RU2542028C1 - Magnesia plugging material and method for its production - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: magnesia plugging material comprises a magnesium-containing binding agent, magnesium chloride and additives, at that the builder's calcined magnesite is used as the magnesium-containing binding agent, among the additives it contains a water-repellent agent being silicone oil and a hardening retarder being nitrilotrimethylphosphonic acid with the following ratio of components, wt %: builder's calcined magnesite - 70-80, magnesium chloride - 20-30, silicone oil - 0.1-0.5% above 100%, nitrilotrimethylphosphonic acid - 0.02-0.1 above 100%.

EFFECT: improved rate of the solution hardening and strength of the produced cement stone.

2 cl, 3 tbl

Description

The invention relates to grouting materials used in cementing oil and gas wells, mainly to special cements for fixing wells that have opened saline deposits, represented mainly by magnesium salts.

Traditional Portland cement under conditions of magnesian aggression is rapidly destroyed, therefore, cement is used to fix the wells, which contain magnesium oxide, which, when interacting with water, can form an artificial stone. However, magnesia cement has a low hardening rate; therefore, magnesium salts must be present in the composition of the mixing fluid: magnesium chloride or magnesium sulfate.

Known compositions of cementing materials, incorporating a magnesia binder [Daniushevsky B.C. and others. The reference guide for well drilling. - M .: Nedra, 1987, p.135-137]

Known magnesium phosphate cement, which as a magnesium oxide contains reactive magnesium oxide, or caustic magnesite, or sintered magnesite [RF patent No. 2344101, С04В 9/04].

Grouting material is also known, containing, wt.%: Caustic magnesite powder 26.75-34.56; superphosphate double 0.92-1.23; magnesium chloride 13.75-16.01; palygorskite clay powder 2.30-4.12; condensed silica fume 9.22-10.29; sodium tripolyphosphate 0.92-1.23; water - the rest [RF patent No. 2366682, C09K 8/467].

Closest to the proposed technical essence and the achieved result to the claimed object, i.e. the prototype is a magnesia grouting material containing, wt.%: caustic magnesite powder - 19.98-26.29; magnesium chloride - 17.63-19.29; double superphosphate - 1.11-1.18; sodium tripolyphosphate - 0.61-0.91; boric acid - 0.40-0.73; palygorskite clay powder - 3.03-4.54; condensed silica fume - 11.12-11.81; water - the rest [RF Patent No. 2374293, C09K 8/467]. The functions of the substances included in the prototype are as follows: caustic magnesite powder (PMC) - magnesium binder, magnesium chloride - hardening accelerator, clay powder - structure-forming agent, water - mixing liquid, other ingredients - additives.

A grouting solution of this grouting material is prepared by mixing a magnesium-containing binder and additives in an aqueous solution of magnesium chloride.

The disadvantage of grouting material is not sufficiently low density of the mortar and low strength of the resulting cement stone.

Upon receipt of grouting materials, as a rule, the ingredients are mixed and subsequently mixed in a previously prepared mixing fluid, in particular, for magnesia grouting materials, this is an aqueous solution of magnesium chloride of a certain concentration.

Known methods for producing cementing materials by co-grinding a cementitious base, weighting, activating and other additives, or by separate grinding with the subsequent mixing of these components [Reference for fastening oil and gas wells. Under the general editorship of prof. A.I. Bulatov. M .: "Nedra", 1977, 252 p. Auth .: A.I. Bulatov, L.B. Izmailov, V.I. Krylov et al., P. 41].

A known method of preparing magnesia cement material, including caustic magnesite, magnesium chloride, sodium tripolyphosphate, double superphosphate, starch-containing reagent and water in the following ratio of ingredients, wt.%: Caustic magnesite powder - 48.61-50.43, magnesium chloride - 12, 75-13.80, sodium tripolyphosphate - 1.00-1.96, double superphosphate - 0.25-0.50, starch-containing reagent - 0.12-0.37, water - the rest. With this method, a mixture of caustic magnesite powder is mixed with a liquid in which all other ingredients are dissolved [RF Patent No. 2295554 C09K 8/467].

The disadvantage of these methods is the low quality of the resulting cement materials due to poor homogenization of the components.

The aim of the invention is to obtain a magnesia grouting material and a method for its production, providing magnesia grouting solutions by mixing grouting material in fresh water and providing an increase in the rate of hardening of the mortar and the strength of the resulting cement stone.

This goal is achieved by the fact that in the grouting material, including a magnesium binder, magnesium chloride and additives, according to the invention, calcined building magnesite (MKS) is used as a magnesia binder, it contains a hydrophobizing agent - an organosilicon liquid (GCR) and a hardening retardant - nitrite nitrile nitrite (NTF) in the following ratio of components, wt.%:

Construction magnesite calcined 70-80 Magnesium chloride 20-30 GKZH 0.1-0.5% over 100% NTF 0.02-0.1 in excess of 100%

In terms of the method of producing magnesia grouting material, the goal is achieved by the fact that solid magnesium chloride is treated together with a water repellent in a disintegrator at a particle collision speed of up to 50 m / s, then mixed with a magnesium-containing binder and hardening retarder, previously processed together in a disintegrator at a particle collision speed not less than 200 m / s.

Thus, in the present invention uses new ingredients and new technology, which gives reason to assert that the proposed solution meets the criterion of "novelty."

Calcined construction magnesite (MKS) - is a new magnesian product that differs from the known products of the PMK type (caustic burned magnesite) by firing temperature and chemical composition. The ISS is produced by the Magnezit Group LLC according to TT 72664728-63-2009.

Previously, this product was not used in grouting materials.

In the scientific, technical and patent literature, information on the use of integrated technology for the production of magnesia cements, including the disintegrator treatment of solid magnesium chloride with a water repellent, was not previously provided. This stage of the technology is justified by the fact that solid magnesium chloride, being a highly hygroscopic substance, actively absorbs moisture from the air and crumbles. Such a substance can not be mixed in dry form with magnesia cement, since it will begin to hydrate before the solution is prepared due to hygroscopic water. Therefore, in practice, magnesium chloride is always added to the mixing liquid. To exclude the process of absorption of moisture from air in the present invention, magnesium chloride is treated with a water repellent, and for grinding solid magnesium chloride and better homogenization, the treatment is carried out in a disintegrator. These provisions are confirmed by the following experiment.

Four samples of materials were prepared:

1 - magnesium chloride;

2 - crushed magnesium chloride;

3 - a mixture of magnesium chloride with GKZH (0.5%), prepared by manual mixing;

4 - a mixture of magnesium chloride with GKZH (0.5%), prepared during disintegration processing.

Weighed 50 g samples of materials were simultaneously installed in a cabinet, and every day the increase in the mass of samples was measured, which was due to adsorption of moisture from the air. Table 1 shows the experimental results.

Table 1 - Weight gain of samples Sample No. The initial mass, g. Mass of samples, g in a day. one 2 3 four 5 one fifty 54 58 61 66 69 2 fifty 55 60 64 69 73 3 fifty 52 54 56 58 59 four fifty 50,5 50.8 51.3 51.6 51.8

From table 1 it is seen that the higher the dispersion of magnesium chloride, the stronger the adsorption of water from air on its surface (comparison of samples 1 and 2). The addition of HCL more than halves the absorption of moisture from air by magnesium chloride (comparison of samples 2 and 3). The mixture of HCL and magnesium chloride during disintegration processing provides minimal moisture absorption (comparison of samples 3 and 4). This shows the emergence of a new effect provided by one of the ingredients of the composition and one of the elements of the method of preparation of grouting material.

Since all types of magnesia binders are characterized by a low hardening rate, the claimed invention proposes its disintegration activation, the experience of which is known in the preparation of grouting mixtures [RF patent No. 2486225, C09K 8/467, ЕВВ 33/13]. At the same time, the application of this technology for processing magnesia cements is unknown from the literature, which, by increasing the specific surface of the binder and activating it, gives it new properties - accelerated hardening even at normal temperatures. This is confirmed by the results of the following experiments, the results of which are shown in table 2.

For the experiments, two ISS samples were taken, one of which (No. 1) was prefabricated, the other (No. 2) was additionally subjected to disintegration processing. Both ISS samples were shut with an aqueous solution of mania chloride of the same concentration (brine density 1220 kg / m ³ ), and they determined the setting time using a Vic needle.

table 2 - The effect of disintegration processing on the setting time of the ISS aqueous suspension No. ISS Processing Beats surface, cm ² / g W / C Dates of time, hour-min Start end one Factory cooking 1650 0.5 2-45 4-30 2 No. 1 + disintegrator processing 2370 0.5 1-15 2-25

From table 2 it is seen that the disintegrating treatment of the proposed magnesian binder provides a new effect - a sharp reduction in the setting time of its solution.

To regulate the hardening of the proposed binder, in this case, the delay in setting time, the use of an NTF reagent (nitrilotrimethylphosphonic acid) is proposed, the use of which is described, for example, in RF patent No. 2486225.

At the same time, there is no information in the literature on the use of NTF reagent with an ISS magnesia binder subjected to disintegration processing.

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

In the invention, the following were used:

MKS Magnesite calcined construction production of LLC “Group of Magnesite according to TT 72664728-63-2009; Magnesium chloride produced by CJSC NikoMag, Volgograd, TU 2152-002-93524115-2010;

GKZh Organosilicon liquid produced by Penta Ural LLC, Yekaterinburg;

NTF Nitrilotrimethylphosphonic acid produced by JSC Khim-Prom, Novocheboksarsk, TU 2439-347-05763441-2001, amendment 1;

An example implementation of the invention.

Solid magnesium chloride is treated in a disintegrator at a particle collision speed of up to 50 m / s together with the estimated amount of GKZH water repellent. This treatment mode (particle collision rate) ensures good homogenization of magnesium chloride and water repellent. In this case, magnesium chloride, having a low strength, reaches the ultimate degree of grinding. At high impact speeds, magnesium chloride turns to dust.

Calcined construction magnesite is treated in a disintegrator at a particle impact velocity of more than 200 m / s together with the estimated amount of NTF hardening moderator. The high strength of the ISS requires more intense activation modes (particle collision velocities); therefore, at lower collision velocities, the specific surface of the ISS does not increase sufficiently, and the hardening acceleration effect is small.

Solid magnesium chloride and calcined building magnesite, treated appropriately, are mixed in the required proportions.

A grouting material prepared in this way is shut with water to obtain a grouting mortar.

As an example, we consider the technology for the preparation of grouting material with a ratio of MKS - 75% and magnesium chloride 25% (composition No. 9 from table 3).

To prepare the grouting material, 1,500 g of calcined building magnesite (MKS) and 500 g of crystalline magnesium chloride were taken. A mixture of 500 g of magnesium chloride and 6 g of HCL was subjected to disintegration processing at collision speeds of 40 m / s. A mixture of 1500 g of ISS and 1.5 g of NTF was subjected to disintegration processing at impact speeds of 200 m / s. Then these ingredients were mixed by hand, thus obtaining a dry magnesia grouting material. From the obtained grouting material, solutions were prepared with a water-cement ratio of 0.4 by mixing in 800 ml of fresh water.

The prepared solutions were used to determine their properties and manufacture samples for bending tests, as well as to determine the coefficient of linear expansion (CLC). Tests of the resulting grouting material were carried out according to GOST 1581-96 at a temperature of 22 ° C and atmospheric pressure. The test results of this sample, as well as other compositions are shown in table.3.

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

This grouting material is delivered to the drilling rig in rubber-fabric containers, and grouting mortar is prepared from it using conventional technology.

The table shows that the grouting materials developed by the proposed method are effective 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. Zero water separation confirms high sedimentation stability and excludes channel formation in cement mortar (stone) before it hardens.

When this solution has a low fluid loss, which does not exceed 60 cm ^3/30 min.

Table 3 - Properties of cement slurry and stone No. Structure, % Additives,% over 100% W / C Solution properties Bending strength, MPa at the age of 2 days CLR,% ISS Magnesium chloride GKZH NTF The density of the solution, g / cm ³ 2R mm Water separation, ml Dates of time, hour-min Thickening time up to 30 Vs, min Start end one 70 thirty 0.1 0.02 0.4 1.78 185 0 1-25 2-50 80 5.7 4,5 2 80 twenty 0.1 0.02 0.4 1.82 160 0 3-50 4-25 90 6.4 5.3 3 75 25 od 0.02 0.4 1.81 200 0 3-00 4-20 90 6.0 5.1 four 70 thirty 0.5 0.3 0.4 1.80 250 0 4-10 5-15 190 5,0 4.7 5 80 twenty 0.5 0.3 0.4 1.81 240 0 5-45 6-10 260 5.7 5,0 6 75 25 0.5 0.3 0.4 1.80 220 0 5-35 6-25 220 5.3 5,4 7 70 thirty 0.3 0.15 0.4 1.75 260 0 2-55 3-50 110 4.9 5,4 8 80 twenty 0.3 0.15 0.4 1.82 240 0 2-30 4-00 160 5,6 5.8 9 75 25 0.3 0.15 0.4 1.80 220 0 2-45 4-15 120 5.2 2,8 10 75 25 0.1 0.02 0.5 1.71 260 1,6 3-45 4-25 150 3.8 2,3 eleven 75 25 0.1 0.02 0.55 1,67 > 260 2,3 4-10 5-55 190 3.2 2.0 12 75 25 0.1 0.02 0.6 1,63 > 260 3,7 5-15 6-30 230 2,3 1,5

Claims (2)

1. Magnesia cementing material, including magnesium-containing binder, magnesium chloride and additives, characterized in that the magnesia binder contains calcined building magnesite, as additives it contains a water repellent - organosilicon liquid and a hardening retardant - nitrilotrimethylphosphonic acid, in the following ratio: :
construction magnesite calcined - 70-80,
magnesium chloride - 20-30,
organosilicon liquid - 0.1-0.5% in excess of 100%,
nitrilotrimethylphosphonic acid - 0.02-0.1 in excess of 100%. 2. The method of producing magnesia grouting material according to claim 1, characterized in that the solid magnesium chloride is treated together with a water repellent in a disintegrator at a particle collision speed of up to 50 m / s, then mixed with a magnesium-containing binder and hardening retarder, previously processed together in a disintegrator at particle collision speeds of at least 200 m / s.