CA2353859A1 - Agent and method for sealing or consolidating rock, loose rock or soils, especially boreholes - Google Patents
Agent and method for sealing or consolidating rock, loose rock or soils, especially boreholes Download PDFInfo
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- CA2353859A1 CA2353859A1 CA002353859A CA2353859A CA2353859A1 CA 2353859 A1 CA2353859 A1 CA 2353859A1 CA 002353859 A CA002353859 A CA 002353859A CA 2353859 A CA2353859 A CA 2353859A CA 2353859 A1 CA2353859 A1 CA 2353859A1
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- rock
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- 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
- C09K8/50—Compositions for plastering borehole walls, i.e. compositions for temporary consolidation of borehole walls
- C09K8/504—Compositions based on water or polar solvents
- C09K8/5045—Compositions based on water or polar solvents containing inorganic compounds
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
- C04B28/24—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing alkyl, ammonium or metal silicates; containing silica sols
-
- 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
- C09K17/00—Soil-conditioning materials or soil-stabilising materials
- C09K17/02—Soil-conditioning materials or soil-stabilising materials containing inorganic compounds only
- C09K17/12—Water-soluble silicates, e.g. waterglass
-
- 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
- C09K17/00—Soil-conditioning materials or soil-stabilising materials
- C09K17/40—Soil-conditioning materials or soil-stabilising materials containing mixtures of inorganic and organic compounds
- C09K17/42—Inorganic compounds mixed with organic active ingredients, e.g. accelerators
- C09K17/46—Inorganic compounds mixed with organic active ingredients, e.g. accelerators the inorganic compound being a water-soluble silicate
-
- 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
- C09K8/50—Compositions for plastering borehole walls, i.e. compositions for temporary consolidation of borehole walls
- C09K8/504—Compositions based on water or polar solvents
- C09K8/506—Compositions based on water or polar solvents containing organic compounds
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
- C04B2111/00474—Uses not provided for elsewhere in C04B2111/00
- C04B2111/00732—Uses not provided for elsewhere in C04B2111/00 for soil stabilisation
Landscapes
- Chemical & Material Sciences (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Inorganic Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Ceramic Engineering (AREA)
- Soil Sciences (AREA)
- Structural Engineering (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Soil Conditioners And Soil-Stabilizing Materials (AREA)
- Sealing Material Composition (AREA)
- Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)
- Curing Cements, Concrete, And Artificial Stone (AREA)
- Road Paving Structures (AREA)
- Revetment (AREA)
- Aftertreatments Of Artificial And Natural Stones (AREA)
- Catching Or Destruction (AREA)
- Consolidation Of Soil By Introduction Of Solidifying Substances Into Soil (AREA)
Abstract
The invention relates to a an aqueous agent for sealing or consolidating rock, loose rock or soils that are in contact with water containing Ca2+ ions. Said agent contains 2 to 40 wt. % SiO2 (dry matter, in relation to the agent) in the form of an aqueous silica sol and hardening stabilisers from the class of inorganic polyphosphates, phosphonic acids, aminoethylenephosphonic acids, phosphonic acid esters, phosphonocarboxylic acids and polycarboxylic acids or mixtures of these substances, in concentrations of 0.01 to 400 ppm.
Description
Agent and Method for Sealing or Consolidating Rock, Loose Rock or Soils, Especially Boreholes This invention relates to a composition and a process for sealing or consolidating rock, mantle rock or soils and to the use for this purpose of certain silica sols containing hardness stabilizers.
The consolidation or sealing of rock, mantle rock or soils is a measure regularly necessary in construction engineering, for example for underpinning buildings, for sealing building pits or tips, in tunnel and canal construction and, above all, in geological exploration, such as the drilling of oil or natural gas pools. In the last of these applications, the sealing of wells is particularly important. Wells are sunk into the ground until a formation carrying oil, gas or - in well construction - water is reached. The well is stabilized against the formation by a cement casing. This cement casing is broken open at the bottom of the well so that the material to be brought up is able to pass freely from the formation into the well. Besides oil or gas, however, water also enters the well and has to be removed from the oil/gas by elaborate processes. Accordingly, efforts are made to minimize or avoid the penetration of water, so that the water-carrying parts of the formation are sealed off by suitable binders. However, consolidation or sealing is also a standard measure in the protection of agricultural land against wind or water erosion.
In general, binders, such as cement, bitumen, calcium salts or waterglass, are used in construction engineering. However, cement has the disadvantage that the particles are often not small enough to be able to penetrate into fine cracks or pores, resulting in an unsatisfactory sealing or consolidating effect. Even the use of waterglasses (an aqueous solution of sodium silicate) or microsilicas (an aqueous dispersion of amorphous silicon dioxide) does not always produce the required sealing effect.
Accordingly, EP 530 600 proposes the use of silica sots for sealing or consolidation. Silica sots are colloidal solutions of amorphous silicon dioxide which has a particle size of 7 to 50 nm. These silica sols gel in the presence of certain electrolytes or in the event of changes in the pH of the aqueous sols. By crosslinking of the Si02 units, the gel becomes more viscous until consolidation is complete. Electrolytes which initiate gelation are generally present in the material to be consolidated or sealed. They are preferably salts of aluminium, iron, calcium or magnesium. However, EP 0 530 600 A1 proposes using silica sots in combination with a calcium donor in order to achieve rapid conversion of the sol into the gel.
Now, applicants have found that, surprisingly, the use of silica sots does not always lead to the required sealing or consolidating effects. This is particularly the case in the sealing of wells against penetrating formation water. According to applicants' observations, a free water phase frequently occurs which is a sign that no gelation and hence no sealing has taken place. Accordingly, without being confined to one particular theory, applicants assume that, in contrast to the teaching of EP 0 530 600 A1, the formation of alkaline earth metal silicates and, above all, calcium silicate can inhibit the gelation process. Accordingly, one of the problems addressed by the present invention was to provide a sealing or consolidating process which could even be carried out in the presence of water containing alkaline earth metal ions.
In addition, it is often not desirable in the sealing of wells to achieve rapid solidification of the binder. The binder is transported under pressure to the bottom of the well through a suitable pipe and is forced into the formation there. The effect of rapid solidification of the binder would be that the binder would also gel in the pipe itself which of course is not what is wanted. On the contrary, the gelling effect should be delayed to the extent that the entire binder is forced into the formation by flushing, for example with water, so that gelation and consolidation only occur in the required places. Accordingly, another problem addressed by the present invention was to provide a process for the delayed consolidation or sealing of rock, mantle rock or soils.
It has now surprisingly been found that a mixture of aqueous silica sol and certain inhibitors for Ca2+ ions solves the problems stated above.
In a first embodiment, the present invention relates to a water-based composition for sealing or consolidating rock, mantle rock or soils in contact with water containing Ca2+ ions, the composition containing 2 to 40% by weight of Si02 (dry matter, based on the composition) in the form of an aqueous silica sol and, in addition, hardness stabilizers from the class of inorganic polyphosphates, phosphonic acids, aminoethylene phosphonic acids, phosphoric acid esters, phosphonocarboxylic acids and polycarboxylic acids or mixtures of these substances in concentrations of 0.01 to 400 ppm.
The compositions according to the invention are generally suitable both for the consolidation and for the sealing of any type of rock, mantle rock or soils in contact with water containing Ca2+ ions. Typical applications include construction engineering, particularly tunnel and well construction, and geological exploration, more particularly the sealing of wells, more precisely their walls, against penetrating formation water.
Besides water, the compositions according to the invention contain silica sols containing amorphous Si02 in quantities of 2 to 60% by weight, expressed as dry matter and based on the sol, as carrier liquid. However, silica sols containing 25 to 50% by weight amorphous Si02 are preferred for the compositions according to the invention. The amorphous Si02 is present in the form of non-interlinked spherical individual particles surface-stabilized by hydroxyl groups. The average particle diameter is in the range from 1 to 150 nm, preferably in the range from 5 to 70 nm and more particularly in the range from 5 to 40 nm. The specific surface of the silica sols is in the range from 50 to 700 m2lg, as measured by the BET method.
By virtue of the colloidal distribution of the particles, no sedimentation of particles is observed with silica sols. Accordingly, the sots may be stored for years. Aqueous silica sols are generally used. However, amorphous Si02 may also be converted into sols in other solvents, for example acetone or short-chain organic alcohols, such as methanol, ethanol or propanol (cf. Ullmanns Encyklopadie der Technischen Chemie, 4th Edition, Vol. 21, pages 456 to 463, Weinheim 1982). However, the compositions according to the invention contain only aqueous silica sols.
The compositions according to the invention contain in all, i.e.
including the water content of the silica sots, between 60 and 98% by weight and more particularly between 60 and 80% by weight of water which preferably contains only small amounts of electrolytes, for example between 0.001 and 0.1 % by weight. The water is preferably free from electrolytes. Electrolytes in the present context are understood in particular to be cations of mono- and divalent alkali metal and alkaline earth metal ions, i.e. Na+, K+, Ca+ and Mg2+ ions. Aqueous silica sols of the type described above are present in the compositions in quantities of 20 to 60%
by weight. According to the invention, so-called hardness stabilizers are added to the mixture of silica sol and water in concentrations of 0.01 to 400 ppm. Hardness stabilizers are compounds which, in less than stoichiometric quantities known for the purpose, are capable of completely and permanently preventing the precipitation of hardness ions from supersaturated aqueous solutions. To this extent, it was surprising that the addition of these compounds only leads to delayed gelation of the silica sols but does not permanently suppress their gelation. Hardness ions are mainly alkaline earth metal ions, more particularly calcium and magnesium ions (threshold effect). Particulars can be found in Rompps Chemie Lexikon, 9th Edition, Vol. 6, 1994, pages 5000 to 5002.
The compositions according to the invention contain compounds from the class of inorganic polyphosphates, phosphoric acid, aminoethylene phosphoric acids, phosphoric acid esters, phosphonocarboxylic acids and polycarboxylic acids or mixtures thereof as hardness stabilizers. Salts of these compounds are also suitable.
Compositions containing hardness stabilizers from the group consisting of aminotris(methylenephosphonic acid), 1-hydroxyethane-1,1-diphosphonic acid, phosphonobutane tricarboxylic acid, polyacrylic acid, polyaspartic acid, polymaleic acid or derivatives thereof or mixtures of these compounds are particularly preferred. Compositions containing tetrakis-[(phosphono-methyl)-imino]-bis-[2,1-ethanediylnitrido-bis-methylene]-phosphonic acid andlor salts thereof as hardness stabilizers are most particularly preferred.
Preferred mixtures of these stabilizers contain, for example, 1-hydroxyethane-1,1-diphosphonic acid sodium salt and polyacrylic acid or 1-hydroxyethane-1,1-diphosphonic acid sodium salt, aminotris-(methylenephosphonic acid) and polyacrylic acid. The concentration in which the hardness stabilizers are used is between 0.01 and 400 ppm, more particularly in the range from 0.1 to 200 ppm and preferably in the range from 1 to 100 ppm, based on hardness stabilizer active substance.
In another embodiment, the present invention relates to a process for sealing or consolidating rock, mantle rock or soils in contact with water containing Ca2+ ions, in which the material to be consolidated or sealed is contacted with a solution containing aqueous silica sol and hardness stabilizers from the class of inorganic polyphosphates, phosphonic acids, aminoethylene phosphonic acids, phosphoric acid esters, phosphono-carboxylic acids and polycarboxylic acids or mixtures of these substances.
Aqueous silica sols containing 20 to 60% by weight Si02 (dry matter, based on the aqueous sol) are preferably used for this purpose. In general, the composition is forced under pressure into the material to be sealed or consolidated. The hardness stabilizers are then added during or after the treatment with the silica sol. They are preferably used in such quantities that the stabilizer concentration, based on the aqueous silica sol solution, is in the range from 0.01 to 400 ppm, preferably in the range from 0.1 to 200 ppm and more particularly in the range from 1 to 100 ppm.
In one particularly preferred embodiment, the process according to the invention is used for sealing underground formations, more particularly wells. To this end, the silica sollwaterlstabilizer mixture is pumped through the feed pipe by suitable pumps to the bottom of the well, such a pressure being applied that the mixture penetrates deeply into the formation. This is followed by flushing with water until the mixture has been completely removed from the pipe. In this connection, the process according to the invention enjoys another advantage because the composition used only gels with a certain delay. Under the temperature, pH and pressure conditions at the bottom of the well, the composition preferably solidifies some 30 to 60 minutes after contacting with the material to be consolidated or sealed and hence with the water containing Ca2+ ions. The temperatures at the bottom of the well are normally in the range from 30 to 200°C, depending on the depth. The pressure is typically between 10 and 500 bar, again dependent on depth.
The most suitable stabilizer concentration can be selected in dependence upon the concentration of Ca2+ ions in the water with which the material to be consolidated or sealed is in contact. It has been found that the hardness stabilizers should preferably be present in the compositions according to the invention in such quantities that, based on a predetermined volume, the ratio by weight of Ca2+ ions to the hardness stabilizers is in the range from 0.5 to 5.0:1. The quantity of Ca2+ ions may readily be calculated through the determination of the water hardness.
The water in contact with the material to be consolidated or sealed generally has a content of Ca2+ ions of greater than 2 mmolll and preferably greater than 4 mmolll. Typical Ca2+ concentrations are in the range from 3 to 8 mmol/l. The pH of the formation water is generally in the acidic to mildly alkaline range, i.e. between 6 and 9. It has been found that a reduction in pH to values of 2 to 5 can generally prevent gelation.
Accordingly, the process according to the invention is preferably carried out at pH values of 6 to 9 or the composition according to the invention is preferably formulated by addition of acids or bases in such a way that its pH value is in the range mentioned.
The present invention also relates to the use of the compositions described in the foregoing for consolidating or sealing rock, mantle rock or soils in contact with water containing Ca2+ ions.
Examples The effectiveness of the process according to the invention was determined as follows: 11 g of a silica sol (Kostrosol~ 0830 of Chemiewerk Bad Kostritz) were mixed with 40 g of deionized water and hardness stabilizers were subsequently added to the sol in various quantities. Between 0.7 and 1.0 ml of a calcium chloride solution (concentration of Ca2+ ions: 28,200 ppm) was then added dropwise to the resulting mixture, followed by heating for 15 minutes to 100°C. The vessel was left standing without stirring to cool. After 30 minutes, the degree of gelation was visually determined.
The following evaluation was made:
100% solid ++
80 to almost 100% solid +
less than 80% solid -The following hardness stabilizers were tested:
A: 1-hydroxyethane-1,1-diphosphonic acid B: amino-tris-(methylene phosphonic acid) C: 1-hydroxyethane-1,1-diphosphonic acid disodium salt D: mixture of B and C and polyacrylic acid The stabilizers were used in the form of commercially available aqueous solutions (all products of Henkel KGaA):
A: 60% by weight active substance (Turpinal~ SL) B: 50% by weight active substance (Turpinal~ D2) C: 10% by weight active substance (Turpinal~ -2-NZ) D: 30% by weight active substance (Fostex~ 617 B) The quantities in Table 1 are based on active substance.
The results of the tests are set out in Table 1.
Table 1 No. StabilizerStabilizerCaCl2 Ca2+ contentRatio by Gelation concentrationsolutionin the weight after ppm] ml solution Caz+atabilizer30 % b wei mins.
ht 1 A 0.1 0.8 0.04 0.7 ++
2 A 0.2 0.8 0.04 1.0 ++
The consolidation or sealing of rock, mantle rock or soils is a measure regularly necessary in construction engineering, for example for underpinning buildings, for sealing building pits or tips, in tunnel and canal construction and, above all, in geological exploration, such as the drilling of oil or natural gas pools. In the last of these applications, the sealing of wells is particularly important. Wells are sunk into the ground until a formation carrying oil, gas or - in well construction - water is reached. The well is stabilized against the formation by a cement casing. This cement casing is broken open at the bottom of the well so that the material to be brought up is able to pass freely from the formation into the well. Besides oil or gas, however, water also enters the well and has to be removed from the oil/gas by elaborate processes. Accordingly, efforts are made to minimize or avoid the penetration of water, so that the water-carrying parts of the formation are sealed off by suitable binders. However, consolidation or sealing is also a standard measure in the protection of agricultural land against wind or water erosion.
In general, binders, such as cement, bitumen, calcium salts or waterglass, are used in construction engineering. However, cement has the disadvantage that the particles are often not small enough to be able to penetrate into fine cracks or pores, resulting in an unsatisfactory sealing or consolidating effect. Even the use of waterglasses (an aqueous solution of sodium silicate) or microsilicas (an aqueous dispersion of amorphous silicon dioxide) does not always produce the required sealing effect.
Accordingly, EP 530 600 proposes the use of silica sots for sealing or consolidation. Silica sots are colloidal solutions of amorphous silicon dioxide which has a particle size of 7 to 50 nm. These silica sols gel in the presence of certain electrolytes or in the event of changes in the pH of the aqueous sols. By crosslinking of the Si02 units, the gel becomes more viscous until consolidation is complete. Electrolytes which initiate gelation are generally present in the material to be consolidated or sealed. They are preferably salts of aluminium, iron, calcium or magnesium. However, EP 0 530 600 A1 proposes using silica sots in combination with a calcium donor in order to achieve rapid conversion of the sol into the gel.
Now, applicants have found that, surprisingly, the use of silica sots does not always lead to the required sealing or consolidating effects. This is particularly the case in the sealing of wells against penetrating formation water. According to applicants' observations, a free water phase frequently occurs which is a sign that no gelation and hence no sealing has taken place. Accordingly, without being confined to one particular theory, applicants assume that, in contrast to the teaching of EP 0 530 600 A1, the formation of alkaline earth metal silicates and, above all, calcium silicate can inhibit the gelation process. Accordingly, one of the problems addressed by the present invention was to provide a sealing or consolidating process which could even be carried out in the presence of water containing alkaline earth metal ions.
In addition, it is often not desirable in the sealing of wells to achieve rapid solidification of the binder. The binder is transported under pressure to the bottom of the well through a suitable pipe and is forced into the formation there. The effect of rapid solidification of the binder would be that the binder would also gel in the pipe itself which of course is not what is wanted. On the contrary, the gelling effect should be delayed to the extent that the entire binder is forced into the formation by flushing, for example with water, so that gelation and consolidation only occur in the required places. Accordingly, another problem addressed by the present invention was to provide a process for the delayed consolidation or sealing of rock, mantle rock or soils.
It has now surprisingly been found that a mixture of aqueous silica sol and certain inhibitors for Ca2+ ions solves the problems stated above.
In a first embodiment, the present invention relates to a water-based composition for sealing or consolidating rock, mantle rock or soils in contact with water containing Ca2+ ions, the composition containing 2 to 40% by weight of Si02 (dry matter, based on the composition) in the form of an aqueous silica sol and, in addition, hardness stabilizers from the class of inorganic polyphosphates, phosphonic acids, aminoethylene phosphonic acids, phosphoric acid esters, phosphonocarboxylic acids and polycarboxylic acids or mixtures of these substances in concentrations of 0.01 to 400 ppm.
The compositions according to the invention are generally suitable both for the consolidation and for the sealing of any type of rock, mantle rock or soils in contact with water containing Ca2+ ions. Typical applications include construction engineering, particularly tunnel and well construction, and geological exploration, more particularly the sealing of wells, more precisely their walls, against penetrating formation water.
Besides water, the compositions according to the invention contain silica sols containing amorphous Si02 in quantities of 2 to 60% by weight, expressed as dry matter and based on the sol, as carrier liquid. However, silica sols containing 25 to 50% by weight amorphous Si02 are preferred for the compositions according to the invention. The amorphous Si02 is present in the form of non-interlinked spherical individual particles surface-stabilized by hydroxyl groups. The average particle diameter is in the range from 1 to 150 nm, preferably in the range from 5 to 70 nm and more particularly in the range from 5 to 40 nm. The specific surface of the silica sols is in the range from 50 to 700 m2lg, as measured by the BET method.
By virtue of the colloidal distribution of the particles, no sedimentation of particles is observed with silica sols. Accordingly, the sots may be stored for years. Aqueous silica sols are generally used. However, amorphous Si02 may also be converted into sols in other solvents, for example acetone or short-chain organic alcohols, such as methanol, ethanol or propanol (cf. Ullmanns Encyklopadie der Technischen Chemie, 4th Edition, Vol. 21, pages 456 to 463, Weinheim 1982). However, the compositions according to the invention contain only aqueous silica sols.
The compositions according to the invention contain in all, i.e.
including the water content of the silica sots, between 60 and 98% by weight and more particularly between 60 and 80% by weight of water which preferably contains only small amounts of electrolytes, for example between 0.001 and 0.1 % by weight. The water is preferably free from electrolytes. Electrolytes in the present context are understood in particular to be cations of mono- and divalent alkali metal and alkaline earth metal ions, i.e. Na+, K+, Ca+ and Mg2+ ions. Aqueous silica sols of the type described above are present in the compositions in quantities of 20 to 60%
by weight. According to the invention, so-called hardness stabilizers are added to the mixture of silica sol and water in concentrations of 0.01 to 400 ppm. Hardness stabilizers are compounds which, in less than stoichiometric quantities known for the purpose, are capable of completely and permanently preventing the precipitation of hardness ions from supersaturated aqueous solutions. To this extent, it was surprising that the addition of these compounds only leads to delayed gelation of the silica sols but does not permanently suppress their gelation. Hardness ions are mainly alkaline earth metal ions, more particularly calcium and magnesium ions (threshold effect). Particulars can be found in Rompps Chemie Lexikon, 9th Edition, Vol. 6, 1994, pages 5000 to 5002.
The compositions according to the invention contain compounds from the class of inorganic polyphosphates, phosphoric acid, aminoethylene phosphoric acids, phosphoric acid esters, phosphonocarboxylic acids and polycarboxylic acids or mixtures thereof as hardness stabilizers. Salts of these compounds are also suitable.
Compositions containing hardness stabilizers from the group consisting of aminotris(methylenephosphonic acid), 1-hydroxyethane-1,1-diphosphonic acid, phosphonobutane tricarboxylic acid, polyacrylic acid, polyaspartic acid, polymaleic acid or derivatives thereof or mixtures of these compounds are particularly preferred. Compositions containing tetrakis-[(phosphono-methyl)-imino]-bis-[2,1-ethanediylnitrido-bis-methylene]-phosphonic acid andlor salts thereof as hardness stabilizers are most particularly preferred.
Preferred mixtures of these stabilizers contain, for example, 1-hydroxyethane-1,1-diphosphonic acid sodium salt and polyacrylic acid or 1-hydroxyethane-1,1-diphosphonic acid sodium salt, aminotris-(methylenephosphonic acid) and polyacrylic acid. The concentration in which the hardness stabilizers are used is between 0.01 and 400 ppm, more particularly in the range from 0.1 to 200 ppm and preferably in the range from 1 to 100 ppm, based on hardness stabilizer active substance.
In another embodiment, the present invention relates to a process for sealing or consolidating rock, mantle rock or soils in contact with water containing Ca2+ ions, in which the material to be consolidated or sealed is contacted with a solution containing aqueous silica sol and hardness stabilizers from the class of inorganic polyphosphates, phosphonic acids, aminoethylene phosphonic acids, phosphoric acid esters, phosphono-carboxylic acids and polycarboxylic acids or mixtures of these substances.
Aqueous silica sols containing 20 to 60% by weight Si02 (dry matter, based on the aqueous sol) are preferably used for this purpose. In general, the composition is forced under pressure into the material to be sealed or consolidated. The hardness stabilizers are then added during or after the treatment with the silica sol. They are preferably used in such quantities that the stabilizer concentration, based on the aqueous silica sol solution, is in the range from 0.01 to 400 ppm, preferably in the range from 0.1 to 200 ppm and more particularly in the range from 1 to 100 ppm.
In one particularly preferred embodiment, the process according to the invention is used for sealing underground formations, more particularly wells. To this end, the silica sollwaterlstabilizer mixture is pumped through the feed pipe by suitable pumps to the bottom of the well, such a pressure being applied that the mixture penetrates deeply into the formation. This is followed by flushing with water until the mixture has been completely removed from the pipe. In this connection, the process according to the invention enjoys another advantage because the composition used only gels with a certain delay. Under the temperature, pH and pressure conditions at the bottom of the well, the composition preferably solidifies some 30 to 60 minutes after contacting with the material to be consolidated or sealed and hence with the water containing Ca2+ ions. The temperatures at the bottom of the well are normally in the range from 30 to 200°C, depending on the depth. The pressure is typically between 10 and 500 bar, again dependent on depth.
The most suitable stabilizer concentration can be selected in dependence upon the concentration of Ca2+ ions in the water with which the material to be consolidated or sealed is in contact. It has been found that the hardness stabilizers should preferably be present in the compositions according to the invention in such quantities that, based on a predetermined volume, the ratio by weight of Ca2+ ions to the hardness stabilizers is in the range from 0.5 to 5.0:1. The quantity of Ca2+ ions may readily be calculated through the determination of the water hardness.
The water in contact with the material to be consolidated or sealed generally has a content of Ca2+ ions of greater than 2 mmolll and preferably greater than 4 mmolll. Typical Ca2+ concentrations are in the range from 3 to 8 mmol/l. The pH of the formation water is generally in the acidic to mildly alkaline range, i.e. between 6 and 9. It has been found that a reduction in pH to values of 2 to 5 can generally prevent gelation.
Accordingly, the process according to the invention is preferably carried out at pH values of 6 to 9 or the composition according to the invention is preferably formulated by addition of acids or bases in such a way that its pH value is in the range mentioned.
The present invention also relates to the use of the compositions described in the foregoing for consolidating or sealing rock, mantle rock or soils in contact with water containing Ca2+ ions.
Examples The effectiveness of the process according to the invention was determined as follows: 11 g of a silica sol (Kostrosol~ 0830 of Chemiewerk Bad Kostritz) were mixed with 40 g of deionized water and hardness stabilizers were subsequently added to the sol in various quantities. Between 0.7 and 1.0 ml of a calcium chloride solution (concentration of Ca2+ ions: 28,200 ppm) was then added dropwise to the resulting mixture, followed by heating for 15 minutes to 100°C. The vessel was left standing without stirring to cool. After 30 minutes, the degree of gelation was visually determined.
The following evaluation was made:
100% solid ++
80 to almost 100% solid +
less than 80% solid -The following hardness stabilizers were tested:
A: 1-hydroxyethane-1,1-diphosphonic acid B: amino-tris-(methylene phosphonic acid) C: 1-hydroxyethane-1,1-diphosphonic acid disodium salt D: mixture of B and C and polyacrylic acid The stabilizers were used in the form of commercially available aqueous solutions (all products of Henkel KGaA):
A: 60% by weight active substance (Turpinal~ SL) B: 50% by weight active substance (Turpinal~ D2) C: 10% by weight active substance (Turpinal~ -2-NZ) D: 30% by weight active substance (Fostex~ 617 B) The quantities in Table 1 are based on active substance.
The results of the tests are set out in Table 1.
Table 1 No. StabilizerStabilizerCaCl2 Ca2+ contentRatio by Gelation concentrationsolutionin the weight after ppm] ml solution Caz+atabilizer30 % b wei mins.
ht 1 A 0.1 0.8 0.04 0.7 ++
2 A 0.2 0.8 0.04 1.0 ++
3 B 0.3 0.8 0.04 1.4 +
4 B 0.3 0.7 0.04 2.0 ++
C 0.7 1.0 0.06 1.3 ++
6 C 0.7 1.0 0.06 1.5 +
7 D 0.7 1.0 0.06 4.0 ++
Tests were also carried out at elevated temperature and pressure in order to simulate the conditions prevailing at the bottom of the well.
Quantities of 5 g of a 50% by weight aqueous silica sol were diluted with 45 g of water and a certain ratio by weight of Ca2+ to Si02 was then adjusted by addition of a CaCl2 solution (0.04% by weight Ca2+). The system was then heated for 30 minutes to 150°C in an autoclave under 10 bar pressure (nitrogen atmosphere) and left under those conditions for two hours. The results of the visual evaluation of the solutions are set out in Table 2.
Table 2 Solution Ca:Si02 Effect b wei ht]
8 0.005 Thinly liquid 9 0.010 Slight gelation 0.020 Gelation 11 0.030 Gelation Various quantities of stabilizer D were then added to solution 10 under the described conditions. It was found that the addition of 100 and 200 ppm of stabilizer resulted in delayed gelation after three hours. At higher concentrations, there was no sign of gelation. Accordingly, the process according to the invention leads to a desired delay in the gelation of the silica sol solutions, even at elevated temperature and pressure.
C 0.7 1.0 0.06 1.3 ++
6 C 0.7 1.0 0.06 1.5 +
7 D 0.7 1.0 0.06 4.0 ++
Tests were also carried out at elevated temperature and pressure in order to simulate the conditions prevailing at the bottom of the well.
Quantities of 5 g of a 50% by weight aqueous silica sol were diluted with 45 g of water and a certain ratio by weight of Ca2+ to Si02 was then adjusted by addition of a CaCl2 solution (0.04% by weight Ca2+). The system was then heated for 30 minutes to 150°C in an autoclave under 10 bar pressure (nitrogen atmosphere) and left under those conditions for two hours. The results of the visual evaluation of the solutions are set out in Table 2.
Table 2 Solution Ca:Si02 Effect b wei ht]
8 0.005 Thinly liquid 9 0.010 Slight gelation 0.020 Gelation 11 0.030 Gelation Various quantities of stabilizer D were then added to solution 10 under the described conditions. It was found that the addition of 100 and 200 ppm of stabilizer resulted in delayed gelation after three hours. At higher concentrations, there was no sign of gelation. Accordingly, the process according to the invention leads to a desired delay in the gelation of the silica sol solutions, even at elevated temperature and pressure.
Claims (10)
1. A water-based composition for sealing or consolidating rock, mantle rock or soils in contact with water containing Ca2+ ions, the composition containing 2 to 40% by weight of SiO2 (dry matter, based on the composition) in the form of an aqueous silica sol, characterized in that it contains hardness stabilizers from the class of inorganic polyphosphates, phosphonic acids, aminoethylene phosphonic acids, phosphoric acid esters, phosphonocarboxylic acids and polycarboxylic acids or mixtures of these substances in concentrations of 0.01 to 400 ppm.
2. A composition as claimed in claim 1, characterized in that the hardness stabilizers are selected from the group consisting of aminotris(methylenephosphonic acid), 1-hydroxyethane-1,1-diphosphonic acid, phosphonobutane tricarboxylic acid, polyacrylic acid or mixtures of these compounds.
3. A composition as claimed in claim 1 or 2, characterized in that it contains the hardness stabilizers in concentrations of 0.1 to 200 ppm and preferably in concentrations of 1 to 100 ppm.
4. A process for sealing or consolidating rock, mantle rock or soils in contact with water containing Ca2+ ions, in which the material to be consolidated or sealed is contacted with a solution containing aqueous silica sol and hardness stabilizers from the class of inorganic polyphosphates, phosphonic acids, aminoethylene phosphonic acids, phosphoric acid esters, phosphonocarboxylic acids and polycarboxylic acids or mixtures of these substances.
5. A process as claimed in claim 4, characterized in that aqueous silica sols containing 20 to 60% by weight of SiO2 and preferably 25 to 50% by weight of SiO2 (dry matter, based on the aqueous sol) are used.
6. A process as claimed in claim 4 or 5, characterized in that the hardness ions are added in such quantities that their concentration in the aqueous silica sol solution is between 0.01 and 400 ppm, preferably between 0.1 and 200 ppm and more particularly between 1 and 100 ppm.
7. A process as claimed in any of claims 4 to 6, characterized in that the material to be consolidated or sealed is in contact with water having a concentration of Ca2+ ions of more than 2 mmol/l
8. A process as claimed in any of claims 4 to 7, characterized in that it is used to seal underground formations, preferably wells.
9. A process as claimed in any of claims 4 to 8, characterized in that the consolidating or sealing effect begins 30 to 60 minutes after contacting of the composition with the material to be consolidated or sealed.
10. The use of the compositions claimed in any of claims 1 to 3 for sealing or consolidating rock, mantle rock or soils in contact with water containing Ca2+ ions.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19856729A DE19856729A1 (en) | 1998-12-09 | 1998-12-09 | Repair solution for sealing drill holes |
| DE19856729.4 | 1998-12-09 | ||
| PCT/EP1999/009404 WO2000034412A1 (en) | 1998-12-09 | 1999-12-02 | Agent and method for sealing or consolidating rock, loose rock or soils, especially bore holes |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2353859A1 true CA2353859A1 (en) | 2000-06-15 |
Family
ID=7890467
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002353859A Abandoned CA2353859A1 (en) | 1998-12-09 | 1999-12-02 | Agent and method for sealing or consolidating rock, loose rock or soils, especially boreholes |
Country Status (11)
| Country | Link |
|---|---|
| EP (1) | EP1149139B1 (en) |
| AT (1) | ATE260328T1 (en) |
| CA (1) | CA2353859A1 (en) |
| DE (2) | DE19856729A1 (en) |
| DK (1) | DK1149139T3 (en) |
| ES (1) | ES2217876T3 (en) |
| HU (1) | HUP0104601A3 (en) |
| NO (1) | NO20012851L (en) |
| PT (1) | PT1149139E (en) |
| RU (1) | RU2227152C2 (en) |
| WO (1) | WO2000034412A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105201528A (en) * | 2015-09-21 | 2015-12-30 | 中国矿业大学 | Silica sol slow infiltration reinforcing method of argillaceous soft rock |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6511944B2 (en) * | 2001-02-23 | 2003-01-28 | Halliburton Energy Services, Inc. | Methods and compositions for treating subterranean formations with gelled hydrocarbon fluids |
| DE10218771B4 (en) * | 2001-05-18 | 2006-06-08 | Bauer Spezialtiefbau Gmbh | Construction pit enclosure and method of making a construction pit enclosure |
| EP2522626B1 (en) * | 2011-05-12 | 2016-07-20 | Kemira Oyj | Method of producing silica-based sol, silica-based sol and its use |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4043830A (en) * | 1975-10-02 | 1977-08-23 | Kyokado Engineering Co., Ltd. | Method of consolidating poor quality soils |
| US4056937A (en) * | 1976-01-08 | 1977-11-08 | Kyokado Engineering Co. Ltd. | Method of consolidating soils |
| US4430369A (en) * | 1982-06-01 | 1984-02-07 | Nalco Chemical Company | Silica sol penetration and saturation of thermal insulation fibers |
| GB2186879B (en) * | 1985-04-22 | 1989-07-05 | Mta Termeszettu Domanyi Kutato | Method for improving the strength and impermeability of soils and engineering structures |
| US4596838A (en) * | 1985-05-30 | 1986-06-24 | The Celotex Corporation | Mine stopping caulk |
| EP0530600A1 (en) * | 1991-08-28 | 1993-03-10 | Sika AG, vorm. Kaspar Winkler & Co. | Consolidating agent for rocks, crumbly rock, porous natural or arteficial stones and soils, and process of consolidation using this agent |
-
1998
- 1998-12-09 DE DE19856729A patent/DE19856729A1/en not_active Withdrawn
-
1999
- 1999-12-02 ES ES99966911T patent/ES2217876T3/en not_active Expired - Lifetime
- 1999-12-02 CA CA002353859A patent/CA2353859A1/en not_active Abandoned
- 1999-12-02 DE DE59908675T patent/DE59908675D1/en not_active Expired - Lifetime
- 1999-12-02 RU RU2001119048/12A patent/RU2227152C2/en not_active IP Right Cessation
- 1999-12-02 EP EP99966911A patent/EP1149139B1/en not_active Expired - Lifetime
- 1999-12-02 DK DK99966911T patent/DK1149139T3/en active
- 1999-12-02 PT PT99966911T patent/PT1149139E/en unknown
- 1999-12-02 HU HU0104601A patent/HUP0104601A3/en unknown
- 1999-12-02 WO PCT/EP1999/009404 patent/WO2000034412A1/en active IP Right Grant
- 1999-12-02 AT AT99966911T patent/ATE260328T1/en not_active IP Right Cessation
-
2001
- 2001-06-08 NO NO20012851A patent/NO20012851L/en not_active Application Discontinuation
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105201528A (en) * | 2015-09-21 | 2015-12-30 | 中国矿业大学 | Silica sol slow infiltration reinforcing method of argillaceous soft rock |
Also Published As
| Publication number | Publication date |
|---|---|
| EP1149139B1 (en) | 2004-02-25 |
| NO20012851L (en) | 2001-07-03 |
| DE19856729A1 (en) | 2000-06-15 |
| ATE260328T1 (en) | 2004-03-15 |
| HUP0104601A2 (en) | 2002-03-28 |
| EP1149139A1 (en) | 2001-10-31 |
| ES2217876T3 (en) | 2004-11-01 |
| DK1149139T3 (en) | 2004-06-21 |
| HUP0104601A3 (en) | 2004-09-28 |
| DE59908675D1 (en) | 2004-04-01 |
| WO2000034412A1 (en) | 2000-06-15 |
| RU2227152C2 (en) | 2004-04-20 |
| PT1149139E (en) | 2004-07-30 |
| NO20012851D0 (en) | 2001-06-08 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Discontinued |