ~00 kg m 3 final solution. Comparative solutions E and E' were prepared with the san~ ccmposition except that potassium formate was replaced by potassium acetate. ~he solutions were then sealed PS04.001 in glass b~ttles inside gas-ti.ght pressure pots and hot-rolled in an oven for 16 hours at 165C. Viscosities before and after rolling ~ere deternuned at 30C and 10 s 1 shear rate as in Exan~les 1 to 4. Results are shown in Table 6.
Table 6 Conc ntration of % of initial Examplepotassium formate viscosity Number (kg m 3) retained 400. 79 10Ccmparative E 400. 13 i6 600. 93 Comparative F600. 20 PS04.001
Claims (11)
1. An aqueous polysaccharide composition comprising 0.03 to 5% w/v of a water-soluble polysaccharide, 5 to 120%
w/v of at least one salt of at least one mono- or divalent cation, wherein at least 0.05% w/v, based on the composition, of the at least one salt is formate, the balance of the at least one salt, if any, being at least one halide.
w/v of at least one salt of at least one mono- or divalent cation, wherein at least 0.05% w/v, based on the composition, of the at least one salt is formate, the balance of the at least one salt, if any, being at least one halide.
2. A composition according to Claim 1 wherein the halide is selected from chloride and bromide.
3. A composition according to Claim 1 wherein the at least one cation is selected from the group consisting of ammonium, barium, caesium, calcium, lead, lithium, magnesium, manganese, potassium, rubidium, silver, sodium, strontium, thallium and zinc.
4. A composition according to Claim 1, 2 or 3 wherein the water-soluble polysaccharide is a microbial polysaccharide.
5. A composition according to Claim 1, 2 or 3 wherein the water-soluble polysaccharide is a Xanthan polysaccharide.
6. A composition according to Claim 1, 2 or 3 wherein the water-soluble polysaccharide is present in an amount from 0.1 to 2% w/v.
7. A composition according to Claim 1, 2 or 3 wherein the water-soluble polysaccharide is present in an amount from 0.25 to 0.75% w/v.
8. A composition according to Claim 1, 2 or 3 wherein the at least one salt is present in an amount of at least 9%
w/v, and the formate is present in an amount of at least 2%
w/v.
w/v, and the formate is present in an amount of at least 2%
w/v.
9. A composition according to Claim 1, 2 or 3 wherein the formate is present in an amount of at least 10% w/v.
10. A process for preparing a composition according to Claim 1, 2 or 3 which comprises dissolving the at least 0.05%
w/v of the formate salt in an aqueous composition containing the water-soluble polysaccharide, with, when present, the at least one halide.
w/v of the formate salt in an aqueous composition containing the water-soluble polysaccharide, with, when present, the at least one halide.
11. Use of a composition according to Claim 1, 2 or 3 as a completion fluid, a work-over fluid or drilling fluid in a well-drilling operation.
Priority Applications (10)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB868622032A GB8622032D0 (en) | 1986-09-12 | 1986-09-12 | Aqueous polysaccharide compositions |
| CA000545750A CA1295120C (en) | 1986-09-12 | 1987-08-31 | Aqueous polysaccharide compositions |
| US07/094,249 US4900457A (en) | 1986-09-12 | 1987-09-04 | Aqueous polysaccharide compositions |
| OA59190A OA08656A (en) | 1986-09-12 | 1987-09-09 | Aqueous polsaccharide compositions. |
| AU78249/87A AU600519B2 (en) | 1986-09-12 | 1987-09-10 | Aqueous polysaccharide compositions |
| NO873783A NO175750C (en) | 1986-09-12 | 1987-09-10 | Aqueous polysaccharide preparation, process for its preparation and use of the preparation |
| EP87201743A EP0259939B1 (en) | 1986-09-12 | 1987-09-10 | Aqueous polysaccharide compositions |
| DK198704725A DK174277B1 (en) | 1986-09-12 | 1987-09-10 | Aq. polysaccharide compsn. used in well drilling - contains formate salt to improve thermal stability |
| NZ221772A NZ221772A (en) | 1986-09-12 | 1987-09-10 | Aqueous polysaccharide compositions and their use in well-drilling operations |
| DE8787201743T DE3785279T2 (en) | 1986-09-12 | 1987-09-10 | AQUEOUS POLYSACCHARIDE COMPOSITIONS. |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB868622032A GB8622032D0 (en) | 1986-09-12 | 1986-09-12 | Aqueous polysaccharide compositions |
| CA000545750A CA1295120C (en) | 1986-09-12 | 1987-08-31 | Aqueous polysaccharide compositions |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1295120C true CA1295120C (en) | 1992-02-04 |
Family
ID=25671489
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000545750A Expired - Lifetime CA1295120C (en) | 1986-09-12 | 1987-08-31 | Aqueous polysaccharide compositions |
Country Status (10)
| Country | Link |
|---|---|
| US (1) | US4900457A (en) |
| EP (1) | EP0259939B1 (en) |
| AU (1) | AU600519B2 (en) |
| CA (1) | CA1295120C (en) |
| DE (1) | DE3785279T2 (en) |
| DK (1) | DK174277B1 (en) |
| GB (1) | GB8622032D0 (en) |
| NO (1) | NO175750C (en) |
| NZ (1) | NZ221772A (en) |
| OA (1) | OA08656A (en) |
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| AR030020A1 (en) * | 1999-05-21 | 2003-08-13 | Cabot Corp | A POLYMERIC COMPOSITION, A FLUID WATER MAINTENANCE FLUID, A PROCESS TO PREPARE A WATERPROOF POLYMERIC COMPOSITION AND A METHOD TO CARRY OUT DRILLING OR WELL MAINTENANCE OPERATIONS. |
| FI112950B (en) * | 1999-12-02 | 2004-02-13 | Kemira Oyj | Use of formic acid salts and their aqueous solutions as a hydraulic medium and medium |
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| FR2593823B1 (en) * | 1986-01-31 | 1988-09-16 | Rhone Poulenc Chimie | PSEUDOPLASTIC ACID COMPOSITIONS FOR USE IN CLEANING SURFACES |
-
1986
- 1986-09-12 GB GB868622032A patent/GB8622032D0/en active Pending
-
1987
- 1987-08-31 CA CA000545750A patent/CA1295120C/en not_active Expired - Lifetime
- 1987-09-04 US US07/094,249 patent/US4900457A/en not_active Expired - Lifetime
- 1987-09-09 OA OA59190A patent/OA08656A/en unknown
- 1987-09-10 EP EP87201743A patent/EP0259939B1/en not_active Expired - Lifetime
- 1987-09-10 AU AU78249/87A patent/AU600519B2/en not_active Expired
- 1987-09-10 DE DE8787201743T patent/DE3785279T2/en not_active Expired - Lifetime
- 1987-09-10 DK DK198704725A patent/DK174277B1/en not_active IP Right Cessation
- 1987-09-10 NO NO873783A patent/NO175750C/en unknown
- 1987-09-10 NZ NZ221772A patent/NZ221772A/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| OA08656A (en) | 1988-11-30 |
| EP0259939A2 (en) | 1988-03-16 |
| AU600519B2 (en) | 1990-08-16 |
| DK472587D0 (en) | 1987-09-10 |
| GB8622032D0 (en) | 1986-10-22 |
| NO873783L (en) | 1988-03-14 |
| NO873783D0 (en) | 1987-09-10 |
| NO175750C (en) | 1994-11-30 |
| AU7824987A (en) | 1988-03-17 |
| EP0259939B1 (en) | 1993-04-07 |
| NZ221772A (en) | 1990-04-26 |
| NO175750B (en) | 1994-08-22 |
| EP0259939A3 (en) | 1989-10-18 |
| DK472587A (en) | 1988-03-13 |
| DE3785279T2 (en) | 1993-07-29 |
| DE3785279D1 (en) | 1993-05-13 |
| DK174277B1 (en) | 2002-11-04 |
| US4900457A (en) | 1990-02-13 |
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| Date | Code | Title | Description |
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| MKEX | Expiry |