Process for sealing out water leakage from geological rock formations

A method is described, using a polyurethane resin mixture, for sealing off points through which water enters geological rock formations. The method utilizes an isocyanate component (a) and a polyol component (b), to be intimately mixed in a static mixer. The mixture is introduced under pressure into the rock formation through boreholes or injection lances. Primary or secondary di or polyamines are substituted for a portion of the polyol component (b) in quantities such that the polyol remains in excess. These amines greatly accelerate the gelation time for the resin, resulting in an instantaneous increase in viscosity of the gel.

The invention concerns a method for sealing out water leakage from 
geological rock formations according to the general idea of the claim. 
It is known from U.S. Pat. No. 4,454,252 how to inject fast-reacting 
polyurethane binary component systems of polyol and isocyanate to stop and 
seal water leakage from geological rock formations. The two components are 
blended in a static mixer immediately before entering the rocks. When 
making contact with water, they form a foam and harden without water and 
without forming foam. Since the initially injected material displaces the 
water, the subsequently injected resin forms an unfoamed and, thus, 
permanently dense water block. However, if the water leakage is 
considerable, the two components become intensively mixed with the water 
before the reaction can occur. The result is that the water and polyol 
form a stable emulsion and the water-insoluble isocyanate reacts to form 
polyurea in the form of a brittle foam or sludge, so that a water seal can 
no longer be achieved. 
The purpose of the invention is to provide a method for reliable sealing of 
even heavy water leakage. 
This purpose is achieved, according to the invention, by the characteristic 
features of the patent claim. 
Tests have revealed, surprisingly, that the binary synthetic resin mixture 
according to the invention takes on a gellike consistency several seconds 
after the mixing, i.e., generally before leaving the injection lance. Even 
heavy water flow is not able to break up this mixture, so that the resin 
hardens undisturbed and only produces foam at its surface, due to the 
water contact. 
In the binary polyurethane resin according to the invention, the isocyanate 
component is reacted with a polyol component, which contains an 
unsaturated moiety of primary and secondary diamines or polyamines. The 
amino compounds react much more quickly than the hydroxyl compounds with 
these isocyanates. The reaction of the slight amount of amine in the 
polyol component surprisingly accomplishes a significant increase in 
viscosity in a few seconds, imparting quasithixotropic properties to the 
system. The resin mixture no longer flows by gravity, and it must be moved 
by pump pressure. 
The polyisocyanate component a) to be used in the process according to the 
invention comprises, preferably, polyphenyls-polymethyls-polyisocyanates, 
such as are produced by aniline/formaldehyde condensation and subsequent 
phosgenation ("polymeric MDI") or derivates of these polyisocyanates that 
are liquid at room temperature and possess carbodiimide, biuret, urethane 
and/or allophanate groups, as well as their prepolymeres, i.e., products 
of the reaction of polyisocyanates with polyols in deficit quantity. The 
polyols to be considered for preparation of prepolymeres are the generally 
known compounds from polyurethane chemistry, preferably long-chain polyols 
with OH-index below 150 mg KOH/g of substance. The polyisocyanate mixtures 
that are liquid at room temperature and are produced by phosgenation of 
aniline/formaldehyde condensates ("polymeric MDI"), as well as their 
liquid, NCO-group-containing products of reaction with deficient 
quantities (NCO/OH molar ratio=1:0.005 to 1:0.3) of polyvalent alcohols in 
the molecular weight range of 62-3000, especially polyols containing ether 
groups in the molecular weight range of 106-3000, are preferred. Liquid 
mixtures (at room temperature) of 2,4'- and 
4,4'-diisocyanatodiphenylmethane are also suitable as polyisocyanate 
components a). But basically other polyisocyanates can also be considered 
according to the invention, such as those familiar from, e.g., DE-OS 28 32 
253, page 10 and 11. Most especially preferred are polyisocyanate mixtures 
of the diphenylmethane series with a viscosity at 25.degree. C. of 50-500 
mPa.s with an NCO content of around 30-32 wt. %. 
The polyol component b) comprises mixtures of organic polyhydroxyl 
compounds with OH-index between 30 and 2000, while the OH-index of the 
mixture is between 200 and 500 mg KOH/g of substance. 
The polyhydroxyl compounds are preferably the polyether polyols familiar 
from polyurethane chemistry or mixtures of various polyether polyols of 
this type. Suitable polyether polyols are, for example, propoxylation 
products of divalent to octovalent starter molecules, such as water, 
1,2-dihydroxypropane, trimethylolpropane, pentaerythrite, glycerine, 
sorbite, ethylene diamine, and possibly cane sugar. In general, the 
component (i) has a medium hydroxyl functionality of 2.0-5.0, preferably 
2.0-3. Suitable mixtures of this type can be obtained, for example, by 
subjecting corresponding mixtures of starter molecules of the kind 
mentioned as examples to a propoxylation reaction. However, it is also 
possible to mix separately prepared polyhydroxyl polyether with the 
component (i) to be used according to the invention. 
Primary or secondary diamines or polyamines and mixtures thereof are used 
as the amines according to the invention. 
Suitable aromatic amines are, for example: 4,4'diaminodiphenylmethane, 
3,3'dimethyl4,4'diaminodiphenylmethane, 
3,3'dichlor-4,4'diaminodiphenylmethane, 
1,3,5-triisopropyl-2,4-diaminobenzene, 
1-methyl-3,5-diethyl-2,4diaminobenzene, 
1-methyl-3,5-diethyl-2,6-diaminobenzene, 1,3,5-triethyl-2,4-diaminobenzene 
and technical mixtures with the last three mentioned compounds, 
3,5-di(methylthio)-2,4-toluene diamine, 3,5-di(methylthio)-2,6-toluene 
diamine and their technical mixtures, 1,2-ethylene-di-(4-amino)thiophenol 
ether, 1,3-propane diol-di(p-amino)-benzoate, 
isobutyl-3,5-diamino-4-chlorobenzoate, and 1,3-propylene 
di-(4-amino)benzoate. 
Suitable cycloaliphatic amines are: isophorone diamine, 
4,4'diaminodicyclohexylmethane, 3,3'dimethyl-4,4'diaminocyclohexylmethane, 
N-cyclohexyl-1,3-diaminopropane, N-(.beta.-aminoethyl)piperazine. 
Suitable aliphatic amines are, for example: diethylene triamine, 
triethylene tetramine, tetraethylene pentamine, and di-isopropyl triamine. 
The conventional adjuvants and additives c) that are familiar from 
polyurethane chemistry can be used: 
Catalysts to accelerate the various isocyanate addition reactions, such as, 
in particular, organobismuth or organotin compounds, such as dibutyl tin 
dilaurate, organic alkaline salts, such as potassium acetate or tertiary 
amines, e.g., triethylene diamine, dimethylethanol amine or N-ethylene 
morpholine. These catalysts are generally used in a quantity of up to 2 
wt. %, preferably in a quantity of 0.1-1 wt. %, in relation to the total 
mixture. 
Water capturing agents to produce nonfoamed or slightly foamed products, 
such as zeolite paste, which are used in a quantity between 0.2 and 10 wt. 
%, preferably between 1 and 5 wt. %. 
Foam regulators, i.e., foam stabilizers or destabilizers, preferably those 
based on polysiloxane. They are added in a quantity up to 2%, preferably 
between 1 ppm and 1000 ppm, in relation to the total mixture. 
Possibly water as an expanding agent, which can be added in amounts up to 5 
wt. %, preferably 0.5-2 wt. %. 
Possibly physical expanding agents, such as partly halogenated hydrocarbons 
or other liquid compounds, e.g., dichlorfluormethane or pentane, of which 
tip to 20% can be added. 
Possibly organic or inorganic fire retardants, e.g., phosphates or aluminum 
hydroxide derivates in quantities up to 20 wt. % for liquid and 50 wt. % 
for solid agents. 
Possibly fillers, e.g., urea, quartz meal, or talc in quantities up to 50%. 
In the reaction mixtures to be used according to the invented method, 
moreover, the individual components are present in such an amount as 
corresponds to an isocyanate index of 90-150, preferably 120-140. By 
"isocyanate index" is meant the quotient formed from the number of 
isocyanate groups present in the reaction mixture and the number of groups 
present in the reaction mixture that are reactive with respect to 
isocyanate groups, multiplied by 100, water being considered a 
difunctional compound in the calculation. 
Before carrying out the invented process, the adjuvants and additives c) 
possibly being used are generally combined with the polyol component b), 
followed by a processing according to the two-component principle. This 
means that, in order to produce the reaction mixtures, the polyisocyanate 
component a) is intensively mixed with the polyol component b) or the 
mixture of polyol component b) and the adjuvants and additives c). The 
familiar mixing equipment in the state of the art can be used for this.

DESCRIPTION OF THE PROCESS 
The process technology is identical to the conventional one for binary 
resins, i.e., access to the water-bearing region is created by driving in 
a lance or by drilling a hole and then installing a supply pipe with end 
seal. The two components are brought in by a double delivery pump, taken 
separately to the lance or supply pipe, combined with each other here, and 
mixed by means of a static mixer. After flowing through the lance or pipe, 
the mixture hardens in the water-bearing zone. 
The following sample embodiments according to Tables 1-4 will help further 
explain the method. All percentages refer to mass percent. 
EXAMPLES 
In the examples per Tables 3 and 4, the starting components for the system 
components b) and c) as indicated in Tables 1 and 2 are used: 
TABLE 1 
______________________________________ 
OH-Index 
System Starting (mg KOH/ Viscosity 
component b) 
components g) at 25.degree. C. 
(mPa .multidot. s) 
______________________________________ 
Basic polyol I 
Glycerine and 380 450 
Propylene oxide 
Basic polyol II 
Saccharose, 1,2- 
380 580 
Propane diol, 
Propylene oxide 
Basic polyol III 
Trimethylolpropane 
380 600 
Propylene oxide 
Flexibilization 
1,2-propane diol 
56 324 
polyol I propylene oxide 
Flexibilization 
1,2-propane diol 
260 73 
polyol II propylene oxide 
Flexibilization 
Butane diol 176 277 
polyol III tetrahydrofuran 
Flexibilization 
Triethanol amine 
27 870 
polyol IV Propylene oxide 
Ethylene Glycol 
-- 1808 16 
Diethylene Glycol 
-- 1057 26 
Glycerine -- 1827 750 
Castor Oil -- 160 680 
Diamine I (N-(.beta.-amino- 
ethyl)piperazine) 
Diamine II (N-cyclohexyl-1,3- 
diaminopropane) 
Diamine III (3,3'dimethyl- 
4,4'diaminocyclo- 
hexylmethane) 
Diamine IV 1,3,5-triethyl-2,4- 
diaminobenzene, 
technical grade 
______________________________________ 
TABLE 2 
______________________________________ 
System Starting 
component c) 
components 
______________________________________ 
Catalyst I Dimethylethanolamine 
Catalyst II 
Triethylene diamine, 33% in ethylene glycol 
Catalyst III 
Dibutyl tin dilaurate 
Catalyst IV 
Potassium acetate 
Catalyst V 2,4,6-tris(dimethylaminomethyl)phenol 
Zeolite Paste 
Zeolite type T 50% in castor oil 
______________________________________ 
It follows from Tables 1-4 that, for the binary component polyurethane 
system according to the invention, a broad palette of starting components 
[is available?], especially for system component b) (Table 1), as well as 
for system component c) (Table 2). 
Of course, besides the starting components listed, others are also 
suitable, since the components given in Tables 1 and 2 only concern those 
which are listed in Tables 3 and 4 in alternating compositions or 
formulations, provided they have resulted in suitable binary component 
polyurethane mixtures in trial series in combination with the system 
components a) mentioned in Tables 3 and 4, which gel to a gellike 
consistency within fractions of a minute and which are capable, in this 
quasithixotropic condition, to hold back even strongly flowing water until 
a hardening has occurred after a time measured in minutes. 
TABLE 3 
__________________________________________________________________________ 
1 2 3 4 5 
__________________________________________________________________________ 
Polyol 
System components 
b) and c) 
b) 
Basic polyol 
% 50 I 50 I 40.8 
II 73 III 76 III 
" Flex polyol 
% 39 I 38 IV 50 II 10.9* 10 III 
" Cross-linking agent 
% 2 DEG 2 MEG 1 DEG 5 Glycerin 
5 MEG 
" Diamine % 6 I 6 II 6 III 10 IV 6 I 
c) 
Catalyst % 1 I 1 II 0.2 
III 0.1 
IV 1 V 
" Zeolite paste 
% 2 Z.P. 
2 Z.P. 
2 Z.P. 
2 Z.P. 2 Z.P. 
Hydroxyl number 
mgKOH/g 
305 317 328 401 453 
(including amine 
equivalents) 
Viscosity mPa .multidot. s 
378 510 197 517 499 
Density g/cm3 1.036 1.032 1.028 1.044 1.030 
Isocyanate 
System components 
a) 
Type MDI MDI Prepolymer 
MDI MDI 
NCO content % 30.5 30.5 18 30.5 30.5 
Viscosity mPa .multidot. s 
220 220 250 220 220 
Density g/cm3 1.23 1.23 1.16 1.23 1.23 
Reaction 
100 g polyol with 
g 87.7 92.5 164 128.5 133 
isocyanate 
Gelation time 
min 0.02 0.02 0.06 0.08 0.10 
Setting time 
min 1.25 0.30 15.0 12.30 2.15 
NCO coefficient 117 119 120 130 120 
__________________________________________________________________________ 
TABLE 4 
__________________________________________________________________________ 
6 7 8 9 10 
__________________________________________________________________________ 
Polyol 
System components 
b) and c) 
b) 
Basic polyol 
% 40 I 57 II 40 III 30 II 70 I 
" Flex polyol 
% 43 IV 36 III 47 III 57.9 
III 15 IV 
" Cross-linking agent 
% 5 DEG 2 MEG 2 Glycerin 
2 DEG 2 DEG 
" Diamine % 8 II 8 I 8 III 8 III 10 IV 
c) 
Catalyst % 2 II 1 V 1 V 0.2 
III 1 I 
" Zeolite paste 
% 2 Z.P. 
2 Z.P. 
2 Z.P 2 Z.P. 
2 Z.P. 
Hydroxyl number 
mgKOH/g 
310 379 312 278 328 
(including amine 
equivalents) 
Viscosity mPa .multidot. s 
495 434 477 372 341 
Density g/cm3 1.031 1.041 1.011 1.013 1.054 
Isocyanate 
System components 
a) 
Type Prepolymer 
MDI Prepolymer 
Prepolymer 
Prepolymer 
NCO content % 18 30.5 13 13 13 
Viscosity mPa .multidot. s 
250 220 4060 4060 4060 
Density g/cm3 1.16 1.23 1.011 1.013 1.054 
Reaction 
100 g polyol with 
g 146 111 213 192 215 
isocyanate 
Gelation time 
min 0.05 0.08 0.10 0.10 0.20 
Setting time 
min 1.00 13.00 11.30 7.30 8.00 
NCO coefficient 113 119 119 120 114 
__________________________________________________________________________ 
TABLE 5 
______________________________________ 
11 
______________________________________ 
Polyol 
System components 
b) and c) 
b) Basic polyol % 80 III 
" Flex polyol % 12.1* 
" Cross-linking agent 
% 5.6 Glycerin 
" Diamine % -- -- 
c) Catalyst % 0.1 IV 
" Zeolite paste % 2.2 Z.P. 
Hydroxyl number 
mgKOH/g 444 
(including amine 
equivalents) 
Viscosity mPa .multidot. s 
510 
Density g/cm3 1.045 
Isocyanate 
System components 
a) 
Type MDI 
NCO content % 30.5 
Viscosity mPa .multidot. s 
220 
Density g/cm3 1.23 
Reaction 
100 g polyol with 
g 128.5 
isocyanate 
Gelation time min -- 
Setting time min 13.00 
NCO coefficient 110 
______________________________________ 
*Castor Oil 
Tables 3 and 4 present 10 examples containing the corresponding formulation 
instructions to ensure the aforesaid reaction results. 
Table 5, Example 11, presents an example demonstrating the opposite, in 
which the system component b) was formulated without a diamine, otherwise 
being similar in composition to 
Examples 1-10. When such a mixture is used, the special effect of a quickly 
occurring gelling into a gellike consistency or a quasithixotropic 
condition suitable to hold back flowing water was not achieved. 
As will be seen from FIG. 1, a steep rise in viscosity within fractions of 
a minute is accomplished only for mixtures in which a diamine 
cross-linking agent is used, as indicated in the mixture of Example 4, and 
only a gradual increase in viscosity occurs without a diamine 
cross-linking agent, as demonstrated by Example 11. 
With injection resins based on binary polyurethane resins which do not form 
a gellike consistency after the mixing of the components, when used in 
heavily fissured rock, seepage results on account of gravity. In the 
invented polyurethane resin system based on a binary polyurethane, after 
the mixing of the low-viscosity individual components in a volume ratio of 
1:1, this increases to a greaselike product after 2-12 seconds, which 
hardens after 4-5 minutes. 
The system is to be worked with the familiar injection technique for binary 
polyurethane mixtures, so that no special dispensing pumps are required. 
EXAMPLE 12 
A vertically upright plexiglass tube of 1.5 m length and 19 cm inside 
diameter, having a bore hole in the middle of its surface and being closed 
by a screen bottom at its lower end, is filled with pebbles of 
particle-size distribution curve 8-32 mm. Water is allowed to flow through 
the packing at a rate of 8 liters per minute. 
A resin per Formula 2 is pumped into the middle of the tube by means of a 
binary component pump (flow rate 1 liter per minute) to form a seal. 
After 24 s, i.e., 4 kg of pumped resin, the water flow is halted. The 
essentially nonfoamed resin fills up the free volume of around 20 cm 
column height. The effluent water is clear. 
EXAMPLE 13 
Using the same experimental layout as Example 12, a resin mixture of 
following formula is pumped. 
Polyol Component: 
45 parts by weight Desmophen 4012 (polypropylene glycol based on 
trimethylol propane with OH index of 380) 
45 parts by weight Desmophen 4000Z (polypropylene glycol based on propylene 
glycol, OH index 270) 
3 parts by weight Triethylene Diamine, 33% in dipropylene glycol 
7 parts by weight Desmophen 3600 (polypropylene glycol based on propylene 
glycol, OH index 50) 
After 35 s, i.e., 6 kg of pumped resin, the water flow is halted. The free 
volume of roughly 70 cm column height is filled with foam of varying 
density. Large quantities of emulsified polyol, polyurea foam, and foam 
clumps are found in the effluent. 
EXAMPLE 14 
The experimental layout of Example 12 is modified as follows. The upper end 
of the tube is closed by gluing on a circular disk, provided with an 
opening. Water with a flow rate of 8 liters per minute and a pressure of 
20 m water column is admitted to this opening. 
Under these conditions, 7 kg of resin must be pumped in 43 s before the 
water flow is halted. The essentially nonfoamed resin fills up the free 
volume of around 50 cm column height. The effluent is clear. 
EXAMPLE 15 
With the same experimental layout as in Example 14, a resin mixture as in 
Example 13 is pumped. 
After 60 s and pumping of 10 kg of resin, the experiment is terminated 
without begin able to halt the water flow, even though the tube below the 
resin entrance is filled with foam. Considerable quantities of emulsified 
polyol, polyurea foam, and foam clumps are found in the effluent.