SU909125A1 - Gel-forming plugging composition for closing formations - Google Patents

Description

I

The invention relates to the drilling of wells, namely to compositions for plugging formations in order to eliminate complications in the wells: acquisitions or gas flows.

Known gelling composition based on hypana, mud, and water. It is prepared by mixing the starting components in the process of injection into the well 1.

The formation of the gel occurs in the pipes and to the plugged horizon, the composition is suitable in the form of a gel. This makes it possible to clog up large channels well, but excludes its penetration due to its high viscosity .; in small pores. In addition, the gel has poor adhesion to the walls of plugged channels.

Also known is a gel-forming grouting composition for plugging formations, containing a water-soluble polymer — polyacrylamide (PAA) filler, a gelling agent — hexarecorcin resin with formaldehyde, and water. The components are mixed on the day surface, after which the mixture is pumped into the formation and left there alone to form gel 2.

However, the formation time of this composition, depending on the conditions, is 2t-72 hours. This circumstance leads to the need for considerably simple drilling equipment and service crews, which is associated with significant additional costs. In addition, too much gel time may be;

15 cause unsuccessful tamponing, since the composition may be eroded by formation waters if there is even a small amount of circulation.

The purpose of the invention is to increase the level of gassing there by reducing the time of gelation in the range of positive temperatures of 0-150 ° C. This goal is achieved by the fact that the composition additionally contains a regulator of gelation, and as a gelling agent a complex system consisting of chromates, namely: Cncr O-, or Na., Or (NH4) 2.Cr. and additives, namely: either NzO3OlO or NH4CNS, Na S FeSO, or hydroxylamine, or hydrazine, or with the following ingredient ratios, wt%: Water-soluble 1.0-15.0 Chromate polymer 0.1-3.0 Additive0 , 1-5.0 Filler O, T-60, O Gel-regulating regulator 0.01-1.0 Water Else Due to the fact that the proposed gelling composition has a higher chemical activity than the known one, it can be used as a water-soluble polymer is not only polyacrylamide, but also other acrylic polymers, such as metas hypan, M-11, Ml, tampocryl, Comet, etc., and tayuhe them with Thou. It can contain cord fiber, rubber rubber, nutshell, seed husks of rice, sunflower, as well as sand barite, hematite, plasmilon, etc. to adjust the composition with enhanced tamponing ability by adjusting the structural-mechanical and operational characteristics as a filler. and mixtures thereof. In order to regulate the time of gelation in each specific embodiment, the composition contains a gel time regulator, which is an addition of acids or alkali. The change in the time of gelation is achieved by changing the pH. To accelerate the gelling reaction, it is necessary to use additives of acids, and to slow down - the addition of alkalis. Example 1 (experiment 7). From the concentrated aqueous solutions a mixture of ingredients is prepared, containing it. %: polyacrylamide 1; ammonium bichromo 0.1; sodium hyposulfite 0, filler (rubber crumb) 5; gel regulator (hydrochloric acid) 0.001 and water 93.799. Example 2. A mixture of ingredients is also prepared from concentrated solutions containing: a Comet 15.0 polymer; sodium chromate 5.0; filler (sand) 26,6; gelation regulator (ammonia alcohol) O, 4 and water 50 (experiment 4). Example 3- By mixing concentrated solutions of ingredients and subsequent smoothing with hematite, a mixture is prepared containing: a polymer (hydrolyzed polymethyl nec tacrylate MH) 5, potassium dichromate 1.2; hydroxylamine hydrochloric acid 1.0; filler (hematite) 60; a gelation regulator (moderator — ammonia alcohol) 1.0 and water 31.8 (run 6). The combined components are thoroughly mixed, thermostatically controlled to the required temperature, and the terms of their gelation are determined in consistometers CC-5 and CC-3. In tab. 1 shows the compositions with intermediate content of ingredients. And table. Figure 2 presents data on the gel time of mixtures at different temperatures. As can be seen from the table. 2, the gelation time of the composition varies over a wide range, which makes it possible to select the necessary formulation for each specific use case. The technical and economic efficiency of the developed composition in comparison with the known one is mainly determined by the possibility of targeted control of the gelation time. This allows, firstly, to increase the likelihood of eliminating complications in the conditions of hydraulic activity of the formation fluid, when the liquid, non-thickened composition can be simply blurred, and secondly, to reduce the amount of time spent in waiting for the reaction to pass. The economic effect calculated only for the 2 nd position is 137.6 rub. For the 1. st operation. In addition, targeted regulation of structural, mechanical and technological properties will also increase the likelihood of eliminating complications.

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Claims (3)

1. A gelling plugging composition for plugging formations containing a filler, a water-soluble polymer, a gelling agent and water, characterized in that, in order to increase plugging capacity by shortening the gelation time in the range of positive temperatures of 0-150 ° C, it additionally contains a gelation regulator , and as a gelling agent, the composition contains a complex system consisting of chromates, namely: ClSrpOy, or NanCr Od, or (and additives, namely: NaxS.Oj, or, or, or FeSO, or hydroxylamine, or a guide azine or NanS the following ratios of ingredients by weight D: Water soluble 1.0-15 polymer Limping: 0.1-3 Additive 0.1-5 Filler 0,1-60 Gel Regulator 0.01-1.0 Water Else 2, the composition according to claim. And with the fact that as a water-soluble polymer it contains polyacrylamide, or metas, or hypan, or tampocryl, or M-11, or M-14, or Comet. 3. The composition according to claim 1, which is based on the fact that, in order to increase the tamping ability by improving the structural-mechanical and operational properties, it contains cord fiber, rubber crumb, or barite, or sand, or asbestos k. A composition characterized in that it contains an acid or alkali as a gel regulator. Sources of information taken into account in the examination 1. USSR author's certificate No. 382806, cl. E 21 V 33/138, 19672. Sherstnev N.M. and others. Prevention and elimination of drilling complications. M., Nedra, 1979, p. 27 4277 (prototype).