RU2250983C1 - Composition for maintenance and isolation operations in wells - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: composition has, in percents of mass: acetoneformaldehyde resin 5-90, hardening agent - 5% water solution of caustic soda 5-40, and bed water - the rest.

EFFECT: higher quality, higher efficiency.

2 ex, 1 tbl

Description

The invention relates to the oil and gas industry and can be used in the repair of well support, the elimination of leaks in the production string, shutting down the reservoir.

Well-known grouting compositions using synthetic resins based on shale phenols (TSD-9, TS-10) [1].

A disadvantage of the known compositions is the relatively low strength parameters of the polymer stone, shrinkage during hardening, deficiency and high cost of raw materials. The initial components of the resin (TSD-9, TS-10) and formalin are toxic liquids with a pungent odor, which creates certain difficulties during the repair and insulation works (RIR).

Closest to the proposed invention is the use of acetone-formaldehyde resin as a hardener, caustic soda is used [2].

The disadvantages of the known composition are the low strength characteristics of the formed polymer stone, the relatively high viscosity of the original resin, which makes it difficult to filter into the zone of violation of the column with low injectivity. Difficulty working with resin at temperatures below minus 20 ° C.

An object of the invention is to improve the quality of RIR during the elimination of violations of the production string, eliminate leakage in the production string at low injectivity, increase success when shutting down formations by developing a grouting composition with increased strength, improved filtration capacity due to a decrease in its viscosity, and improved processability during winter time. .

The problem is solved in that acetone-formaldehyde resin, a hardener and a resin modifier are used as a grouting composition, a 5% aqueous solution of sodium hydroxide is used as a hardener, and Devonian horizon formation water is used as a resin modifier with the following components, wt.%:

Acetone-formaldehyde resin 50-90

5% aqueous solution of caustic soda 5-40

Formation water the rest

The acetone-formaldehyde resin used is a homogeneous liquid from light to brown in accordance with TU 2228-006-48090685-2002, grade ACF-3M-75.

Technical caustic soda is a flaked white mass according to GOST 2263-79.

Produced water from the Devonian horizon is extracted from a depth of 1700-1900 m of oil fields of the Republic of Tatarstan.

The salt component composition is predominantly, wt.%: CaCl ₂ - 5,48; MgCl ₂ - 1.57; KCl 0.23; NaCl - 16.4.

The content of components in the grouting composition, technological parameters of the grouting composition and stone are shown in the table.

The following are examples confirming the possibility of carrying out the invention in laboratory conditions.

Example 1. Prepared a grouting composition with a ratio of acetone-formaldehyde resin, 5% aqueous solution of caustic soda and produced water, wt.%: 50: 37.5: 12.5. For this, formation water was added to the resin and mixed thoroughly. Separately, a 5% aqueous solution of caustic soda was prepared. The prepared aqueous solution of caustic soda in an amount of 37.5 wt.% Was added to the resin with modified formation water and all were mixed. The technological characteristics of the grouting composition were determined: density, spreadability (according to GOST 26798.1-96) 1185 kg / m ³ , 24.5 cm, respectively. The pour point of the cement composition was determined (according to GOST 20287-91). At minus 35 ° C, the grouting composition remains mobile.

The start and end time of curing was determined visually 1-45 hours and 2-10 hours, respectively. The result is a polymer stone. Strength characteristics after 28 days of storage of cured samples in produced water (according to GOST 26798.1-96), MPa: for bending - 4.75, for compression - 9.56. The study of cured samples during long-term storage in produced water showed that their size did not change, i.e. no shrinkage.

Examples 2-10 (see table) are similar to the first, differ in the amount of resin, 5% aqueous solution of caustic soda, modifier.

As can be seen from the table, the tensile strength of the proposed cement composition increased in comparison with the prototype by 37%. The proposed grouting compositions modified with formation water remain mobile at a temperature of minus 35 °, the curing time is ~ 2-18 hours, which is acceptable for RIR. The content of components, greater or less than the specified limits, leads to a deterioration in strength properties, mobility, curing time, the appearance of shrinkage.

The following are examples of industrial use of the proposed cement composition in the well.

Example 1. At a depth of 250 m was discovered leaks 146 mm production casing. The temperature in this range was 20 ° C. The well was received at a pressure of 4.0 MPa. A cement bridge was installed below the breach. Prior to this, conventional cement pouring was carried out. The violation was not resolved. Therefore, 2.5 m ^{3 of} resin modified with 0.5 m ^{3 of} formation water of the Devonian horizon and 1.5 m ^{3 of} 5% aqueous solution of sodium hydroxide were prepared on the surface in the measuring tanks of two cementing units CA-320M. In violation, 2.5 m ^{3 of} resin and 1.5 m ^{3 of a} 5% aqueous solution of caustic soda were simultaneously pumped through a tee. The alkali feed rate was 1.6 times the resin feed rate. Then, the plugging mixture was fixed by pumping 1 ton of cement, leaving a cement cup at a depth of 235 m.The final pressure during injection of the resin was 7.0-8.0 MPa, after stopping the injection, the pressure dropped to 5.0 MPa and remained at that level. After waiting for the mixture to solidify (OZS), the cement cup was drilled. When tested under a pressure of 10 MPa, the production casing showed complete tightness. They completed the development and commissioning of the well.

Example 2. At a depth of 267 m was discovered leaks 146 mm production casing. The temperature in this range was 20 ° C. Pressure drop from 10 to 4 MPa in 30 minutes, which excluded the use of cement mortar. Therefore, 0.70 m ^{3 of} grouting composition was prepared on the surface in the measuring unit of the cementing unit CA-320M in the following sequence of operations: 0.56 m ³ of ACF resin was pumped from barrels, 0.07 m ^{3 of} produced water was added as a solvent and the mixture thoroughly mixed. An aqueous alkali solution of 0.07 m ³ 5% was prepared in a chunk of the aggregate and mixed with resin. The prepared grouting composition was pumped into tubing (tubing), then pumping fluid was pumped into the tubing at the rate of leaving the beaker in the string. They performed a backwash of the well, raised the tubing to a safe height and closed the well at the OZS. After that, by tapping the tubing, a glass from the hardened grouting composition was determined, a glass was drilled, a 146 mm production casing was pressed with a pressure of 10 MPa and its tightness was established. They completed the development and commissioning of the well.

Thus, the proposed grouting composition corresponds to technological indicators that allow it to be used for RIR.

The use of the proposed grouting composition will increase the effectiveness of RIR by adjusting the time of its curing, improving manufacturability when working in the winter season and the possibility of using acetone-formaldehyde resin with different contents of the main substance.

Literature

1. Blazhevich V.A., Umrikhina E.N., Umetbaev V.V. Repair and insulation work in the operation of oil fields. - M .: Nedra, 1981, p. 232.

2. Serenko I. A., N. A. Sidorov, A. T. Koshelev Re-cementing during the construction and operation of wells. - M .: Nedra, 1988, p. 262.

The content of components in the grouting composition, technological parameters of the grouting composition and stone of the proposed composition and prototype №№
p / p The content of the components of the composition, wt.% Technological parameters of the grouting composition Technological parameters of the resulting stone Acetone-formaldehyde resin Cure tel Plastic
water Urea Water Density
kg / m ³ Spreadability
cm Time
beginning
curing
hour min Time
the end
curing
hour min Limit
strength
after 28
day, MPa Shrinkage
across
day,
% to bend on compression 1 2 3 4 5 6 7 8 nine 10 eleven 12 thirteen 1 fifty 37.5 12.5 - - 1185 24.5 1-45 2-10 4.75 9.56 0 2 fifty 40 10 - - 1180 25.0 1-30 2-00 4.89 10.01 0 3 55 thirty fifteen - - 1189 24.5 2-50 3-25 4.23 9.09 0 4 60 twenty twenty - - 1191 24.0 4-00 5-30 4.07 8.99 0 5 70 twenty 10 - - 1198 24.0 3-20 4-35 4.35 9.15 0 6 73 eighteen nine - - 1200 23.5 4-30 5-45 4,56 9.35 0 7 80 10 10 - - 1208 23.0 6-40 8-00 4.42 9.25 0 8 82 thirteen 5 - - 1209 23.0 6-10 7-00 4,50 9.30 0 nine 85 10 5 - - 1210 22.0 8-10 10-00 4.30 9.14 0 10 90 5 5 - - 1215 21.0 12-00 18-00 4.12 9.05 0 eleven 45 45 10 - - 1175 26.0 0-25 0-50 3.89 8.55 0.5 12 95 4 1 - - 1219 19.5 24-00 48-00 3,50 7.67 1,0 The composition of the prototype eleven 80 1,0 - 6 thirteen - - 0-20 - - 9.00 - 12 67 3.0 - 6 24 - - 0-25 - - 6.20 - thirteen 55 0.3 - 6 38.7 - - 2-10 - - 2.26 -

Claims (1)

A grouting composition including acetone-formaldehyde resin, an alkaline hardener and a resin modifier, characterized in that a 5% aqueous solution of caustic soda is used as an alkaline hardener, and Devonian horizon water is used as a resin modifier in the following ratio, wt.%: Acetone-formaldehyde resin 50-90 5% aqueous solution of caustic soda 5-40 Formation water