Insulation method of water influx to production oil wells

FIELD: oil and gas industry.

SUBSTANCE: insulation method of water influx to production oil wells involves pumping of gel-forming compound prepared by introducing the carbamide to polymer-colloidal complex obtained by mixing of water colloidal solution of aluminium pentahydroxochloride with 0.2÷0.3 wt % of water solution of polymer; at that, as polymer there used is weakly charged cationic polyelectrolyte with molecular weight of 6·106-20·106 and content of cationic groups of 1.65 to 9.20% molar.

EFFECT: increasing oil production owing to reducing water content of extracted products.

4 tbl, 5 ex, 1 dwg


The invention relates to the oil industry, in particular to the use of gel-forming compositions, creating a water screen in high permeability washed areas of the reservoir, preventing the penetration of water into the producing wells.

Usually as components of the gel-forming compositions used inorganic salts, acids and bases (salts of chromium and aluminum, sodium silicate and other)reacting "in situ" with the alkaline reagents to form a gel-like precipitation, reducing permeability on water [Surguchev N.A. Methods of extraction of residual oil. M.: Nedra. 1993; Mamyrin V.N., Shvetsov I.A. Physico-chemical methods during flooding. Samara. DOING. 2002].

Limiting water inflow, these gel-like precipitates are characterized by low rheological properties, which have a poor efficiency and low durability. Improvement of operational properties of the gels is achieved through the introduction of special additives, surfactants, polyglycerins and water-soluble polymers [Patent USSR 1654554, MKI EV 43/22, publ. 1998; J. Petroleum engineering. 2002. No. 4, S.11; Altunina L.K., Kuvshinov V.A. Physico-chemical technologies of enhanced oil recovery (review). Chemistry for sustainable development. 2001. No. 9. S]. However, in all these cases arise under certain conditions, a gel-like precipitate PR is dstanley svobodnodispersnye system with a particle size of 20-25 microns and is characterized by low static resistance shift, the result is a relatively rapid washout from channels and fractures in the reservoir.

The improved properties of gel-forming compositions can be achieved by incorporating a water-soluble polymer and a crosslinking salts of chromium and aluminum.

There is a method of developing a heterogeneous reservoir by injection of a dispersion of particles of polymer and crosslinking agent, which is used as salts of polyvalent metal [RF Patent 2167981, MKI EV 43/22. Publ. 2001]. As a result of reaction between the components occurs chemically cross-linked polymer system with enhanced durability.

However, this system eliminates the possibility of removing, if necessary, the gel composition from the wellbore in the event of premature formation of cross-linked hydrogel. In addition, what is happening over time, the oxidation of chromium salts in a highly toxic form of Cr+6limits the practical application of this composition on environmental circumstances.

There is a method of developing a heterogeneous reservoir by injection of hydrogel particles formed in intramolecular merging of polyacrylamide and cellulose ether by polyoxychloride that is accompanied by a change of the filtration characteristics of the heterogeneous layer and improving the manufacturability and sustainability [RF Patent 2298088, KIEV, SC, publ. 2007].

The disadvantage of this method is the injection into the pumping well is not the reagent solution, and the suspension of a powder of the polymer and solution polyoxychloride, resulting svobodnaia system with a broad set of different particle size of from 0.1 to 5.0 μm, the effect of which is reduced to mechanical blockage of the channels of a certain size without a pronounced selectivity for water-saturated zones of the reservoir. In addition, this method relates to injection wells, is designed to align the profile and increase the coverage of the reservoir water flooding and does not affect the water-cut wells.

The known method of regulating the development of heterogeneous stratum consecutive injection of rims of fresh water, an aqueous solution hydroxochloride aluminum, an alkaline reagent, fresh water and a water-soluble polymer - polydimethyldiallylammonium chloride [RF Patent 2224092, MKI EV 43, publ. 2004].

The disadvantage of this method is that the resulting gel-like precipitate is svobodnodispersnye system with low strength, as evidenced by the fall in viscosity of the gel from 4.5 PA·s to 0.2 PA·s at low shear stress of 10 PA. The method involves the separate injection of the reagents, in which the process of mixing in the borehole becomes uncontrollable,and the used polymer, acts as a flocculant, such conditions cannot guarantee the formation of a uniform and dense sediment. In addition, this method is designed to increase coverage of the reservoir water flooding and does not directly affect the water cut wells.

Closest to the present invention is a method in which to isolate water production to producing oil wells carry out the injection of the gel-forming composition containing an aqueous solution of pentahydrochloride aluminum, an aqueous solution of polyacrylamide and urea. The components are mixed in sootnosheniyah, wt.%:

Pentahydrochloride aluminum3-6

[RF patent 2348792, MKI EV 33/138, publ. 2009].

Obtained by mixing the solution obtained in the flushed zone of the formation where the temperature, a gel is formed of aluminum hydroxide, reducing permeability of rocks by water, slightly altering the permeability of oil, thus providing selectivity of action.

The disadvantages of this innovation is on the way include the following:

First used in this composition polyacrylamide is characterized by relatively low molecular weight (1÷2·106), and has low resistance to hydrolysis. Already in the process of polymerization of acrylamide produced commercial product polyacrylamide contains a small amount of carboxyl groups [Abramova L., Baiburdov T.A., Grigoryan AP and other Polyacrylamide. Edited Vthkurthv. M.: Chemistry. 1992]. In the same diluted aqueous solutions of their content increases and "nonionic" (trademark) polyacrylamide becomes slaboosnovnym. At the same time, it is shown that the interaction of pentahydrochloride aluminum with anionic polyelectrolyte leads to the formation of insoluble polycomplexes [novaki I.A., Radchenko FS, Ozerin A.S., Rybakova EV news VSTU. Meiwes. Coll. Vol. chemistry and technology of organic monomers and polymeric materials. Q.5 2008. No. 1. P.150] is not suitable for use as a waterproofing gel-forming composition.

Secondly, the molecular weight of the used polycrylamide is relatively low, at the same time it plays a major role in the formation of gels coagulation structure, and the higher it is, the lower the required dosage of the polymer and the stronger the net intermolecular bonds.

Thirdly, the COI is the whether this composition on the basis of polyacrylamide leads to a decrease in permeability" of water to the producing wells, however, filtration of water is not fully terminated and may lead to a gradual leaching of the gel and reduce the filtration resistance of waterproofing screen, i.e. the reduction of the durability of the gel composition.

The objective of the invention is to increase oil recovery by reducing the water content of produced fluids by isolating water production to producing wells when using the gel-forming compositions with improved processing properties, and expansion of assortment of water-soluble polymers suitable for use in this composition.

When implementing the proposed method are the following technical result:

first, the composition based on pentahydrochloride aluminum (PGA), urea (KA) and a water-soluble polymer forms a stable structured gel in a wide range of formation temperatures (65÷85°C), with "locking effect" in the pore space of terrigenous reservoir in relation to the water and causes the termination of water filtration in high-permeability zones to producing wells;

secondly, to prepare a working solution of the composition before injection into the well using a water-soluble polymer is a high molecular weight weakly charged cationic polyelectrolyte (SCPA) with cationic saradomin +1.65 to +9,20 mol.%, having a high adhesion to the terrigenous rocks of the reservoir in permeable zones;

thirdly, as SCPA use widely used and produced by domestic and foreign manufacturers of so-called high-molecular flocculants ("superfluously") with a broad set of specific properties, which allows the optimization of composition, taking into account characteristics of oil-saturated reservoir rocks;

fourthly, the initial solution composition can be prepared on any type of water (natural, technical, bottom, layered with salt content up to 40 g/l and has a close to neutral pH (pH 5,5-7,0), without adversely corrosive effect on metal equipment wells;

fifthly, the use of high-molecular SKA with a molecular mass of 6·106-20·106causes a high degree of cooperative relations in polymer-colloid complex and related high strength resulting from it ("in situ") structured gel.

The technical result is achieved in the way of insulation water production to producing wells by injecting the gel-forming composition obtained by mixing pentahydrochloride aluminum, urea and an aqueous solution of the polymer, the mixing is carried out by injection of urea in the polymer-Collot the command complex, obtained by mixing aqueous colloidal solution of pentahydrochloride aluminum with 0,2÷0,3 wt.%-tion aqueous solution of the polymer, and the polymer used weakly charged cationic polyelectrolyte with a molecular mass of 6·106-20·106and cationic groups from 1.65 to 9.20 mol.%.

This method provides education in the saturated zone of the formation of a structured gel, in which the amphoteric inorganic gel of aluminum hydroxide, reinforced at the expense of ties dispersed particles of polyelectrolyte macromolecules, distributed in the pore space of rocks, not only reducing its permeability for water, but almost completely stops water filtration, i.e. has a "locking"effect.

The mechanism of formation of polymer-colloid complex (PAC)that occur in the original solution while mixing pentahydrochloride with a solution of polyelectrolyte consists of intermolecular interaction of colloidal particles of aluminum hydroxide with macromolecules of the polymer due to non-covalent bonds of different nature (hydrophobic, donor-acceptor, hydrogen). The most long-range ion depending on the sign of the charge (opposite or same) will strengthen this interaction or to oppose him. The interaction of positively sarajanegallagher particles of PGA with negatively charged macromolecules (polyanionic) is very strong, leads to severe compaction of macromolecules and the loss of their affinity to the solvent in water. The result is the formation of a strong, but insoluble polycomplexes. The interaction of these particles with positively charged macromolecules (polycationic) leads to the opposite effect - the repulsion of the charged particles and macromolecules of the polymer, resulting in the formation of the PAC becomes impossible. Characteristic data of the PAC is that for them to get use of cationic polyelectrolytes with molecular weight (6·106-20·106) and cationic groups from +1.65 to +9,20% molar, preferably used are copolymers of acrylamide - weakly charged with cationic groups from +1.65 to +9,20 mol.%). When the high molecular weight of such polymers (6·106-20·106and a rare arrangement of the cationic groups in the polymer chain in the latter there are long stretches without ionic groups, which form a non-covalent link with the surface of colloidal particles of PGH. Formed PAC, composed of positively charged groups, has a high affinity for negatively charged surface of silica, part of the terrigenous rocks. The consequence of this is the increased adhesion of the structured gel to the breed, about ulavlivaya its resistance to leaching from cracks and pores of the formation.

Example 1. In this example, due to the impact of polyelectrolyte on its adsorption properties with respect to silica. As the material containing silica (SiO2use quartz sand, specially treated by the method of [Persianas M.N., Kabirov M.M., Senchenkova LE EOR heterogeneous reservoirs. Orenburg. Orenburg book publishing house. 1999] and fractionated (0,30-0,40 μm).

The polymer solutions of different concentrations in a volume of 100 cm3poured into a conical flask with 20 g of quartz sand and placed on the shaker.

Periodically from the flasks take samples of the solutions to lighten the centrifuge (n=6000-1and measure viscosity by capillary viscometer. The samples are selected to the constant value of viscosity, i.e. before the onset of static adsorption equilibrium. Pre-build the calibration graphs of the dependence of viscosity on concentration for each participant copolymer. Based on these graphs determine the residual concentration of polymer in the solution after adsorption and adsorption value:

where a is the index of the polymer adsorption, mg/g;

Withabout- initial concentration of polymer, g/DL;

C - concentration after adsorption, g/DL;

V - volume of solution, l;

m is the mass of quartz sand,

In the drawing, not only the t dependence of adsorption on the concentration of polymers in solution: 1 - Praestol 851BC, 2 - PAA, 3 - Superfloc/V 300 LMW, from which it follows that the maximum rate of adsorption and limit its value has laboratiory copolymer Praestol 851 sun. Nonionic same PAA and anion active Superfloc/V 300 LMW significantly inferior in adsorption properties.

Example 2. In this example, due to the effect of the concentration of SKA in the composition at its waterproofing properties. As SCPA used Praestol 851BC having high molecular weight and a small cationic charge +6,9 mol.%. As the reservoir model using quartz sand, prepared according to example 1, fall asleep on the porous bottom of a glass column with a shirt, heated from an external thermostat.

In a column on silica sand is poured a solution of the composition in the amount of 1 pore volume bulk model and incubated at a given temperature until the formation of gel in the entire volume of the model. To determine the time of gelation in parallel in a glass tube heated similar in composition, recording visually (on the loss of fluidity) the moment of transition of the solution into the gel. After the formation of the gel in the column from top to supply water from the dropping funnel, while maintaining it at a constant level above the surface of the sand, at the same time taking away the water from the bottom of the column in the measuring cylinder.

As the main parameter, which measures Vaudoise azione model properties, the treated composition, use permeability.

The permeability coefficient:

where Q is the flow rate of water passing through the bulk model (m3·with-1);

L - height of the layer model (m);

µ is the viscosity of water (PA·s);

Δp is the pressure drop in the model layer (PA);

S is a sectional area of the bulk model (m2).

The effect of waterproofing calculated by the formula:, %

where ko- permeability model in the initial state (μm2);

ko- the same, after processing composition (μm2).

Table 1
The effect of the concentration of SKA (Praestol 851 SC) in the composition, the effect of waterproofing. The ratio of PGA:CA=1:1 (wt.), temperature 80°C
No. p.pThe concentration of SKA, wt.%Filtration rate, cm3/sk pronic. (μm2)W %
20,050,134 10,7033,00

From table 1 it follows that the resistance of the filtration of water through the treated composition model depends on the amount of polymer in the composition, which is associated with the number of PAC formed from this polymer. The maximum reduction in the rate of water infiltration corresponds to the concentration of SKA in a solution of 0.2 wt.% above.

Example 3. In this example due to the influence of the number of PGA in the composition, as the source of the dispersed phase in obrazem the gel, providing resistance to filtration of water through the formation model. The experience carried out analogously to example 2, using the 0.2%solution Praestol US, preparing the composition with various content of PGA, as shown in table 2.

Table 2
The effect of the concentration of PGA in the composition, the effect of waterproofing. The concentration of Praestol VS - 0.2 wt.%, the ratio of PGA:CA=1:1 (wt.), temperature 80°C
No. p.pThe concentration of PGA, wt.%Filtration rate, cm3/sk pronic. (μm2)W %
24,00,041with 3.2770,50
46,01,2·10-4 0,0199,99

As follows from the data of table 2, the filtration rate of water significantly decreases with the increasing content of PGA in the composition, and at a concentration of 6.0% or more filtering is completely stopped.

Example 4. In this example due to the influence of temperature and mass ratio (PGHA:KA) on the gelation time (transition time of a solution of the composition in a gel state). In the experiment, the calculated sample PGHA and KA corresponding to the specified relationship (table 3), is loaded into a glass test tube, add 0.2%solution Praestol 851BC. The contents of the tubes are heated in a thermostat at a predetermined temperature, fixing the time of gel formation by loss of yield.

Table 3
The influence of the ratio of PGA:KA and temperature on the gelation time. The concentration of PGA to 6.0 wt.%
No. p.pThe ratio of PGA:KA, wt.The gelation time at temperature (hours) °C
the 6570758085
21:0,542,016,0to 12.06,55,0
61:4to 12.05,02,11,8

From table 3 it follows that the gelation time is determined by the temperature and depends on the number gidrolizuemye agent is urea. Thus, for each temperature in situ is possible by selection of the ratio of PGA:AC to select the desired process time for delivery of the composition in a given interval of the formation.

Example 5. In this example due to the influence of the type of polyelectrolyte on the possibility of formation of soluble PAC and waterproofing properties obtained on the basis of a structured gel. As water-soluble polymers used are copolymers of acrylamide with cation - and anion active the comonomers in the form of commercial products series Praestol, Organopol, Zetag, Superfloc and nonionic polyacrylamide and 100%poly-KF - 99. The experiment is carried out by analogy with example 2, using the 0.2%solution of the polymer at the concentration of PGA 4.0 wt.%, the ratio of PGA=2:1 (wt.) and a temperature of 80°C.

Table 4
The influence of the form of water-soluble polymer on the formation of the polymer-colloid complex and waterproofing properties of the gel based on it
No. p.pType of polymerThe content of cationic groups, mol.%Education polymercontaining complexFiltration rate, cm3/sk pronic. (µm)W %
1Pure SiO2--0,13911,100,00
2Gel PGA--0,0282,2280,00
3PAA (prototype)0formed soluble0,0090,7293,50
4Organopol 6400+1,65formed soluble1,4·10-40,0199,99
5Organopol 6405 +2,94formed soluble1,3·10-40,0199,99
6Praestol VS+6,52formed soluble1,4·10-40,0199,99
7Praestol 851BC+6,90formed soluble1,3·10-40,0199,99
8Zetag 92+9,20formed soluble1,4·10-41,1289,80
9Praestol 650+19,20not formed0,0201,13or roughly 85.60
10KF-99+100,0not formed0,03078,30
11Praestol 2500-1,10formed partially0,0120,9691,35
12Superfloc N-300-3,73insoluble0,0251,92at 82.70

From table 4 it follows that the anion active copolymers (11 and 12) form insoluble polymer-colloid complexes falling out of solution prior to gelation process, resulting in the hydrolysis in the presence of urea is formed amphoteric gel of aluminum hydroxide with a low effect of waterproofing on the level of PGA and PAA (2 and 3). The polymer-colloid complexes on the basis of kationaktivnaya copolymers are formed up to a certain limit of the content of cationic groups (6,9 mol.%), above which the complexes are not formed because of the strong electrostatic otalgia the Oia between the positively charged colloidal particles of PGA and macromolecules of polycationic. Arise in this case, hydrolysis of the gel is a mechanical mixture of amphoteric gel of aluminum hydroxide and a solution of a copolymer with low waterproofing properties (8, 9, 10). Copolymers with a low content of cationic groups (4-7) form a stable soluble polymer-colloid complexes with colloidal particles of PGA, which upon hydrolysis of the urea give structured gels with high waterproofing properties. The permeability of the saturated model treated with such compositions is reduced by more than 1000 times, resulting in locking the effect of such compositions, when filtering water almost stops. The positive point is also quite a wide range suitable for these purposes, commercial copolymers with a low content of cationic groups.

The way to isolate water production to producing oil wells, including injection of the gel-forming composition obtained by mixing pentahydrochloride aluminum, urea and an aqueous solution of polymer, and mixing is carried out by injection of urea in polymer-colloid complex obtained by mixing aqueous colloidal solution of pentahydrochloride aluminum of 0.2-0.3 wt.%-tion aqueous solution of the polymer, characterized in that the polymer used sebesar is defined cationic polyelectrolyte with a molecular mass of 6·10 6-20·106and cationic groups from 1.65 to 9.20 mol.%.


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SUBSTANCE: fluid for treatment of wells contains a water-based liquid, a crosslinking agent and a gel-forming agent, containing a crosslinked polymer and a non-crosslinked biopolymer, where a molecule of the latter consists only of glucose or has the main chain, comprising a glucose link and a linear or cyclic monosaccharide link of the specified type, and ratio of a biopolymer to a crosslinked polymer makes 0.05-1:1. The method for treatment of a part of an underground bed includes provision of the above-specified liquid and its injection into a well shaft that penetrates into an underground bed. The above-specified method, where the liquid for treatment comprises a crosslinked polymer and diutan with diutan ratio to crosslinked polymer equal to 0.05-1:1.

EFFECT: improved rheological properties and temperature stability of gel-forming agents.

21 cl, 3 ex, 3 tbl, 4 dwg

FIELD: chemistry.

SUBSTANCE: anti-agglomerates are surface-active non-quaternary nitrogen-containing compounds with 1-5 nitrogen atoms, which have at least one hydrophobic group with 6-24 carbon atoms, and where the hydrophobic group is bonded to the remainder of the molecule by an amine moiety, an ether moiety or an amide moiety, provided that when the hydrophobic group is bonded by an amide moiety to the remainder of the molecule, the compounds must contain a total of at least two nitrogen atoms, and optionally contain 1-12 -CH2CH2O- groups and/or 1-6 hydroxyalkyl groups with 3-4 carbon atoms; and compounds having at least one C2-C3 acyl group and/or at least one hydroxyalkyl group with 3-4 carbon atoms; or a salt thereof. The method of inhibiting agglomeration of gaseous hydrates in a conduit, containing a fluid mixture which contains hydrocarbons with 1-4 carbon atoms and water, involves adding to the mixture said agglomerate in amount of 0.05-10% of the content of water in the fluid mixture. The composition contains said anti-agglomerate of gaseous hydrates, a corrosion inhibitor and/or a paraffin deposition inhibitor.

EFFECT: high efficiency of the anti-agglomerate for gaseous hydrates and biodegradability thereof.

9 cl, 2 ex, 2 tbl

FIELD: gas and oil production.

SUBSTANCE: quick-setting spacer mix for water and gas flow insulation in low-temperature oil and gas wells, including carbamide-formaldehyde resin, acid solidifier, barite and water, with 2% aqueous solution of nitryltrimethylphosphonic acid as acid solidifier, at the following component ratio, wt %: carbamide-fimraldehyde resin 45.0-50.0, 2% aqueous solution of nitryltrimethylphosphonic acid 2.5-4.5, barite 40.0-49.0, the rest is water. The invention is developed in dependent points of formula.

EFFECT: reduced gas permeability, increased oil recovery from beds, intensified oil production.

3 cl, 2 ex, 1 tbl

FIELD: gas and oil production.

SUBSTANCE: invention refers to structured spacer fluids with adjustable density, applied in separation of backfilling and drilling slurry of different composition and density and in efficient displacement of drilling slurry from well cementing interval with abnormally high bed pressure (AHBP). Complex powder composition for structured spacer fluid preparation includes, wt %: the rest is lignin-alkaline agent of fraction composition, % at mesh sieve: N 0.9 - 2.12; N 0.315 - 22.35; N 0.08 - 34.10, N 0.08 and others are the rest; 80.0-85.0, carboxymethyl cellulose 15.0-20.0, nitrylotrimethylphosphonic acid 0.01- 0.15 above 100%.

EFFECT: increased quality of well bore preparation for cementing, improved cement contact with string and rock, bed separation quality in wells with AHBP.

1 ex, 1 tbl

FIELD: chemistry.

SUBSTANCE: invention relates to chemical engineering and specifically to methods of recycling monochloroacetic acid production wastes, used in production of carboxymethyl cellulose, pharmaceutical preparations, pesticides and ethylene diamine tetraacetic acid. Methods of recycling monochloroacetic acid production wastes involve treating the mother solution obtained from purifying monochloroacetic acid, wherein treatment is carried out by neutralising the mother solution with 30-44% aqueous sodium hydroxide solution at temperature 40-45°C until achieving pH 7-7.5, followed by reaction of the reaction mixture with 25% aqueous ammonia solution in molar ratio of monochloroacetic acid to ammonia equal to 1:1.39-1.46 until achieving pH 8.5-9, with step-wise increase in temperature, first to 50-70°C for 2-3 hours, maintaining pH of the mixture by adding 30% aqueous sodium hydroxide solution, and then to 80-105°C for 1-2 hours, followed by cooling and, if necessary, followed by neutralisation of the reaction mixture with hydrochloric acid at temperature 15-60°C for 0.5-2 hours until pH of the mixture equals 1.

EFFECT: recycling monochloroacetic acid production wastes using a simple, non-waste method to obtain a commercial-grade, mixed reagent for preventing deposits of inorganic salts during oil and gas extraction.

2 cl, 2 tbl, 12 ex

FIELD: gas and oil production.

SUBSTANCE: according to procedure for preparation of light-weight magnesium-silicate propping agent including heat treatment of magnesium containing component - source of magnesium oxide, combined mixture with silica-containing component, granulation of produced charge, produced granules roasting and their spread, charge contains (in terms of calcinated substance) wt %: SiO2 64-72, MgO 11-18, natural additives - the rest. Heat treatment is performed at temperature not over 1080°C. The distinguished feature of this light weight magnesium-silicate propping agent is its production by means of the above said procedure. The invention is developed in dependent points of formula.

EFFECT: reduced loose weight of propping agent at simultaneous increased strength, and increased strength of granules-raw product.

8 cl, 2 ex, 1 tbl

FIELD: production and exploratory well drilling, particularly foaming drilling fluids used during penetration through incompetent rock intervals and during primary productive oil and gas deposit opening in the case of abnormally low formation pressure.

SUBSTANCE: foam composition comprises surfactant, foam stabilizer, water, water hardness control additive and lubricant. The water hardness control additive is sodium silicate. The lubricant is VNIINP-117 emulsion. The foam stabilizer is polyacrylamide, the surfactant is sulphonole. All above components are taken in the following amounts (% by weight): sulphonole - 0.8-1.5, sodium silicate - 0.2-0.5, polyacrylamide - 0.1-0.5, VNIINP-117 - 0.5-2, remainder is water.

EFFECT: reduced power inputs for well drilling, as well as reduced coefficient of friction between drilling tool and well wall.

1 tbl