RU2263201C1 - Method to prevent corrosion caused by sulfate-reducing bacteria - Google Patents

Abstract

FIELD: oil industry, particularly to inhibit sulfate-reducing bacteria growth and control corrosion in oil gathering and processing systems.

SUBSTANCE: method involves injecting aqueous antibacterial solution in oil production well characterized by pipe corrosion at well outlet caused by sulfate-reducing bacteria; sealing hole annuity and bringing the killed well into operation. Antibacterial solution includes antibacterial substance added in amount of 1.5-2.5% by weight to mineralized water having 1.15 g/cm³ density. Before antibacterial solution injection mineralized water used for antibacterial solution preparation is forced through the well in amount of not less than well volume. Antibacterial solution is supplied so that antibacterial solution fills tubing space and hole annuity.

EFFECT: increased efficiency and reduced consumption of antibacterial solution.

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Description

The invention relates to the oil industry and may find application in suppressing the growth of sulfate-reducing bacteria and inhibiting corrosion in oil collection and treatment systems.

A known method of inhibiting the growth of sulfate reducing bacteria and inhibiting corrosion, including the use as a chemical reagent of the product of the interaction of monoethanolamine with formaldehyde, taken in a molar ratio of monoethanolamine: formaldehyde = 1: (2.01-3). The interaction product is used in the form of a solution previously prepared by reacting monoethanolamine with a 30-40% formaldehyde solution (formalin), preferably taken in a molar ratio of monoethanolamine: formaldehyde = 1: (2.01-3.0). In this case, an aqueous or aqueous-alcoholic solution of the reaction product is introduced in an amount of 0.007-2.0 wt.% (RF patent No. 2197605, publ. 2003.01.01).

The known method does not allow to reliably protect the equipment of oil wells and flow lines from corrosion caused by sulfate-reducing bacteria.

A known method of inhibiting the growth of sulfate-reducing bacteria in an oil reservoir, comprising determining for each well a zone of active biocenosis of sulfate-reducing bacteria, the volume of an agent with a bactericide, necessary to suppress sulfate-reducing bacteria, injecting the required volume of an agent with a bactericide equal to the volume of a zone of active biocenosis, into a reservoir through a maintenance system reservoir pressure and shutdown of each injection well for the time necessary to completely suppress vital activity microorganisms (RF patent No. 2169259, publ. 2001.06.20).

The known method allows you to suppress the vital activity of sulfate-reducing bacteria near the injection well, however, the method does not protect against corrosion caused by sulfate-reducing bacteria, an oil-producing well, flow line and subsequent pipelines and tanks. The method for its application requires a large volume of an agent with a bactericide.

The closest to the proposed invention in technical essence is a method of inhibiting the growth of sulfate-reducing bacteria, including determining the well area of the active biocenosis of sulfate-reducing bacteria, the volume of the bactericide solution necessary to suppress sulfate-reducing bacteria, injecting the volume of the bactericide solution through an operating oil producing well, at the outlet of which pipe corrosion was detected caused by sulfate reducing bacteria, supply at atmospheric pressure in the annular space of the well of a solution of bactericide, prepared on water of increased density, stopping the well for the time necessary to completely suppress the activity of sulfate-reducing bacteria, during which the used solution of bactericide is poured into the annulus, saturation in the bottom-hole zone of the well with a bactericide of the zone of active biocenosis of sulfate-reducing bacteria, use saturated with a solution of bactericide of the bottomhole zone of the well as a reservoir for storage and flow dovaniya germicide solution in the flow line with the borehole, the closing of the annulus and commissioning of the stopped oil wells (RF patent №2233973, opubl.10.08.2004 - prototype).

The known method allows to suppress the vital activity of sulfate-reducing bacteria near an oil well, however, the method is not always effective due to the use of an uncontrolled viability solution of a bactericide prepared on high density water. The method for its application requires a large volume of a solution of the bactericide.

In the proposed invention solves the problem of increasing the efficiency of the method and reducing the used volume of the solution of the bactericide.

The problem is solved in that in a method of combating corrosion caused by sulfate-reducing bacteria, which includes injecting a volume of a solution of a bactericide, prepared on high-density water, into an oil-producing well, at the outlet of which pipe corrosion caused by sulfate-reducing bacteria is detected, closing the annulus and putting the stopped tube into operation oil wells, according to the invention, as a solution of a bactericide, prepared on high density water, use a solution of bacte itsida unlimited pot life before injection solution is pumped through the well bactericide used for solution preparation water of the bactericide increased density in an amount not less than the volume of the well, and used germicide solution was filled in tubular and annular space of the well.

The features of the invention are:

1. injection of the volume of a solution of a bactericide, prepared on water of increased density, into an oil producing well, at the outlet of which pipe corrosion caused by sulfate-reducing bacteria was detected;

2. closure of the annulus;

3. putting into operation a stopped oil production well;

4. use as a solution of a bactericide, prepared on water of high density, a solution of a bactericide with unlimited viability;

5. before injection of the bactericide solution, pumping through the well used to prepare the bactericide solution of high density water;

6. the same in volume, not less than the volume of the well;

7. Filling with the used bactericide solution of the pipe and annular space of the well.

Signs 1-3 are common with the prototype, signs 4-7 are the salient features of the invention.

SUMMARY OF THE INVENTION

When developing an oil reservoir in a reservoir, conditions are created for the production of sulfate-reducing bacteria, which in turn cause equipment corrosion. Existing methods to combat pipe corrosion caused by sulfate-reducing bacteria are not always able to fully protect oil equipment. The proposed invention solves the problem of protection against corrosion caused by sulfate-reducing bacteria, oil producing wells, flow lines and subsequent pipelines and tanks. The problem is solved as follows.

Measures to combat corrosion caused by sulfate-reducing bacteria are carried out in an oil well, at the outlet of which pipe corrosion caused by sulfate-reducing bacteria is detected. As a solution of a bactericide, prepared on high-density water, a bactericide solution with unlimited viability is used. It was experimentally found that the viability of a solution of a bactericide prepared on water of high density, significantly depends on the density of water. As a rule, previously used mineralized water of natural or artificial origin with a density of 1.15-1.20 g / cm ³ . When the density of the water used is 1.15 g / cm ³ and above, a rapid, less than a day, precipitation of the bactericide from the solution occurs. Previously used bactericide solutions often did not have sufficient viability, and their use occurred after a viability period, i.e. after a day from the date of preparation. In fact, water of increased density was pumped into the well without a bactericide or with its minimal residues. This mainly explains the lack of success with a number of previous work. According to recent studies, to prepare a solution of bactericide with unlimited viability, it is necessary to use mineralized water with a density of up to 1.15 g / cm ³ . In this case, the optimal amount of bactericide should be 1.5-2.5% by weight. When the density of the water used is less than 1.15 g / cm ³ there is no loss of the bactericide from the solution.

As a bactericide, reagents SNPCH-1004, sulfane, Head-1007, etc. are used.

Very useful for solving this problem is the preliminary pumping of high density water used to prepare a bactericide solution through the treated well in a volume not less than the volume of the well. This manages to additionally flush the well and, most importantly, to increase the compatibility of the injected bactericide solution and the well fluid, as well as the wettability of the surface of the downhole equipment with a bactericide solution.

The used bactericide solution is used to fill the pipe (cavity of the tubing string) and the annulus (cavity between the tubing string and casing) of the well. After that, the annulus is closed and the stopped oil well is put into operation.

An example of a specific implementation of the method

Measures to combat corrosion caused by sulfate-reducing bacteria are conducted in an oil producing well, at the outlet of which pipe corrosion caused by sulfate-reducing bacteria is detected, with the following characteristics: column diameter 146 × 8 mm, length - 1200 m, diameter of the tubing string 73 × 8 mm, length - 1000 m.

The produced water used to prepare the bactericide solution is pumped through the well with produced water with a density of 1.07 g / cm ³ in the well volume.

As a solution of a bactericide, prepared on water of increased density, use a 2% solution of SNPCH-1004 with unlimited viability, prepared on produced water with a density of 1.07 g / cm ³ . Used bactericide solution fill the tube and annular space of the well. The annulus is closed and a stopped oil production well is put into operation.

Previously, for the fight against corrosion caused by sulfate-reducing bacteria, at least 40-50 m ^{3 of} solution was required. According to the proposed method for carrying out such work requires 15 m ³ solution. Success of work, i.e. guaranteed protection of the well and flow lines from corrosion caused by sulfate-reducing bacteria was 90% versus 65% according to previously used technology.

The application of the proposed method will allow to solve the problem of increasing the efficiency of protection against corrosion caused by sulfate-reducing bacteria, and to reduce the volume of the used bactericide solution.

Claims (1)

A method of combating corrosion caused by sulfate-reducing bacteria, which includes injecting a volume of a bactericide solution prepared on water into an oil producing well, at the outlet of which pipe corrosion caused by sulfate-reducing bacteria is detected, closing the annulus and putting a stopped oil-producing well into operation, characterized in that as a bactericide solution is used 1.5-2.5% bactericide by weight of the solution prepared in mineralized water to a density of 1.15 g / cm ³ before Zack Coy bactericide solution is pumped through the well used for the preparation of germicide solution mineralized water in a volume not less than the volume of the well, and used germicide solution was filled in tubular and annular space of the well.