RU2252311C1 - Method for effecting face-adjacent well area - Google Patents

Abstract

FIELD: oil industry.

SUBSTANCE: method for effecting face-adjacent zone of well, by preferably horizontal, non-overlapped casing string, by pumping buffers of effect mixture and pressing it into bed, first buffer is fed with mixture of dichlorinemethane, cation-active surfactant, while previously on basis of geophysical data productive ranges of bed are determined, into which at least two hydraulic perforators on tubing strings are lowered, through which into buffers a mixture is fed for effecting productive ranges of bed with nozzle jet flow speed 50-150 m/s, into first buffer, in percents of mass, following is fed: dichlorinemethane 30-50, aromatic hydrocarbon in conjunction with aliphatic hydrocarbon in relation (1-1.5):(1.5-1) - 20-60 and additionally spirits, preferably isopropyl or methyl, r ethylene - 10-30. as surfactant special substance is used with concentration 0.1-0.3 percents of mass. Pumping of mixture is performed from calculation of overlapping of productive ranges of bed for following delivery of it into bed with closed behind-pipe space with pressure lower then compactions pressure of casing column. After pressing mixture into bed technological exposure is performed, about 0.5-1.0 hours, and bed decolmatation by mixture is estimated by its acceleration level, and second buffer is separated in two portion, while both portions are fed with spirits-acidic mixture in percent of mass, of: hydrochloric or fluorine-hydrogen acid 0.5-155, isopropyl spirits or methyl spirits or ethylene spirits 10-30 and surfactant, while first portion of second buffer surfactant is fed 0.8-1.0, into second 0.1-0.3, the rest is water, said mixture is pumped with circulation of it in well through tubing column, hydraulic perforators and behind-pipe space, with forming of excessive pressure.

EFFECT: higher efficiency.

2 tbl

Description

The invention relates to the oil industry and can be used to increase the reservoir properties of the bottomhole formation zone, mainly in wells with a horizontal end in the reservoir, which is not blocked by the casing.

A known method of processing the bottom-hole zone (BHP) of the formation by injecting a solvent containing halogenated hydrocarbons, where fluorine or fluorine and chlorine, for example fluorodichloroethane is used as halogen (RF patent No. 2103477, class E 21 B 37/00, 1999).

The disadvantage of this method is the use of solvents that destroy the ozone layer of the atmosphere, and therefore their use is prohibited by the 1987 Montreal Protocol and its subsequent amendments, starting in 2001. The technology of their use should include the use of special protective equipment for operators, which leads to low productivity and possible injury.

There is also known a method of SCR formation by injection into the reservoir of solvents, including dichloromethane, various aromatic hydrocarbons or mixtures thereof in combination with water or a surface-active substance (surfactant) to form a stable emulsion (US patent No. 4475489, CL 123-90.52, 1988).

It has low efficiency when processing wells, because the bottomhole zone of the borehole rather quickly becomes clogged again by emulsions, resins and asphaltenes.

A known method of processing the bottom-hole formation zone (PZP) by injecting a mixture of the composition, wt.%: Dichloromethane 30-70 and aromatic hydrocarbon 30-70. The specified mixture is pumped with rims, and an additional demulsifier is introduced into the first rim. As a demulsifier, block copolymers based on ethylene oxide and propylene are used. As aromatic hydrocarbons, use toluene, ethylene benzene fraction, concentrates of aromatic hydrocarbons C ₉ -C ₁₀ , xylene (RF patent No. 2182655, cl. 7 E 21 B 43/22, 2001).

The disadvantages of this known method are: a significant dissolution time of paraffins and asphalt-resinous substances, low hydrophobization of the surface of pores and cracks due to reprecipitation of surfactants from the produced oil, significant volumes of this composition are required for the SCR of a horizontal well. Under these conditions, insufficient lyophobization of the surface of pores or cracks will again lead to blockade of the formation.

There is also known a method of treating the bottom-hole zone of a well, including injecting a surfactant composition in a mixture of aliphatic and aromatic solvents, selling the composition into the bottom-hole zone of the formation, holding the technology, and putting the well into operation, salts of gossypol resin 0 are used as a surfactant. 01-0.1% concentration. Moreover, they can pre-treat the well with a solvent or acid solution (RF patent No. 2203409, class E 21 B 43/22, 37/06, 2001).

The disadvantages of this known method are: pre-treatment with a solvent depends on the specific application, and an acid solution does not give a result due to its poor contact with the rock of the productive formation due to the fact that paraffin, asphalt-resinous substances or a polymolecular layer of oil adsorbed in it, a significant reaction time of the composition .

Closest to the claimed (prototype) is a method for treating the bottom-hole formation zone (PZP) by injecting dichloromethane or its mixture with aromatic hydrocarbon and water-insoluble cationic surfactant (CPAS) with rims at a concentration of CPAV in the first rim of 0.01-0.05 wt. %, in the second 0.2-0.5 wt.%. At least one component from the group of dialkyl dimethyl ammonium chloride or dialkyl benzyl ammonium chloride or alkyl trimethyl ammonium chloride is used as a surfactant.

Moreover, the mixture contains, wt.%: Dichloromethane 30-70, aromatic hydrocarbon 30-70. As an aromatic hydrocarbon use toluene, ethylbenzene fraction, a concentrate of aromatic hydrocarbons C ₉ -C ₁₀ , xylene (RF Patent No. 2200232, CL E 21 B 43/22, 2001).

However, when using the known method, it takes a long time to dissolve the resins and asphaltenes, water is not sufficiently removed from the bottomhole formation zone, large volumes of the mixture are needed especially for injection into wells with horizontal completion, it is impossible to achieve 100% permeability of the bottomhole zone, because the mixture does not penetrate well into the intervals that are completely caked with asphaltene-tar-paraffin deposits (AFS), mechanical colmatants are not removed from the pore channels and microcracks, and low-permeability reservoir zones are not involved in the filtration.

The aim of the invention is to increase the efficiency of hydrodynamic treatment of wells, mainly with a horizontal end in the reservoir, which is not blocked by the casing, by reducing the time of dissolution of resins and asphaltenes, the destruction of emulsions, providing more intensive extraction of water from the BCP and mechanical muds, reducing the volume of the mixture for injection into wells, increasing the permeability of the bottomhole formation zone, as well as increasing the time until the sedimentation of paraffin deposits is repeated.

This objective of the invention is solved by the fact that in the method for processing the bottom-hole zone of a well, mainly a horizontal, uncovered casing, by injecting the rims of the treated mixture and pushing it into the formation, the mixture of dichloromethane, aromatic hydrocarbon and cationic surfactant is pumped into the first rim ( CPAV), in contrast to the prototype, previously based on geophysical data determine the productive intervals of the reservoir, in which I drop on tubing (tubing) at least two hydroperforators with nozzles interconnected, through which the mixture is pumped into the rims to process the productive intervals of the formation, at a flow rate of nozzles of 50-150 m / s, while the first rim is introduced with dichloromethane - 30-50 wt.%, aromatic hydrocarbon in a mixture with an aliphatic hydrocarbon - 60-20 wt.% in the ratio (1-1.5) :( 1.5-1) and additionally alcohol, mainly isopropyl, or methyl, or ethyl - 10- 30 wt.%, And SNPCH-PKD-515 according to TU-39-05765-670-OP-211-95 at con CAPA concentrations are 0.1-0.3 wt.%, the mixture is injected based on the overlap of the productive intervals of the formation for its subsequent pushing into the formation with a closed annulus at a pressure lower than the pressure of the casing string, after the mixture is pushed into the formation, the process a shutter speed of 0.5-1.0 h, the decolmation of the formation with a mixture is judged on its injectivity, and the second rim is divided into two parts, while the alcohol-acid mixture of the composition, wt.% hydrochloric and / or hydrofluoric acid is pumped into both parts 0.5-15, isopropyl or methyl, or ethyl 10-30, and surfactants, and 0.8-1.0, surfactants are pumped into the first part of the second rim, 0.1-0.3 into the second, the rest is water, the mixture is injected with its circulation in the well through tubing, hydroperforators and annulus, with the creation of excess pressure.

It is known that productive strata of wells, including and with a horizontal ending, as a rule, contain productive intervals with both high permeability and low or, so-called, non-collector. Therefore, in order to reduce the time for processing several productive intervals at once with high-pressure jets of the process fluid, at least two hydroperforators are lowered into the well with the selection of the number and diameter of nozzles depending on the installed hydraulic power of the pump units. The movement of hydroperforators is carried out continuously or discretely-continuously through 0.5-1.0 m during the injection of the processed mixture of the first rim, consisting of dichloromethane, a mixture of aromatic and aliphatic hydrocarbons, alcohol and surfactant at a speed of its discharge from nozzles 50-150 m / s . The outflow speed of 50 m / s can be provided with pumping units, for example, type CA-320, while 150 m / s will require pumping units of high hydraulic power. Pumping this mixture through nozzles of hydroperforators with a flow rate of 50-150 m / s allows, due to the high-pressure head, to penetrate it more effectively into capillaries and fractures of the reservoir, and, accordingly, to quickly destroy high-viscosity oil emulsions, dissolve paraffins and asphalt-resinous substances, and hydrophobize bottom-hole cationic surfactants formation zone (PZP). When jets collide with the reservoir, their reflected flows have an even higher velocity head, which flushes paraffins and asphalt-resinous substances from the surface of the reservoir. Preferably, the mixture contains, wt.%: Dichloromethane 30-40, aromatic hydrocarbon and aliphatic hydrocarbon in the ratio (1-1.5) :( 1.5-1) 60-40, alcohols 10-20, cationic surfactants 0.1- 0.3.

The use of dichloromethane makes it possible to increase the flash point of an aromatic solvent, significantly decreases its volatility during the summer period, the ozone layer of the atmosphere is not destroyed, and the working conditions of operators improve. The solvent used, for example, is a mixture of aromatic and aliphatic hydrocarbons, for example SNPCH-7870 according to TU 39-05765670-OP-239-97. The following are used as aromatic solvent: ethylbenzene fraction according to TU 6-01-10-37-78, toluene, concentrates of aromatic hydrocarbons (Nefras A-120/200, A-150/330), xylene, wide fraction of light hydrocarbons (BFLH) according to TU 38.1011026-85 and others. As aliphatic solvents use: hexane fraction according to TU 3.8.10381-93, BR gasoline in accordance with GOST 443-76, kerosene in accordance with GOST 443-76 and others. As a surfactant, it is preferable to use, for example, SNPCH-PKD-515 according to TU-39-05765-670-OP-211-95, a harmoniously combining composition of non-ionic and cationic surfactants Lacrol and Alcomon D, which has a synergistic effect on rock hydrophobization and acid corrosion protection . It has acidic corrosion protection and reduces the surface tension at the water-oil border due to hydrophobization of the KPAV IVV-1 rock according to TU 2482-006-48482528-99, which is a mixture of alkyl dimethylbenzylammonium chloride and tertiary amine quaternary ammonium salt, etc. Alcohols such as isopropyl (IPA ), methyl, ethyl, etc. increase the rate of destruction of high-viscosity oil emulsions, paraffins, asphalt-resinous substances and salvate shells of the aqueous phase on the rock in capillaries and fractures of the formation. The concentration of surfactants is justified by the fact that at a concentration of less than 0.1%, the surface tension at the interface between water and oil increases significantly, and at a concentration of more than 0.3% it decreases slightly. The minimum mixture is injected at the rate of 2.0-3.0 volumes of the productive interval of the well depending on its parameters, followed by the sale of its anhydrous oil with a low content of paraffins and asphalt-resinous substances into the formation with a closed annular space with a holding time of 0.5- 1.0 h and at a pressure lower than the pressure of the casing Moreover, the sale of oil into the reservoir is not performed. When applying the high-pressure head of the jets of a mixture of hydroperforator, it is quite enough for its deep penetration into the formation, and accordingly its decolmation. The formation decolmation mixture is judged by its injectivity. When using this mixture, the permeability of the PPP, as a rule, reaches, as shown by laboratory experiments, 90-93%. The deposition rate of paraffins and asphalt-resinous substances in the bottomhole formation zone significantly decreases compared to the beginning of the operation of the well, the water cut of the produced products decreases. After treatment with such a mixture of productive intervals of the formation, its residues are washed with oil to the surface.

In order to significantly increase the permeability of the bottomhole formation zone and the well operating time without paraffin, emulsions and asphalt-resinous substances, to remove the mechanical collimating particles from the bottomhole zone, to connect oil-saturated low-permeability zones of the formation, hydrodynamic processing of the formation intervals through hydroperforators with a flow rate of 50-150 m / s alcohol a mixture containing wt.%:

- hydrochloric and / or hydrofluoric acid - 0.5-15;

- alcohols isopropyl or methyl, or ethyl - 10-30;

- cationic surfactants (SNPCH-PKD - 515, IVV-1, etc.) in the first part of the second rim 0.8-1.0, in the second part - 0.1-0.3;

- water - the rest.

It is known that the concentration of acid in an acid solution depends on the type of acid that is used to process the PPP. So for hydrofluoric acid (HF), the optimal concentration is 0.5-5%, for “clay acid” 8-12% HCl and 1-3% HF, for hydrochloric acid 8.0-15% HCl. The addition of alcohol to the acid solution allows increasing the rate of dissolution of the rock, it is better to remove water, and when using hydroperforators, the effect is enhanced due to the hydromonitor effect. For alcohol, the optimal concentration is 10-30%. To better protect the equipment from acid corrosion, the concentration of surfactants in the first part of the acid rim (0.2-0.5 m ³ ) is increased to 0.8-1.0%.

The use of surfactants allows you to protect the pumping and equipment of the well from acid corrosion by 85-96%, penetrate the acid composition deeper into the formation, it is better to hydrophobize the surface of its capillaries or cracks. In order to determine the degree of protection against acid corrosion of tubing, surfactant additives conducted special experiments. In laboratory conditions, the corrosion rate of tubing steel samples in technical acid, inhibited by a factory corrosion inhibitor B-2 with a concentration of 12% and a mixture of hydrochloric and hydrofluoric acids (“mud acid”), consisting of 15.5% HCl and 0.65% HF, was studied . As a corrosion inhibitor stable at a temperature of + 80 ° C, SNPCH-PKD-515 was used. The exposure time of the samples at a temperature of + 80 ° C was 1 h (Table 1). Similar results were obtained for IVA-1 CPAS.

Table 1 №№
pp Corrosive environment Sample area, m ² Weight loss g Corrosion rate, g / m ² h Inhibitory effect Degree of protection, % 1 12% HCl Chem. clean 6.23 × 10 ^-4 0.7085 1137.78 2 12% HCl + B-2 6.14 × 10 ^-4 0.41005 667,834 1,704 41,304 3 12% HCl + 1% SNPCH-PKD-515 6.16 × 10 ^-4 0,0242 39.29 28.96 96.25 4 12% HCl + film coating SNPCH-PKD-515 6.10 × 10 ^-4 0,05975 97.05 11.62 91.39 5 15.5% HCl + 0.65% HF in the ratio with water 1: 1 without inhibitor 6.12 × 10 ^-4 0.46265 755,964 6 15.5% HCl + 0.65% HF + 1% SNPCH-PKD-515 6.168 × 10 ^-4 0,0681 110,426 6.85 85.39 7 15.5% HCl + 0.65% HF + film coating SNPCH-PKD-515 6.21 × 10 ^-4 0,19945 321,176 2,35 57,514

As can be seen from the table, at a temperature of + 80 ° C, the B-2 inhibitor has weak protective properties, while SNPCH-PKD-515 protects the metal well even with a film coating. As laboratory experiments have shown, other corrosion inhibitors, for example, IVB-1, dialkyl dimethyl ammonium chloride, dialkyl benzyl ammonium chloride and alkyl trimethyl ammonium chloride, also have satisfactory protective and hydrophobizing properties.

An example of hydrophobic properties is the results of laboratory experiments on a stalagmometer on the effect of cationic active surfactant SNPCH-PKD-515 on the surface tension at the interface with kerosene (Table 2).

table 2 №№pp Solution Surface tension, × 10 ^-3 , N / m 1 Distilled water 65.09 2 HCl chem. net 12.04% 55.95 3 HCl chem. net 12.04% + 1% SNPCH-PKD-515 1,07 4 HCl chem. net 12.04%, neutralized with carbonates 44.62 5 HCl chem. net 12.04%, neutralized with carbonates + 1% SNPCH-PKD-515 8.41

KPAV SNPCH-PKD-515 plays the role of a corrosion inhibitor, not only protects the underground equipment of the well from corrosion (it better protects the underground equipment of the concentration of 0.8-1.0% KPAV), but also has a positive effect on the formation treatment as by reducing the speed reactions of acid with rock due to hydrophobization of the surface and reduction of deposits in pores and fractures of the formation of iron oxide (gel) sediments, and the rapid extraction of reaction products.

In acid treatment, the technological operation is carried out both during the injection of paraffin solvents and asphalt-resinous substances, and discrete-continuously in a closed cycle: acid capacity - acid aggregate - tubing-hydroperforator - annular space - fountain fittings - acid capacity. At the same time, high-pressure jets of acid penetrate deeply into the capillaries and cracks of the productive interval, washing out the mechanical clogging particles from there, more effectively dissolving and destroying both rock cement and the rocks themselves. Reflected streams of acid carry the reaction products to the surface, and the hydrodynamic flow circulating in the annulus of the well, especially when creating repression, penetrates into the formations more efficiently and processes them. With a discrete-continuous process of hydrodynamic treatment of a well, hydraulic perforators move with the help of tubing pointwise based on the calculation of the impact of 10-20 minutes, because this time is sufficient for passing through the colmated zone and obtaining a cavity of sufficient depth. During acid treatment of carbonate deposits with high-pressure jets, cavities have a smooth surface, which significantly reduces the AFS process. It should also be taken into account that, when an acid interacts with a rock, its activity decreases, and a significant number of horizontal well intervals must be processed in one cycle. Acid circulation is continued until its active part drops to - 1.0-3.0% due to its neutralization by rock minerals. Hydromonitor nozzles during alcoholic acid treatment are installed at the same intervals that were treated with a mixture of solvents. After such treatments, as shown by bench tests with jets of hydrochloric acid (12.08% Hcl, 1% SNPCH-PKD-515, the rest is water) of sandstone with a carbonate cement content of 4-6%, through which oil was pumped, the permeability increases from 100 % to 130%, i.e. in real wells, less oil-saturated and low-permeable intervals of the formation are connected to the work, the time of deposition of paraffin and asphalt-resinous substances is also additionally delayed. To increase the permeability of the bottom-hole zone, especially of carbonate reservoirs, when injecting rims, it is possible to use depression-repression technology, which allows to increase well productivity by creating additional fractures in the formation. As a result of the complex impact on the dissolution of paraffin deposits, the production of smooth cavities and additional cracks, the heterogeneity of the reservoir is reduced, the exposure coverage increases and the time of sedimentation of paraffin deposits is significantly delayed.

An example of processing the bottom-hole zone of a producing well with a horizontal completion.

The horizontal part of the well was drilled in an interval of 1173-1421 m at an oil field in a carbonate reservoir of a fractured-pore type, with an oil inflow in the range of 1304-1314 m, 1325-1355.5. Analysis of well production showed:

- water content in the production of the well,% - 5.4;

- sulfur content,% - 2.96;

- silica gel resins,% - 17.47,

- paraffin content,% - 3.67;

- the content of asphaltenes,% - 11.15.

The oil production rate for 1 year decreased from 12.5 tons / day to 1.8 tons / day. Based on geophysical data, oil inflow intervals were determined. It was established that the bottom-hole zone is significantly crippled with paraffin deposits and emulsion (water in oil). Two hydroperforators were lowered onto the tubing to the mark of 1355 m, pumped into the pump unit 2.0 m ³ solvent mixture (0.6 m ³ dichloromethane, 1.2 m ³ SNPCH-7870, 0.2 m ³ isopropyl alcohol and 6 liters of explosive -1), they were sold with anhydrous oil with a low paraffin content, and discontinuously continuously moving the puncher, at a speed of outflow of the jet from the nozzles of the puncher 80-100 m / s, we processed one meter at first the interval 1355-1325 m, and then, moving the hydroperforators; interval 1314-1304 m. We pumped 0.750 m ^{3 of} oil through the annulus, determined the well injectivity and left the well under pressure to dissolve the paraffin for 16 hours. We again determined the injectivity of the well, which increased 1.5 times. A calculated volume of the acid mixture was prepared — 1 part in a volume of 0.5 m ³ (8.5% hydrochloric acid + 15% IPA + 1% IVV-1, the rest is water), 2 part in a volume of 22.0 m ³ (8.5 % hydrochloric acid + 10% IPA + 0.1% IVV-1, the rest is water) and pumped into the well during continuous circulation in a cycle: tank with a mixture - acid aggregate - tubing-perforators - annular space - fountain fittings - tank with sweep. During the continuous-discrete circulation of the alcohol-acid mixture along the intervals of 1355-1325 m and 1314-1304 m, a pressure of 2.0-3.0 MPa was created in the annulus. During the treatment with the alcohol-acid mixture, the concentration of the active part of the acid was controlled. After 16 hours, the concentration of the active part of the acid decreased from 8.5% to 3.0%. During the treatment with the alcohol-acid mixture, pressure was annually created in the annulus of 4.0-5.6 MPa by closing the gate valve on the field and quickly opening it to depress and repress the well bottom-hole zone in a pulsed mode using the so-called variable pressure method .

The well was developed for fluid production. Water cut decreased to 3.5%, and oil production increased to 14, 3 t / day, i.e. 1.15 times.

We give a specific example of processing the bottom-hole zone of a producing horizontal well drilled in a carbonate oil reservoir using only a solution of hydrochloric acid through two hydroperforators. The initial production rate is 8.9 tons / day, the current production rate is 2.4 tons / day. We conducted geophysical surveys and determined the injectivity of the well. An 8.65% aqueous hydrochloric acid solution was pumped through the tubing through the entire well. During discrete-continuous movement with tubing through hydroperforators, the productive interval was processed for 16 hours. When using only technical acid, its concentration decreased over this period to 1.0%. The oil production rate after treatment with hydrochloric acid was restored to 6.9 tons / day, i.e. by 77.5%.

Thus, the application of the proposed processing method in the form of 2 rims - with a solvent mixture, and then with an alcohol-acid mixture flowing out through nozzles of hydroperforators, provides not only the restoration of the oil production rate to the initial one, but also involves the previously accumulated intervals of the reservoir in the development.

Claims (1)

A method of treating a bottomhole zone of a well, mainly horizontal, not covered by a casing string, by injecting the rims of the treated mixture and pushing it into the formation, while a mixture of dichloromethane, aromatic hydrocarbon and cationic surfactant (CPAS) is pumped into the first rim, characterized in that preliminarily, based on geophysical data, productive intervals of the formation are determined, in which at least two hydraulic guides are lowered on tubing (tubing) a perforator with nozzles through which the mixture is pumped into the rims to process the productive intervals of the formation at a nozzle flow rate of 50-150 m / s, while dichloromethane is introduced into the first rim - 30-50 wt.%, aromatic hydrocarbon mixed with aliphatic hydrocarbon - 20-60 wt.% In the ratio of (1-1.5) :( 1.5-1) and additionally alcohol, mainly isopropyl, or methyl, or ethyl - 10-30 wt.%, And it is preferable to use as a surfactant SNPCH-PKD-515 according to TU-39-05765-670-OP-211-95 at a concentration of surfactants of 0.1-0.3 wt.%, The mixture is injected h calculating the overlap of productive intervals of the formation for subsequent selling it into the formation with a closed annular space at a pressure lower than the pressure of the casing string, after the mixture is pushed into the formation, technological shutter speed is 0.5-1.0 hours; by its injectivity, and the second rim is divided into two parts, while the alcohol-acid mixture of the composition, wt.%, is pumped into both parts, hydrochloric and / or hydrofluoric acid - 0.5-15, isopropyl alcohol, or methyl, or ethyl - 10-30 and KPAW, and in the first part of the second rim, KPAW 0.8-1.0 are injected, in the second - 0.1-0.3, the rest is water, the specified mixture is pumped with its circulation in the well through tubing, hydroperforators and annulus with overpressure.