Light-weight grouting mortar. RU patent 2244098.

FIELD: oil and gas production.

SUBSTANCE: invention relates to grouting mortars used for cementing casing pipes of gas, gas-condensate, and oil wells complicated by presence of formations with low hydraulic rupture pressure as well as presence of permafrost rocks. Light-weight grouting mortar contains 47.0-60.0% special-type cement, 6.6-11.8% clinoptilite as light-weight additive, and water. As a result, casing-pipe annulus incidents during boring and running wells are avoided owing to improved parameters of grouting cement, in particular increased sedimentation stability of mortar, dimensional stability and needed strength of cement stone at low positive and negative temperature in early hardening stages are achieved at simultaneous lowering of grouting mortar density.

EFFECT: improved performance characteristics of grouting mortar.

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The invention relates to cement mortars used in the cementing of gas, gas condensate and oil wells, complicated by the presence of loosely coupled, prone to fracturing of rocks, and rocks with low positive and negative temperature.

Known lightweight cement slurry [1], containing Portland cement, facilitating mineral Supplement - gidrofobizirovannogo clinoptilolite rock in the following ratio of components in the solution, wt.%:

cement 30,0-40,0

gidrofobizirovannym

clinoptilolite rock 13,0-23,0

water the rest

The disadvantages of this solution is its shrinkage during curing, resulting in deteriorating the adhesion of cement to casing strings and low for geocryological conditions of sedimentation stability.

The closest in composition and purpose cement is a solution of the reduced density [2], containing the grouting cement SNUB facilitating mineral Supplement - vermiculite.

A disadvantage of the known cement slurry is that the vermiculite is an inert filler, not involved in the hydration reactions of cement, therefore, does not increase its durability.

Object of the invention is the improvement of the parameters of a lightweight cement slurry and stone, providing high-quality cementing in the range of permafrost), preventing annular manifestations, lifting cement to the wellhead.

The technical result of the claimed invention is to improve the sedimentation stability and strength of cement cement, reducing the contraction.

The essence of the invention is that the inventive lightweight cement slurry includes grouting cement SNUB facilitating additive - ceritadewasa rock clinoptilolite, actively participating in the formation of cement and water in the following ratio, wt.%: cement low temperature SNUB - 60,0-47,0; clinoptilolite - 6,6-11,8; water - the rest.

Comparative analysis of the prototype allows us to conclude that the proposed lightweight cement slurry is different from the known to the introduction of new components, namely clinoptilolite when the above ratio of the components, i.e. the claimed invention meets the criterion of “novelty”.

Cement cement SNUB contains: finely ground gypsum-free Portland cement clinker (90%), annealed solid residue soda production (10% of the content of clinker), plasticizing additive - NTF (0.1 to 0.13% of the weight of the dry mixture), the electrolyte is sodium carbonate (3.8 to 5.0% of the weight of the dry mixture). Cement production SNUB established in Sterlitamak JSC “Soda”.

The composition of zeolites are framework silicates, in particular, clinoptilolite - (Na, K) 4 Sa Al 6 Si 30 O 70 24 H 2 O. It is natural microporous frame silicate, in its structure there are four types of channels of capillary dimensions. The main structural parameters of clinoptilolite following: the effective diameter of the input Windows of 0.43-0.35 nm; the amount of free intracrystalline space of 30-40%. Clinoptilolite lies a powerful formations in many fields tseolitopodobnyh tuff (Sokolnice, Azami, Eastern Siberia, and others).

The effect of supplementation of clinoptilolite is not only to reduce the density of the solution, but also in reducing contraction and hardening of cement stone.

This is because in zeolites, as a rule, part of the silicon ions substituted for aluminum. This substitution leads to an excess negative charge, which should be more than offset by additional ion located in the intracrystalline cavities of the structure. In addition, ion-exchange centers can occur on the surface of minerals in connection with deviations from electroneutrality at the phase boundaries. The presence of a charge on the outer surface contributes to the interaction of particles of clinoptilolite with ions and associates Zola cement dispersion. Physico-chemical status of colloidal particles in the cement-zeolite solution meets the conditions subsequent formation of a strong individual contacts in the microstructure of the stone, the hydration process is constantly renewed on purified from tumors sites of the zeolite.

Because the grouting cement SNUB represented mainly calcium oxide, the solubility of which at low temperatures is high enough, the system assumes its interaction with the surface of the particles of clinoptilolite with the formation of hydrated compounds. Thus, clinoptilolite will facilitate the creation of lightweight cement slurry, forming a stone with increased strength and insulation properties.

A high content of active calcium oxide in the calcined solid residue soda production activates the process of hardening of gypsum-free Portland cement, increases sedimentation stability and provides expanding properties of the cement stone.

Comparison with known cementing slurries was performed for compounds that meet the requirements of GOST 1881-96 for density lightweight cement slurries.

The presented experimental data used cement grouting SNUB on STF-1-39-91 (“arcticmorneftegasrazvedka), zeolite on THE 113-12-98-852, water tap according to GOST 2874-82.

Comparison with known solution was produced according to the density, effective flowing property, odottelen, duration of seizure, cement slurry and strength formed of stone. All compounds (known and declare) have the same conditions of curing, the samples at a temperature of minus 2°and atmospheric pressure. Determination of the basic properties of the lightweight cement slurry and stone were carried out in accordance with GOST 267981-96, 267982-96 “Cement grouting”, “test Methods and methodology, proposed in [3]. The density of the cement slurry is determined by hydrometer AG-1, the flowing - in cone of lubricant additives, the timing setting device vetch, the tensile strength of cement stone on a bend, on a test machine to the STAND-100, water segregation using a measuring cylinder.

To identify distinctive features and technical result of changed mass ratios of ingredients in a wide interval of values.

Lightweight cement slurry is prepared as follows. The required amount of zeolite is mixed with cement SNUB, and the mixture is then shut water at a given water-cement ratio.

To prepare 1 kg lightweight cement slurry (composition No. 6) it is necessary to take 601 g of cement SNUB mixed with 66 g of zeolite (clinoptilolite) and shut 333 g of water.

The composition is stirred for 3 minutes, after which determine its density, flowability, water segregation. For definitions of terms, tensile strength of cement stone bending the prepared solution is poured in a mold and maintained at a temperature of minus 2°C. Backfill stone are tested for strength after 2 days from the beginning of his mixing. The results are given in the table.

The prepared structure 6 has a density of 1660 kg/m3 , a fluidity - 180 mm, start setting after 7 h 15 min, the end of the stiffening - 10 hours, the tensile strength of stone on the curve is 0.95 MPa, water segregation of 1.4%. Shrinkage deformation of the cement was observed.

Examples of the preparation and testing of other compounds listed in the table similar to the one described above.

To identify distinctive features and positive effect changed the mass ratio of ingredients in a wide interval of values. It is established that the mortar compositions No. 6, 10, 14, 15 are optimal.

As can be seen from the table, declared cement slurry has low water separation from 0.0% (composition 14) to 1.4% (6) at a density 1610-1660 kg/m 3 . Strength of stone, formed from the inventive cement is in the range of from 0.90 MPa (solution No. 15) to 0.97 MPa (solution No. 10) at a density 1510-1640 kg/m 3 .

We offer cement slurry improves the quality of low-temperature fixing wells and prevent neopolyol cement to wellheads, which occur when cementing known compounds.

Comparative characteristics of known and proposed a lightweight cement slurry (test temperature -2°) # PP the composition of the cement slurry, wt.% Density, kg/m 3 Flowability, mm setting Time, hour-minutes Strength, MPa ·(2 day) The water segregation, %   SNUB Free. additive Water is the Beginning of the End of the Famous lightweight cement slurry (prototype) 1. 59,4 Vermiculite 3,1 37,5 1600 200 5-25 11-10 0,90 7,4 Offer a lightweight cement slurry 2. 63,4 3,.3 33,3 1740 190 6-20 8-15 1,10 2,4 3. 59,4 3,1 37,5 1620 240 6-30 9-30 1,00 4,7 4. 55,9 2,9 41,2 1510 250 6-35 9-55 0,90 6,0 5 64,3 7,1 28,6 1780 170 5-40 8-25 1,06 0,0 6. 60,1 6,6 33,3 1660 185 7-15 10-00 0,95 1,4 7. 56,3 6,2 37,5 1550 240 7-20 10-20 0,81 4,1 8. 52,9 5,9 41,2 1490 250 7-20 10-40 0,85 5,3 9. 60,7 10,7 28,6 1750 170 6-30 9-00 1,0 0,0 10. 10,0 56,7 33,3 1640 185 6-50 9-35 0,97 0,5 11. 53,1 9,4 37,5 1530 230 7-10 10-30 0,91 2,3 12. 50,0 8,8 41,2 1470 250 7-25 10-45 0,88 3,6 13. 57,1 14,3 28,6 1720 165 6-50 9-45 1,0 0,0 14. 53,4 13,3 33,3 1610 180 6 : 45 a.m. 10 : 00 hrs 0,92 0,0 15. 50,0 12,5 37,5 1510 215 7-40 10-30 0,9 0,90 16. 47,0 11,8 41,2 1440 240 7-20 10-50 0,80 2,4

Sources of information:

1 A.S. USSR №1099051, CL E 21 In 33/138.

2 Ovchinnikov V., Frolov A.A., A. A. Shatov, Vyakhirev V.I. Sorokin V.F., Ovchinnikov PV Salt and cement compositions on the basis of secondary material resources of production of soda. - M.: OOO “Nedra-business Center”, 2000. - 214 S.

3. Khlusov A.A., Lanew E.N., Nikulin VA and other Features testing of grouting materials for low-temperature wells// Overview. Series Drilling of gas and gas condensate wells. - M.: Negatron, 1989, No. 2, 30 C.

Lightweight cement slurry comprising cement cement SNUB facilitating mineral Supplement - ceritadewasa rock and water, characterized in that as ceritadewasa breed contains clinoptilolite in the following ratio, wt.%: