DE2039727A1 - Method of treating the vicinity of wells in a subterranean formation - Google Patents

Description

" Methods of Treating the Environment of Wells in a Subterranean Formation "

The invention relates to the treatment of loose, non-consolidated or only partially consolidated earth formations that Surrounded the holes by introducing a solution for the electroless metal deposition in these formations, covering the walls of the pore spaces of the formations with a metal coating can provide. The hole can be used to extract oil and / or Serve gas and / or water from an earth formation.

This treatment can thereby, according to patent 1,298,474 be accomplished that a subterranean formation is first brought into contact with an activating agent is and then the walls of the pore spaces »it one Solution for electroless metal deposition are brought into contact.

10M0I / U7

1A-38 329

The solution for electroless metal deposition consists of a solvent in which a preparation for metal deposition is dissolved, which is composed of a compound of a polyvalent metal and a reducing agent. This solution also contains water. The solvent used to dissolve these components can be water or a solvent Be a water-miscible solvent such as a lower alcohol, acid, or mixtures thereof.

Metals deposited on loose grains of sand in non-consolidated * 'or partially consolidated earth formations are, form excellent binders that make the loose grains of sand stable, permeable, forming a whole Solidify formations that resist large compressive forces.

The metal coatings on the grains also form impermeable layers that protect the grains and the consolidating agents or cementitious compounds from destruction protect with hot liquids such as hot water and / or steam. The metal coating of silica components in earth formations also prevents the dissolution of the ^ Silica, which comes into contact with hot aqueous liquids when such liquids are allowed to flow through earth formations, such as in the Extraction of hydrocarbon fluids from these formations is the case. The invention can thus also be used in consolidated formations are applied to the dissolution the grains or the substances that bind the grains together prevent au.

Depending on a set of variables, such as the type of formation and the temperature and pressure conditions in the formation, as well as the reaction rate, the solution for the metal deposition can be acidic with buckets pH from 2 to 6, such as 4 to 6 or alkaline with a pH value of β to 14, such as 8 to 10,

10ΙΙ #> 147

BATH ORIGINAL

• 2038727

1A-38 329

- be 3.

A disadvantage of the known methods of treating subterranean formations with the aid of solutions for Hetallabscheidung is the very high reaction rates of the Hetallabscheidungereaktlon, especially at relatively high temperatures such as above 120 ⁰ C. The metal is then deposited mainly on the sand grains of the formation portion of the immediately surrounding the wellbore, while treatment to a greater depth into the formations would be more desirable. I.

The subject of the invention is a metal deposition! that for the treatment of subterranean formations with relatively slow reaction rates of the solutions used is suitable for metal separation.

According to the invention this goal is achieved in that a Phosphite ion-containing compound is used as a reducing agent in the solution for metal deposition.

Accordingly, there is a method of treating the environment of drilling in an underground formation where one goes through the hole in the forum space of the formation j a first, an activation medium for metal separation containing solution and then injected a second solution, the one compound of a metal, which can occur in several valency levels and contains a reducing agent, and the first solution by the second reading from the portion of the formation to be treated with the deposition of a metal layer on the grains of the portion surrounding the wellbore the formation displaced, according to Patent 1,298,474, characterized in that a second solution for the currentless Hetallabscheid used which contains a phosphite ion-containing compound as a reducing agent.

109809/1479

BATH

1A-38 329-4 -The invention is explained in more detail below.

As already mentioned, one uses in the solidification ▼ experience according to the invention, an activating agent that is injected into the formation before the metal separation solution is injected.

"Activating agent" is understood to mean an agent that is able to convert the walls of the forum room to a formation activate or process them so that these walls can be made metallizable by a solution for metal deposition can be. Examples of activation agents are solutions of palladium eels and tin (II) salts, e.g. chlorides, Bromides, nitrates and sulfates. Certain palladium compounds can be in the form of colloids. A Another example is a hydrazine solution. This solution can used together with tin-II-chloride and falladium chloride will. The solutions with these activation agents can optionally be used individually or in combination with one another. Amounts between 0.001 and 1% by weight, in particular between 0.01 and 0.1% by weight of activating agent can be used in the solution. To make the formation more susceptible to metallization, the The pore space wall can be pretreated with an acid solution, e.g. with a sulfuric acid solution or hydrochloric acid solution. This acid solution can also be injected at the same time as the activator solution.

The activator solutions can be the above-mentioned solutions of activating agents, those with weak organic acids and their salts can be buffered. Preferred solutions of activating agents are given in Tables I and II.

1O88O0 / U78 _BirlMAL

BATH ORIGINAL

11-58 329

IABE! ».. JLl - I

Activating agent solution (Α ..)

water . ViSO c) I54 Liter '■. ■ Gum arabic ' T * dSÜlÜ '■ 20, 6 β ■ 256 Ot ^ ■ (or 400 cb ^
55 % hmteaiin.) ) 636 T $ P ^ P ξΡ ¹ ** * ™ frya, P '«jillliJrnllliijj lSüä% * aMi WMf ^ MvM j ^
3
OUT Hydrazine hydrate (85%) Palladium chloride lousy 90 % formic acid or
Glacial acetic acid (as required
for a pH value = 4, #) * Ί 60 - 320 approx ⁵ let go, - if buffer
be used "Buffer

Iron acid- (90 %) ■ 640

ÜTatriumiTormiat ■ 3 _S 2 kg

Acetic acid or glacial acetic acid 6.4- fan

Hatriueaetat 4-? .5 t &

Bemerloiiigi The chemicals miss the water in (Lav

Auxiliary sequence can be added and fully taxable daiait must be mixed and dissolved before the · mS-shotc compound is added.

a) containing 10.2 g BäCi _2/160 liter Tb) - requires about 15 minutes' araa dissolving

c>. contains 1.6 g FdCl ₉ , 10 em ⁵ koasB. HCl, 90 cm distilled or deionized water / 100

oT) 5'.o ;; ; '■ "■

1A-38 329 - 6 -

TABLE II Activation Agent Solution (B ₁ )

900 cbT of water

100 ce 'solution

919 cm ' ^{5 of} water
81 cm * gum arabic solution, content 0.4 g / liter 0.4 cm ⁵ hydrate (85% solution) 1.0 car solution

1.6 g PdCl ₂ .2H ₂ O 10 approx? conc. HCl 90 cm * water added glacial acetic acid up to pH value ■ 4.2

In the solution for metal deposition, a metal ion in solution is reduced to the corresponding metal in that the required number of electrons is absorbed. The source of these electrons is the oxidation of another ion in solution called a seductant. To explain these reactions in alkaline solution (Table III, solution 1 or 2 and 3 and 6), nickel ions are reduced by hydrogen phosphite ions (HPOt) * as follows:

Ii ⁺⁺ + 2e ~ - Ii ⁰ (reduction)

(HPO ₅ ) "+ 3OH" m Pu ₄ m + 2H ₂ 0 ♦ 2e ~ (oxidation)

By combining these separate reactions, the following overall reaction is obtained:

+ (HPO ₅ ) "+ 30H" * - »i ° + PO ₄ - + 2H ₂ 0.

109800/147

- 7 - 111 1A-3B Components 1 : 61.1
.92.6 2 IiQBX 329; 86i 0 • 6th T A. B E: L L 1 792 Ia citrate. 2HgO. - g / liter.
Ha-acetate · 3H ₂ O. <- g / Lit ·?
Eiseseig - en ^ / Lit «
pH-Mert ■. ■ 9D5
Density ».g / cmr 1.06 695 37 , 3 8? 2 HetaXlabeoheidttiigBluBinigeit 2 37.1 39.5 825 46 , 5 41 _f i. IiGl ₂ .6H ₂ O - g / liiter Ia ₂ HPO ₅ .- 5H ₂ ⁰ "* e / * Atex9Ov3 39.5 ■ 37.8 mg Ir «. .51.3 HaH ₂ PO ₂ .H ₂ O g / liter 89 * 4 4th '■ 61
51 , 4
, 2 HH ₄ Cl - g / liter.
29.4 m * e » ^J / I» it © r 65.0
217 '. 0 _s 92 338 ■ 8 , β 61.5 60.5
64.3 ' "37.3 ■ 61..5.
14.4
■ 5.6
1.09 ,,, 90.6_. O _p 95 61.4
51.2

Comment: . . .

The hiosphite should also be added

felling while pissing at TerUjadem #

Thus, the two electrons, oil, are required for the formation of divalent metal ions to form the metal, and are surely added to the phosphate ion by the oxidation of a Rioephitioiis. Reactions which are given in the above equation for nickel are Simplified by the fact that the hickelion is not present in the free form, but rather complete gel> unden with ammonia or slycolic acid, in order to be able to regulate the leaction rate and / or to prevent the precipitation of metal salts in the solution the phosphatlon can each in one or more

109809 / U7 »

1A-38 329 - 8 -

There are ionization stages, as in the forms ΡΟ, Ξ, (HPO,) * or (HpPO,) "" for the phosphite ions and in the forms PO ₄ «, (HPO ₄ ) * or (H ₂ PO ₄ )" for the phosphate ions , Depending on the pH of the solution.

Examples of suitable polyvalent metal compounds are inorganic compounds including nickel, cobalt, Copper and iron, such as nickel chloride, cobalt chloride, nickel sulfate or cobalt sulfate, or mixtures of at least two of these connections. They concentration of the metal compound in the solution can vary within a wide range, for example from 1 to 50% by weight or in particular from 5 to 40% by weight.

In order to solidify a sand layer, the metal is allowed to deposit on the catalyzed sand grains until about 15% (on average) of; Pore space are consumed. At the points of contact with the bodies, the metal forms bridges from one grain to the next, thereby solidifying it. A compressive strength of the order of magnitude of 2,100 to 2,800 kg / cm ² is achieved with a loss of permeability of about 30 %. The sand grains are also completely coated, which protects them from dissolving in hot water, as in the case of water vapor flooding.

A preferred deposition reaction for nickel is achieved by reducing nickel, which is complexed with ammonia, by oxidation of hydrogen phosphite (HPO,) * to phosphate P0 ₄ »according to the following equation:

A. Half-exhaust reactions and standard potentials E ° (HPO ₃ ) "+ 3OH" PO ₄ = + 2H ₂ O + 2e "+1.12

Ni (NH ₃ ) ₆ ⁺⁺ 4- 2e ~ * = ^ Ni ⁰ + 6NH ₅ (aq) - 0.47 B. Total reaction and standard potential (sum of half-elements

__ te)

(HPO ₅ ) "+ Ni (NH ₃ ) J ⁺ + 3OH" PO ₄ - + Ni ⁰ + 6NH ₃ (aq) +

2H ₂ O -1- 0.65 E °

109809 / U79

1A-38 329

The overall reaction is spontaneous for units of activity, as can be seen from the positive potential value ^{E 0.} The equilibrium is strongly shifted to the right under most practical conditions.

Experiments and their results on the consolidation of formations by the method according to the invention for electroless metal deposition are shown in Table IV.

TABLE IV:

. - 10

109809/1479: ''

Procedure:

Results:

Ver Abachei- Abauek duaga- atand-Hr. lSanng holder

code

Ir.

TABLE IY Rohratutzenveraucha - 15QQC to 180 ⁰ C

Sand Mr. 5 β) in tube statuettes (42 kg / cB ² nüaaigkeitadruck) H ₂ O flushing + IPA * flushing + E ₂ O flushing

cca Pd activator solution c)

Spacers as required (see below) Abacheeidelöaung (Code Hr. Corresponds to Löeunga-Hr. In table

if necessary, buffer flushing (see below) III)

Buffer-

apü-

lung

T ⁰ C

(PT /,

Am)

(ρτ)

Time t (bin) Pressure capacity extrapolated to feed kg / ca2

1 1 1 Λ

9.1

8.8 8.8 8.6 9.5 9.5

no

C ^
C.

no

HpO

R ₂ O

no

Il

9.5 H ₂ O

no no

no no

169 169 169 169 169 169 154 174

2.1

4.9 2.8 3.0 3.0 2.2

140

137 162 66 159 159

0.84 114 3l3 112

363 7.7 186

68 28 59 21 53 71

24 high

high w2800 (1630 please) high good - after 10 days of treatment bit

hot least. Vaseerstro »at 290 ⁰ C high

ω -ο m

VM

1A-38 329

- 11 -

Comments on Table I ?:

a) F * flow velocity through solidified zone in

Solidified zone pore volumes / min

b) N = number of pore volumes of the used separation »

solution (a forum volume «a pore volume only the hardened zone)

c) 144-1 field water + activator A ₁ according to Table I.

d) 144 1 spacer / 160.-1 H ₂ O (10.5 kg IiH ₄ Cl per 160 1 H conc. NH ₄ OH (29.40 MH ₅ ); pH 9.3 "

e) Sand No. 5 is a pure blown sand with grain sizes from 125 to 175 / um diameter

·) IPA »isopropyl alcohol Discussion of the results according to Table 17

A. Activation

The colloidal falladium solution A ₁ was found to be effective for sand activation in this high temperature range.

B. Spacers

An induction period of a few minutes is required to set the deposition reaction in motion, such as yourself by the small amount of unused deposition solution shows that comes out of the system at the beginning of each attempt. This makes it unnecessary to use spacers use to prevent loose solid metal particles from Solids form in the feed pipes and the inside

- 12 -

101809/1479

ORIGINAL INSPECTED

1A-38 329

clog the sand pack. This is done through the trials No. 6 and No. 7 shown. Run # 7 did not have a spacer between the activator solution and the Separation solution, however, apparently had identical results like experiment no. 7 with a spacer in the form of water.

The best results were obtained when a buffer was used as a spacer (experiment no. 5). However, this is how it is believed not necessary in practical use.

C. Composition of the deposition solution

The deposition solutions used (Trials # 1 to # 3) contained a small amount of hypophosphite to get this going put the response support. However, as was found, this was not necessary, which is why (see experiments No. 5 to 9) this use was not continued.

No attempt was made ^{to keep the amount of Nickel ++} and (HPO,) ⁼ at an optimum. An arbitrary amount of 3 moles (HPO _x ) ″ / mole Ni was therefore used, except for experiment No. 4. At this ratio, there appears to be an excess (HPO,) ⁼ % , since the solution is colorless (apparently nickel-free) after a few minutes Unfortunately, Run No. 4 clogged so soon after the deposition reaction started that no information was obtained regarding the utilization of (HPO,) ". It must be stated that the disodium hydrogen phosphite salt used in these experiments cannot be commercially available. In this case a mixture of orthophosphorous acid H ₂ (HPO,) and NaOH may be more practical to use.

The pH of the solution is critical to prevent precipitation before and after the deposition reaction. At the pH 8.8 (Trials No. 2, No. 3 and No. 4) became a

- 13 109809 / U79

1A-38 329 - 13 -

major clogging noted, probably due to the precipitation of (Ni), (PO ^) ₂ in the feed lines, etc. At pH 9.1 (experiment # 1) significant amounts of loose solids were noted, but not enough to keep the liquid flowing seriously restrict the feeding of the sand pack. At pH 9 * 5, practically no loose solids were noticed in the feed and a small amount that. was found to be due to poor flushing in the less accessible areas of the feed cap of the sand pack. Box with a pH value of around 10, precipitation can occur in the separation solution due to the formation of Ni (OHg) «. However, this RuAt has not yet been investigated in detail.

D. Formation of gas and rise in pH during the reaction

Very little gas (probably hydrogen) was observed in the depleted effluent in the d® & em solidification attempt. This small amount was completely dissolved in the solution at 42 kg / cm. The practical absence of gas as a by-product may indicate a higher efficiency for the recovery of (H PO ^) "than the greater or less 30% obtained in older attempts on systems using (HoPOo)". This is also indicated by a slight increase in the pH value, which occurs during the 'metal separation (instead of a waste' as is the case _{with both systems with (H 2} PO ₂ ) ', which indicates that during the heating if at all, very little acid is formed.

E. Compressive strength

In general, the size of the solidified zone in each experiment was too small to determine this size exactly *. From the visual inspection and the determination of the difficulty with which the solidified zone overall away uad as core

. 1098-09 / 1479

1A-38 329

could be sawed, but it was evident that in most cases a high compressive strength had developed at the feed of the sand pack. In one case (Trial No. 6), however, the size of the solidified zone was sufficient to obtain a measurement. The high expected value (1400 to 2800 kg / cm) was confirmed from the absence of a gas phase. It was applied long 10 days also in an experiment (no. 8) a hot water stream at 29o C ^0. No bites developed and there was no loss of sand. The solidification was very good after the hot water treatment. However, there was some evidence that the scale had degraded to a small extent.

If there is no clogging at the feed due to debris or other material brought in from the outside, it can the loss of permeability from the number of forum volumes of the deposition solution consumed in solidification can be estimated. Following this procedure was in experiment no. 1 and in experiments nos. 5 to 9 no more than 30% of the permeability was lost.

The deposition solution at pH 9.5 (solution no.1) appears to be depleted with no formation of solids except on the desired metal surface, thereby creating none excessive leakage can be expected.

Temperature dependence of the reaction rate constant

Ee was found that the reaction rate constant doubled with each 10 ⁰ C in the range of 150 to 180 ° C. This value is roughly the same as that which is found in the range from 40 to 90 ^° C. when hypophosphite is used as a reducing agent.

- 15 -

109809 / H73

1A-38 329

... - 15 Regulation of

Metals that do not have a catalytic effect, such as iron and copper, can be used successfully when added to the deposition solution in a low concentration to regulate the rate of reaction. . . ■. ■. ■

.The speed of reaction can continue to decrease due to falling pH values' are regulated - whereby an, acidic deposition solution - is formed will. In such acidic solutions should. the metal ions, like nickel ions, are coaplesed with a compound be like citric acid, im the metal ions in solution too hold «A mixture of glacial acetic acid and fiatrium ace-tat forms a / suitable buffer to stabilize the pH value such an "acidic Abecheiäungsloeung". .

To solidify * the fefiförsastionon at temperatures is range from 130 to 2öö®G sit-des.
According to the invention, the Ketrlumhyörogesphosphit g'u achieve, it was found that better.'Results. © Aalten can be added if a Glycolation 2 for complexing.des-Hetffills, for example Iiekel or cobalt, added

Notable KemiEe-ich®E of the invention are the regulation the seaction speed of the electroless metal deposition process at relatively high temperature »In the consolidation of relatively hot subterranean formations, relative reached extensive depths of consolidation. Eei one The metal deposition process helps such consolidation processes also to reduce corrosion and the Loss of heat in or through Eohrstrangen in the bores be used as during, the injection of the activating liquid. and the separation liquid .in the underground Erdformatioaen the pipe string through the invented

. - 16 -

109809 / 14-79- ^; bad original

I · · ■

* fl

t ■ ι

f t

1A-38529

- 16 -

are metallized according to the process. As these fluids will be injected into the loose formations Both the earth formations and the piping are metallized with a Mickelmetall protective coating and so are the others Parts of the equipment and devices with which these metallizing fluids come into contact.

PATENTAL SPEECH:

109809 / U7Ö OFtIGiNAL INSPECTED

Claims (5)

PA 0? E N T A N S P RU CHE 1) A method for treating the vicinity of boreholes in a subterranean formation, in which a first solution containing an activating agent for metal deposition is injected through the borehole into the pore space of the #or -itioh and then a second solution containing a compound of a metal, this can occur in several valency stages, and a reducing agent containing, and the \ first solution surrounding by the second solution from the treated part of the! formation with deposition of a metal layer on the grains of the bore! displaced portion of the formation according to Patent 1,298,474 ·, Characterized in that a second solution for electroless metal deposition is used which contains a compound containing phosphite ions as a reducing agent. 2) Method according to claim 1, characterized in that the metal deposition reaction is carried out at a temperature of about 120 to 200 ⁰ C · 3) Method according to claim 1, characterized in that geke η η - ί is characterized in that a nickel-depositing solution with a pH above and a compound containing phosphite ions is used as a metal deposition solution, an alkali metal hydrogen phosphite. 4) Method according to claim 1, characterized in that there is used as an activating agent Solution used an acidic aqueous solution containing palladium chloride and used as a metal-separating solution a nickel plating solution is used, the sodium hydrogen phosphite contains. 10 980 9/1 47.Ö-. ■ bad orjqinal 2U39727 1A-38 329 - 18 - 5) Method according to claim 1 to 4-, characterized in that the metal is present in the Metallabacheidungslöung as a Metallkoaplexverbindungen. 109809 / U79