RU2655490C2 - Method of bottom water cone cutting - Google Patents

Abstract

FIELD: oil industry.

SUBSTANCE: invention relates to the oil industry, in particular to a method of bottom water cone cutting to limit water inflows in oil wells. Method of bottom water cone cutting in oil wells involves stopping the well, extracting downhole equipment from the production column of the main trunk, installing a packer plug 1 m below the lower perforations. After that, the tubing string with the packer is lowered and the isolation composition of the selective action is pumped, then the grouting on a micro-cement basis and the last cement-based grouting composition. Then, the cement beaker is installed to the roof of the productive formation, the tubing string is lifted with the packer and the cement is set to harden. Drill a cement beaker with a packer-stopper, lower the perforator on the tubing into the oil-saturated interval of the formation and perform perforation of the formation, development of the well and its withdrawal to the regime.

EFFECT: proposed method allows to increase the radius, thickness and area of the waterproofing composition, and also to prolong the anhydrous operational life of the well.

1 cl, 4 dwg, 3 tbl

Description

The invention relates to the oil industry, and in particular to a method for cutting off a bottom water cone to limit water inflows in oil wells.

Currently, most of the oil fields in Western Siberia are in the final stages of development.

Huge oil reserves are concentrated in water-oil zones, where the water cut at the main operational facilities reaches more than 90%, which negatively affects the value of the final oil recovery coefficient. The most acute problem is the high (premature) water cut of well products.

The rational use of technology to limit water inflows significantly increases the efficiency of oil field development. Currently, there are many ways to carry out waterproofing works, having one or another advantages and disadvantages.

A known method of waterproofing work in wells with plantar bedding of aquifers, carried out by "stratification" of the screen [Skorodievsky, V.G. Development of technology for waterproofing works in wells with plantar bedding of aquifers [Text]: author. dis. ... cand. tech. Sciences / Skorodievsky Vadim Gennadievich. - Krasnodar - 24 s. - 2007 year.

The method is based on injection into the formation at various costs of several (three to four) portions of the composition of AKRON with different initial viscosity and time loss of fluidity. Moreover, after selling each portion to the formation, technological stops are made for 20-60 minutes or more, depending on the reservoir temperature. The time loss of fluidity of the injected portions is regulated by the amount of dilution of freight trains with water.

The disadvantage of this method is the low strength of the created waterproofing screen and the additional waiting time (technological stand).

There is a method of isolating the influx of formation water, including pumping grouting mortar under pressure into the water-developing part of the reservoir and holding the well for the time of setting cement grout [Reference book for the current and overhaul of wells / A.D. Amirov et al. - M .: Nedra, 1979. - S. 238-241].

The disadvantage of this method is the insufficient radius of the waterproofing screen, beyond which plantar water will bypass the waterproofing screen and watering of the well will continue.

The closest technical solution chosen for the prototype is a method of isolating the influx of formation water into oil and gas wells [Patent RU 2247224 / Kleshenko II, Baimurzina TN (RU) Telkov A.P. (RU) Yagafarov A.K. (RU), Sukhachev Yu.V. (RU) Sokhoshko S.K. (RU), in which the composition for selective waterproofing is injected, after it is injected, a hydrophobizing liquid or gas is additionally pumped to push the specified composition from the bottom of the well into the formation at a distance equal to the radius of the created screen, while this composition will take the form of a shell, the lower part of which when in contact with water, it becomes impermeable to the hydrophobizing liquid or gas injected after it, and the upper part is carried into the well when it is put into operation.

The disadvantages of this method are the complexity of the operation, as well as the risk of a breakthrough of the injected gas through the selective composition, as a result of which well formation water is inevitable during well operation.

The objective of the invention is to increase the efficiency of waterproofing work in oil wells, by creating an extended and sufficient thickness of the waterproofing screen.

The technical result that results from the creation of the invention is to increase the power, radius of the waterproofing screen, as well as delaying the time of watering the well.

The task and the technical result are achieved by the fact that the method of cutting off the bottom water cone in oil wells includes stopping the well, removing downhole equipment from the production casing of the main trunk, installing a packer plug 1 m below the lower perforations, lowering the tubing string from packer, injection of an insulating composition of selective action, followed by pumping of cement slurry on a microcement basis, followed by pumping of cement slurry cement-based tava, installing a cement cup to the top of the reservoir, raising the tubing string with a packer, waiting for the cement to solidify, drilling a cement cup with a packer plug, lowering the perforator on the tubing to the oil saturated interval of the reservoir, perforating the reservoir, developing the well and putting it into operation . In FIG. 1-4 presents the scheme of the method.

The method is as follows.

A well 1 operating a producing formation 2, at the bottom of which bottom water 3 lies, is stopped due to high water cut resulting from the formation of a bottom water cone 4, which overlaps the lower perforation interval 5. The downhole equipment 6 is removed with an operational packer 7 from the production string of the main trunk , set the packer plug 1 m (not shown) below the lower perforations (Fig. 1), lower the tubing string with packer 8, pump the insulation the composition of the selective action 9 (Fig. 2), followed by pumping the grouting composition on a microcement basis 10, which allows you to push the selective composition deep into the reservoir (Fig. 3), followed by the pumping of the grouting composition on a cement base 11, which allows you to push the grouting composition on a microcement basis and selective composition deep into the reservoir, as well as fix the waterproofing screen (Fig. 4). Injection in three cycles will allow cutting off the bottom water cone 4 and creating an extended reliable water-proof screen in the interval of the oil-water supply. After the third portion is injected, the cement cup is installed to the top of the reservoir (not shown), the tubing string is raised with packer 8, the cement is solidified, the cement cup is drilled with a packer plug (not shown), the perforator is lowered onto the tubing into the oil-saturated interval of the reservoir, perforation formation, well development and its conclusion to the regime.

The proposed method for cutting off the bottom water cone in the wells allows to increase the radius, thickness and area of the water barrier screen and increase the anhydrous period of operation of the well, delaying the inevitable flooding of the well.

As a grouting composition of selective action, it is recommended to use a selective composition for repair and insulation works in oil and gas wells, including 10 vol. % hydrophobizing organosilicon liquid (GKZH-11N), as a catalyst, 85 vol. % ethyl silicate ETS-40, as a thickener 5 vol. % diatomite [US Pat. 2529080, Russian Federation, IPC Е21В 33/138 (2006.01), C09K 8/506 (2006.01). Selective composition for repair and insulation works in oil and gas wells / Dolgushin VA, Kleschenko II, Leontiev DS, etc. - application No. 2013125841/03, 06/04/2013; publ. 09/27/2014, Bull. Number 27. - 6 p.]. The composition and technological characteristics of a selective waterproofing composition based on ETS-40 with diatomite are presented in table 1.

As a cement slurry composition on a microcement basis, a solution is recommended that contains a 2.0% aqueous solution of PVA-B1H polyvinyl alcohol and a mixture of microdura "U" with calcium hypochlorite Ca (ClO) ₂ in the following ratio of components, vol. %: 2.0% aqueous solution of PVA-B1H - 50.0; a mixture of microdura "U" with calcium hypochlorite Ca (ClO) ₂ - 50.0, including microdura "U" - 48, Ca (ClO) ₂ - 2.0. [Pat. 2326922 Russian Federation, IPC C09K 8/504 (2006.01). Composition for repair work in wells / Kleshenko II and others. - Application No. 2006134101/03, 09.25.2006; publ. 06/20/2008, Bull. Number 17. - 6 p.].

The composition and results of determining the curing time and the formation of a durable waterproofing material are presented in table 2.

The change in the relative permeability of core samples after treatment with the composition for repair work is presented in table 3.

Description:

1 - well;

2 - oil-saturated part of the reservoir;

3 - water-saturated part of the reservoir;

4 - water-oil contact;

5 - perforation holes;

6 - downhole equipment;

7 - operational packer;

8 - tubing with a packer;

9 - selective composition;

10 - cement composition on a microcement basis;

11 - cement-based grouting composition.

Claims (1)

A method of cutting off the bottom water cone in oil wells, including shutting down the well, removing downhole equipment from the production casing of the main trunk, installing the packer plug 1 m below the lower perforations, lowering the tubing string with the packer, injecting an insulating composition of selective action, s subsequent pumping of cement slurry on a microcement basis, followed by pumping of cement slurry on a cement basis, installing a cement cup to the roof and a productive formation, raising a tubing string with a packer, waiting for cement to solidify, drilling a cement cup with a packer plug, lowering the perforator on the tubing into the oil saturated interval of the reservoir, perforating the formation, developing the well and putting it into operation.

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