RU2530805C1 - Plugging material - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: plugging material contains portland cement, silica-containing component, calcium chloride hardener and a plasticizing agent, at that portland cement, calcium chloride and silica-containing component are subjected to joint disintegrating treatment, and silica-containing component consists of tripoli powder and silica sand with the ratio of 1:10, besides plugging material contains additionally an expansion agent and reinforcement additive with the following ratio, wt %: portland cement - 50-70, silica-containing component consisting of tripoli powder and silica sand with the ratio of 1:10 - 30-50, reinforcement additive - 0.2-0.3 above 100%, plasticizing agent - 0.1-1.0 above 100%, calcium chloride - 0.1-3.0 above 100%, expansion agent - 3.0-5.0 above 100%.

EFFECT: producing the plugging material that ensures fast hardening at normal temperatures and thermal stability of cement stone with high strength properties.

1 ex, 3 tbl

Description

The invention relates to cementing materials used in cementing oil and gas wells, mainly to special binders for fastening steam injection wells.

The specificity of fastening steam injection wells is that the fastening of the wells takes place at normal (20-40 ° C), and the subsequent work of the cement stone must take place at high (more than 150 ° C) temperatures.

Conventional Portland cement can be used to mount wells that have temperatures below 100 ° C. At temperatures above 100 ° C, cement stone begins to lose its strength and increase permeability due to thermal corrosion. Resistant to thermal corrosion are cements, the composition of products, the hardening of which is represented by low-basic calcium hydrosilicates, having the ratio CaO / SiO ₂ (C / S) <1.2.

Known compositions of cementing materials with heat resistance, for example: cement-sand mixtures [Danyushevsky B.C. and others. The reference guide for well drilling. - M .: Nedra, 1987, p.135-137], slag-sand cements [Daniushevsky B.C. and others. The reference guide for well drilling. - M .: Nedra, 1987, p.138-139], lime-siliceous binders [Daniushevsky B.C. and others. The reference guide for well drilling. - M .: Nedra, 1987, p. 152-153].

A disadvantage of the known compositions is their insufficient heat resistance or low rate of curing at temperatures below 40 ° C.

A well-known grouting composition for steam injection wells, containing in wt.%: Clinker 25-40; gypsum 3-6; silica sand 35-38; main slag 20-22 and the additive "IR-1" 2-9 [RF Patent No. 2220275, cl. E21B 33/138, publ. 2003].

Grouting material is also known, containing in wt.%: Portland cement clinker 76-80; gypsum 4-5; ground nickel slag 15-20 [RF Patent No. 2111340, cl. E21B 33/138, publ. 1998].

Grouting material is also known, containing in wt.%: Slag-sand cement 30-70 and Portland cement 30-70. In this case, slag sand cement contains 50-60% of slag and 40-50% of quartz sand [Auth. certificate of the USSR No. 981585, class E21B 33/138, publ. 1982].

Well-known grouting material intended for use in wells exposed to thermal methods of exposure, and containing in wt.%: Grouting Portland cement 55-77; silica sand 20-35; synthetic calc-alumina slag 3-10 [Auth. certificate of the USSR No. 1654540, class E21B 33/138, publ. 1991].

These known compositions are characterized by the same disadvantages as the above analogues.

The closest to the proposed technical solution for the totality of the characteristics is the grouting material for steam injection wells [RF Patent, No. 2359988, cl. C09K 8/467, publ. 2009, bull. 19], containing Portland cement, quartz sand, amorphous silicon dioxide and water in the following ratio of components, parts by weight:

Portland cement 50-80

Quartz sand 10-45

Amorphous silicon dioxide up to 10

Water to W / C = 0.35-0.52

The grouting composition additionally contains technological properties regulators, which are used as an accelerator of setting time calcium chloride or sodium chloride up to 5 parts by weight, and / or hydroxyethyl cellulose up to 0.5 parts by weight, and / or plasticizer lignosulfonates or Melflux, or Zemplast MF brand b. up to 0.7 parts by weight, and / or reagent Police DF up to 0.3 parts by weight, antifoam - a modified silicone polymer.

The disadvantage of this grouting material is its low hardening rate at low temperatures and low heat resistance of the stone after hardening at high temperatures.

The aim of the invention is to obtain a composition of grouting material that provides quick hardening at normal temperatures and provides thermal stability of cement stone with high strength characteristics at temperatures of 150-250 ° C.

The goal is achieved in that the grouting material, including Portland cement, silica-containing component, hardening accelerator - calcium chloride and plasticizer, according to the invention contains Portland cement, calcium chloride and silica-containing component, subjected to joint disintegration treatment, and the silica-containing component consists of tripoli and quartz sand at a ratio 1:10, in addition, the grouting material further comprises an expanding additive and a reinforcing additive in the following ratio NII, wt.%:

Portland cement - 50-70;

silica-containing component, including tripoli and quartz sand in a ratio of 1:10 - 30-50;

reinforcing additive - 0.2-0.3 in excess of 100%;

plasticizer - 0.1-1.0 in excess of 100%;

calcium chloride - 0.1-3.0 in excess of 100%

expanding additive - 3.0-5.0 in excess of 100%.

In the present invention uses new ingredients and their disintegrant processing, which indicates the compliance of the invention with the criterion of "novelty."

The invention consists in the following.

Replacing part of the active cement with inert additives at temperatures below 100 ° C, in this case with silica-containing components, slows down the hardening of cement at normal and low temperatures. Therefore, the strength of the resulting stone is significantly reduced. Disintegrating treatment of Portland cement activates it, increases the hardening speed and strength of the resulting stone, thereby compensating for the decrease in strength from a decrease in the proportion of cement in the grouting material.

Joint disintegration treatment with cement of calcium chloride leads to the fact that the latter dissolves faster in the liquid of dissolution in comparison with calcium chloride, not subjected to disintegration processing. Therefore, calcium chloride earlier begins to act as an accelerator of hardening of cement, further increasing the strength of cement stone. In the scientific and technical literature, the use of disintegrating treatment of grouting cements is known. However, from the scientific and technical literature it is not known its use to activate the dissolution of calcium chloride, providing accelerated hardening of cement.

The introduction of an expanding additive into the grouting material will provide additional hardening of cement stone hardening in the annular space or against dense impermeable rocks.

The presence of a reinforcing additive ensures the stability of the cement slurry and enhances the expansion effect. This is due to the fact that two competing processes occur during hardening of cements. The first is shrinkage caused by contraction, the second is the expansion associated with an increase in the volume of cement gel formed compared to the volume of cement. The total result of these processes, multidirectional affecting the change in the volume of the hardening system, will determine the shrinkage or expansion during hardening of cements. Since the reinforcing additive reduces shrinkage, even with a minimum amount of expanding additives in cement, a slight increase in the volume of cement stone during hardening can be obtained.

In the scientific and technical literature, the use of dispersed reinforcement of cement cements is known. However, from the scientific and technical literature its application is not known to increase the effect of expansion and additional hardening of cement stone in the early stages of hardening.

The presence in the silica-containing component of the proposed application of quartz sand and tripoli leads to the fact that quartz sand, converted after disintegration processing into quartz flour, interacting with calcium hydroxide formed during cement hydration, forms low-basic calcium hydrosilicates with high thermal stability at temperatures, above 100 ° C. Tripoli, possessing a highly developed amorphized surface, begins to bind the resulting calcium hydroxide even at temperatures of 40-60 ° C. On the one hand, this leads to the formation of low-basic calcium hydrosilicates at these temperatures, on the other hand, it provides a sharp thickening of the cement slurry, drastically shortening the period between the end of the cementing process and the beginning of setting of the cement slurry, eliminating the negative processes of sedimentation and delamination of the cement slurry developing in the annulus wells.

In the scientific and technical literature, the use of ground silica in grouting cements is known. However, from the scientific and technical literature it is not known its use after disintegration processing together with tripoli in a ratio of 1:10.

Thus, the foregoing indicates the conformity of the claimed invention to the criterion of "inventive step".

In the invention, the following were used:

grouting portland cement PTsT-I 50 GOST 1581-96;

silica sand having at least 95% SiO ₂ in its composition;

tripoli containing at least 80% SiO ₂ ;

CaO based oxide expanding agent;

reinforcing additive - basalt fiber with a fiber length of 3 mm;

plasticizer - Polyplast SP-1 according to TU 5870-005-58042865-05;

calcium chloride technical calcined in accordance with GOST 450-77.

An example implementation of the invention.

The grouting material is prepared as follows: Portland cement, calcium chloride, quartz sand and tripoli are jointly processed in a disintegrator.

Then, all additives are added to the resulting mixture in the required proportions.

As an example, consider the technology of preparing cementing material with the ratio: Portland cement - 60%; silica-containing component - 40%; reinforcing additive - 0.2%; plasticizer - 0.5%; calcium chloride - 0.1%; expanding additive - 5% (composition No. 3 from tables 1 and 2). The amount of reinforcing additives, plasticizers, calcium chloride and expanding additives was taken in excess of 100%.

To prepare the grouting material, 1200 g of Portland cement, 2 g of calcium chloride, 800 g of a silica-containing component consisting of 72 g of tripoli and 720 g of silica sand were taken, which were processed in a disintegrator at a particle collision speed of 250 m / s. To the resulting dry mixture was added 4 g of basalt fiber, 100 g of expanding additive and 10 g of plasticizer SP-1.

From the obtained grouting material, solutions were prepared with a water-cement ratio of 0.5. The prepared solutions were used to determine their properties and to manufacture samples for bending and compression tests, as well as for conducting X-ray diffraction studies. Tests of the resulting grouting material were carried out in accordance with GOST 1581-96. The test results of this sample, as well as other compositions hardening at temperatures of 40, 160 ° C, are given in Tables 1 and 2.

Table 1 Properties of grouting mortar and stone (Hardening temperature - 40 ° C, pressure - 10 MPa) No. Structure, % Solution properties Water separation, ml Strength, MPa
after 24 hours ΔV,% HRC QC HELL Pl HC RD W / C 2R mm ρ, kg / m ³ bend compression one 70 thirty 0.2 0.1 3.0 4.0 0.45 220 1850 1,0 4.4 9.1 1,5 2 fifty fifty 0.2 1,0 1,5 3.0 0.45 260 1830 1,5 3.4 8.2 0.5 3 60 40 0.2 0.5 0.1 5,0 0.45 230 1820 1,5 3.9 8.4 2.6 four 70 thirty 0.25 0.1 0.1 4.0 0.45 220 1850 3,5 4.0 8.9 1.4 5 fifty fifty 0.25 1,0 1,0 3.0 0.45 250 1830 3,5 3.3 8.0 0.6 6 60 40 0.25 0.5 0.5 5,0 0.45 220 1820 4.0 3.8 8.1 3.0 7 70 thirty 0.3 0.1 0.1 4.0 0.45 210 1850 2,5 4.2 8.8 2.7 8 fifty fifty 0.3 1,0 1,0 3.0 0.45 250 1830 3.0 3.2 7.8 0.8 9 60 40 0.3 0.5 0.5 5,0 0.45 220 1820 3,5 3,7 8.0 3.0

table 2 Properties of grouting mortar and stone (Hardening temperature - 160 ° C, pressure - 40 MPa) No. Structure, % Solution properties Water separation, ml Strength, MPa
after 24 hours HRC QC HELL Pl HC RD W / C 2R mm ρ, kg / m ³ bend compression one 70 thirty 0.2 0.1 3.0 4.0 0.45 220 1850 1,0 12.5 28.0 2 fifty fifty 0.2 1,0 1,5 3.0 0.45 260 1830 1,5 11.0 26.3 3 60 40 0.2 0.5 0.1 5,0 0.45 230 1820 1,5 11.7 28.0 four 70 thirty 0.25 0.1 0.1 4.0 0.45 220 1850 3,5 11.7 28.5 5 fifty fifty 0.25 1,0 1,0 3.0 0.45 250 1830 3,5 10.3 26.0 6 60 40 0.25 0.5 0.5 5,0 0.45 220 1820 4.0 11.6 27.6 7 70 thirty 0.3 0.1 0.1 4.0 0.45 210 1850 2,5 12.0 27.9 8 fifty fifty 0.3 1,0 1,0 3.0 0.45 250 1830 3.0 11.3 27.0 9 60 40 0.3 0.5 0.5 5,0 0.45 220 1820 3,5 11,4 27.1

Notes: PC - Portland cement; KK - silica-containing component; AD - reinforcing additive; Pl - plasticizer; HC - calcium chloride; RD is an expanding supplement.

Thus, the example implementation of the invention shows its compliance with the criterion of "practical applicability".

At the drilling site, cement slurry is prepared from this grouting material using conventional technology.

The tables show that the grouting materials developed by the proposed method are effective at temperatures of 40-160 ° C and satisfy GOST 1581-96. The effect of the expansion of the grouting material during hardening will provide high tightness of the contacts: cement stone - casing and cement stone - rock.

When this solution has low fluid loss of 50 cm ^3/30 min.

In addition, the stone prepared from the proposed cementing material at a temperature of 22 ° C (composition 6 of Table 1) was subjected to cyclic exposure to high temperature (220 ° C). The test results shown in table 3 show the completeness of the binder hydration processes for a short time and the absence of thermal corrosion in the stone.

W / C Bending / compressive strength under cyclic exposure to a temperature of 220 ° C, MPa Bcc
48 h 1 cycle (3 days) 2 cycle (4 days) 3 cycle (5 days) 4 cycle (6 days) 5 cycle (7 days) 0.45 3.07 / 11.17 3.65 / 11.8 5.66 / 15.6 4.06 / 17.8 4.64 / 19.6 5.2 / 19.6

This was also shown by studying the phase composition of hardening products after 2 and 7 days of hardening at a temperature of 160 ° C. X-ray diffraction analysis was performed on a DRON 407 X-ray diffractometer using the DIFWin 1 software for controlling the shooting process and the ToUDFpr data processing program. The diffraction patterns of the samples obtained as a result of the survey are identical, and they are represented by low-basic calcium hydrosilicates, which are thermodynamically stable compounds. The results of x-ray phase analysis showed that neither free calcium hydroxide nor highly basic calcium hydrosilicates were found in the tested samples. This indicates that even for a short hardening period of the tested cement, the formation of low-basic calcium hydrosilicates has completed, and corrosion processes are not possible in them.

Claims (1)

Grouting material, including Portland cement, silica-containing component, hardening accelerator - calcium chloride and plasticizer, characterized in that it contains Portland cement, calcium chloride and silica-containing component, subjected to joint disintegration treatment, and the silica-containing component consists of tripoli and quartz sand at a ratio of 1:10 in addition, the grouting material additionally contains a CaO-based expanding additive and a reinforcing additive - basalt fiber with a fiber length of 3 mm, as The plasticizer contains Polyplast SP-1 in the following ratio, wt.%: Portland cement - 50-70; silica-containing component, including tripoli and quartz sand in a ratio of 1:10 - 30-50; basalt fiber with a fiber length of 3 mm - 0.2-0.3 in excess of 100%; plasticizer Polyplast SP-1 - 0.1-1.0 in excess of 100%; calcium chloride - 0.1-3.0 in excess of 100%; CaO-based expanding additive - 3.0-5.0 in excess of 100%.