RU2259468C1 - Complex reagent for grouting mortar and grouting mortar - Google Patents

Abstract

FIELD: oil production industry, particularly for grouting mortar preparation during oil and gas well casing.

SUBSTANCE: complex reagent includes fluid loss reducing agent, plasticizer and antifoaming agent. The reagent additionally has structure-forming agent. All above components are taken in the following amounts (% by weight): fluid loss reducing agent - 30-94, plasticizer - 2-25, antifoaming agent - 1-14, structure-forming agent - 3-25. Structure-forming agent comprises at least one aluminum compound selected from the group including hydroxychloride, tetrahydroxychloride, pentahydroxychloride or amorphous aluminum oxide. Grouting mortar includes cement and above complex reagent added to cement in amount of 0.6-1.5% of dry cement weight. For grouting mortar production light-weight cement with lightweight additive is used. Lightweight additive is clay, diatomite, vermiculite, pearlite or microspheres. The cement is Portland cement with additives or without additives, expandable cement or gypsum cement.

EFFECT: reduced water losses, increased sedimentary stability, hardened grouting mortar uniformity over the full column dimension, possibility to use grouting mortar with normal density, as well as light and superlight grouting mortar.

4 cl, 3 ex, 1 tbl

Description

The invention relates to the oil and gas industry and is used in the process of fixing oil and gas wells in the preparation of cement slurries.

A well-known complex reagent for grouting mortars is a fluid loss reducer containing water-soluble hydroxyethyl cellulose (sulfacell) and C-3 superplasticizer. Known cement slurry containing this reagent [1].

The disadvantage of the reagent and grouting mortar is that this reagent causes foaming of grouting mortar, which reduces the ability to pump in the annulus, slows down the setting time of grouting mortars, is effective for non-additive Portland cement, for light cements sedimentation resistance is low.

A well-known complex reagent for cement slurries, providing pumping the solution into the annulus, reducing its water loss and increasing sedimentation in a wide temperature range (from 50 to 150 ° C), reduces foaming, having the following composition:

Water loss reducer 60-90 Plasticizer 9-25 Antifoam agent 1-15.

The disadvantage of this reagent and the cement slurry containing it is an increase in the density of the cement slurry up to 1.9-2 kg / cm ³ and long setting time in the low temperature range. In addition, for lightweight grouting systems, the reagent does not provide sedimentation-resistant solutions.

The mechanism of action of these reagents is based on the plasticization of cement slurry systems and a decrease in the water-cement factor, which may adversely affect the long-term strength of the stone due to the lack of water for hydration in the later stages of hardening.

The aim of the invention is to obtain a comprehensive reagent for cement slurries, providing the elimination of these disadvantages of cement systems.

This goal is achieved in that the complex reagent for cement slurry, including a loss of fluid loss, a plasticizer, antifoam, further comprises a structure-forming agent in the following ratio of components, wt.%:

Water loss reducer 30-94 Plasticizer 2-25 Antifoam agent 1-14 Structure former 3-25.

The complex reagent as a builder contains at least one aluminum compound from the group: hydroxychloride, tetrahydroxychloride, pentahydroxychloride, amorphous alumina.

This goal is also achieved by the fact that the grouting mortar, including cement and a complex reagent, as the last contains the described inventive reagent in an amount of 0.6-1.5% by weight of dry cement.

As a cement, it contains lightweight cement with a lightweight additive, one of the group: clay, tripoli, diatomite, vermiculite, perlite, microspheres. As cement, it may also contain additional or non-additive Portland cement, or expanding cement, or gypsum cement.

The new inventive combination of known components of the reagent and cement slurry provides a change in the concentration of the hardening mortar, providing increased sedimentation stability, not reducing the density of the cement slurry, ensuring its non-shrinkage, adhesion to pipes and rocks, the necessary setting time at temperatures from 20 to 90 ° C. The thixotropy of the resulting system provides a decrease in pressure during pumping. Low water loss, sedimentation resistance, uniformity of the stone throughout the column is provided not only with cement slurry of normal density, but also with light and ultralight cement slurry.

As a fluid loss reducer in the inventive reagent, there can be PVA (polyvinyl alcohol), MC - methyl cellulose, sulfacell, hydroxyethyl cellulose and other water loss reducers.

As antifoam can be used: TBP tributyl phosphate, glycol ethyl silicate-polymethyl siloxane liquid (PMS), lapiropylene glycol LPG-40, etc.

Inorganic salts - aluminum compounds: hydroxychloride, tetrahydroxychloride, pentahydroxychloride, amorphous alumina (AOA) and mixtures thereof can be used as a structurant.

As a binder can be cement without additives (PCTB-G), additive (PCT-II-100), lightened with various fillers: clays, tripoli, microspheres, expanding cement, gypsum cement, etc. As a plasticizer can be C-3, nitrilotrimethylphosphonic acid (NTP) or their salts, lignosulfonates, etc.

Example No. 1 (tab., Experiment 1). To obtain take 94% (94 g) of the PVA fluid loss reducer, 2% (2 g) of the C-3 plasticizer, 9% (9 g) of aluminum hydroxychloride and 1% (1 g) of TBF defoamer. All mix thoroughly. Caking and stickiness (unlike PVA) of the reagent are reduced, it becomes homogeneous. It is well dissolved in water. Take 1.5% (15 g) of the reagent to a mass of 1 kg of lightweight cement containing microspheres, mixed with water and get a homogeneous cement slurry having zero water sludge, almost zero contraction and adjustable setting time. Due to the synergistic effect of organic and inorganic reagents structurants solution contraction effect is stretched in time and becomes zero water loss solution is reduced to 20 cm ^3/30 min.

Example No. 2. To obtain the reagent, 30% (30 g) of hydroxyethyl cellulose (OEC) is taken, NTF Corilate salt is a plasticizer 25% (25 g), 25% (25 g) aluminum pentahydroxychloride, 14% (14 g) of polymethylsiloxane liquid. Stir until smooth. Take 0.5% (5 g) of the reagent to a mass of 1 kg of unattended Portland cement PCT II -100. Prepare the grouting mortar according to existing GOSTs and test it (see table, experiment 4).

Example No. 3 (tab., Experiment 7). To obtain the reagent, 94% (94 g) of MC are taken, 2% (2 g) of C-3 plasticizer, 3% (3 g) of amorphous alumina, 1% (1 g) of Laprol-L-21.024 antifoam are added. Mix thoroughly.

Take 0.75% (7.5 g) of the obtained reagent to a mass of 1 kg of lightweight clay-containing cement, prepare a grouting mortar according to GOST and test for physicochemical characteristics: water-sludge, contraction, water loss, setting time (see table, experience 6).

Used sources.

1. Application for patent of the Russian Federation No. 97106934/03 from 04/28/97. E 21 B 33/138.

2. RF patent No. 2194149, 2001

Claims (4)

1. A comprehensive reagent for cement slurries containing a loss of fluid loss, a plasticizer and an antifoam, characterized in that it further comprises a structure-forming agent in the following ratio of components, wt.%: water loss reducer 30-94 plasticizer 2-25 antifoam 1-14 builder 3-25, wherein the structure-forming agent contains at least one aluminum compound from the group: hydroxychloride, tetrahydroxychloride, pentahydroxychloride, amorphous alumina. 2. A cement slurry comprising cement and a complex reagent, characterized in that it contains the complex reagent according to claim 1 in an amount of 0.6-1.5% by weight of dry cement. 3. The grouting mortar according to claim 2, characterized in that the cement contains lightweight cement with a lightweight additive, one of the group: clay, tripoli, diatomite, vermiculite, microspheres. 4. The grouting mortar according to claim 2, characterized in that it contains as the cement an additive-free or additive Portland cement, or an expanding cement, or gypsum cement.