Solid reagent for acid treatment of well and process of acid treatment of well, preferably water-supply well

FIELD: mining industry.

SUBSTANCE: invention preferably relates to treatment of water-supply wells exposing sand producing formation and producing drinking, mineral, and industrial waters, mineral solutions, etc. Solid reagent used in this operation contains 37.5-73.2% of nitric acid/urea reaction product and 24.4-61.5% of oxygen-containing sulfur compound, the rest being sodium polyphosphate. Process solution, which is 10-30% solution of above-indicated solid reagent, is supplied to well provided with filter descended by means of tubing string, injected into formation through reagent conduit, and held in formation during a certain time, after which the well is pumped through. When process solution is held in formation, it is made to reciprocate with the aid of compressed air periodically injected to pressure-sealed wellbore, after which wellbore is depressurized. During the period of time when compressed air is injected, level of fluid in wellbore is lowered below static level at a distance not exceeding length of filter and time point when fluid reaches lower end of the filter is recorded. When this time point is stabilized, reciprocation of process solution is ended. When performing subsequent pumping of well, specific electrical resistance value of fluid pumped out of well is also measured and, when this value approaches or attains the value of specific electrical resistance of the formation fluid, pumping is terminated.

EFFECT: increased dissolving capacity of solid reagent for dehydrated ferruginous mudding deposits and prevented subsequent deposition thereof within near-filter zone, enhanced treatment efficiency due to increased permeability near-filter zone of formation, and intensified dissolution of mudding deposits.

6 cl, 6 tbl, 2 ex

 

The invention relates to the mining industry, namely the solid reagents for acid treatment of the well and to methods of its use for the treatment of wells, mostly water, revealing a sandy reservoir and production from this reservoir of drinking, mineral, industrial water, mineral solutions, etc. and can be used to stimulate the flow of useful formation fluid from the reservoir composed of sandy rocks, including the inclusion of carbonates. The invention can be used in municipal, agricultural, and oil and gas industry on water supply on the basis of groundwater and other

Currently, the vast majority of acid treatment of wells using the reagents in the liquid phase, of which technological (working) solutions prepared directly at the wellhead or in the factory. In commercial practice, there are many ways to handle wells that involves injection into the well of various technological solutions prepared on the basis of acid reagents, including substances of organic and inorganic origin (U.S. Patent№4280560, 4519455, 4531586, 4553597, 4560003, 3374835, 3915233, 3946883 and others).

However, in the preparation of process solutions in the liquid phase directly to the public at the wells you want to use a large amount of equipment. Complexity arises with the dosage, the exact observance of which depends on the qualification of the staff. There is a probability of unproductive losses of a number of components (due to large volumes of acidic compounds on the well is quite difficult to put components in a quantity required by the recipe, usually, because of the nature of packing, the number of components is in excess, which leads to unjustified losses).

Preparation of liquid acid compositions in the factory eliminates the above disadvantages, but leads to increased costs in the transport and storage of such composition due to the presence of ballast - water.

This implies a need to use when acid treatment reagents in the solid phase, which can be prepared in the factory and who would not lose their active properties during storage and transport.

Known composition for the acid treatment of wells, a basis which contains the product of the interaction of nitric acid with urea and sodium nitrite (Ed. the certificate of USSR No. 1739014, CL EV 43/27, 1989).

However, this known structure is designed to remove sediment deposits and may be chemically treated (dissolve) the materials composing the carbonate reservoir. The aluminosilicates and Arcevia materials, included in the composition of terrigenous reservoir, the above-mentioned known composition to dissolve can't. He is also not effective when dissolved clay mudding.

Closest to the proposed technical solution - solid reagent to the technical essence and purpose is a solid reagent is a solid Foundation stock for the acid treatment of wells containing the product of the interaction of nitric acid with urea and supplements: the product of the interaction of tertiary amines with hydrogen peroxide complex of cationic surface-active agent (surfactant), organic derivatives of phosphonic acid and nitrogen-containing corrosion inhibitor (Patent RF №2257467, CL EV 43/27, 2004).

Technological solutions (i.e. aqueous solutions) of the specified well-known solid reagent showed high efficiency when used in carbonate reservoirs, however, with terrigenous indicators for the dissolution of the latter is very low. And considering, for example, that water wells in the bulk drilled in sand (i.e. terrigenous) collectors, the efficiency of the acid exposure to a known reagent is insufficient. In addition, technological solutions known solid reagent does not ensure complete dissolution digidrirovanny glandular is x clogging formations wells continuous operation (more than 3-5 years).

The known method the acid treatment of wells, according to which have pumped into the well of the technological solution, which is an aqueous solution of the solid reagent, which consists of the product of the interaction of nitric acid with urea and sodium nitrite (Ed. the certificate of USSR No. 1739014, CL EV 43/27, 1989).

However, this known method is not universal, as it is only intended for use in oil wells to remove paraffin deposits and is inefficient for water wells, in which there are digidrirovannye glandular clogging of education.

Known methods of acid water wells, including injection of a solution of sulfamic acid, prepared by dissolving its granules in water, extract it into the reservoir and subsequent pumping wells (Jonson E.E. Ground Water and Wells. Fitst Edition. Saint Paul, Minnisota. 1966, 440 p.; Auth. the certificate of USSR No. 314883, CL EV 43/27, 1966).

These known methods do not provide complete dissolution digidrirovanny glandular clogging formations wells, continuous operation (more than 3-5 years).

Also there is a method of acid treatment of wells, including injection into the well of a solution of a weak acid(acetic acid, citric, tartaric, Teterboro) with dissociation constant Kd=10-3the extract solution under pressure for 10-48 hours, subsequent pumping of wells for removal of acid solution and its reaction products, the subsequent injection of a solution of potassium bicarbonate, or potassium hypochlorite, or mixtures thereof, the alkaline extract solution for 1-36 hours with the final pumping the well to remove the alkaline solution and its reaction products (U.S. Patent No. 4541488).

The disadvantages of this method include the possibility of secondary deposition already dissolved clogging formations in the first stage acid treatment, incomplete dissolution digidrirovanny glandular clogging formations wells, continuous operation (more than 3-5 years), and the absence of reasonable criteria for determining the end time of the treatment wells. The latter is based on the duration of interaction between technological solution with clogging formations. When there is insufficient time processing of borehole permeability of the treated area, as practice shows, not fully recovered, leading to a lack of recovery well performance. The excessive processing time of the well itself uneconomical, negatively affects to nstructive elements well and can lead under certain conditions to reduce the permeability of the treated area of the reservoir due to secondary formation of various kinds of rigid and semi-rigid connections.

The known method of chemical treatment of wells, including injection into the well of a solution of the salt of a strong acid, heating the solution in the filter well and the subsequent pumping of wells (Ed. the certificate in No. 610980, CL EV 43/27, 1975).

However, this known method does not provide complete removal of clogging formations in the reservoir at low (4-8° (C) reservoir temperatures due to insufficient warm-up kolmat prefiltrov zone, due to the method of heating (in the filter well). For example, during warm-up of the solution in the filter well at 80°above the temperature of formation waters in prefiltrov zone at a distance of 220 mm from the wall of the filter temperature increase is not fixed (the Dissertation on competition of a scientific degree of candidate of engineering science Tarabanov PV Termoneeny regeneration wells. - M., 1986, C, RES).

Closest to the proposed invention the technical essence is the way the acid treatment of wells, mostly water, including flow in the well equipped lowered on tubing (tubing) filter, and the injection of the preheated first process solution is an aqueous solution of sodium polyphosphates concentration of 1-3% and the subsequent injection prefiltrov zone preheated second those of the ideological solution an aqueous solution of sodium polyphosphates (0,05-0,1%concentration), and salts of strong acids (10-12%concentration), and then create a reciprocating motion of the technological solution in the treated area for 4-6 hours and keep it in the reservoir for 8-12 hours (Patent RF №2042802, CL EV 43/27, 1992).

The disadvantages of this known method are the lack of increase in the degree of dissolution digidrirovanny clogging formations, lack of regulatory operations, allowing to determine sufficient processing time borehole and pumping after treatment. In addition, used in the known method process operation for heating process fluids before being injected into the reservoir is very time consuming and does not provide sufficient warming prefiltrov zone of the reservoir due to the short duration of action of the generated effect. All these drawbacks reduce the effectiveness of acid treatment.

In the claimed invention is a solid reagent for acid treatment of wells, the aim was to increase its dissolving ability in relation digidrirovanny glandular clogging formations and secondary prevention of their loss in prefiltrov zone, while ensuring a high dissolving ability in respect to the NII as glandular, and clay clogging formations.

Additional technical result is the preservation of adaptability and stability of the solid reagent in a long time.

To solve this problem is proposed solid reagent for acid treatment of wells, comprising the product of the interaction of nitric acid with urea and additives, the additives it contains oxygen-containing sulfur and sodium polyphosphate in the following ratio, wt.%:

the product of the interaction of nitric acid with urea37,5-73,2
the oxygen-containing sulfur compound24,4-61,5
polyphosphate sodium100

As a product of the interaction of nitric acid with urea it contains nitrate of urea in the form of ammonium salt of CO(NH2)2·HNO3and/or oxanabol salt (NH2)2CO·HNO3.

As the oxygen-containing sulfur compounds it contains sodium bisulfate aqueous NaHSO4·N2Oh, and/or sodium pyrosulfite Na2S2O7and/or the potassium pyrosulfite To2S2About7and/or the ammonium peroxodisulfate (NH4)2S2O8.

As polyphosphate on the model it contains sodium tripolyphosphate, Na 5P3About10and/or sodium hexametaphosphate (NaPO3)6.

In the claimed invention is a method of acid treatment of wells, mostly water, the aim was to improve processing efficiency by increasing the permeability kolmat prefiltrov the reservoir area, the intensification of the process of dissolution of clogging formations, secondary prevention of loss of dissolved clogging formations in prefiltrov area while ensuring optimum sufficient processing time well.

Additional results provided by the claimed method, is to reduce the complexity, cost and improving industrial hygiene.

The problem is solved by the proposed method, the acid treatment of wells, mostly water, providing for the supply of process solution in the well equipped lowered on tubing filter, its injection into the reservoir, the shutter speed in the reservoir and the subsequent pumping of wells, while the new is the fact that as a technological solution using 10-30%aqueous solution of solid reagent containing in wt.%:

the product of the interaction of nitric acid with CT is amidon 37,5-73,2
the oxygen-containing sulfur compound24,4-61,5
polyphosphate sodium100

as the injection process solution is produced by reagentnogo, then when the shutter speed in the reservoir creates a reciprocating motion of the technological solution by periodic supply of compressed air in a sealed wellbore with subsequent depressurization, and when the specified compressed air fluid level in the wellbore reduces below the static level at the distance not exceeding the length of the filter, fixing the time of promotion fluid to the lower end of the filter, and when stabilization of the mentioned indicator reciprocating motion of the technological solution is stopped, and the subsequent pumping of wells additionally measure the value of the specific electrical resistance pumped from the well fluid and when we achieve this by values close or equal to the value of the specific electrical resistance of the formation fluid, the pumping ceased.

Before applying technological solution in the well last supply level sensors, which are placed at a depth of static water level in the well and on the lower level to the NCA filter.

The proposed solution is based on the revealed regularities of formation of clogging formations in wells when drilling and operation, established the fact of the influence on the intensity of the destruction and dissolution of clogging formations, thermodynamic, redox conditions and pH in prefiltrov the well area.

To understand the substance of the question it should be clear that in the construction of wells in sedimentary rocks rotational method is the clogging of the pore space prefiltrov zone clay colloid-dispersed particles, resulting in lower productivity wells. The composition of the clay clogging formations is defined as the composition of the actual washing liquid, and the composition formed during the drilling of natural clay mud. Enrichment mud clogging particles occurs not only when the roof of the productive formation strata of clay, but also in the presence of the reservoir interlayers of clay (with a capacity of from 0.5 to 3 m).

In the study of colmatage processes established that during drilling using as a wash liquid natural and mud density more than 1050 kg/m3the sizes of the zones of intensive sedimentation in the General case, the e exceed 150 mm When used as drilling fluid low concentrated suspensions (less than 1050 kg/m3), which is typical for the opening of the aquifer with the replacement of the washing liquid to clean water, the size of the sedimentation zone does not exceed 1 meter. The subsequent construction of the pumping wells, which produce the pumping fluid contributes substantially to remove clay clogging formations (at least 30-40% by weight), and in practical calculations for these conditions into account may be taken of the size of the sedimentation zone is not more than 0.5 m But the specified construction pumping well does not ensure the full removal of clay formations of prefiltrov zone, which significantly reduces the potential wells.

During well operation the selection process of formation fluids is accompanied hydrodynamic disturbance in prefiltrov area that leads to the violation of the chemical equilibrium state of the main components of the fluid and to the loss of inorganic compounds, clogging of the pore space. Mineral composition of these formations are represented by limonite FeOOH, gidrogenit FeOOH·ag, hydrogenation Fe2O3·ag, siderite FeCO3, pyrrhotite FeS, calcite, caso3and other Practices found that the extraction of groundwater in part to matroushi formations dominated by glandular component (up to 70% by weight).

Formed polymineral compounds fill the pore space adsorbed on delayed when drilling shale formations, which leads to the reduction of the first space:

n=n0-b

where n is the current porosity, n0- initial porosity, b is the specific volume of clogging of the entities forming the saturation of the pore space clogging formations and the reduction of the initial filtration coefficient prefiltrov zone:

,

where k is the current coefficient of permeability, k0- initial filtration coefficient, α - saturation of the pore space clogging units, m is the exponent (m=2,8-3,3).

Research has shown that the size of the intensive zone sedimentation for these conditions for gravel-wire filters are limited by the size of gravel package for filters block designs and gravel-adhesive filter thickness filter unit, and a mesh filters, in General, not exceed 20 mm

During the beginning steps of colmatage processes formed loose sediments visco-plastic consistency with a water-colloidal links. These sediments are easily dissolved when in contact with solvents. In the process of diagenesis clogging compounds water-colloidal communications market is lo-plastic formations are replaced by crystallization, resulting in the filter and in prefiltrov area of a dense glandular digidrirovanny cement fouling, filling the pore space.

Oxygen-containing sulfur compounds included in the formulation of the inventive solid reagent interact with glandular dehydrated clogging formations as follows.

For sodium bisulfate aqueous NaHSO4×N2O. When it is dissolved in water hydrolysis of salt and water as follows:

NaHSO4×N2About→NaHSO4+H2About;

NaHSO4↔Na++HSO4-;

HSO4-↔N++SO42-;

H2O↔2H++HE-;

SO42-+2N+↔H2SO4(acidic environment).

Formed in the acidic action of the dissolution occurs glandular clogging formations according to the following equations:

Fe2About3·ag+6H+→2Fe3++3H2About;

FeO·ag+6H+→2Fe2++H2O;

FeS+2H+→Fe2++H2S↑.

For the sodium of persulfate Na2S2O7. When it is dissolved in water hydrolysis of salt and water as follows:

Na2S2O7+H2O→2NaHSO4.

For potassium pyrosulphate K2S2O7 . When it is dissolved in water, hydrolysis of salts similar to the hydrolysis of sodium salt.

For persulfate ammonium (NH4)2S2O8. By dissolving ammonium persulfate in water hydrolysis of salt and a peroxide according to the following reaction scheme:

(NH4)2S2O8↔(NH4)2SO4+H2O2.

Released during the reaction the hydrogen peroxide destroys clay clogging of education, effectively dispersive them.

Then there is the dissolution of ferrous compounds in the above reactions.

At the same time the dissolution of ferrous compounds through oxidation-reduction process:

FeO·ag+S2O8-+e→Fe3++2SO42-;

FeS+S2O8-+e→Fe3++2SO42-+S2-.

Here in the acidic environment of trivalent iron is in the form of ions. In the presence of hydrogen sulfide released the interaction of ammonium hydroxide with hydrogen sulfide according to the following equation, as well as the oxidation of hydrogen sulfide by hydrogen peroxide:

NH4OH+H2S→(NH4)2S+2H2O;

H2S+H2O2→SO2+H2O.

This prevents the hydrogen sulphide in the processing of wells.

One who temporarily when dissolved in water the product of the interaction of nitric acid with urea is the release of free nitric acid and urea:

CO(NH2)2HNO3=CO(NH2)2+HNO3.

In aqueous solution, the dissociation of nitric acid is accompanied by the release of a proton, and simplistically, you can write:

HNO3↔N++NO3-.

Then there is the dissolution of ferrous carbonate and clogging of the compounds according to the following equations:

Fe2About3·ag+6H+→Fe3++3H2O;

FeO·ag+6H+→Fe2++H2O;

FeS+2H+→Fe2++H2S↑;

FeCO3+2H+→Fe2++H2O+CO2↑;

CaCO3+2H+→Ca2++H2O+CO2↑;

MgCO3+2H+→Ca2++H2O+CO2↑.

Introduction to solution within the stated ratios of sodium polyphosphate (sodium tripolyphosphate and/or sodium hexametaphosphate) stabilizes aqueous solution by preventing secondary deposition of salts at low concentrations. The stabilizing effect of such additives offer is associated with adsorption processes: phosphate anions adsorbed on the buds or growing crystals that block the active centers and thereby prevent the deposition of salts in the sediment. This property is used to prevent coagulation already dissolved clogging entities in solution. Due to the above-mentioned chemical and f is Zico-chemical processes and ensures the achievement of a technical result.

The present invention may also be used in injection wells (oil and gas), as in current commercial practice for flooding of productive reservoir to maintain reservoir pressure using surface and underground water, passing the waste water or various mixtures. As a rule, in the fields of the missing high-performance filtration equipment for the treatment of injected water from the suspension, which determines the clogging of the perforated well bore area and decrease of injection wells. For injection into productive reservoirs of river waters the main components of clogging formations are the oxides and hydroxides of polyvalent metals, clay mineral (78%) and partly of organic matter. The presence of iron, nitrobacteria and sulfate-reducing bacteria in river waters additionally leads to the formation of mucous glandular biobrane and yazvennah corrosion of the metal in the injection conduit. When the injection into the injection well bottom water in the composition of the injected water solids content varies widely (from 3.5 to 10.0 mg/l), and up to 90% mechanical impurities has a size in the range of 1-4 microns. As a rule, in the mineral content of mechanical impurities prevail guide the iron oxides (corrosion products). For injection into injection wells underground water main clogging substance is ferrous compounds, formed as part of the injected water as a result of the displacement of the equilibrium state of Fe2+due to changes of temperature, pressure and hydrodynamic perturbations. Advanced corrosion processes in hardware form solids, entirely represented by iron oxides in the most varied form.

Offer solid reagent for acid treatment of wells was prepared and tested in laboratory conditions. For its preparation were used the following substances:

the product of the interaction of nitric acid with urea - crystalline powder from white to gray in color, produced according to TU 27081564.042-98 under the trademark "Nitrol, characterized by the mass fraction of acids in terms of nitric acid of at least 46%, mass fraction of moisture 5-8%;

- oxygen-sulfur compounds:

-- sodium bisulfate aqueous NaHSO4×N2About GOST 6053-77;

-- sodium pyrosulfite Na2S2O7on 18344-78;

-- the potassium pyrosulfite K2S2O7according to GOST 7172-76;

-- the ammonium peroxodisulfate (NH4)2S7O8according to GOST 20478-75;

- polyphosphates sodium:

-- sodium tripolyphosphate, Na5P3O10on THE other 2148-037-00194441-02, the OST 13493-86;

-- sodium hexametaphosphate (sodium polyphosphate technical NaPO3)6according to GOST 20291-80.

For use as process water solution when implementing the proposed method used:

- water technical.

The inventive solid reagent was prepared as follows.

Example. To obtain the claimed solid reagent in the laboratory took 56 g Nitrol and was added 40 g of sodium bisulfate, water and 4 g of sodium tripolyphosphate, the dry mixture was stirred and got a solid reagent of the following composition, wt.%: Nitrol - 56; sodium bisulfate water - 40; sodium tripolyphosphate - 4. For the preparation of the obtained solid reagent technological solution took 12.5 g of the specified solid reagent and dissolved it in to 87.5 g of water, obtaining a solution of 12.5%concentration.

Solid reagents and technological solutions on their basis with other content components was prepared in the same way.

In laboratory tests was determined by dissolving ability of technological solution prepared by dissolving the solid reagent in water, in relation to cemented digidrirovanny glandular formations selected from prefiltrov area well # 34 Zamoskvoretskaya drainage. According to analyses of the chemical composition of precipitation - formations selected from prefiltrov zone specified wells, represented by the following components (wt.%): Fe2About3- 73,02; FeO - 3,66; Al2About3- 0,18; MgO - 0,14; CaO - 3,15; SiO2- 0,12; MnO - 0,15. Loss on ignition are 19,58%. The mineral composition of these formations are represented by limonite FeOOH, goethite α-FeO(OH), calcite, caso3polymorphic quartz and illite.

During the experiments the samples clogging formations were placed in the studied technological solution was subjected to shaking for shuttel-apparatus for 30 minutes at a temperature of 20°and was determined in the filtrate dissolved iron by colorimetric method (ΔFe1). The residual iron content in the sample was determined by secondary processing of the sample is heated with concentrated hydrochloric acid (37%) for 30 minutes. In the secondary filtrate was also measured the concentrations of dissolved iron (ΔFe2and dissolving ability was evaluated as the ratio of the concentrations of dissolved iron after processing technological solution to the total concentration of dissolved iron after two treatments.

Determination of the optimal ratio between the components of the proposed solid reagent, and the optimal concentration of the solid reagent in the technological solution was carried out in accordance with known methods (see chrushing L.P., Slobodchikov RI. Planning experiment in chemistry and chemical technology. - M, Chemistry, 1980. - A series of Chemical Cybernetics". - 280 C.). The results of the experiments are presented in table 1.

As can be seen from the presented data, the dissolving ability of the glandular clogging formations reaches a plateau when the claimed limits of the components of the solid reagent.

Reduction of the concentration of components in comparison with the claimed concentrations does not provide the maximum possible dissolution of clogging compounds (experiments # 7 and 8), and their increase does not improve the efficiency of the dissolution process.

The presence in the technological solution obtained from the proposed solid reagent, nitrol - product of the interaction of nitric acid with urea, provides for the dissolution of carbonate compounds, excepting the decarbonisation of the oxygen-containing sulfur compounds.

An important property of the technological solution, obtained from the developed solid reagent is its high damaging ability coagulation contacts between clay aggregates, filling the pore space of the reservoir, and the leaching of silicates, forming the skeleton of clay minerals. As a result of this clay clogging of education go into p the lithium phase and are easily removed during the pumping wells.

Solving the above technical problem, provided the proposed method is achieved by the next.

On the basis of the basic theoretical concepts of kinetics of dissolution of salts in porous media, creating in the present method the reciprocating motion of the technological solutions in kolmat area significantly intensifies the process of dissolution of clogging formations. In the proposed method, this movement is generated by periodic supply of compressed air in a sealed wellbore with subsequent loss of pressure and fluid level in the wellbore decrease from the static level at the distance not exceeding the length of the filter that is controlled, for example, by means of level sensors, installed at a depth static level and the depth of the lower end of the filter.

The total duration of treatment of the well is determined by the kinetics of dissolution of clogging formations, hydrodynamic, temperature conditions of the process of dissolution and the initial permeability kolmat zone. Therefore, as a benchmark when the well treatment adopted permeability prefiltrov zone, depending, in turn, from the saturation of the pore space clogging education is I. Based on this operation, which allows to reliably and accurately determine enough time of creating the reciprocating motion of the solution in kolmat area of each well.

This operation, the proposed method is implemented as follows. When compressed air in the annulus is sealed borehole record the time of movement of the liquid level from the static level at the distance not exceeding the length of the filter (i.e. not below the lower end of the filter)that is controlled by level sensors. After that, well lasermedizin, the fluid level in the wellbore rises to static (or may just not be up to static, but only if by this time the curve recovery level at this depth appeared on the plateau), the well seal again and the cycle is repeated. When stabilization of the specified time push (time of movement from the static level to the lower end of the filter), fixed in each cycle, reciprocating movement of the stop solution. Stabilization of the measured time values indicates the maximum possible saturation of the pore space clogging formations in specific conditions and the feasibility of such termination the ode processing.

The usefulness of this kind of technological operations and its feasibility in the processing of wells proposed method is confirmed by the results of field experiments.

The proposed method was tested on three wells. This special minibarmirror of filter wells were selected fluid sample and determine its content of dissolved ferrous clogging formations (the concentration of dissolved iron). The results of the experiments are presented in table 2.

Table 2
Data on field testing of the proposed method
The processing time minWell No. 1Well No. 2Well No. 3
The movement of fluid from the static level to the lower end of the filterThe concentration of dissolved iron mg/lThe movement of fluid from the static level to the lower end of the filterThe concentration of dissolved iron mg/lThe movement of fluid from the static level to the lower end of the filterThe concentration of dissolved iron mg/l
0330 0,614920,155581,05
302763,284801,524143,09
602345,134502,48243with 4.64
902046,18305is 3.081865,42
1201686,703363,52150of 5.81
1501507,052943,68966,10
1801327,283123,95986,10
2101207,393523,85966,15
2401257,452343,97976,17
270120to 7.322224,05
3001237,382044,12
330 2004,08
3602024,11

As can be seen from the presented data, the stabilization time of the movement of the fluid level in the wellbore when the compressed air in the considered conditions corresponds to stabilize the concentration of dissolved clogging formations in this liquid to the fact that the almost complete dissolution of the technological solution of these clogging formations in the reservoir and the absence of further need for creating a reciprocating motion of the solution in the well.

To determine the duration of pumping wells after processing the value of the specific electrical resistance pumped from the well fluid were conducted three field experiments in which when pumping wells were measured electrical resistivity of the pumped liquid. The value of electrical resistivity of pure brine (is a useful reservoir fluid intake wells) consisted of 2,000 Ohms. The results of the experiments are presented in table 3.

Table 3
No.IndicatorsWell No. 1Well No. 2Well No. 3
1The flow of pumping fluid from a well, m3per hour10,98,913,0
2Electrical resistivity in the first fluid sample with pumping, MD6432130
3The commit time of the specific electrical resistance of 2000 Ohms at the pumped liquid through ..., h1310,56,5

After fixation, the samples of the pumped liquid volume of specific electric resistance of 2000 Ohms (or values close to it), which corresponds to the clean reservoir waters were selected water samples for analyses. The analysis is in full compliance indicators selected samples to net formation water. Thus, the above measurement values of electrical resistivity of the pumped fluid in the implementation of the proposed method can accurately and reliably determine the time of completion of the work.

Examples of specific implementation method.

The proposed method was tested on eleven boreholes intake of užupis. With the vazhiny captious aquifer, dedicated to Paleogene medium-grained Sands. The thickness of the aquifer is 13-18 m Wells drilled to a depth of 45-80 m rotational manner and equipped gravel-wire filters with a diameter of 245 mm Thickness of gravel package is 100-150 mm Groundwater composition hydrocarbonate sodium mineralization 0.5 g/l, and an iron content of from 0.5 to 1.5 mg/l Static groundwater level is at a depth of 8 meters

For the period of operation within 5-7 years specific production wells decreased to 19.4-43,1% relative to the initial value due to clogging of different formations. As part clogging formations in the reservoir is dominated by ferrous compounds (average 72%), calcium and magnesium are presented in small amounts. Polymineral composition clogging formations are mainly limonite, hydrogenation, montmorillonite, illite.

The size of the treated area were taken 0.5 m from the borehole wall when the porosity of the Sands of 20%. The technological solution for the well treatment adopted 3,4 m3.

Characteristics of the wells, which were tested by the inventive method, are given in table 4.

Table 4
is harakteristiki wells, which tested the inventive method
No. wellsDepth, mThe filter length, mThe specific flow rate, m3/(hour×m)
OriginalBefore processing by the claimed method
150107,21,4
254105,82,5
372127,72,4
478125,51,7
546105,61,8
662127,92,8
76812of 5.41,9
875127,02,4
948104,61,3
1055104,61,6
1168123,51,2

The composition of the solid reagent and the concentration cooked the C it technological solution, used in the implementation of the proposed method are presented in table 5.

Table 5
The composition of the solid reagent and the concentration prepared from it the technological solution used in the implementation of the proposed method on specific wells
Well number (from table 4)The ratio of components in the solid reagent, wt.%The concentration of the solid reagent in the technological solution, %
Oxygen-containing sulfur compoundsNitrolPolyphosphates sodium
160,237,52,315,5%
260,038,02,020,0%
331,763,54,8of 15.75%
434,163,82,123,5%
538,8to 58.13,125,8%
635,961,52,619,5%
752,243,54,323,0%/td>
824,472,33,320,75%
954,5of 40.94,622,0%
1041,955,82,321,5%
1137,051,911,113,5%

Example. As the object to illustrate the proposed method was chosen well No. 1, depth 50 meters Well equipped gravel-wire filter with a diameter of 245 mm and a length of 10 m Thickness of gravel package is 100-150 mm Static groundwater level is at a depth of 8 m the Life of the well 6 years. The initial specific flow rate, i.e. when the input wells in operation, was 7.2 m3/(hour×m), and before implementation of the proposed method - 1.4 m3/(hour×m). Electrical resistivity of reservoir fluid is pure water amounted to 2000 Ohms.

After disassembly of water-lifting equipment mounted readinterval, set the sensor threshold 8,15 m (0.15 m below the static level, because by this time the curve recovery level at this depth will hit a plateau, and for the release of the full static level will require at least another 30% of the total recovery time level that substantially the m will increase the processing time as well) and at the level of 18 m (corresponds to the lower end of the filter). Readinterval connected to sealing the wellhead to the end. The well seal and check compressed air leak. To tip well connect the compressor with a capacity of 6 m3/min, pump and discharge line.

The pump unit is prepared technological solution with a volume of 3.4 m3the next component content (wt.%): the sodium bisulfate water 9,3, nitrol 5,8, sodium tripolyphosphate, 0.4 and water - 84,5 (specified technological solution was prepared by making a 15.5%aqueous solution of solid reagent of the following composition, wt.%: the sodium bisulfate water - 60,2, nitrol - 37,5, sodium tripolyphosphate, and 2.3). For dissolution of the solid components of the reagent unit include in operation in the circulation mode. The electrical resistivity of the solution was 75 Ohms. Next, make the injection of the solution into the aquifer with flow injection 5.5 m3/hour.

Then in the well annulus serves compressed air and record the time of movement of the liquid level from 8.15 m to a depth of 18 m (installation place the bottom of the sensor). After that, well lasermedizin, the fluid level in the wellbore rises to a static, well seal again and the cycle is repeated. When stabilization of the mentioned indicator of time passing Jew the spine to the lower end of the filter, fixed in each cycle, reciprocating movement of the stop solution. Stabilization of the measured values of the time occurred after 5 hours of processing.

Then the well lasermedizin, purge the pump station compressed air for 30 minutes to disassemble the equipment for processing and mounted pumping equipment for pumping wells.

Next produce pumping the well to remove the products of the reaction solutions. In the process of leveling measure the electrical resistance of the pumped liquid. After 3.5 hours, pumping the value of the specific electrical resistance of the pumped liquid was 1955 Ohms, which is approximately equal to (near) the value of electric resistance of useful formation fluid is brine (≈2000 Ohms), and pumping wells ceased.

The yield after processing was determined equal to 6.1 m3/(hour×m), which is 85% of the original.

Similarly produced processing other wells. The results of the treatment of wells is presented in table 6.

Table 6
Data processing results of the wells proposed method
No. wellsSpecific de is it after processing the proposed method, m3/(h m)The increase in the specific production rate, timeThe increase in the specific production rate relative to the initial, %Processing time wells, hTime pumping wells after treatment, h
16,14,38553,5
2of 5.752,31004,54,0
36,92,9903,55,5
44,82,88762,5
5of 5.43,09634,2
67,42,6946,53,6
75,93,11093,55,2
86,22,688,572,8
94,23,2for 91.34,54,1
104,83,010453,2
11the 3.83,2108 62,8

In the treatment of eleven wells in the catchment of the proposed method using the inventive solid reagent specific flow rate has been increased from 2.3 to 4.3 times, and the water supply to consumers increased by 79%. Thus the yield of wells relative to the initial values was 85-108%, indicating a high degree of dissolution of ferrous and clay clogging formations offer solid reagent in the implementation of the proposed method.

1. Solid reagent for acid treatment of wells, comprising the product of the interaction of nitric acid with urea and additives, wherein the additives it contains oxygen-containing sulfur and sodium polyphosphate in the following ratio, wt.%:

the product of the interaction of nitric
acid with urea37,5-73,2
the oxygen-containing sulfur compound24,4-61,5
polyphosphate sodium100

2. Solid reagent according to claim 1, characterized in that as a product of the interaction of nitric acid with urea it contains nitrate of urea in the form of ammonium salts of CO(NH2)2*HNO3 and/or oxanabol salt (NH2)2CO·HNO3.

3. Solid reagent according to claim 1, characterized in that as the oxygen-containing sulfur compounds it contains sodium bisulfate aqueous NaHSO4·H2O, and/or sodium pyrosulfite Na2S2O7and/or the potassium pyrosulfite K2S2O7and/or the ammonium peroxodisulfate (NH4S2O8.

4. Solid reagent according to claim 1, characterized in that as polyphosphate sodium it contains sodium tripolyphosphate, Na5P3O10and/or sodium hexametaphosphate (NaPO3)6.

5. The way the acid treatment of wells, mostly water, providing for the supply of process solution in the well equipped lowered on tubing filter, its injection into the reservoir, the shutter speed in the reservoir and the subsequent pumping of wells, characterized in that as a technological solution using 10-30%aqueous solution of solid reagent according to claim 1, and the injection process solution is produced by reagentnogo, then when the shutter speed in the reservoir creates a reciprocating motion of the technological solution by periodic supply of compressed air in a sealed wellbore with subsequent depressurization, and when the specified compressed air UB is the tier of fluid in the wellbore reduces below the static level at the distance, not exceeding the length of the filter, fixing the time of passage of fluid to the lower end of the filter, and when stabilization of the mentioned indicator reciprocating motion of the technological solution is stopped, and the subsequent pumping of wells additionally measure the value of the specific electrical resistance pumped from the well fluid, and upon reaching this value, close to or equal to the value of the electrical resistivity of formation fluid, the pumping ceased.

6. The method according to claim 5, characterized in that before applying the technological solution in the well last supply level sensors, which are placed at a depth of static water level in the borehole and at the lower end of the filter.



 

Same patents:

FIELD: mining, particularly underground mining of highly explosive and gas-bearing coal seams.

SUBSTANCE: method involves removing methane from tension zones adjacent to block boundaries; drilling additional wells in geodynamic block massif; performing hydraulic fracturing thereof and well linkage with wells drilled in tension zones. Hydraulic fracturing is carried out with liquid including oxygen containing reagents. Then temperature is increased in wells up to level, which provides oxygen emission from oxygen-containing solutions and coal material is oxidized. Oxidizing products and evolved gas is removed via previously drilled wells in tension zones. To provide maximal fissure opening after hydraulic fracturing coal-containing massif is heated and acid solutions are injected in the massif.

EFFECT: increased efficiency of coal seam degassing due to increased completeness of methane removal from total geodynamic block volume including coal containing gas-bearing thickness.

5 cl, 2 dwg

FIELD: well drilling in underground reservoir for oil and gas obtaining.

SUBSTANCE: device for processing liquid injection in underground reservoir comprises drilling string having at least one plugging means to isolate selected well section from another one. Flow string additionally includes liquid flow passage having inlet communicated with opened area in selected well section. Each plugging means includes inflatable member, which may be shifted between radially retracted state and radially expanded state. Drilling string additionally has means for selectively communicating inflating channel with liquid passage. Said means includes tubular bush located in inner surface of tubular drilling string part and sliding between closed and opened positions relatively orifice made in tubular part wall. Processing liquid injection method involves bringing drilling string into operation in decreased hydrostatic well pressure regime to advance thereof to underground reservoir zone to be treated; stopping drilling operation when said underground reservoir zone reaches predetermined well section selected by sealing means arrangement in drilling string; moving sealing means from radially retracted state to radially expanded state; injecting processing liquid flow via liquid passage and outlet orifice in selected well section and in reservoir zone to be treated, wherein remainder well section is under decreased hydrostatic pressure.

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13 cl, 8 dwg

FIELD: oil industry, particularly to operate injection wells.

SUBSTANCE: method involves insulating lower reservoir having high injectivity by installing cement-and-chalk bridge within interval of lower reservoir having high injectivity along with cement-and-chalk mix injection in said interval under pressure within time period enough for partial cement-and-chalk mix penetration in well zone through design depth; performing time-delay for cement-and-chalk mix setting and hardening; operating upper reservoirs after lower reservoir isolation by injecting working agent, namely water, therein. For secondary operation of lower reservoir having high-injectivity acid bath is arranged in well for cement-and-chalk bridge damage. Then new casing pipe having lesser diameter is lowered in well and cement mix is injected in space between old and new casing pipes. After that technological time-delay is carried out for cement mix setting and hardening and both casing pipes are perforated within productive interval reservoir for depth exceeding design depth of partial cement-and-chalk mix penetration into well zone.

EFFECT: possibility to keep producing ability of well.

1 ex

FIELD: oil production, particularly to operate well drilling in stacked pool including reservoirs with different injectivities.

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EFFECT: possibility to create isolation screen, which may be easily removed during well development with the use of acid solution along with well deliverability keeping.

1 ex

FIELD: oil and gas production industry, particularly development of wells having productive reservoir formed of carbonate basin and penetrated along with elongated radial channels creation.

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2 cl

FIELD: oil and gas production.

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EFFECT: enhanced formation treatment efficiency.

4 cl, 3 tbl, 9 ex

FIELD: oil production, particularly methods for stimulating production by forming crevices or fractures using eroding chemicals.

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EFFECT: increased deliverability of well drilled in non-uniform reservoir.

1 ex

FIELD: oil production, particularly means to apply action to bottomhole formation zone.

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2 cl, 2 dwg

FIELD: oil industry, particularly methods for stimulating production by forming crevices or fractures.

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EFFECT: increased amount of oil to be produced and increased oil recovery.

2 cl, 1 ex

FIELD: oil industry, particularly methods for stimulating production by forming crevices or fractures by use of eroding chemicals.

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EFFECT: increased efficiency of well bottom zone treatment.

1 ex

FIELD: oil and gas production.

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EFFECT: improved strength and adhesion properties of grouting mortar.

1 tbl

FIELD: oil industry, particularly non-uniform reservoir development.

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2 cl, 3 tbl, 3 ex

FIELD: oil and gas production.

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EFFECT: improved and valuable technical properties of liquid.

2 tbl

FIELD: petroleum-extracting industry.

SUBSTANCE: invention relates, in particular, to development of viscous-elastic liquids as sand-carriers for hydraulic disruption of low-penetrable gas- and oil-carrying seams in order to enhance their oil output. Proposed cross-linked liquid as sand-carrier based on hydrocarbon liquid and gel-forming agent comprises as a gel-forming agent a mixture of complexes of lithium tert.-butyltrialkyl borates - K [t-C4H9OB(OR)3]Li wherein R means (C4-C12)-alkyl, and a solvating agent - CA in the mole ratio K : CA = (1:1)-(1:2). As components of a gel-forming agent it comprises fraction of B(OR)3 wherein R means (C4-C12)-alkyl, and lithium tert.-butylate t-C4H9OLi in their mole ratio = 1:1, and in the following ratio of these components, wt.-%: trialkyl borates, 0.5-10.0; lithium tert.-butylate, 0.2-2.5, and hydrocarbon liquid, the balance. CA represents a compound of the following classes: saturated alcohol ROH, dialkyl esters R2O, primary H2NR, secondary HNR2, and tertiary alkylamines NR3 wherein R means (C4-C12)-alkyl. Invention provides expanding assortment of gel-forming agents, improvement of technological effectiveness of process in preparing liquid and enhancing its thermosedimentation stability.

EFFECT: improved and valuable properties of liquid.

3 cl, 3 tbl, 34 ex

FIELD: gas and oil production industry.

SUBSTANCE: invention relates to chemical compositions used in treatment of holes, among them absorbing holes, for decreasing hydrogen sulfide content in gaseous space in carrying out repairing, research and other works. Invention proposes a solid-phase composition for hydrogen sulfide neutralization that comprises the following components, wt.-%: surfactant, 0.5-7.4; polyvinyl acetate, 26.6-5.7 and water glass, 2.6-4.6 as reagent-stabilizing agents of foam, and sodium nitrite and sulfamic acid taken in stoichiometric ratio with respect to each component in reaction with hydrogen sulfide, the balance. Proposed composition can be used in gas and oil production industry under normal and low seam pressures. Invention provides development of effective and simple in preparing and technological composition used in neutralization of hydrogen sulfide in holes, enhancing neutralizing activity of hydrogen sulfide neutralizing agent with respect to hydrogen sulfide in seam space both in gaseous and dissolved state.

EFFECT: improved and valuable properties of composition.

6 tbl, 1 ex

FIELD: gas and oil production industry.

SUBSTANCE: invention relates to chemical composition used in treatment of holes, among them, absorbing holes, for decreasing the content of hydrogen sulfide in gaseous space in carrying out repairing, research and other works, and can be used in gas and oil production industry under conditions of normal and low seam pressures. Proposed composition comprises the following components, wt.-%: sodium peroxocarbonate, 10-40; surfactant (surface-active substance), 0.5-10; polyacrylamide, 0.02-0.1; sulfamic acid, 17-53, and sodium nitrite, 21-52. The slid-phase composition can comprise water glass also. Invention provides development of effective and simple in preparing and technological composition used for neutralization of hydrogen sulfide in holes.

EFFECT: improved and valuable properties of composition.

2 cl, 7 tbl, 2 ex

FIELD: oil and gas extracting industry.

SUBSTANCE: invention relates to damping holes in their overhaul repair. Proposed technological liquid used in damping oil and gas holes comprises the following components, wt.-%: microbial xanthane biopolymer, 0.5-2.0; modified starch, 0.2-2.5; surfactant (surface-active substance), 0.01-0.2; sodium carbonate, 0.1-1.0; aluminum power, 0.005-0.08, and water, the balance. Method for preparing indicated aphron-containing technological liquid used in damping oil and gas holes involves mixing its components to obtain two solution wherein one solution contains sodium carbonate and surface-active substance obligatory, and other solution contains aluminum powder. Mixing these solution is carried out at temperature from 50°C to 90°C. Invention provides preparing aphron-containing liquid for damping under static conditions without using special gas-dispersing equipment and based on available reagents.

EFFECT: improved and valuable technical properties of liquid.

2 cl, 3 tbl, 3 ex

Grouting mortar // 2322471

FIELD: gas and oil industry.

SUBSTANCE: invention relates to grouting mortars used in cementing casing strings in gaseous, gas-condensate or petroleum holes in zone of productive seam at moderate temperatures. Proposed grouting mortar comprises the following components, wt.-%: grouting Portland cement, 64.41-66.24; sulfacell, 0.13-0.40; microsilica MK-85, 0.33-1.99, and water, 33.20-33.30. Invention provides preparing grouting mortar of reduced water yield in face conditions and with simultaneous enhance of strength of cohesion of cement stone with a casing string.

EFFECT: improved and valuable properties of grouting mortar.

1 tbl, 1 ex

FIELD: organic chemistry, chemical technology.

SUBSTANCE: invention relates to synthesis of unknown early N-[alkylphenoxypoly(ethyleneoxy)carbonylmethyl]-morpholinium chlorides. Invention proposes novel compounds - N-[alkylphenoxypoly(ethyleneoxy)carbonylmethy]-morpholinium chlorides of the general formula: wherein R means aliphatic hydrocarbon radical comprising 8-12 carbon atoms; n means an average degree of oxyethylation equal to 3, 6, 7, and a method for synthesis of these compounds. Synthesized compounds possess property of inhibitors of asphalt-resin-paraffin deposits and can be used in oil industry for prevention of precipitation of asphalt-resin-paraffin deposits from the oil in its extraction, preparing and transporting.

EFFECT: improved and valuable properties of compound.

2 tbl, 7 ex

FIELD: oil production, particularly to block bottomhole reservoir zone and to kill gas well drilled in highly-permeable productive reservoir, as well as well workover.

SUBSTANCE: method involves serially injecting blocking liquid and killing liquid in bottomhole reservoir zone. Blocking liquid is magnesium hydrogel comprising microshperes added in proportion of 10:4. Microsphere dimensions are selected to provide total bottomhole reservoir zone mudding and following microsphere flushing-out from bottomhole reservoir zone.

EFFECT: increased efficiency of reservoir blocking and gas well killing along with reservoir rock property retention and decreased well workover costs.

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

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