RU2255204C1 - Lightened cementing solution, cementing solution for productive zone of well and method for cementing wells - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: lightened cementing solution has Portland cement, lightening admixture, aluminum oxychloride and water, as lightening admixture has admixture from the group: clay, Tripoli powder, diatomite, vermiculite, perlite, and as aluminum oxychloride has at least one compound from the group: aluminum hydrooxychloride, aluminum pentaoxychloride, aluminum tetraoxychloride with following ratio of components in portions of mass: Portland cement - 100, said lightening admixture - 5-10, said aluminum oxychloride - 0.05-1, water - until receiving water-cement relation - 0.6-1.4. Cementing solution for productive well zone has Portland cement, aluminum oxychloride and water, as aluminum oxychloride has at least one compound from the group: aluminum hydrooxychloride, aluminum pentaoxychloride, aluminum tetraoxychloride, and, additionally, water-loss decreasing substance and antifoaming additive, with following ratio of components in portions of mass: Portland cement - 100, said aluminum oxychloride - 0.05-4, water loss decreasing substance - 0.2-0.6, antifoaming additive - 0.02-0.06, water - until receiving water-cement relation 0.45-0.50, while said cementing solution can additionally contain accelerator and/or plasticizer in amounts 0.04-0.6 portions of mass each. Method for cementing wells includes washing with buffer solution with following feeding of cementing solution, after washing by buffer solution serial feeding of condensed pack of cementing solution is performed - metal silicate, said lightened cementing solution, and then said cementing solution for productive well zone. Cementing solution for productive well zone can additionally contain accelerator and/or plasticizer in amounts 0.04-0.6 portions of mass of each.

EFFECT: full filling and reliable engagement of stone with rock and casing string.

3 cl, 11ex, 2 tbl

Description

The invention relates to the construction of oil and gas wells and can be used in the preparation of cement slurries with high insulating properties and cementing wells.

Known lightweight grouting mortar containing Portland cement, hollow microspheres and water (US No. 4305758, 12/15/1981). However, this composition due to the presence of water retention, poor adhesion of the mortar and stone with the rock and casing, does not provide reliable isolation of the layers.

The closest technical solution is a lightweight cement slurry, including Portland cement, aluminum hydroxychloride, microspheres and water (RU No. 2165006 C1, 04/10/2001). The disadvantages of this solution include high water loss, which contributes to the rapid filtering of water when it is pumped into the well and, as a result, to quick thickening of the grouting mortar, incomplete filling of the annulus and a decrease in its insulating ability.

A well-known cement slurry for the productive zone of wells, containing Portland cement, setting accelerator, basic aluminum chloride (OXA) and water (SU No. 1435662, A1, 1985). The disadvantage of this solution is its rapid thickening with increasing concentration of aluminum oxychloride and also the incomplete filling of the annular space, leading to complications in cementing.

Closest to the proposed solution is a cement slurry comprising Portland cement, aluminum oxychloride and water (RU No. 2068490 C1, 10.27.1996). However, it has a significant drawback - high water loss. Quick filtering of water and thickening of grouting grout makes it difficult to pump, causes contamination of the reservoir and adversely affects the insulating ability of the grout.

A known method of cementing wells, including the injection of cement mortar through the pipe space of the tubing and forcing it with drilling fluid (SU No. 46,034, A1, 1973). However, it does not provide maximum adhesion of the stone to the rock and casing, complete filling and reliable isolation of annular space.

Closer to the proposed technical solution is a method of cementing a well, including flushing it with a buffer solution, followed by pumping cement grout (SU No. 1774986 A2, 07.11.1992). This method has the following disadvantages:

- according to ACC, it provides no more than 50% of continuous contact of cement stone with the column and rock;

- does not meet the specifics of the use of solutions in the productive zone. The objective of the invention is the development of lightweight cement slurry, cement slurry for productive zones of the well and a method of cementing oil and gas wells that increase the filling of the annulus, insulating ability and ensure reliable adhesion of the mortar and stone with the rock and casing (up to 100% in the ACC device).

The essence of the invention lies in the fact that a lightweight cement slurry, including Portland cement, a lightweight additive, aluminum oxychloride and water, as a lightweight additive contains an additive from the group of clay, tripoli, diatomite, vermiculite, perlite, and at least aluminum oxychloride , one compound from the group: aluminum hydroxychloride, aluminum pentaoxychloride, aluminum tetraoxychloride in the following ratio, in parts by weight:

Portland cement 100

Specified Relief Additive 5-10

Specified aluminum hydroxychloride 0.05-1

Water - until water-cement is obtained

relationship 0.6-1.4

A cement slurry for a productive zone of a well, including Portland cement, aluminum oxychloride and water, contains as aluminum oxychloride at least one compound from the group: aluminum hydroxychloride, aluminum pentaoxychloride, aluminum tetraoxychloride and additionally, a fluid loss reducer and antifoam in the following ratio of components, parts by weight:

Portland cement 100

Specified aluminum oxychloride 0.05-4

Water loss reducer 0.2-0.6

Antifoam 0.02-0.06

Water - until water-cement is obtained

relationship 0.45-0.50

The cement slurry for the productive zone of the well may further comprise an accelerator and / or plasticizer in amounts of 0.04-0.6 wt.h. each.

The essence of the proposed method of cementing is that after washing the wells with a buffer solution, sequentially pump a “thickened pack” of cement slurry - metal silicate, said lightweight grouting mortar, and then said grouting mortar for the productive zone of the well.

In the cementing method, the inventive cement slurry for the productive zone of the well may be used, additionally containing an accelerator and / or plasticizer in amounts of 0.04-0.6 wt.h. each.

The volume of the buffer solution should ensure the filling of the annulus for wells with a length of cemented bore

from 500 to 2000 m 150-200 m;

from 2000 to 3500 m 300-400 m;

more than 3500 m 500 m.

The volume of the “thickened pack” should ensure the filling of the annulus for wells with a length of cemented bore

from 500 to 2000 m 70-120 m;

from 2000 to 3500 m 150-180 m;

more than 3500 m 200 m.

The “thickened pack” of grouting cement - metal silicate is a kind of “piston” that displaces the drilling fluid from the borehole walls, reducing its residual amount and ensuring high adhesion of the contacting surface of the borehole walls and the pipe with injected grouting composition both in clay deposits and in permeable rock zones.

Lightweight cement slurry is prepared by mixing the components.

Example 1. For the preparation of lightweight cement slurry per 100 wt.h. cement took 10 parts by weight clay, 1 parts by weight aluminum hydroxychloride and 140 parts by weight water to obtain a water-cement ratio of 1.4. All components were mixed, and the resulting solutions and stone were tested according to existing GOSTs.

The test data are shown in table 1, experiment 1.

Example 2. To prepare a lightweight grouting mortar per 100 parts by weight of cement, 5 parts by weight of tripoli, 0.05 parts by weight were taken. aluminum pentaoxychloride and 60 parts by weight water to obtain a water-cement ratio of 0.6.

All components were thoroughly mixed and tested the resulting solution and cement stone in accordance with existing GOSTs. The test results are shown in table 1, experiment 2.

Example 3. For the preparation of lightweight cement slurry per 100 wt.h. cement took 8 wt.h. perlite, 0.8 parts by weight a mixture of aluminum pentaoxychloride and aluminum tetraoxychloride in a ratio of 1: 1 and 100 parts by weight water to obtain a water-cement ratio of 1.0. Test data obtained cement slurry and cement stone are shown in table 1, experiment 3.

Example 4. Analogously to example 1, a mixture of components was prepared, but instead of 1 wt.h. aluminum hydroxychloride was taken 0.5 wt.h. aluminum tetraoxychloride, and vermiculite as a lightening additive. The test results of the mortar and stone are shown in table 1, experiment 4.

Example 5. Analogously to example 1, a mixture of components was prepared, but instead of 1 wt.h. aluminum hydroxychloride was taken 1.0 wt.h. aluminum tetraoxychloride, and as a facilitating additive, 8 parts by weight of a mixture of diatomite and perlite in a ratio of 1: 1. The test results of the mortar and stone are shown in table 1, experiment 5.

As can be seen from table 1, the proposed lightweight cement slurry in terms of basic technological properties is superior to the solution prepared according to patent RU No. 2165006 C1 and, as shown by further tests, provides high quality fastening.

Cement slurry for the productive zone was also prepared by mixing the components.

Example 6. For 100 parts by weight of cement, 4 parts by weight were taken. aluminum hydroxychloride, 0.6 parts by weight loss of fluid loss, for example methyl cellulose, 0.4 wt.h. defoamer, for example tributyl phosphate (TBP) and water - 50 wt.h. to obtain a water-cement ratio of 0.5. The mixture of components was thoroughly mixed and the properties of the mortar and stone were checked according to existing GOSTs. The verification results are presented in table 2, experiment 6.

Example 7. For 100 parts by weight cement took 2 wt.h. a mixture of aluminum pentaoxychloride and aluminum tetraoxychloride in a ratio of 1: 1, 0.4 wt.h. loss of fluid loss, for example sulfacell, 0.2 wt.h. defoamer, for example L-21024 (Laprol) and 40 parts by weight water to obtain a water-cement ratio of 0.4. All components were thoroughly mixed and checked the properties of the mortar and stone according to the requirements of existing GOSTs. The verification results are presented in table 2, experiment 7.

Example 8. For 100 parts by weight cement was taken 0.05 wt.h. aluminum tetraoxychloride, 0.2 parts by weight loss of fluid loss, for example sulfacell, 0.2 wt.h. defoamer, for example, TBP, and 45 parts by weight water to obtain a water-cement ratio of 0.45. Tested mortar and stone according to GOST. The results are presented in table 2, experiment 8.

Example 9. They took the components, as in example 6, and added 0.6 wt.h. plasticizer C-3. The test results of the mortar and stone are presented in table 2, experiment 9.

Example 10. They took the components of example 6 and added 0.6 wt.h. accelerator CaCl ₂ . The test results of the mortar and stone are presented in table 2, experiment 10.

Example 11. They took the components of example 8 and added 0.04 wt.h. mixtures of plasticizer and CaCl ₂ accelerator in the ratio (9: 1) of NTF. The test results of the mortar and stone are presented in table 2, experiment 11.

Table 2 shows that the inventive cementing material has high technological readings and provides high-quality cementing of the well.

Examples of the proposed method of cementing.

1. The initial data of the well:

- depth of 2750 m vertically, 3150 m - along the trunk

- temperature 87 ° C

- reservoir pressure - hydrostatic 27.5 MPa

- well diameter 0.2159 m

- diameter of production casing 0.146 m

For cementing, a lightweight cement slurry was prepared according to Example 1, cement slurry for the productive zone — as described in Example 6 and a “thickened pack” of highly viscous, for example, with a density of 1.92 g / cm ³ cement slurry — sodium silicate.

6 m ^{3 of} washing buffer liquid based on MBPM buffer powder, a “thickened pack” of 4 m ³ , which was pressed as a “piston” using the calculated portion (42 m) of the inventive lightweight cement slurry, was pumped into the well, and then the estimated amount (10 m ³ ) of the inventive cement slurry for the productive zone of the well and the estimated amount (40 m ³ ) of squeezing fluid.

Measurements of cementing quality were carried out, which showed good contact of cement stone formed by lightweight cement slurry (78% continuous contact), as well as cement stone formed by solution for the productive zone - 92% continuous contact with the walls of the column and with the rock.

2. Similar results were obtained in wells with a temperature of 30 ° C.

3. The cementing method is similar to that described, but the grouting mortar for the productive zone was prepared according to Example 10.

The results of cementing quality measurements also showed up to 100% (ACC) of continuous contact of cement stone in the productive zone of the well.

Thus, the inventive method of cementing a well provides high-quality replacement of the drilling fluid with cement, the formation of high-quality stone and preservation of the permeability of the rock of the reservoir.

Claims (5)

1. A lightweight cement slurry comprising Portland cement, a lightweight additive, aluminum oxychloride and water, characterized in that as a lightweight additive it contains an additive from the group: clay, tripoli, diatomite, vermiculite, perlite, and at least aluminum oxychloride , one compound from the group: aluminum hydroxychloride, aluminum pentaoxychloride, aluminum tetraoxychloride in the following ratio, wt.h .: Portland cement 100 Specified Relief Additive 5-10 Specified aluminum oxychloride 0.05-1 Water - until water-cement is obtained relationship 0.6-1.4 2. A cement slurry for a productive zone of a well, including Portland cement, aluminum oxychloride and water, characterized in that it contains at least one compound from the group of aluminum oxychloride: aluminum hydroxychloride, aluminum pentaoxychloride, aluminum tetraoxychloride and, additionally, a loss of fluid loss and antifoam in the following ratio of components, parts by weight: Portland cement 100 Specified aluminum oxychloride 0.05-4 Water loss reducer 0.2-0.6 Antifoam 0.02-0.06 Water - until water-cement is obtained relationship 0.45-0.50 3. The cement slurry according to claim 2, characterized in that it further comprises an accelerator and / or plasticizer in an amount of 0.04-0.6 wt.h. each. 4. A method of cementing wells, including rinsing with a buffer solution followed by injection of grouting cement, characterized in that after washing with a buffer grout, a “thickened pack” of grouting mortar — metal silicate, lightweight grouting mortar according to claim 1, and then grouting mortar are sequentially injected for the productive zone of the well according to claim 2. 5. The method according to claim 4, characterized in that the cement slurry for the productive zone of the well further comprises an accelerator and / or plasticizer in an amount of 0.04-0.6 wt.h. everyone.