RU2325420C1 - Lightened grouting mortar - Google Patents

Abstract

FIELD: inorganic chemistry.

SUBSTANCE: invention refers to grouting mortars used for cementation of casing pipes, condensate or oil wells, complicated with loosely-coupled, hydro failure rocks, as well as oil-and-gas and water-and-gas saturated in section of various pressure values. Technical result of invention lies in development of lightened grouting mortar with high sedimentary stability and improved cement stone resistance. Lightened grouting mortar contains the following composition, mass.%: oil-well portland cement 48.8-51.8, silica-alumina hollow microspheres 5.8-9.1, Monasile 0.6-1.2, water 39.4-41.2.

EFFECT: production of lightened grouting mortar with high sedimentary stability and improved cement stone resistance.

1 tbl, 1 ex

Description

The invention relates to cement slurries used in the cementing of casing strings for gas, gas condensate or oil wells, complicated by the presence of loosely coupled rocks prone to hydraulic fracturing, as well as the presence of oil and gas saturated and water and gas saturated formations with different pressures.

Known lightweight grouting mixture, including grouting cement, flotation product of fly ash and water / auth. No. 1573141, ЕВВ 33/138, publ. 06/23/90, bull. No. 23 /.

A disadvantage of the known mixture is the low spreadability of the solution, which is in the range of 19-20 cm, which leads to rapid structuring of the solution, lower back pressure on the productive formations and the risk of penetration of formation fluids into the wellbore and overlying permeable formations. An increase in the period of early structuring of a lightweight grouting mixture due to an increase in the water-water ratio or the introduction of plasticizing additives adversely affects the stability of the solution, since water separation sharply increases and the solution has low sedimentation stability, which also contribute to the formation of inter-layer flows and oil and gas manifestations in the waiting period for cement hardening.

The closest in composition and purpose is a lightweight grouting mortar containing Portland cement grouting, a lightweight additive - aluminosilicate hollow microspheres, clay powder and water / Patent No. 21511267, IPC ЕВВ 33/138 dated 06/20/2000 /.

The disadvantage of this solution is increased water separation, insufficient sedimentation stability and low strength characteristics of cement stone when cementing directional or subhorizontal sections of the well.

When creating the invention, the problem was solved of improving the quality of reservoir separation by preventing the occurrence of annular and intercolumn gas manifestations in directional and subhorizontal wells.

The technical result of the invention is the development of lightweight cement slurry with high sedimentation stability and increased strength of cement stone.

The solution to this problem is achieved in that a lightweight grouting mortar, including grouting Portland cement, facilitating the addition of aluminosilicate hollow microspheres and water, in contrast to the known, additionally contains monasil, in the following ratio of components, wt.%:

Portland cement grouting 48.8-51.8 Aluminosilicate Hollow Microspheres 5.8-9.1 Monasil 0.6-1.2 Water 39.4-41.2

In the experiments we used monasil with a silicate module 2.94 manufactured by Vitakhim LLC according to TU 2145-001-75105538-2005, which is a white granular powder, completely soluble in water. The main component of monasil is a modernized sodium silicate. A positive property of monasil in the composition of grouting mortar is its ability to dissolve during the dissolution process with Portland cement hydration products and cations dissociated in an alkaline medium from the surface of aluminosilicate hollow microspheres with the formation of highly dispersed hydrosilicates of various compositions. Filling the pore space between the binder particles and the microspheres, the reaction products of monasil, cement and aluminosilicate hollow microspheres make it possible to obtain a highly stable grouting system and improve its suffusion resistance. The formation of these compounds also determines the compaction of the stone structure and increase its strength.

In the experiments presented, we used Portland cement grouting PCT 1-100 according to GOST 1581-96 of Sukholozhskcement OJSC, aluminosilicate hollow microspheres according to TU 5712-001-49558624-2003, monasil according to TU 2145-001-75105538-2005, drinking water GOST 2874-82 .

The basic properties of lightweight grouting mortar and stone were determined at a temperature of 75 ± 3 ° C in accordance with GOST 26798.1-96 Cement grouting. Test Methods. " The density of the lightweight grouting mortar was determined by a pycnometer, the spreadability was determined by the cone of the AzNII, sedimentation stability was determined by the water separation of the cement in four cylinders with a volume of 250 ml (RD 39-00147001-767-2000 "Instructions for fastening oil and gas wells", M .: 2000, p. 26-27). The bending strength of the stone is on the MII-100 testing machine, the compressive strength and adhesion to metal are on the P-10 hydraulic press.

Lightweight cement slurry was prepared as follows. A dry mixture of Portland cement grouting, aluminosilicate hollow microspheres and monasil in predetermined proportions were closed with a measured amount of water in a laboratory mixer SL-1. After this, the solution was additionally mixed in a laboratory stirrer (n = 150 ± 20 rpm) for 40 minutes to completely dissolve the monasil and give the solution sedimentation stability. After that, the parameters of the solution and the properties of the formed stone were measured.

The prototype solution is also prepared in laboratory conditions and its parameters are measured.

Example. To prepare 1 kg of lightweight grouting mortar (table, composition 2), you need to take 650 g of water, then prepare a dry mixture of 830 g of grouting Portland cement, 20 g of monasil and 150 g of aluminosilicate hollow microspheres. The composition is stirred for three minutes, then the solution is additionally mixed for 40 minutes and the density, spreadability are determined. The solution is poured into four 250 ml cylinders with a vertical, horizontal, at an angle of 45 ° and 60 ° location to determine water separation. The solution is poured into molds to determine the strength of the stone in bending, compression and adhesion. Samples are kept in a thermostat at a temperature of 75 ° C until the test time.

The prepared composition has a density of 1.46 g / cm ³ , a spreadability of 218 mm, a water separation of 0.0 ml in all four cylinders, the solution is homogeneous, sedimentation stable, stable (there are no water zones and water channels). The bending strength of 2.7 MPa, the compressive strength of 8.5 MPa, the adhesion strength of 2.1 MPa.

Examples of preparation and testing of the remaining compositions shown in the table are similar to the above.

To identify the distinguishing features and the positive effect, the mass ratios of the ingredients were changed.

As can be seen from the table, the inventive lightweight cement slurry with an optimal / ratio of components has better properties than the prototype, namely, it is characterized by the absence of water separation in all four cylinders and sedimentation stability of the solution. Formed cement stone has a strength of 35% higher (2.7 MPa) than that of the prototype (2.0 MPa). The prototype solution is sedimentary unstable and is characterized by increased water separation: in a vertical cylinder, 2.0 ml; in the cylinder at an angle of 45 ° 5.0 ml and the formation of water channels; in a cylinder at an angle of 60 ° 2.2 ml and a small water belt; in a horizontal cylinder of 5.0 ml.

An increase in the concentration of monasil in the mixture up to 3% (table, composition 6) leads to a thickening of the solution (a spreadability index of 160 mm) and does not significantly affect the strength characteristics of the cement stone. The minimum amount of monasil (composition 5) does not allow to prepare a sedimentation-stable solution.

Thus, from grouting Portland cement, aluminosilicate hollow microspheres and monasil can be prepared lightweight grouting mortars with acceptable technological characteristics, which can be used for cementing directional and subhorizontal sections of wells.

Table Technological properties of lightweight cement slurries with the addition of monasil No. p / p The composition of the solution, wt.% Density, g / cm ³ Spreadability, mm Water separation, ml Strength, MPa, 2 days cement monasil AFM water vertical at an angle of 45 ° at an angle of 60 ° horizon. bend compression clutch one 50.9 0.6 9.1 39,4 1.47 285 0,0 0,0 0,0 0,0 3,1 10.1 1.7 2 50.3 1,2 9.1 39,4 1.46 218 0,0 0,0 0,0 0,0 2.7 8.5 2.1 3 48.8 1,2 8.8 41.2 1.44 242 0,0 0,0 0,0 0,0 2.6 8.8 1.3 four 51.8 1,2 5.8 41.2 1.51 260 0,0 0,0 0,0 0,0 2,8 9.0 1.4 Outrageous values 5 52.8 0.3 9,4 37.5 1.47 280 0,0 0.2 0.2 0,0 3.3 13,2 1.9 6 42.0 3.0 5,0 50,0 1,52 160 0,0 0,0 0,0 0,0 2,8 10,4 1,6 Prototype 53.12 1.5 clay. 9.38 36.0 1,50 220 2.0 5,0 2.2 5,0 2.0 6.5 0.8

Claims (1)

Lightweight grouting mortar, including grouting Portland cement, facilitating the addition of aluminosilicate hollow microspheres and water, characterized in that it additionally contains Monasil in the following ratio, wt.%: Portland cement grouting 48.8-51.8 Aluminosilicate Hollow Microspheres 5.8-9.1 Monasil 0.6-1.2 Water 39.4-41.2