SU1239270A1 - Method of isolating porous and fissured formations - Google Patents

Description

The invention relates to mining, and more specifically to oil and gas production, and can be used in the drilling of wells to isolate porous and fractured formations.

The aim of the invention is to increase the efficiency of the insulation by increasing the sealing capacity of the resulting insulation screen while at the same time simplifying the technology of injection and displacement of the components into the formation.

The method of isolating porous fractured formations is carried out as follows.

Firstly, a gelling agent is pumped into the formation, which is used as an aqueous suspension of bentonite containing solution of alkali metal silicate (in 1 m aqueous suspension of bentonite contains 0.5 to 200 kg of bentonite and 50 to 350 kg of alkali metal silicate), or aqueous alkaline. solution of acrylic polymer (the content of alkali in the solution is 5 -; 10%, and the acrylic polymer - 1 - 20%).

The content of bentonite and alkali metal silicate is chosen depending on the size and configuration of the pores. Gelling agent is forced into the reservoir with water buffer. Then, a solution of spent melt of titanium chlorinators, having a concentration corresponding to a density of 1200-1300 kg / m, is pumped into the formation. . The density of the solution is chosen depending on the coefficient of porosity of the reservoir.

The spent melt of titanium chlorinators is, mainly, a mixture of water-soluble chlorides with the following average chemical composition,% by weight of dry matter

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After that, a cement slurry with a density of 1,400-2,200 kg / m is pumped into the formation with the addition of spent melt of titanium chlorinators from 30 to 500 kg per 1 m of cement slurry.

After all the components are pumped into the reservoir due to the diffusion of alkali metal silicate and polyvalent metal chlorides contained in the spent melt of titanium chlorinators, a reaction takes place in the pore volume, resulting in the formation of hydrous silicic acid gel, precipitation of water-insoluble silicates of polyvalent metals, also clots of coagulated bentonite. If polyvalent metal cations are contained in the formation water, they also participate in the reaction with alkali metal silicate, increasing the amount of gelatinous substance.

When using an alkaline solution as a gel-forming substance, it is rapidly coagulated, caused by the chlorides of magnesium, iron, manganese, chromium, cadmium, etc., contained in the solution of the spent melt of titanium chlorinators.

Polyvalent metal cations, which are not bound to the polymer, give gel-like hydroxides when reacting with an alkali contained in a solution of an acrylic polymer. The reaction between the substances of the first and third of the successively completed components occurs in the pores, cracks and other layers of the reservoir as a result of smearing and thinning of the aqueous buffer as it is pumped into the reservoir, as well as diffusion of water from the first and third components into the reservoir. water buffer. i

Cement mortar with the addition of spent melt of titanium chlorinators has a delayed setting. and enhanced thixotropic properties. This allows the entire combination to be produced into the formation at a low speed and at the same time prevents the screen being eroded after the completion of the slip,

The thixotropy of the water-cement slurry occurs as a result of the precipitation of gel-like hydroxides of magnesium, iron, and manganese.

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chromium in the reaction of the corresponding salts from spent molten titanium chlorinators with calcium hydroxide from cement (Portland cement). A thin gel dispersion creates a colloid system in the liquid phase of the cement slurry and gives it the properties of a finely structured dispersion. In particular, such a fluid acquires a shearing pro-. ness and reversibility of the structure destruction, i.e. thixotropy.

Cement mortar with the addition of spent melt of titanium chlorinators is well combined with an aqueous solution of spent melt of titanium chlorinators, when smayivanie there is no significant change in the rheological properties and the speed of setting of the cement mortar.

Increased screen strength is ensured by the fact that, when the formation fluid moves from the formation to the wellbore, there is an intensive mixing of unreacted volumes of alkali metal and polyvalent metal chlorides contained in the spent melt of titanium chlorinators, with the formation of additional quantities of gel and insoluble precipitates, clogging pores. An additional amount of clogging substances is formed by contact of the fluid with an alkali metal silicate solution, if the fluid is

150 kg per 1 m in the amount of 15 then 1 m of water as a buffer, and then 5m of the spent melt of titanium chlorinators with a density of 1300 kg / m. After that, 10 m cement slurry is pumped in at a density of 1400 kg / m, containing 500 kg of spent melt of titanium chlorinators per I m cement slurry

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it is represented by reservoir water, containing- 35 Two days after the salt of polyvalent metals.

The part of the screen formed by the hardened cement mortar prevents it from being extruded. (solution) into the wellbore.

When isolating absorbing horizons, the improvement of the insulating properties is provided by a higher viscosity of the bentonite suspension containing a solution of alkali metal silicate, and higher thixotropic properties

Neither the isolation works resume drilling. .

The proposed method of porous and fractured formations makes it possible to regulate the rheological and plugging properties of the pumped in a wide range. the reservoir of the system depending on the hydrodynamic and physicochemical conditions in the insulated reservoir.

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you cement solution with the addition of spent melt of titanium chlorine; ritorov.

The volumes of sequentially injected reagents are chosen based on the power and hydrodynamic characteristics of the isolated interval, as well as the purpose and depth of the created screen.

10 Characteristics of injected solutions are given in the table.

Example. Isolation of the washing liquid absorption zone is performed. P & absorption occurs at a specific weight of washing fluid of 1220 kg / m. Presumably, the absorbing formation is represented by fractured limestones. The temperature in the absorption zone is about.

To isolate the absorption zone in. the well is pumped through a 5m thick bentonite slurry (viscosity n. through SPB-5 — does not flow) with 200 kg bentonite and sodium silicate through drill pipes lowered to the roof of the submerged horizon.

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150 kg per 1 m in the amount of 15 then 1 m of water as a buffer, and then 5m of the spent melt of titanium chlorinators with a density of 1300 kg / m. After that, 10 m of cement with a density of 1400 kg / m, containing 500 kg of spent melt of titanium chlorinators per I m of cement mortar, are injected.

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Neither the isolation works resume drilling. .

The proposed method of porous and fractured formations makes it possible to regulate the rheological and plugging properties of the injected fluid within wide limits. the reservoir of the system depending on the hydrodynamic and physicochemical conditions in the insulated reservoir.

Gelling agent bentonite 200 kg per 1 m and sodium silicate 150 kg / m ORTH buffer solution, r 1300 kg / m Cement solution 500 kg ORTH per 1 r p 1400

Gelling agent - bentonite 0.5 kg per 1 m and sodium silicate 350 kg / m Water buffer ORTH, r 1200 kg / m Cement mortar 30 kg ORTH per 1 m, r 1600 kg / m

Gelling. the substance is bentonite 100 kg per 1 m and sodium silicate 50 kg per 1 m. Water buffer ORTH, Р 1300 kg / m Cement solution 200 kg ORTH per 1 m% р 2200 kg / m

Metas solution in alkaline aqueous solution 10%, Metas 30 by dry matter. Water buffer ORTH, r 1300 kg / m; Cement mortar

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500 kg ORTH per 1 m - 1400 kg / m.

1% solution of hypane in 0.5% solution of alkali (NaOH)

Water buffer ORTH, p

 1200 kg / m. Cement mortar

30 kg ORTH per 1 m, p

 1600 kg / m

10% solution of Hypan in 10% solution of alkali (NaOH)

Water buffer ORTH, r 1300 kg / m

1 vol., H-, 10% hypan + 1 h, 10% aqueous solution of calcium chloride + cement

solution, 1850 kg / m

PJ is the pressure at which the cylinder of the plugging mixture is unitized for the gas in a tube with an inner radius of 18 mm,

ORTH - spent melt of titanium chlorinators.

VNIIPI Order 3365/27

Tiraok 543 Subscription

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Tiraok 543 Subscription

Claims (1)

METHOD FOR INSULATION OF POROUS AND CRACKED STREDS, including injection of a gel-forming substance and coagulator in the form of a salt ιβογο mortar into the well, subsequent injection of cement mortar with a salt additive and injection of components into the formation, characterized in that, in order to increase the insulation efficiency due to increased plugging the resulting insulating screen while simplifying the technology of injecting and selling comonents into the formation, and injecting a gelling agent and saline into the well t sequentially, with separation by buffer, moreover, an aqueous suspension of bentonite containing 0.5 to 200 kg of bentonite and 50 to 350 kg of alkali metal silicate in 1 m3 is used; la, or an aqueous alkaline solution of acrylic polymer containing 0.5 to 10% alkali and 1 to 30% acrylic polymer, a solution of spent melt of titanium chlorinators with a density of 1200-1300 kg / m ^{3 is} used as a saline solution, and as a cement solution mortar - cement mortar with a density of 1400 -2200 kg / m ³ containing 30-500 kg of waste solution of titanium chlorinators per 1 m of solution. SU ... 1239270