JPS61196096A - Injection composition for filling and reinforcing ground - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a composition intended specifically for injection into the earth for filling or strengthening it.

In particular, such compositions are used to create fluids for filling string locks in oil fields.

Generally, during oil recovery, a displacement fluid is injected, particularly through an injection well drilled into the oil field, to force the remaining crude oil contained in the string rock into the producing well.

To obtain the highest oil recovery, the permeability of oil i must be homogeneous, because otherwise the displacement fluid will find preferential passage through the highly permeable areas without penetrating the less porous areas. . In order to eliminate this drawback, it is planned to fill the most permeable areas before injection of the replacement fluid.

For this purpose, fill fluids containing gelling compositions, such as those based on silica, are used.

Filling with silica gel is known and has been used for many years for auxiliary recovery of coconut oil (U.S. Pat. No. 3,375,877).
No. 2). It is generally carried out in two steps, so that in the first step an aqueous solution of alkali metal silicate is injected into the oil well, and then in the second step the reactive material is injected to transform the resulting solution into a gel. become

It is known to give various ratios of Mho/810 snow (M represents an alkali metal) and to use aqueous solutions of sodium, potassium or lithium silicates in variable concentrations from 0.1 to 10 wt. U.S. Patent No. 3805893
No. 3882938, No. 4004639, No. 40
69869 and 4081029).

Reactive gelling substances include mineral salts such as calcium chloride (U.S. Pat. No. 3,658,131), ammonium sulfate (U.S. Pat. No. 4,069,869), or organic halogenated derivatives such as sodium trichloroacetate, which can be decomposed by hydrolysis upon release of hydric acid. (U.S. Patent No. 4,293,440
(U.S. Pat. No. 4,069,869), formaldehyde, glyoxal, etc., which yield carboxylic acids through the Canitzaro reaction.

Although such filling in each method has substantially improved production in old oil wells, the ever-increasing cost of oil products in recent years has led to research to find more efficient filling with fluids.

The problem to be solved is to provide a stable gel with high sealing capacity, i.e. the lowest possible shrinkage and syneresis phenomena, and to
The object of the present invention is to obtain at best cost a filling fluid which gels at variable temperatures from 0.degree.

Gels from the gelation of aqueous solutions of organic polymers such as polysaccharides or polyacrylamides (Chemical Engineering Reu, January 24, 1977, No. 12)
pages 13 to 13) generally deteriorate gradually over time and must therefore be removed.

There is therefore a need for silica-based mineral polymer gels. In order to convert an aqueous solution of alkali metal silicate into a silica polymer gel, it is necessary to use a reactive gelling substance, referred to in the art as a curing agent, and the amount of gel obtained depends in part on it. There is. When such reactive gelling substances are metal salts or acids, premature gelation is obtained, which makes the gel poorly dispersed in the string lock and makes injection of the filler difficult due to its increased viscosity. Or even become impossible.

Replacement of metal salts or acids by organohalogenolytic products with hydrolytic release of hydrogen acid results in virtually no gel formation, and rounding of too high acidity provides a non-interfering silica mass providing high syneresis rates. bring the body. Curing agents based on low molecular weight aldehydes have an unacceptable curing time that is too long in the case of formaldehyde and too short in the case of glyoxal; Although it is possible to adjust the temperature to a variable temperature range of 100°C to 100°C, it is difficult.

It is therefore an object of the present invention to provide a satisfactory solution to the above-mentioned problem, namely to create an aqueous solution of an alkali metal silicate, which can be injected into the earth in order to consolidate or seal it. , high sealing capacity, limited shrinkage, low syneresis rate, stable over time even when subjected to high temperatures and pressures, several minutes to several minutes at temperatures above 40-100 °C The object of the present invention is to provide a fluid composition having an adjustable curing time.

However, the inventors have surprisingly discovered that the aldehyde is formaldehyde, glyoxal or a mixture of glyoxal and formaldehyde, the nitrogen compound is urea, and certain aqueous solutions in the form of mixtures with aqueous solutions of alkali metal silicates. To make such a silicage, the aminoplast resin is stable even at high temperature and pressure, is adhesive, inexpensive, has high sealing properties, limited shrinkage, low syneresis rate and high curing time. I found out.

The composition for underground injection according to the invention therefore comprises at least one water-soluble aminoplast resin in which the aldehyde is selected from the group consisting of formaldehyde, glyoxal and mixtures of glyoxal and formaldehyde, and the nitrogen compound is urea. and an aqueous solution of an alkali metal silicate.

The aqueous solutions of alkali metal silicates used are those commonly used in this field by those skilled in the art.

For example, the composition according to the invention may contain, for 100clI,
Density between 1.36 and 1.38, 8101 equal to 3.35
Contains 10-30 cd of a commercially available aqueous solution of sodium silicate in a weight ratio of 10 to 30 cd/Nano.

Experience shows that urea-glyoxal resins are particularly effective within the temperature range of 40-80°C, while urea-glyoxal-formaldehyde resins are well suited for higher temperatures of 80-100°C. For temperatures above 100°C, urea-formaldehyde resins are preferred.

Water-soluble aminoplast resins of this type are known and used in the textile industry as finishing resins, and some of them are found in the literature, such as Textile Research Journal 1969, Vol. 39, p. 86- Page 93; Encyclopedia of Chemical Technology, 3rd edition, Volume 2, pages 454-456, published by John Wiley & Sons, New York City, 1979.

These water-soluble aminoplast resins can be prepared by known methods, for example by adding urea to formaldehyde or glyoxal, or a mixture of glyoxal and formaldehyde, or continuously adding glyoxal to the mixture in an aqueous medium at a pH of 5 to 9 at a temperature below 100°C. It is then condensed with formaldehyde. The molar ratio of each of these components can vary within a wide range, and these resins are generally obtained in the form of aqueous solutions in concentrations that can reach 70% by weight of dry material.

8i of water-soluble aminoplast resins to be introduced into aqueous solutions of alkali metal silicate in order to obtain compositions according to the invention with the desired curing time and syneresis rate at constant temperature in simple laboratory tests. and the amount can be easily determined.

These experiments were carried out by adding an aqueous solution of silicic acid, e.g.
g of water-soluble aminoplast resin and water to bring the final volume of the composition to 100-g, generally between 40 and 10 g.
The test is carried out at a constant temperature θ of 0°C. The time interval between curing into a mass, which can be observed when the composition no longer flows when tipped over, and the previous production of the composition determines the curing time. The syneresis rate was evaluated by measuring the volume of liquid separated from the gel after 5 days of storage at temperature θ, and is expressed in general terms for 100 d of gel.

Starting from laboratory tests, various curves are plotted, such as those that allow calculation of curing time depending on either the amount of water-soluble aminoplast resin used or the temperature. The very easy evaluation of water-soluble aminoplast resins as described above and the simplicity of testing for determining cure time and syneresis rate can make problem-solving compositions according to the invention a reality.

To illustrate, a commercially available urea-glyoxal-formaldehyde resin, ARKOFIX NG (ARKOF
IX NG) 5, 4 and 3f, respectively,
A syneresis rate of 0 and a syneresis rate of 8 at a temperature of 95 °C under the conditions described above.
Curing times of 0.90 and 120 minutes can be obtained. Under the same conditions, a cure time of 180 minutes and a syneresis rate of 0 are obtained using a commercially available urea-formaldehyde resin 4t with a molar ratio of formaldehyde to urea equal to 1.8. Using 3 t of urea-glyoxal resin in the form of a 50 wt % aqueous solution with a molar ratio of glyoxal to urea equal to 2.1, the urea-glyoxal resin was
Curing times of 380 minutes at 60° C. and 95 minutes at 80° C. can be obtained, with syneresis rates of less than 5 inches in all cases.

The composition of the invention is very easily obtained by simply mixing its constituent components. Typically, the selected water-soluble aminoplast resin is dissolved in a commercially available aqueous solution of the alkali metal silicate in the desired amount, and then, if necessary, the resulting solution is brought to the desired concentration.

As mentioned above, the composition according to the invention consisting of an alkali metal silicate and at least one water-soluble aminoplast resin of urea-formaldehyde, urea-glyoxal, or urea-glyoxal-formaldehyde condensation is suitable for porous substrates, especially oils. It is particularly useful in making fluids for filling string locks in oil fields for auxiliary recovery of oil. However, it can be successfully used in soil consolidation when building tunnels, dams and other underground structures of this kind.

Although the invention has been presented in purely illustrative form, it is not in any way limited to it, and it will be appreciated that useful modifications may be made thereto without departing from the scope of the invention.

L 岑'tt4iL 弥いしみきょう W) (nshi master, enter b
9. Form 1, 3, Relationship with the case of the person making the amendment Special pae, Taki P1 Koseiro 4, Agent Go, ;v=vI Keizen Kesen

Claims (1)

[Scope of Claims] 1. A composition used for underground injection comprising an alkali metal silicate and at least one water-soluble aminoplast resin, wherein the aldehyde is formaldehyde, glyoxal, and a mixture of glyoxal and formaldehyde. A composition selected from the group consisting of urea, characterized in that the nitrogen compound is urea. 2. A composition according to claim 1 for use in aiding oil recovery. 3. The composition according to claim 1, which is used for compacting soil.