WO2015005890A1

WO2015005890A1 - Composition for decolmatation and cleaning a bottomhole zone of oil- and gas- saturated formations

Info

Publication number: WO2015005890A1
Application number: PCT/UA2014/000073
Authority: WO
Inventors: Ihor HUBYCH
Original assignee: "SPK-GEO" LLC
Current assignee: "SPK-GEO" LLC
Priority date: 2013-07-11
Filing date: 2014-07-10
Publication date: 2015-01-15
Anticipated expiration: 2016-01-11

Abstract

The present invention relates to the oil and gas producing industry, and in particular to the complex composition created to be used for restoration of the functioning of the oil and gas wells having the bottomhole zones mudded because colmatation by the formation water, condensate, or swelling of the clay rocks, resin-asphaltene and paraffin components. The aim of the present invention is to improve a composition for decolmatation and cleaning the bottomwell zone of oil- and gas-saturated formations by means of imparting to the composition a complex of properties which provide the restoration of the well operation and increase of the hydrocarbon extraction level. The claimed composition includes the nonionogenic SAA: poly glycosides and/or ethoxylated higher C₈ - C₁₈ alcohols, and/or fatty acid amides, ionogenic SAA: alkylamides and/or fatty acid cocoamides, a mineral and/or organic acid, potassium and/or sodium salts, and/or ammonium salts, II and III valent metal salts, which are capable of decrease swelling of clay in the formation zone, and water, in which the ratios of said components correspond to a highest level of decolmatation and cleaning of the bottomwell zone.

Description

COMPOSITION FOR DECOLMATATION AND CLEANING A BOTTOMHOLE ZONE OF OIL- AND GAS- SATURATED

FORMATIONS Technical Field

The present invention relates to the oil and gas producing industry, and in particular to the complex composition designed to be used for restoration of the productive oil and gas wells having bottomhole zones mudded by colmatation with the formation water, condensate, or swelling of the clay rocks, resin-asphaltene (RAC) and paraffin components (RAPC).

Background Art

The increase of the production of the oil, gas, and gas condensate depends substantially on the operation efficiency of the existent fond of productive wells. For example , in many fields of the Dnieper-Donetsk lowland, Crimea, and Carpathians, in which are concentrated the main oil and gas deposits, an important part of the fond of productive wells operates at the levels considerably lower of their potentials. One of the basic reason of this challenge is a technology-related factor induced by high water saturation of a bottomhole formation zone (BFZ) .

Premature stoppage of a well can be caused not only by liquid fluids which accumulate on the well bottom, but also through sand- clay plugs which arise and decrease filtration properties of a formation in the bottomhole zone, leading to the loss of reservoir energy at the movement of fluids from the reservoir into the well, and decreasing a hydrocarbon extraction level.

Flooding or colmatation of a bottomhole zone can occur also in assistance of a filtrate of the washing liquids. The latter becomes possible when technologies of the formation opening are used without taking into account geophysical characteristics of a section. In particular, at that as washing liquids are used the freshwater solutions, or the clay solutions which had not been chemically processed in a right way .

In the case of oil deposits, a considerable reason of decreasing productivity and debit of hydrocarbon fluids is colmatation of a bottomhole zone during the opening of productive formations and during a well operation with the dispersed particles of drilling and cement solutions, and other liquids, products of corrosion of equipments , sediments formed at interaction of a reservoir water and washing solutions, as well as with the polar oil components - resins and asphaltenes which adsorb on the surfaces of filtration channels . Cooling of a productive formation with drilling solutions, well killing solutions etc, as well as oil gas throttling lead to the precipitation (crystallization) of high molecular paraffins from oil.

As a result of penetration of a liquid filtrate into formation is decreasing of phase penetrations for oil and gas and creation of stable high-viscose water-oil emulsions. All these factors result in a rise of a considerable hydrodynamic resistance to the oil movement, consequences of which are not only losses of a substantial part of the reservoir energy and drop of well debits, but also lowering of efficiency of the development of deposits as a whole.

A complicated character of c olmatation of a productive formation suggests that solving a problem of increasing of well debits and the achieving the necessary extraction rates is not possible without a wide complex of physicochemical methods for influencing on a bottomhole formation zone.

Actually, it is well known many compositions which are used for decolmatation and cleaning the BFZ.

For instance, RU, 2137796 discloses the composition for removal of RAPC, which in eludes SAA mixture: oxyethylated alkylphenols, oxyethylated higher alcohols and sulfonated products. A drawback of this known composition is a limited application sphere wh ich is directed only to a n arrow part of colmatation problems, and especially is low efficient in the case of colmatation with mineral particles.

RU, 2200831 is related to the composition for treating a BFZ, which comprises a SAA mixture, an emulsion of an anion type polymer, and the rest - water. A significant disadvantage of that composition is connected also with low efficiency in the case of colmatation of a productive formation with mineral particles.

Another composition for decolmatation of wells is disclosed in RU,2257468. This composition comprises hydrochloric acid, diammonium phosphate and a solvent; and, in addition, contains SAA and hydrofluoric acid. As SAA the composition can comprise its nonionogenic cation-active and anion-active species. As a solvent it uses methyl, ethyl or isopropyl alcohols, and a water-methanol fraction.

The main shortage of the known composition consists in that above mentioned SAA are characterized by a foam- formation which amounts to 50 g/1, what in a substantial measure limits their effect in case of the higher salinity of a reservoir water. All known compositions are not of complex character, that is they do not influence simultaneously a complex of causes that induce the colmatation of the BFZ and wells, due to which a necessary restoration of the well operation is not provided.

Taking into consideration that actual indices of hydrocarbon extraction and operation efficiency of wells cannot be considered as satisfactory, creation of new, highly effective compositions and respective methods for intensifying oil and gas production process, should be confirmed as being urgent and important ones.

The present invention is aimed to improve a composition for decolmatation and cleaning a bottomwell zone of an oil and gas saturated formation by means of imparting to the composition a complex of properties which provide restoration of well operation and increase of the hydrocarbon extraction level.

Disclosure of Invention

The present invention aims at providing an improved composition for decolmatation and cleaning a bottomwell zone of an oil and gas saturated formation which comprises nonionogenic SAA such as poly glycosides and/or ethoxylated higher C8 - CI 8 alcohols, and/or fatty acid amides; ionogenic SAA such as alkylamides and/or fatty acid cocoamides; mineral and/or organic acid; potassium and/or sodium salts, and/or ammonium salts; II and III valent metal salts which are capable to decrease a clay swelling in a formation zone, and water ,

a ratio of said components being corresponded to the results of modeling the processes of colmatation of oil displacement, obtained before and after treating of the model of the test core and formation fluids with an appropriate composition.

Furthermore, as fatty acid amid in this composition cocamid diethanolamin, cocamid monoethanolamin or cocamid triethanolamin may be used.

The ionogenic SAA represented by fatty acid alkylamide and cocoalkylamide salts may be used, in addition, as corrosion inhibitors.

And as mineral acid a hydrochloric acid may be preferably used and as organic acid - acetic acid.

The composition of the invention may further contains a solvent of the RAC in the amount of 0.1 - 30.0 wt %.

As a solvent of the RAC, the composition contains a light oil selected from the group consisting of benzine , kerosene, diesel oil, and n-methyl-2-pyrrolidone.

In the preferred embodiments of the invention the components of the composition should be taken at the following ratios, % by weight :

nonionogenic SAA 0.1 - 20.0 ionogenic SAA 0.1 - 20.0 mineral and/or organic acid 0.1 - 20.0 potassium and/or sodium salts, and/or ammonium salts and/or II, III valent metal salts 0.1 - 40.0 water the rest

The author of the invention found out that a key position in creating of a new composition is a selection of an SAA mixture possessing high emulsifying properties for the water-oil system, where with its participation both direct and inverse emulsions are formed. This aspect is very significant, since in the operations with oil and gas saturated formations the process of emulsification of the system is of great importance, inasmuch as it is just this process which, firstly, improves an access of the components of the composition to a swollen clay and, secondly, allows to form, from a complex multi phase system ( gas-oil, including RAP C - wa ter), a homogeneous mobile emulsion which further is removed from BFZ for cleaning the letter.

Brief Description of Drawings

The invention is further described with reference to, though not limited by, the following drawings, in which:

Fig. 1 is a scheme of the effect of the composition of the invention on a productive formation:

(a) migration of a reagent through the filtration-active zones,

(b) plugging of these high-permeable zones with a foamy emulsion,

(c) surrounding of the low-permeable parts of the collector by a reagent;

Fig. 2 - dynamics of restoration of the effective gas permeability over time after action of the composition of the invention on a reservoir model which contained 18% of the residual water and 54 % of a condensate;

Fig. 3 - porometrical characteristic of model N° 2 with following parameters: Kn=10.4 %, Knp=2,9 mD, K3B=24 %; Fig. 4 - variation of the effective gas-permeability of the model after it has been colmated by the clay swelling and treated with hydrochloric acid and then - with the composition of the invention.

Fig. 5 - precipitation of the resin-asphaltene and paraffin components in the PST tubes during oil extraction.

Fig. 6 - different stages (a,b,c) of dissolution of the resin- asphaltene and paraffin components (RAPC) by means of the claimed composition

Fig. 7 - removing of the oil-saturated sand from the oil by means of the composition of the invention.

Fig. 8 - emulsification of the oil with water for the effective cleaning of a reservoir from flooding by means of the composition of the invention (samples 1 1-13).

Fig. 9 - dynamics of restoration of the effective permeability of the oil-saturated model at modeling the cleaning of the bottomhole zone by means of the composition of the invention.

Fig. 10 - mixing of the composition with kerosene in the tanks of CA-320 aggregate before bringing these components into a well.

Fig. 11 - the debit of the heavy oil on H-l well in Carpathians before and after treatment of the colmated oil-saturated reservoir by means of the composition of the invention under the name of "SPK GIOKIS".

Best mode for Carrying out the Invention

Because at the beginning of penetration of the composition into a productive formation a direct emulsion (oil in water) is formed, which further is transformed into an inverse one (water in oil), the author , in this work, used an SAA mixture to form both the direct and the inverse emulsions. In the letter, the dispersed exterior phase is a hydrocarbon liquid (oil or gas-condensate), while the dispersed interior phase is the water of any grade of salinity. According to the research and practical industrial results, the most effective and universal emulsifiers for the inverse emulsions are the nitrogen-containing SAA. In addition to the nitrogen-containing SAA, in the composition of the invention the polyglycosides and oxyethylated C₈-C₁₈ alcohols were used.

Choice of the SAA for the composition of the invention was fulfilled in such a manner that the new formed composition: 1 - possesses solubilization and wetting properties; 2 - effectively emulsifies both the direct (oil in water) and inverse (water in oil) emulsions, which are formed at cleaning a productive formation; 3 - has hydrotrops to improve the solubility of an oil in water and to prevent separation of emulsions. According to these requirements, a composition of nonionogenic and ionogenic SAA has been created, which possessed high washing properties and foaming capacity even at water salinity of 200 g/1, in contrast to the known compositions .

For cleaning the BFZ-s containing heavy oil, further solvents of the RAPC are used , which are represented first of all by light oils (benzine or/and kerosene or/and diesel oil) or/and also by n-methyl- 2-pyrrolidone.

The next feature of the composition of the invention is a high mineralization of its salt components which contain uni- and/or di-, and/or trivalent cations which allow to decrease dimensions of the boundary diffusion layer in clay minerals and hence their swelling. In addition to this, the composition of the invention contains organic and/or mineral acids, the aim of which is coagulation of clay, dilution of carbonate minerals and mixing the new-formed emulsions due to gassing.

Laboratory researches and industrial tests of the claimed composition ha ve confirmed its considerably higher efficiency in comparison to the known ones. This is because the foam system, which is formed by the composition of the invention, results in leveling the reagent penetration into an inhomogeneous medium. Temporary foam plugging of the high-permeable zones enables to engage into filtration and to release the low-permeable parts of the collector, what considerably increases efficiency of its influence on the productive formation (Fig. 1).

To obtain an experimental confirmation of the theoretical predictions the author has investigated a productive formation laboratory model which was represented with a sand rock of the Maikopsk series from sv. Subbotin-403 (int. 2288-2294m). The filtration-capacitance parameters were: K_np = 2,9 mD (absolute gas- permeability, dry sample); K_npe=2.6 mD (the effective gas- permeability in the presence of residual water); K_n=10.4% (the porosity at saturation with the water salinity of 15 g/1); K_3B=24.0 % (residual water-saturation).

Stages and results of the investigation are as follows

1) Modeling of the residual water-saturation of the productive formations and the investigations of a pore space structure. The result: the effective permeability of the water- saturated model has decreased from 2,9 to 2.6 mD as compared to the absolute one.

2) The sample with residual water was extra saturated with kerosene for modeling the creation of a condensate in a porous space. The result: the effective permeability of the condensate-saturated model has decreased from 2.6 to 0.6 mD.

3) The effect of the composition upon the condensate-saturated model. The result: the effective gas- permeability on the forth day has increased from 0.6 to 2.2 mD, that is in 3.6 times as compared to the condensate-saturated one (Fig- 2).

The claimed composition restores the gas permeability and improves the filtration-capacitance parameters of a reservoir. The restoration of the gas-permeability of the model, colmatated with condensate, under the action of the composition amounts to 84 % based on the start value before colmatation. The composition has restored the permeability of the capillary pores, the content of which was more than 50 %, what together with supercapillary pores gave nearly 80 % of the porous space of the model (Fig. 3).

To compare thus obtained results with those of known methods, an experiment has been carried out with treating the same by hydrochloric acid (HCT).

Stages and results of the investigation are as follows.

1. Modeling the residual water-saturation of the formations-collectors with the reservoir water, and the investigations of a pore space structure. The result: the effective permeability of the model with residual water has decreased from 6.9 to 0.2 mD as compared to the absolute one (Fig. 4).

2. The hydrochloric acid treating of the model colmatated by swelling of the clay minerals. The result: the effective gas permeability has increased from 0.2 to 0.7 mD, that is in 3.5 times.

3. After treating with hydrochloric acid, the colmatated model has been treated with the composition of the invention.

Results of these investigations had demonstrated that treating a productive formation with the composition of the invention was more effective than HCT treating. The gas permeability of the model treated with the composition of the invention has increased on the third day after treating from 0.7 to 2.6 mD (Fig. 4), that is in 3.7 times as compared with HCT; from the start value (0.2 mD) of the gas-permeability model, having been colmatated by swelling the clay species, it has increased in 13 times.

An important task to be solved was cleaning the bottomhole zone from the RAC which was adsorbed on the surface of filtration channels , and from high molecular paraffin hydrocarbons which precipitate from the oil when cooling the reservoir with a drilling solution, well killing liquids, throttling the oil gas. It can be seen, for instance, in the production string tubes (PST), where these components precipitate from the oil at cooling.

Precipitation of the RAC and paraffin components in the PST tubes during oil extraction is shown on Fig.5 . It is not excluded that the like occurs in the bottomhole zone of the oil-saturated collector. To solve this problem a known composition has been improved so as to dissolve the RAPC and emulsify the water and oil for the purpose of the effective cleaning of the bottomhole zone. The obtained results are shown on Fig. 6-8.

A practical value of the present invention consists in that, while having solved the problems described above, the present invention has enabled to create an effective mechanism of cleaning of the bottomhole zone from the RAPC, condensate, process water and reservoir water with the aim to restore the well operation, what first of all concerns the heavy oils.

The latter became possible due to that the composition comprises as SAAs a mixture of nonionogenic SAAs, including polyglycosides (PG) which are characterized by a high foaming capacity either in a salt water or in the presence of the condensate, what allows to combine the process of elimination of clay swelling with the cleaning of the bottomhole zone from the condensate and mixture of process water with reservoir water or filtrate. It should be note that PG is ecologically safe and was used only for producing the synthetic washing means.

The efficiency of the composition influence on the BFZ was studied under laboratory conditions using a model of a reservoir- collector (a test core sample) in correspondence with the following stages:

1 - modeling of the residual water-saturation of formations-collectors with the reservoir water, and the investigations of the pore space structure;

2 - the model with the residual water was extra-saturated with oil. The oil-saturation rate was 64 %;

3 - the reservoir water-oil displacement (displacement index was 2 % based on oil-saturated pore volume);

4 - the residual oil was extra-displaced with the composition of the invention followed by the extra-washing off with a solution, which contained 20 % of kerosene and 80 % of the composition, and the final displacement in a filtration plant. The oil displacement index was near 25 %.

5 - The extra-washing-off of the residual oil with kerosene for 1 hour followed by saturation of the model with the composition of the invention for 5 hours. The effective permeability: at the initial stage was 0.12 mD, in 20 hours - 0.6 mD.

6 - The model of extra-saturation, which contained the residual oil, with the composition of the invention followed by measuring the variations of the effective gas-permeability over time. At the initial stage the effective permeability was 0.65 mD; at the transitional part it rapidly increased from 0.65 to 3 mD, and at the final stage it increased from 3 to 3.1 mD (Fig.

9).

Hence, as a consequence of the actions of the composition of the invention there has been achieved a nearly twice restoration of the phase permeability as compared to the initial one (6.1 mD), what is a very positive effect for the oil extraction process, and especially for the high-viscosity oils. The main advantage of the composition of the invention, as compared to the precedent ones, is its complex effect on the productive formation. At the same time, the composition allows to eliminate the influence of all main factors which cause a colmatation of the reservoir and lead to a decrease of the well debit, namely:

I - swelling of the clay rocks and of the remains of the drilling solution;

II - flooding of a reservoir by reservoir-water and process- water;

III -precipitation into the BFZ of a gas deposit, condensate, or sediments of the resin-asphaltene components in the case of BFZ of an oil deposit.

While the first item is solved by the presence of ion exchange and an acid medium, that is an acid and appropriate cations (metal ions), the two others require a somewhat more complicated approach.

As for the second item, it is necessary to emulsify a two-phase system (water- hydrocarbon fluid), while for the third one the task is somewhat complicated because a necessity to fulfill an emulsification of a three-phase system, where to the precedent two else liquid hydrocarbons are added in the case of gas deposit (gas- water-liquid hydrocarbons) or RAPC for an oil deposit (water-gas- saturated oil - RAPC).

In this case, as was already mentioned above, the main question is to provide an effective emulsification of a system, because it is it that assists the access of reagents to the swollen clay and, secondly, enables to involve all the components of the system, including RAC and RAPC, into the emulsification process for the creation of a homogeneous mobile phase, and hence enables in the following to clean, with a sufficiently high quality, the bottomhole zone from colmatants by means of removal the latter from the reservoir.

The choice of the SAAs for the composition of the invention was fulfilled in accordance with the following requirements: solubilization and wetting (polyglycosides); an emulgator of the direct emulsion (oil in water), which is formed at the beginning of the treatment of the reservoir (oxyethylated alcohol); an emulgator of the inverse emulsion (water in oil), which is formed at deeper cleaning of reservoir (amides, fatty acid alkylamides); improvement of the solubility of the oil in water, and prevention of the separation of emulsions - hydrotrops (sodium alkylaminodipropionate or/and sodium cocoiminodipropionate).

It should be noted that the hydrotrops mentioned above are ionogenic SAAs, which in a mixture with nonionogenic SAAs exhibit a synergic effect, that enables to achieve a high degreasing (oil-removing) capability. At the same time, due to use of the latter we have got a possibility to refuse partially from the classic corrosion inhibitors [8] because they realize their function.

To increase the efficiency of the cleaning of the BFZ containing the heavy and high-paraffinic oils, in addition are used the solvents of RAPC, such as light oils (benzine or/and kerosene, or/and diesel oil) or/and also n-methyl-2-pyrrolidone. These components are added into the composition directly on the well when mixing in the industrial tanks of CA-320 aggregate (Fig. 10). Additionally, to improve the cleaning of the BFZ from RAC, it is advisable to use in the composition a carbonic acid which promotes the mobility of RAC and allows to substantially increase the oil debits in the wells under research.

The next feature of the present invention is the mechanism of its functioning. In view of the absence of a possibility to mix reagents in a productive formation, this operation was fulfilled using an acid which not only coagulated the clay, but by means of the boiling gassing, bubbled the system and favored to the mixing of the components, and hence to their effective emulsification.

The description above shows that it is but the complex approach for cleaning a reservoir that allows as much as possible to use the efficiency of each of the components and all their mutual relations, and thus, particularly with achievement of a synergic result, to fulfill the operations for cleaning the BFZ, and hence maximally increase the well debits.

Thus, the offered solution enables: 1 - to remove the clay mud from the bottomhole zone of the formations which are represented by the terigene sand-clay collectors or by those that are colmated with mineral particles of drilling solution; 2 - to remove condensed RAPCs from the BFZ; 3 - to clean the bottomhole zone collector, flooded with a washing liquid filtrate or dropped condensate.

The listed above is based both on a complex effect of various reagents and on creation of a foaming zone in productive formation which favors to the movement of hydrocarbon fluids to the wellbore (Fig. 3). In the preferred embodiments of the invention the components of the composition of the invention may be are used in the following ratios, in weight percents:

Mixture of nonionogenic SAA , 0.1 - 20.0

Poly glycosides and/or ethoxylated higher C8-C18 alcohols, and/or fatty acid amides

Mixture of ionogenic SAA,

Alkyl- and/or fatty acid cocoamides 0.1 - 20.0

Solvent of RAC 0.1 - 30.0 Light oil (benzine or/and kerosene or/and diesel oil) or/and also n-methyl-2-pyrrolidone

Acid or acid mixture 0.1 - 20.0

Potassium and/or sodium salts and/or ammonium salts and/or ΙΙ-ΙΠ valent metal salts 0.1 - 40.0

K⁺ or/and Na⁺, or/and NH₄ ⁺, or/and (Ca₂ ⁺, Mg₂ ⁺, Ba₂ ⁺, Sr₂ ⁺, Al₃ ⁺, Fe₃ ⁺) salts.

It should be noted that quantitative ratios of the components, indicated above, were determined in a substantial extent experimentally, considering the achievement of the most important indices of the efficiency of decolmatation and cleaning of the BFZ. The indicated ratios are determined on the base of modeling of the colmatation and oil-displacement processes under laboratory conditions using the test core and reservoir fluids from the object under investigation. Results of investigations were evaluated by variation of the filtration-capacitance characteristics of the pore space before and after the treatment of the model by the composition of the invention with respective contents of its components; in accordance to these results, a reagent which exhibited a maximum cleaning of the pore space by the data on permeability of the model, has been selected.

Below, the present invention is elucidated by a method for making the claimed composition and by the achieved indices of restoration of effective well operation.

The composition was made in a reactor, filled up with water, at temperature 30 - 40 °C, while stirring. Then metal salts were added and brought up to a complete dissolution state. Obtained solution was being homogenized for 20 - 30 minutes, after which a SAA mixture was entered, and homogenization was being maintained for another 20 minutes. Into the formed mixture, an acid or mixture of acids was added, homogenization of the mixture continued for 20 minutes, and then the mixture was transferred into the tares to transport it up to the wells.

The obtained product was a liquid of yellow to light-brown color and had the density of 1.05 - 1.10 g/cm . Storage: up to 1 year in a plastic or metal tare. Storage temperature: from -10 °C to +50 °C.

Further the present invention is illustrated by some special examples of its practical embodiment.

EXAMPLE 1

nonionogenic SAA

polyglycosides 1.5 - 2.0 ethoxylated higher C8-C 18 alcohols 1.0 - 1.5 cocamid DEA 3.0 - 4.0 ionogenic SAA

alkylaminodipropionate 0.5 - 1.0* mineral and/or organic acid 3.0 - 5.0** potassium chloride 7.0 - 10.0 water the rest

* for hydrocarbon acid 1.0 - 3.0

* * for carbonate formations 4 - 20

The modeling of the oil-extraction process has enabled to restore the phase permeability of the reservoir almost twice as compared to the initial one (6.1 mD), what is a highly positive feature for an oil-extraction process.

EXAMPLE 2

In the embodiments of the claimed composition for cleaning the gas-saturated heavy-oil formations its components are in the following ratios, wt %:

nonionogenic SAA

polyglycosides 0.1 - 1.5

ethoxylated higher C8-C 18 alcohols 0.1 - 1.0

cocamid DEA 0.1 - 1.0

ionogenic SAA

sodium cocoiminodipropionate 0.5 - 1.0* mineral and/or organic acid 3.0 - 5.0** potassium chloride 7.0 - 10.0 water the rest

* for hydrocarbon acid 1.0 - 3.0 ** for carbonate formations 4 - 20

The modeling the cleaning process with decolmatation of the gas-saturated formations has shown that treatment of the formations by means of the claimed compos ition i s more effec tive, than by means of hydrochloric acid which was used earlier. The gas permeability of the model after treating with the claimed composition h as increased o n the third day fro m 0. 7 to 2 .6 mD (Fig. 4), that is else in 3.7 times as compared to HCT; from the initial value (0.2 mD) for the gas-permeability model which was colmated by swelling the clay species, it increased in 13 times.

EXAMPLE 3

Embodiments of making the composition for cleaning the heavy oil formations contained the components in the following ratios, wt %:

nonionogenic SAA

poly glycosides 1.5 - 2.0

ethoxylated higher C8-C 18 alcohols 1.0 - 1.5

cocamid DEA 3.0 - 4.0

ionogenic SAA

alkylaminodipropionate 0.5 - 1.0

acetic acid 3.0 - 5.0

potassium chloride 7.0 - 10.0 solvent of RAC 5.0 - 10.0 water the rest Using this reagent on a heavy-oil well H-1 in Carpathians has enabled to increase the oil debit in 7 times (Fig. 1 1).

EXAMPLE 4

Embodiments of making the composition for cleaning the oil- saturated formations, where the formation water is absent or has a low content of sulphates and carbonates, and also as killing liquid, contained components in the following ratios, wt %:

nonionogenic SAA

alkylaminodipropionate 0.5 - 1.0 organic acid 0.1 - 5.0 calcium and/or barium and/or iron chlorides 2.0 - 20.0 water the rest

EXAMPLE 5

Embodiments of making the composition for cleaning the tanks, engines or metal surfaces from oil products contained components in the following ratios, wt %:

nonionogenic SAA

polyglycosides 1.5 - 2.0 ethoxylated higher C8-C 18 alcohols 1.0 - 1.5 cocamid DEA 3.0 - 4.0 ionogenic SAA alkylaminodipropionate 0.5 - 1.0 acid mixture:

phosphoric acid and/or citric acid and/or ABSA 0.1 - 5.0 potassium and/or sodium salts and/or ammonium salts and/or II-III valent cation salts 0.01 - 1.0* water the rest

* Low salt content, because of use of low-salinity water.

Modeling of the process of cleaning the objects from oil pollution is exhibited by the experiment illustrated by Fig. 7, where is represented an example of cleaning an oil-saturated formation from a heavy oil.

Thus, the task of the present invention has been solved by creation of a reagent-composition which is characterized by a complex effect on a colmatated productive formation. This complex effect is given by synergy of whole components of the composition. Complex

composition for decolmatation and cleaning the bottomwell zone of oil- and gas-saturated formations enables to realize such a

mechanism of its action, that considerably increases the efficiency of the well operation and the quantity of extracted raw material.

Claims

1. A composition for decolmatation and cleaning a bottomwell zone of oil- and gas-saturated formations comprising nonionogenic SAA such as poly glycosides and/or ethoxylated higher Cs - C \g alcohols, and/or fatty acid amides; ionogenic SAA such as alkylamides and/or fatty acid cocoamides; a mineral and/or organic acid; potassium and/or sodium salts, and/or ammonium salts; II and III valent metal salts, which are capable of decrease the clay swelling in the formation zone; and water the ratio of said components being corresponded to the results of modeling of processes of colmatating of oil displacement obtained before and after a treatment of a model of a test core and formation fluids with an appropriate composition.

2. The composition according to claim 1 in which fatty acid amid is represented by cocamid diethanolamin, cocamid monoethanolamin or cocamid triethanolamin.

3. The composition according to claim 1 in which mineral acid is represented preferably by hydrochloric acid and organic acid - preferably by acetic acid.

4. The composition according to any one of claims 1 to 3 in which the components are taken in following amounts, % by weight:

5. The composition according to any one of claims 1 to 4 which further comprising a solvent of resin-asphaltene components in the amount of 0.1 - 30.0 % by weight.

6. The composition according to claim 5 in which the solvent of resin-asphaltene components comprises light oils selected from the group consisting of benzine, kerosene, diesel oil and n-methyl- 2-pyrrolidone.