DE2161277C3 - Fracturing fluid for a method of fracturing earth formations, methods of making them and props for use with the fracturing fluid - Google Patents

Description

3 4

However, the ratio of manganese (VII) ions in potassium perman water is insufficient to the gelling agent to contain this before the ganate or sodium permanganate, crosslinking fully hydrate. called for a pH greater than 5 before they

The crosslinking compositions according to the present hydrogenatable natural gums crosslink. Invention can be any compound that contains the 5 titanium (IV) -io: ien produced by titanium tetrachloride Metal ions in the indicated oxidation state were suitable, natural hydrogenatable state yields: lent rubber at a pH lower than 2 to ver-lead (II), tie.

Arsenic (III), lead (II) ions make useful crosslinked tin (II), ¹⁰ breakable gels, if they are used to convert hydroxy antimony (III), ethyl cellulose at a pH value above 10 to antimony (V ), network. Hydroxy-ethyl-cellulose was AuCu suitable titanium GV), ^to form a Aufbrechgel, which is aimed in the present manganese (VII), the invention in conjunction with tantalum (V) ions ver-chromium (VI), ¹ S, which are obtained by tantalum pentachloride at a tantalum (V), pH value lower than 2. Hydrogenated Niobium (V). Hydroxyethyl cellulose also makes a suitable one

Break-open gel when it is crosslinked with niobium (V) ions

The crosslinking mixture therefore consists of one that is replaced by niobium pentachloride in another the above-mentioned metals and a second element so approximately the same pH value as for the Tanta! (V) -iünen or a second connection. This second element has been preserved.

or this second compound can be any that it was further found that tantalum (V) ions and

Releases metal ions in solution. For example, niobium (V) ions are natural with hydrogenatable

Compounds that are used to make the lead ions gum acidified gel at a lower pH

to obtain crosslinking, Pb (NO ₃ ) ,, PbCl ₂ , »5 form as 2. However, such a rubber is

PbSO ₄ and PbCrO ₄ . lying invention not useful because he is his

Arsenic (I! I) ions can _{not recover from As 2} O ₃ , AsCl ₃ and original viscosity, after-

AsOCl can be derived. Compounds that are once subjected to shear stress

mon (III) ions are Sb ₂ O ₉ , potassium, antimony.

tartrate, molten potassium antimony tartrate, anti-3 ° titanium tetrachloride does not result in crosslinking of a

monoxalate and antimony ammonium fluoride. Anti-gelling agent at pH greater than 2. If

mon (V) ions can from SbCI ₅ and potassium pyro- es, however, a mixture of water and a

antnnonat can be derived. Zinr, (II) compounds gelling agent is added, it forms the ds-

can be derived from SnQ ₂ and SnSO. intermediate hydroxyde and hydrochloride acid

Titanium (IV) ions can be found in TiCl ₄ . 35 in sufficient quantity to make one

Manganese (VII) ions can get _{smaller pH from NaMnO 4} and KMnO ₄ , whereby the crosslinking

be derived. Chromium (VI> ions will enter from

Na ₂ Cr ₂ O ₇ , Na ₂ CrO ₄ and KgCrO _{4 were} obtained. Tantalum (V> Although in any pH range with

Ions can be obtained from tantalum pentachloride. one of the above-mentioned crosslinking agents

Niobium pentachlorides can be used, 4 ° provided gels can be used to

to get the niobium (V) ions. Breaking up earthly formations is done by the

There are various hydratable polysaccharides in petroleum industries that use neutral or acidic

found to be preferred by metal ions in vcr- fracturing fluids because a basic one

different hydrogen ion concentrations, breaking liquid cross-links an undesirable swelling

can be. For example, it becomes hydratable, 45 and migration of those contained in the formation

natural rubber cross-linked with lead (II) ions, which could cause alumina. Therefore are for the

by lead chromate or lead dichromate with a present invention to form the break-up gels

pH greater than pH 8 have been obtained. the cheapest crosslinking agent, which in a pH

The antimony (III) range of 7 or below obtained by antimony oxides act,

ions required to form hydrogenatable 5 ° The amount of crosslinking agent needed to form

natural rubber has a greater pH than a vsr suitable for the present invention

pH = 7, while a break-up gel is necessary due to molten potassium anti-wetting, varies approximately from

Antimony (III) ions obtained montartrat suitably from 0.001 to about 0.5% of the water weight. The pre-

were, a greater concentration of the crosslinking agent is sufficient during the crosslinking reaction

ren pH Wen ais 7 for irgciiiicmcii hjiiriencn naiür- S5 from about 0.01 to about 0.25 °; Ae * water weight,

borrowed rubber to achieve. It has been found that concentrations of the

KaKum antimony tartrate, which with potassium dichromate crosslinking agent of less than about 0.001%

Used to generate ar, timon (III) ions do not yield enough ions to make the hydrogenated

has to be fully crosslinked for crosslinking of hydrogenated natural polysaccharides. Bigger ones

Suitable for rubber at a pH between 2.5 and 7. 6o concentrations of the crosslinking agent than about

It has been found that a similar pH value - 0.5% of the water weight forms crosslinks that

It is necessary if you have hydrogenatable natural in the break-up gel a cohesion and viscosity

Crosslinked rubber with compounds that give tin (II) ions which are not useful. Excessive amounts

result, such as B. tin chloride and tin sulphate, which with the crosslinking agent cause such viscous

Kaüumchromat or dichromate is used. 65 networks that syneresis often occurs.

Compounds that give antimony (V) ions. With the breaking liquid according to the invention

were suitable to hydrogenatable natural rubber can use all different common props

to crosslink at a pH of 5 or below. such as quartz sand grains, heat-treated

5 6

Delte glass beads, rounded pieces of walnut shell, prevent advertising if the pH value of the gelling aluminum tablets, Nylontablecten and similar water is increased. So z. B. in fabrics. Such agents are generally in concen- hydrogenating guar gum by the hydrogenation concentrations between about 0.45 to 3.6 kilograms to 3.8 1 addition of such amounts of a base such as sodium silicate (1 to 8 pounds to a gallon) of Aufbrechflüssig- 5 to that used to hydrogenate the gelation agent. However, the water used can also be delayed so that the pH value is increased to about 10, if necessary higher or lower concentrations of the hydrogenated gel. Which are used. The size of the hydrogenation used is delayed and a clumping agent depends on the particular type of build-up of the gelling agent.
breaking formation from ₅ the available pressure, io After the cross-linked break-up gel in the u: iterating pumping ratios and other factors. In general, particles from a grain may have been formed, it is desirable that the gel disintegrates into a liquid of low viscosity according to mesh size 2 of the "US Sieve, Series Scale" for breaking up Formations that are either pumped or used through the borehole from the Gemisct of the invention can be drawn into the formation. There is no reason to be eliminated; various suitable means of disintegrating the gel into

The networked Aufbiechge! ^w according to the invention or a liquid. Most of the breaker gels that are pumped into an invention lying before the formation to be broken up disintegrate depending on the penetrating borehole, namely it is pumped into a liquid in a sufficient menu, depending on the time and temperature to get the ao low viscosity. However, it is more desirable to break up the general formation - and the props in the breakup - to introduce a predetermined breakup time. to have within relatively narrow limits.

The mixture can therefore be used by

Mixing a certain amount of the hydrogenatable invention disintegrant can be added. As a decay

Polysaccharide gelling agents with an amount of water are medium, mild oxidizing agents are suitable if

prepared to form a hydrated gel. For a networked break-up gel in a formation of

any suitable customary inter- relatively high temperature can be used for this purpose,

intermediate mixing device used although formation temperatures of about 70 ^c C -. Jer

will. After the gelling agent and water higher generally the break-up gel without the help of a

have been mixed long enough to cause a hydrogenated oxidizer to disintegrate. Suitable

To form gel, a lot of the crosslinked agent will oxidizing agents are ammonium persulfate, potassium

mixed with the hydrated gel and the mixture dichromate and potassium permanganate. For breakaway

pumped into the borehole when the crosslinking gels, which become

reaction occurs. The networked break-up gel can be used as a disintegration center] in general

When pumping into the borehole a proppant is used to make enzymes common. Suitable enzymes for

be set. this purpose are «- and / f-amylase, amylogluco-

The quantitative ratio at which the invertase oligoglucosidase, invertase, maltase, cellulase

wetting reaction at normal temperatures (of and hemicellulase.

about 16 to 50 ^° C.) occurs, depends on the break-up pH of the hydrogenated break-up gel formed with potassium permanganate. For example 4 ° gel does not require any disintegrant, although disintegration cannot crosslink KaJum pyroantimonate at pH value medium with such a potassium permanganate concentration than 1.5 hydrogenated guar gum, and break gel can be optimally used. It was found at a pH greater than 5.5 that potassium permanganate cross-links a gelation crosslinking reaction slowly (longer than 2 hours at medium temperature to form a break-up gel that is room temperature). The maximum cross-linking is then oxidized in a predetermined time into a low-reaction viscous liquid in this particular cross-linking system,
occurs at about pH 3 To ensure that the crosslinking reaction occurs in the desired time, the pH of the water is therefore important for crosslinking to occur. while the gel or water-rubber mixture is moved down the borehole to a desired value within the range of about. If the crosslinking takes place either in the pumps 1.5 to 5.5 by adding a pH value in or before the pumps are introduced, chemical substances can be maintained. Since water from the difficulties encountered in the operation of the pumps is essentially neutral in most sources, the crosslinking cannot take place before the gel uses chemicals such as acids for this purpose. If the buffer formation is reached, the gel does not have the necessary acids, mixtures thereof or mixtures of low viscosity, in order to use large amounts of sand in the acids and bases. Examples of formation causing a possible most suitable acids are hydrochloric acid, fumaric acid and sands of the borehole.
Phthalic acid. Examples of Suitable Buffer Acids It is important that the crosslinked break-up gel used according to the invention, potassium biphthalate, sodium hydrogen fumarate 60, has cohesion. and sodium dihydrogen citrate. Examples of mini- by which it has the properties of a mixture of acids and bases for a long time. Fumaric acid semi-solid substance Sodium carbonate. large supports.

When the gelling agent hydrates, a certain cohesion often occurs KiUiupcü & eluung on what is evidently caused by its rapid hydration to a sample consisting of it at room temperature. This lump-doors allows for about 5 minutes on one. Formation during hydration can diminish or wire mesh stall without enforcing it.

Such a wire screen is networked in a grid of regular seeking crosslinking agents, and the properties each of which is a channel length of shafts of the cross-linked breakup obtained thereby 35 mm and a width of about 25 mm. gels are being studied.

A sample applied to such a sieve. Table 1 shows that at different pH

shows no tendency for at least 5 minutes, 5 values indicate the metal ions of the crosslinkers investigated to step through the sieve. sufficient break-up gel with the exception of

Borax, which is used with sodium hydroxide, can further be determined by the fact that a sample of the invention applied to a tabletop and which did not produce satisfactory results in the ball test produces the cohesion of the crosslinked break-up glass. Tantalum pentachloride with a pH value of gels the weight of a 450 g Slahlkugcl with io about 2 is not. ^f are suitably charged mm ör the sieve or the ball test a diameter of about 45th It should also be noted that this can be done with the without the ball touching the table top. Borax-sodium-hydrogen oxide cross-linking mixture formed. Such a gel applied to a sample of this gel after the shear stress its initial sphere remains at least 15 minutes completely viscosity not regained in order to suffice on the surface of this sample. To obtain the 15 viscosities according to the invention. Table I also shows. When prepared in a measuring cylinder, the gel forms a rope-like mass after 500 ml of all other cross-linked break-up gels, which when removed from the shear stress result in a greater viscosity than from the cylinder and hanging at one end without 20,000 cP. Tear stays hung up for about 5 minutes

Another property of the ao example II according to the invention

Gels can be found when there is a trial

vertical metal pipe is prepared, its bottom with

closed with a rubber stopper. The gel remains Samples A to G of the break-up gels are after

in the tube for about 5 minutes, after which the procedure outlined in Example I is removed under a rubber stopper. The gel then flows out of the tube as gelation ash, using an intermediate preparation medium. Samples were subjected to the same verdem tube and gel formed film or ring as in Example I and keep the low viscosity liquid lubricated. The results given in TaMIe II. These experiments show that the gel according to the invention shows that hydroxide-ethyl-cellulose is suitable as a gelling lubricant film from a liquid of less than 3 "average for the present invention. Viscosity than that of the gel forms when it is about
5 minutes is brought into contact with a Melallfläche. The film forms at the point of contact IH point between the gel and the metal surface. Carrying out the experiment

The crosslinked break-open gel according to the invention has in 35

the earth formation has a viscosity of about 20 0OC cP, ten cross-linked break-up gels are

although it wears the crosslinking indicated in Table IH with a pressure similar to that of water The casing of the borehole is pumped. Mixtures with guar gum are prepared. The gel according to the invention is hydrated during its medium and flows with a Flow;" through the casing of the borehole a <° flow velocity of about 5.8 m / sec subjected to turbulent shear, whereby its pipe viscosity is maintained at a constant temperature (27 ° C) is decreased. However, if the flow conduction in which the shear action as a result of pumping mungsgeschwindigkeii doubled at the entry of the crosslinked gel through the Bohrlochverrohmr.g Breaking ice in the formation is reduced, he becomes. The crosslinking agent is added and the If the gel reaches its high viscosity again, it will flow at a speed of about 4.3 m / sec set the stand, break up the formation and a decreased and adhered to for about 3.5 minutes Carrying proppants into this. When the original gel shear off. The flow rate will Viscosity is also not reduced to about 1.4 m / sec in all of the invention, and the seer gels is reached again after the viscosity resistance of the gel is determined to see if has been reduced by the turbulent shear, 50 this resistance increases after the shear. the however, the most preferred gels will have this flow rate then back to about Characteristic. 5.8 m / sec increased to what value they during

The following are some examples of the grounding 4.5 minutes being held, after which they come back on described according to crosslinked break-open gel. Here- about 1.4 m / sec is reduced. The gel will still by only observing certain properties of this gel 55 once in order to determine whether it clarifies after two will. shearing off its flow resistance

regained.

Example I ^ ' ^e test results in Table III indicate that some of the complex break- _{open gels regain their} initial resistance to testing,

Each Sample A through L listed in Table I after sheared and then left alone is prepared by first putting 4, 1/2 g of guar gum in. The gels that counteract their flow 500 ml of tap water are hydrogenated. stand after being sheared off, are Having each sample at room temperature during preferred crosslinked break-up gels because they are safe about half an hour has been hydrated, the 65 will put the breaker gel in the formation one pH adjusted so that it will have the intended viscosity after it has been used during the wetting of the sample in question, pumping sheared through the well casing can. Each sample is then matched with one that has been undermined.

409643/184

Table 1

Metal ions

Seventh test ¹ )

Ball test ¹ ) Viscosity

before the
Scissors ³ )

after
Scissors ⁴ )

Hanging box ⁴ )

Boundary layer ")

PH value')

Potassium Pyroantimonate and Acid.

Tin chloride + potassium dichromate KaIur »anti-tartrate

4 calcium dichromate .... -

Antimony Oxalate -f- Potassium-

Dichromate

Arsenic oxide + chewing dichromate Antimony ammonium fluoride

r potassium dichromate

Tanial Pentachiorid

Potassium permanganate

Titanium tetrachloride

Molten Potassium ⁸ )

Antimony tartrate

Lead sulfate 4-potassium dichromate

4 sodium hydroxide

Borax + Sodium Hydroxide ...

yes yes yes yes yes

Yes

no

Yes

Yes / Yes

yes yes

yes yes yes yes yes

Yes

no

Yes

Yes / Yes

yes no plug

education

220-

+

Plugging
+

+

+
+
,

20Or

Plugging
Plugging

220+

+
+
32+

+

Plugging

+

Remarks:

') The crosslinked gels can sit on the wire mesh for S minutes äie'ien. If they showed no tendency to penetrate the sieve, the gels are considered useful for cross-linked break-up gels.

*) This Veisuch shows the hanging properties of the networked Open to. A 450 g steel ball is placed on top of a Sample of the gel in question placed. If the gel is the Ball, it passes the test.

*) The viscosity of the crosslinked break-open gel is measured with a Rotational viscometer model 35 Fann (No. 4 Feder, Ni. 2 Sleeve) measured at a speed of 100 rpm. The Viskosimeler displays are entered. Values over 30 mean a viscosity greater than 20,000 cP.

⁴ ) The viscosities of the gels are measured with the same rotary viscometer at a speed of 100 rpm after the gels have been sheared in ten passes by a gear pump. The ads of the Vis-Ja
Yes
Yes
Yes
Yes

Yes
Yes
Yes

Yes
Yes

Yes
Yes

5 minutes
5 minutes

5 minutes

6 minutes

7 minutes
10 sec.

5 minutes

5 minutes

6 minutes
Sec.

5 minutes

Minutes

5 minutes
no

230+
Plugging

Kosimcters are registered. Values over 30 mean a? ° ^ ϊ? Y ^iskosit ät as 2000OcP. Every gel has a smaller flow resistance than water during the shearing process.

') P'e formed in a 500 ml graduated cylinder Opening gels hang freely for 5 minutes without tearing off.

«) The metal tube is before the addition of cross-linked gel completely dry, and the crosslinked gel will during held completely motionless for the first 5 minutes. The time it takes for the gel to sit on the between The boundary layer formed between the tube and the gel slides and emerges from the tube, is measured.

Ί pH value of the gels.

^f ) Commercially available potassium antimony tartrate is ^{melted at 200 3} C for one hour.

° 2? ^The sheared gel breaks into small pieces and does not regain its viscosity.

Table II

Crosslinker

Lead chromate

Lead chloride

Bfeichlorid 4-Sodium Dichromate

: jnta'-pentachloride

/. «Conyl-Chorid

Chromium chloride

Niobium pentachloride

Chromium sulfate

Seventh ')

yes yes yes yes yes yes yes yes

Ball test ¹ )

yes yes yes yes yes yes yes yes

: See the remarks for example L

viscosity

before shearing ¹ )

after Scissors ”)

Plug | 40+

education

Plug- I 40+

education

Plug- j 40+

education!

P.'ropfcn- 35 _T

b.'cung

Plug- 50 +

education

Plug- 40 +

education

Plug- 35+

education

Plug- 50+

education

Hanging test ⁵ )

Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes

Boundary layer ")

Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes

pK value ⁷ )

basic

basic

basic

angry

basic

basic

angry

basic

Table III
Temperature: 27 ° C
Gelling agent: guar gum

12th

Vernelzcr

Δ flow resistance still to the shearing (measured at a flow velocity of 1.4 m / scc)

After 1. scissors After the 2nd shear Δ ρ 0φ / αη ·] measured time,
Minutes Δ ρ (kp / cm *) measured time,
Minutes +0.091 2.5 +0.175 10.0 +0.210 3.0 +0.070 10.0 +0.035 3.0 +0.035 4.0 +0.070 3.0 +0.1.40 8.0 0.0 3.0 0.0 1.5 -0.175 3.0 -0.525 8.5 +0.070 3.5 -1.40 8.5 +0.091 3.0 +0.175 8.5 - 4.5 -0.140 - +0.210 3.0 +0.175 8.5

Tin chloride + - potassium dichromate

As ₂ O ₃ H potassium dichronate + Na ₄ CO ₃

Antimony oxalate + K ₂ Cr ₂ Os ₇

Potassium permanganate

Pb (NO ₃ J ₂ + potassium dichromate *)

Molten Potassium Antimony Tartrate

Antimony ammonium fluoride + potassium dichromate

Sodium sulfite + potassium dichromate

Borate + lime *)

Potassium Pyroantimonate

Remarks:

*) After shearing, the Sg resistance is smaller than for the crosslinked hydrogenated guar gum in the same Pump speed

Example IV

Experimental lead

Four samples A through D of the crosslinked break-open gel are prepared as follows:

Sample A: Hydrogenated guar gum in one concentration of about 0.93% of the water weight is combined with potassium pyroantimonate in a concentration crosslinked by about 0.056 by weight of water.

Sample B: Hydrogenated guar gum of my concentration of about 0.93% of the water weight is mixed with sodium dichromate in a concentration of about 0.081% and sodium nitrate in a concentration of about 0.172% of the water weight cross-linked.

Sample C: Hydrogenated guar gum in one concentration of about 0.93% of the water weight is combined with potassium-antimony-thixitrate in a concentration of about 0.93% by weight of water and sodium dichromate crosslinked in a concentration of 0.081% of the water weight.

Sample D: One concentration hydrogenated guar gumrai of about 0.93% of the water weight is mixed with potassium permanganate in a concentration of about 0.025% of the water weight crosslinked.

Each sample is mixed in containers like those commonly found in oil fields, and then through the oilfield pumps into one; 3 ") diameter tubing approximately 1.524'nt pumped, which doubles the ratios as they occur when an oil well is broken open. For each sample is the flow resistance measured through the pipeline and compared with the flow resistance of water through the same pipeline. The flow resistance is measured in kp / cm *. After each sample has passed through the Pipeline has flowed. a portion of it is dropped into a Brookfield viscometer (No. 3 spindle, 6 rpm), to determine its viscosity after a turbulent flow of about 1.524 m.

Table IV indicates that each sample A through D had less drag in turbulent flow than had water. In addition, Table IV shows that each crosslinked break-up gel uses the Brookfield Viscometer clogged after 1.524 ti of a turbulent flow, which corresponds to a viscosity in subterranean formations of about 20,000 ocP.

Table IV

45 sample

A B C D 1160

1160

1160

850

1160

1160

1160

850

Flow resistance
(kp / cm ¹ )
Water I gel

260
260
260
134

105

87.5
105

70

viscosity
after 1.524 m

(cP)

> 20000
> 20,000
> 20000
^> 20,000

Claims (8)

'Patent claims "locns and a ^ *" ver'ei = th metallic pipeline, in which in the middle of the pipe string a 1. Breaking fluid for a method of breaking up highly viscous fluid through a lubricating film of earth formations by means of a drill ring viscosity along the pipe wall hole and a metallic pipe S laid in it is introduced into the earth formation. • line, in which in the middle of the pipe string According to the main patent is called highly viscous Aufeine highly viscous liquid through a lubricating liquid in with the metallic pipeline film of low viscosity along the pipeline reacting and through this reaction the low wall A cross-linked gel that forms a viscous, lubricating film formed through the formation of the earth using a galactomannan gum and water as the highly viscous breaking liquid 10, one reactive with the metallic pipeline. The present invention aims to provide one for this and through this reaction suggested suitable breaking liquid for the low viscosity processes A crosslinked gel that forms a lubricating film. According to the invention that has Galactomannan gum and water used process used according to the main patent, according to patent 2058 629, thus the networked gel initially had a smaller turbulent one indicates that the gel initially has a flow resistance as water and after the smaller turbulent flow resistance than turbulent flow a viscosity greater than Water and after the turbulent flow a 20,000 cP. Such a gel can contain large amounts of one has a viscosity greater than 20 00OcP. Breaking agent in the formation to be broken open 2. Breaking liquid according to claim 1, characterized in that a »carry and usually with a Borhlochgekmarked that as crosslinking agent ion head existing pumping devices and Veraus the group of lead (II), arsenic (III), tin (II), pipes are pumped. This saves a titanium (V), manganese (VII), chromium (VI), tantalum (V) special smear layer between the break-up and niobium (V) a concentration of about liquid and the well piping.
0.001 to 0.5% of the weight of water used 35 It is known from U.S. Patent 3,167,510. the viscosity of one of water, a proppant, 3. Breaking liquid according to claim 1, characterized in that the break-up gel consists of guar gum and a persulfate and contains added enzymes. means of increasing and later decreasing, being 4. breaking fluid according to claim 1, characterized in 3 "the maximum viscosity is 2700 cP. The USA-marked, that the added water describes a patent specification 3 202 556 a break-up pH value from 5 to 8 and has the break-up liquid- liquid using galactomannanity Sodium dichromate in a concentration of gum and a crosslinked gel with a pH value from about 0.06 to 0.1% by weight of water and from 6 to 13. Sodium sulfite in a concentration of 0.2% 35 Die for the breaking liquid according to the invention of the weight added. preferably suitable gelling agents 5. Propellant for use with a hydrogenatable polysaccharide with a molecular breaker fluid according to claims 1 to 4, weight from about 100,000 to about 3,000,000. characterized in that the proppants are suitable hydrogenatable polysaccharides Galactoaus the group of quartz sand grains, heat- 40 mannan gum, glucomannan gum, and cellulose-treated Glass beads, pieces of walnut shell, derivatives. Hydrogenatable polysaccharides with a MoIe-aluminum pills and nylon pills are chosen and weigh less than about 100,000 in watch weight A size 2 or less of the US Sieve Series does not have crosslinked break-open gels that provide the required «Iesh size and in a concentration of about the above-mentioned consistency and viscosity values -0.45 up to 3.6 kg per 4.5 l gel can be used. 45 shafts, and hydratable polysaccharides with 6. A method for producing a break-up liquid having a molecular weight greater than 3,000,000 according to claim 1, characterized in that the gelling agent hydrogenates and a maximum viscosity of about 28OcP when it is subsequently before this the crosslinking agent can be hydrogenated for crosslinking. Which is best set. ^e .o suitable molecular weight for the hydrogenatable 7. The method of claim 6, characterized in that the polysaccharide gelling agent is about 200,000 to draws that a hydrogenatable polysaccharide with about 300,000. For example, guar gum, molecular weight of about 100,000 to locust bean gum, karaya gum, carboxyme, etc. 3,000,000 used as a gelling agent and thyl cellulose, carboxymethylhydroxyethyl cellulose in a concentration of about 0.3 to 3.0 weight percent and hyüroxyathyi cellulose, suitable weight percent of the water weight of the break-up center !. The cellulose liquid used as a gelling agent added wind. Derivatives should be between 0.5 and about 10 molecules 8. The method according to claim 7, characterized in that ethylene oxide per unit is anhydroglucose, characterized in that as a hydrogenatable polysaccharide in addition to For the present invention, guar gum galactomannan gum one from the group of 60 is preferably suitable as a gelling agent.
GIucomannan gum and cellulose derivatives The gelling agent should be used in a concentration of water. tration of about 0.3 to about 3.0% by weight of water to have. Smaller concentrations of the gelling agent means than 0.3% of the water weight have one 65 insufficient gelling agent content to provide the crosslinked break-up gel with the required above Patent 2,058,629 relates to a method for obtaining the properties described. Concentration Breaking up earth formations by means of a drilling tration of the gelling agent over 3.0% of the water