SU1588860A1 - Plugging composition - Google Patents

Abstract

The invention relates to the oil and gas production industry and is intended for carrying out repair and insulation works in wells of an oil or gas reservoir. The goal is to increase the plugging ability by reducing water solubility while increasing the strength of the forming polymer. The composition contains the following components in their ratio, wt. %: technical lignosulfonates 22-30, sodium bichromate 4-8, aluminum chloride - the product obtained by washing with a solution of aluminum chloride in the reaction mass in the processes of alkylation of benzene with propylene 5-10, water the rest. The formulation is prepared by pre-dissolving the components in water, followed by mixing solutions of aluminum chloride, sodium bichromate and lignosulfonates. The use of this cement composition will increase the efficiency of repair and insulation works carried out to isolate the inflow or absorption of fresh and desalinated water. The tensile strength of the polymer formed reaches 0.1–0.12 MPa while maintaining the shape and volume of the samples for three months or more. 1 tab.

Description

The invention relates to the oil and gas industry, in particular to cement compositions for repair and insulation works in oil or gas wells.

The aim of the invention is to increase the tamponing ability of the composition by reducing water solubility while simultaneously increasing the strength of the resulting polymer. .

The tampon composition includes technical lignosulfonates (LST), sodium bichromate, water and, as an additive, an aluminum chloride product obtained by washing with a solution of aluminum chloride of the reaction mass in alkylation processes without propylene with propylene, in the following ratio of components, wt.%:

Technical lignosulfonates22-30

Sodium dichromate 4-8 Alum chloride. 5-10

WaterEverything

Technical lignosulfonates (in terms of dry matter) are a by-product of pulp and paper production, which is calcium, sodium, ammonium or calcium-sodium salts of lignosulfonic acids. Available as liquid or solid product.

The most suitable for use in the preparation of the cement composition are LST liquid grades A and B and LST solid grades T. LST liquid grades A are characterized by improved binding properties and are intended as a binder in the foundry and manufacture of fire stops 5- LST liquid grades B are general purpose products.

LST liquid is a dark brown liquid with a mass fraction of dry substances of at least 47.0% - grade A and 50% - grade B. The density of the LST of these grades at 20 ° C is equal to 1.23 and 1.24 g / cm. LST solid grades T are light brown fine powder with a dry mass fraction of at least 76.0%. The pH of a 20% solution of grade A LST is at least 4.4. Grades B and T - not less than 4.5.

The alumina chloride is a light yellow or gray liquid with a greenish tint with a density of 1.181-1.247 g / cm with the basic substance content in terms of AlCl pa in the range of 200-300 g / l; has acidic properties: pH. commodity solution is in the range of 0.8-2.0.

Aluminum chloride is a product obtained by washing with a solution of aluminum chloride of the reaction mass in the alkylation of benzene with propylene.

Conducted laboratory studies have established that the introduction of aluminum chloride leads to a decrease in solubility while simultaneously increasing the strength of the polymer formed and also the consumption of hardening sodium sodium bichromate decreases.

The table shows, as an example, the results of experimental verification of the composition at.

five

0

five

0

five

0

five

The studies were carried out according to the well-known method: curing - mixtures were determined visually, in glass or porcelain cups., Psecemes into a thermostat with a given temperature; the strength of the resulting polymer - with the gap of standard samples on the Michaelis instrument. At the same time, after curing, the samples were immediately placed in storage in fresh (tap) water.

The solubility of the resulting polymer was evaluated by visually observing samples stored in fresh water by changing the volume and shape of the samples and the color of the water.

As can be seen from the tabular data, the introduction of alumochloride in. the grouting composition practically excludes the dissolution of the formed polymer in fresh water, increasing its tensile strength to 0.1-0.12 MPa. At the same time, the limits of the mass fraction of LSTs are extended, which provide mixtures with an acceptable 1 time of curing and the quality of the polymer formed, and the consumption of hardening sodium bichromate is reduced.

The tamping composition is prepared as follows.

Example 1. For selective isolation of watered intervals, 3.0 m of the composition with hardening time h was pumped into the reservoir at a depth of 1250.0- 1256.0 m (reservoir temperature +24 C) at a ratio of initial components, wt.%: Years 23 , 0; sodium bichromate 4.0; alum chloride 5.0; water 68.0. The density of the composition is 1.178 g / cm, the calculated weight is 3530 kg.

Calculation of the mass and volume of the initial components:

Powdered LST (mass fraction of dry substances 76.0%):

0

i5

Sodium bichromate (density 2.52 g / cm): Alum chloride (density 1.2 g / cm3:

Water

3530x0.23: 0.76 1300 kg

, kg 141: 2, l

, kg 177: 1, l 3530- (1300 + 141 + +177) 1911 kg (l).

five

The composition was prepared with the help of two CAA-320M aggregates by uniformly introducing an aqueous solution of sodium bichromat with alcohloride into the circulating aqueous solution of LST and mixing them for 2 cycles of circulation.

An aqueous solution of sodium bichromate with aluminum chloride was prepared in one of the cavities of the measuring tank of one unit TSA-320M. Initially, 300 l of fresh water is poured at 60 ° C and the calculated amount of alcohol is (the volume of water and its temperature are set arbitrarily); then, the calculated amount of sodium bichromate was dissolved in the formed mixture by gradually introducing it into the circulating flow and circular circulation for 10 minutes.

An aqueous solution of an LST was also prepared by gradually introducing malignant LSTS into the circulating stream of preheated water (1611 liters 1911-300) and circulating the mixture until complete dissolution of the LST.

Example 2. To turn off the upper reservoir at a depth of 1237.0- -1244.0 m (reservoir temperature +24 C), 4.0 m of the composition with a curing time of 40 minutes was pumped over the casing at a ratio of initial components, wt%: LST 30 ,eight; sodium bichromate 4.0; aluminum chloride 5,6; water 59.6.

The density of the composition is 1.175 g / cm, the estimated mass is 4700 kg.

During processing, liquid LST grade A with a mass fraction of dry substances of 47.2% and a density of 1.23 g / cm was used, LST were diluted with water to a density of 1.202 g / cm and a mass fraction of dry substances of 41.4%

Calculation of the mass and volume of the initial reagents:

4700x0.308: 0.41 3531 g 3531: 1.202 2938 l

4700x0 kg

15

20

8860

five

6

1.2 g / cm 3): 4700x0, kg 263g, l

Water 4700- (3531 + 188 +

+ 2bЗ) 718 kg (l)

The preparation of the composition was carried out as described in example I of the scheme .. At that, 300 l of water were consumed for the preparation of an aqueous solution of sodium bichromate with aluminum chloride, and the rest of the water was

25

718-300 418 l at + 18 ° C is introduced into an aqueous solution of LST.

As can be seen from the table, an acceptable grouting mixture based on LST without the addition of apium chloride is only a mixture with a mass fraction of LST and sodium dichromate, respectively, 31.5 and 9.1%. However, placing the polymer formed from this polymer mixture in fresh water after only two days led to its dissolution with loss of form. From mixtures with a smaller mass fraction of LST, g-limer with satisfactory quality is not formed even with a mass fraction of sodium dichromate of 9.1%. A further increase in the mass fraction of sodium bichromate leads to a reduction in the curing time of the mixtures, eliminating the possibility of their practical use.

At the same time, the introduction of aluminum chloride in the tampon mixtures on the basis of LST sharply reduces the solubility of the base of the developing polymer in fresh lead already at a mass fraction of apium chloride in a mixture of 4.0%, and at a mass fraction of 5.0% polymer in fresh water practically does not dissolve. At the same time, the tensile strength of the polymer formed reaches 0.1-0.12 MPa. Studies show that this effect is also observed when the mass fraction of 5 years is reduced to 22.0% in the mixture, and sodium bichromate to 4.0% (experiment 4).

thirty

The use of this cement composition will increase the efficiency of the repair and insulation works carried out to isolate the inflow or eliminate the absorption of fresh and cold desalinated water by eliminating the solubility of the resulting polymer and increasing its strength. According to laboratory data, the tensile strength of the polymer formed from the proposed composition reaches 0.1-0.12 MPa while preserving the shape and volume of the samples for 3 months or more.

invention formula

The grouting composition containing texHH4ecKHie lignosulfonates and Chromium salts, characterized by the fact that, in order to increase tampon-yugey concentration, by reducing water content, | rast- aluminum chloride of reaction-mass in alkylation processes

of benzene with propylene, the following ratio of components, wt.%: Technical lignosulfonates 22-30 Sodium dichromate 4-8 Alumina chloride - a product obtained by washing with a solution of aluminum chloride of the reaction mass in the process of alkylation of benzene with propylene 5-10 Water Remaining

Change in solubility depending on

and strength of the prepolymer of the polymer on the basis of LST of the mass fraction of aluminum chloride

Claims (1)

ma samples for 3 or more benzene propylene in the next months. ratio of components , wt.%: Technical leagues Claim £ nosulfonates 22-30 E Sodium bichromate 4-8 Grouting composition containing Alumochloride - pro Technical lignosulfonates and salts product obtained Chrome, characterized in that when washing that, in order to increase tampon- 10 chlorine solution overall performance by reducing water stainless steel Solubility at the same time reactionary Increasing the strength of the resulting masses in the process Fimera, it contains aluminum chloride - sah alkyl product obtained by washing fifteen benzene thief aluminum chloride reaction sawn wood 5-10 mass in alkylation processes Water Rest Changes in the solubility and strength of the polymer formed on the basis of LST depending on the mass fraction of apumochloride Experience Mass fraction of components in the mixture, Z —------------------ years Swirl-Alumomat Sodium Chloride Water Cure time 4 mi n - Tensile strength, MPa Characterization of cured polymer, including after 2 days of storage in fresh water one 21.6 3.9 2 21.5 5.1 3 22 5 four 22 four 5 22, 5 6 26 four 7 26.2 four 8 22.3 4.1 9 22.3 8 10 thirty four eleven 32 8 12 32 four 13 33.5 3.0 fourteen 31.5 9.1 fifteen 23, θ ' 9.1 16 27.0 9.1 10 64.5 0-4 2 10 63,4 0-35 four 69 0-52 10 ' 64 0-48. 0.1. 10 63 0-35 0.11 5 65 0-45 0.1 10 59.8 1-00 - 7.4 66,2 0-45 - 5 64.7 0-20 0.12 5 61 0-26 -. 10 fifty 0-20 0.1 10 54 Famous 0-28 structure - 63.5 Not cured - 59,4 0-55 - 67.9 > 5-00 - .. 63.9 1-20 - Poor polymer quality, brittle, strength measurement on a Michaelis device impossible to carry out due to cracking of the sample The sample is swollen, partially dissolved, poor polymer quality The sample is solid, retained its shape, no dissolution Also The sample is solid, retained its shape, no dissolution Also When components are mixed, a high-flowing, pumpable mixture is formed. Poor polymer quality, brittle Sample swollen, partially dissolved, lost shape Poor quality of the polymer, brittle, strength measurement with Michaelis instrument impossible