Well stopping method

IPC classes for russian patent Well stopping method (RU 2250360):

E21B43/12 - Methods or apparatus for controlling the flow of the obtained fluid to or in wells (E21B0043250000 takes precedence;valve arrangements E21B0034000000)

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FIELD: oil and gas industry.

SUBSTANCE: method includes preparation of technological liquid - water solution of sylvinite ore mixture with chlorine calcium by solving a mixture of components in hot fresh technical water, drained from oil and water preparation plants or bed water. During solution of sylvinite ore mixture with chlorine calcium in bed water the latter is drained from the well at temperature 60-90°C. Technological liquid is produced with solution density 1.23-1.37 t/m³. Then prepared technological liquid is fed into well shaft a bit lower, oppositely to zone and above ceiling of productive bed with forming of hydraulic column above the latter. Then well shaft to the mouth is filled with water. Value of technological liquid hydraulic column of high density on basis of said mixture, fed into well shaft above ceiling of productive column of technological liquid is taken in amount, necessary and enough from well stopping conditions.

EFFECT: higher efficiency.

6 cl, 1 ex

The invention relates to the oil and gas industry and can find application in various technological operations in wells and, in particular, when the killing of wells, as well as perforation of wells or injection wells.

There is a method well killing fluids based on water solutions of mineral salts, mainly chlorides and bromides of sodium, calcium, magnesium, zinc, etc. individually or in various combinations [1].

However, this method is uneconomical because of the cost of reagents and preparations for killing that significantly exceed the benefits derived from technological works well.

Also known way of killing the well by lowering reservoir pressure at 5-10% below the hydrostatic and subsequent fill the reservoir with water [2].

The disadvantage of this method is the large loss of oil production for the entire period of declining reservoir pressure at the site of the development not only of the wells, but also from the other oil-producing wells located in this area.

The closest in its essence, and the technical result of the claimed technical solution is a method of plugging oil and gas wells, wherein the well bore is injected aqueous solution enriched sylvinite ore inhibitor wasp is cobracobana, moreover, an aqueous solution of sylvinite ore is placed against the zone of the reservoir and above the roof it with the formation of the hydraulic column. The process liquid on this technical solution also contains the target additives, corrosion inhibitors, inhibitors of precipitation, thickeners, etc. [3].

The disadvantage of this method is the reduction of reservoir properties of the bottomhole zone of the reservoir or very long (up to several months) the duration of the relaxation of these properties to the original level after the necessary technological operations in the well.

The technical result of the invention is to improve the effectiveness of plugging wells with aqueous solutions of mineral salts as the main means of stimulation while maintaining its reservoir properties.

Required technical result is achieved by the fact that in the process of killing the well, including the location in the wellbore an aqueous solution of mineral salts with the addition of a precipitation inhibitor, corrosion inhibitor and carrying out technological operations in the well, as a solution of salts using an aqueous solution of sylvinite ore in a mixture with calcium chloride, and this solution is used with a maximum downhole temperature conditions Konz what Tracia solution mixture, and the solution is placed below the reservoir against him, and above the roof of the productive formation with the formation of the hydraulic column above it, with the rest of the height of the wellbore is filled with water to the mouth. Using the solution with the content, wt.%:

Sylvinite ore 60-75

Calcium chloride 25-40

When killing the well pumped water solution of sylvinite ore in a mixture with calcium chloride with a maximum downhole temperature conditions concentration in an amount necessary and sufficient for the formation of the hydraulic column in the wellbore above the roof of the reservoir, and the rest of the height of the trunk well before the mouth is filled with water.

When using an aqueous solution of sylvinite ore in a mixture with calcium chloride as the working fluid injection wells in it enter inhibitor of swelling clay component-bearing layer, for example, nitridation acid in an amount of 0.01 to 0.05 wt.% from the content of sylvinite ore.

When killing the well using an aqueous solution of sylvinite ore in a mixture with calcium chloride with the target additives thickeners, corrosion inhibitors, inhibitors of the precipitation and surfactants and other

An aqueous solution of sylvinite ore in a mixture with calcium chloride is prepared by dissolving a mixture of the decree of the components in fresh technical, waste from oil treatment plants and water or formation water.

In the preparation of a solution of sylvinite ore in a mixture with calcium chloride dissolving in fresh process water or waste from oil treatment plants and water water heated to 60-90°C.

In the preparation of a solution of sylvinite ore in a mixture with calcium chloride dissolution in formation water last pumped from the well with a temperature of 60-90°C.

As an inhibitor of swelling clay component of the hydrocarbon-bearing formation using, for example, nitridation acid in an amount of 0.01 to 0.05 wt.% from the mass of dissolved sylvinite ore (the content of calcium chloride is not taken into account).

As the precipitation inhibitor use NTF (nitrilotriacetate acid) in an amount of from 0.01 to 0.05 wt.% from the mass of dissolved sylvinite ore or snpch-M (the product of the interaction of oksietilidendifosfonovaya acid with an aqueous solution of ammonia and high-boiling fractions of the product of distillation of crude oil).

As the surfactant used, for example, chloride of alkyltrimethylammonium (DON-96” THE No. 2482-010-047695-97), the TRS-1 and other

As water-soluble mineral salts, a mixture of sylvinite ore and calcium chloride composition, wt.%:

Sylvinite ore 60-75

Calcium chloride 25-40

Sylvinite ore, figuratively speaking, modify or enrich by blending in to her calcium chloride. Thus, the content of components of sylvinite ore salts - chlorides of potassium and sodium - reduce and reduce the negative effects of sodium ions on the permeability of the productive formation. It should also be noted that, when dissolved mixture of sylvinite ore and calcium chloride insoluble impurities present in the first component, quickly and fully settle, which significantly improves the quality of the performance of the product when using it as a key component of process liquids oil and gas wells.

The essence of the invention.

Use as a main component liquid solution mixture of sylvinite ore and calcium chloride during technological operations in oil and gas wells creates an exceptionally good opportunity to use cheap natural product (minerals sylvinite ore) and cheap by-product of large-scale industrial production (calcium chloride) to prepare aqueous solutions of mineral salts, virtually no polluting bottom-hole zone of the well in the process operations. When it is determined that the penetration of this technology is hidcote in the reservoir permeability is not reduced, and in some cases even increased, which leads to the preservation of reservoir properties of the bottomhole zone of the reservoir.

We offer aqueous solutions of mixtures of sylvinite ore with calcium chloride can be used as the working fluid in the injection wells. During injection of a fluid into the formation of terrigenous last type may contain an inhibitor of swelling clay component of the reservoir. In both the cases is preserved and even increased permeability of the formation. Of course, in each case, the use of these aqueous solutions, the concentration of dissolved components is accordingly adjusted and adjusted depending on the purpose of process fluid.

Despite the heat of hydration by dissolving a mixture of sylvinite ore with calcium chloride water, the use of hot (60 to 90° (C) water increases the dissolution rate of 3-7 times, and the density of the solution reaches a value of 1.23 to 1.37 tons/cubic meters Although in fairness it should be noted that the freezing point depression properties of solutions containing calcium chloride, can operate with them at temperatures from -20 to -40°and below that in Siberia (and this is the main oil-producing region of Russia) is important.

The method is as follows. Liquid CH is the solution (an aqueous solution of a mixture of sylvinite ore with calcium chloride) is prepared by known techniques dissolution of the mixture components in hot (60 to 90° C) fresh technical, waste from oil treatment plants and water or formation water. Technical fresh or waste water is heated, and in the preparation of the process liquid by dissolving a mixture of sylvinite ore with calcium chloride in the reservoir water last pumped from the well with a temperature of 60-90°C. Receive the process liquid with the density of a solution of 1.23 to 1.37 tons/cubic meters needless to say that in the preparation of process fluid enter the appropriate targeted supplements, and in the same sequence in the same quantities, which are determined by the purpose liquid for killing or for injection into the injection well. Then thus prepared process fluid (liquid damping) is placed in the wellbore below, against zone and above the roof of the productive formation with the formation of the hydraulic column above the latter. Further, the wellbore to the mouth fill with fresh technical, waste from oil treatment plants and water or produced water.

The magnitude of the hydraulic column (and, respectively, and the volume of kill fluid high density-based solution mixture of sylvinite ore with calcium chloride) is placed in the wellbore above the roof productive post process fluid take, depending on the type of the process about what erali, held in the wellbore. As is clear from the description, these process steps may be killing the well, the suppression of neftegazopromyshlennoj or the removal of downhole equipment for repair or replacement, etc.

Example 1 a specific implementation of the method.

Technical data bore: the Diameter of the production casing - 146 mm, the current face - 1648 m, the volume of the production string is 28 cubic meters, the reservoir pressure - 186 ATM, the density of the reservoir fluid - 1,09 t/cubic meter, the volume of extraction fluid 78 cubic meters/day (27 cubic meters of oil and 51 cubic meters of water).

Carry out killing the well with the following parameters.

Injection into the well of process fluid based on the aqueous solution of the mixture of sylvinite ore with calcium chloride in the amount of 23.5 cubic meters with a density of 1.32 t/cubic meter and pumping industrial water to the wellhead in the amount of 4.5 cubic meters Further carry out technological replacement operation of the pump and return the well to a working state (oil and gas).

The volume of extraction fluid after killing 83 cubic meters (29 cubic meters of oil and 54 cubic meters of water).

Example 2 specific implementation of the method.

Technical data discharge hole: Diameter of the production casing 127 mm, depth of injection - 1670 m, the pressure of 190 MPa, the injection well is 42 cubic meters/day.

Shall discharge those the ideological liquid-based aqueous mixture of sylvinite ore with calcium chloride density of 1.10 tons/cubic m with the addition of 0.03 wt.% inhibitor of swelling clay component of the reservoir. The injection capacity of the well increases to 117 cubic m/day.

As can be seen from the description and examples of specific implementation of the method, the invention provides for the preservation of reservoir properties of the bottomhole zone of the reservoir oil and gas wells.

Sources of information taken into account when drawing up the proposal

1. Zaripov SZ and other liquids to push the wells at their repair. M., “Nedra”, 1981, p.45.

2. RF patent 2096591, MCL E 21 In 43/02, publ. 1998

3. RF patent 2169832, MCL E 21 In 43/02, publ. 2000 - the prototype.

1. The method of killing the well, including the location in the wellbore an aqueous solution of mineral salts with the addition of a precipitation inhibitor, corrosion inhibitors and carrying out technological operations in the wellbore, wherein the wellbore is placed aqueous solution of a mixture of sylvinite ore with calcium chloride, and use the solution with a maximum downhole temperature conditions concentration and upload it in an amount necessary and sufficient for the formation of the hydraulic column in the wellbore above the roof of the reservoir, and in the rest of the height of the trunk well before the mouth is filled with water.

2. The method according to claim 1, characterized in that use is a mixture of sylvinite ore with calcium chloride content at the level of components, wt.%:

sylvinite ore 60-75;

calcium chloride 25-40.

3. The method according to claim 1, characterized in that an aqueous solution of a mixture of sylvinite ore with calcium chloride is prepared by dissolving the latter in fresh process water, wastewater from treatment plants oil and water or formation water with a temperature of 60-90°C.

4. The method according to claim 3, characterized in that in the preparation of a solution of a mixture of sylvinite ore with calcium chloride dissolution in formation water last pumped from the well with a temperature of 60-90°C.

5. The method according to one of claims 1 to 4, characterized in that use an aqueous solution of a mixture of sylvinite ore with calcium chloride with a density of 1.23 to 1.37 t/m³.

6. The method according to claim 5, characterized in that an aqueous solution of a mixture of sylvinite ore with calcium chloride contains an inhibitor of swelling clay component-bearing layer, for example nitridation acid in an amount of 0.01 to 0.05% by weight of dissolved sylvinite ore.