SU1154438A1 - Method of selective plugging of flooded zones of formation - Google Patents

Abstract

1. METHOD FOR SELECTIVE DIPPING OF WATERED ZONES OF THE FORM, which consists in injecting an aqueous solution of an alkali metal salt, for example sodium carbonate, into the formation, and subsequently injecting liquid glass, with the chain preventing oil saturation from decreasing parts of the reservoir and increasing the efficiency of blocking water channels, before pumping liquid glass into the reservoir, reduce its silica module to a value of 0.3-1.8 and determine it by the formula mf 5.66 K & , where 1.5 K Czech K 6, K ,,, (t, - 0-Ip ,,, - 1 K is the concentration of the original liquid glass, May, 7, (from 1.5 to 46 wt.% is taken depending on the permeability of the reservoir; -silica module using spun liquid glass. 2. Method POP.1, characterized in that, with the use of commercial liquid glass, the silica module is reduced by mixing liquid glass with units (L soda, amount which is determined by the formula - + 7.6-10% K

Description

The invention relates to oil and gas production, in particular, to the isolation of water inflows into oil, gas and gas condensate wells. Methods are known for selectively isolating water inflows by pumping fresh water into the reservoir and then pumping into it a plug-in material (hypana, polyacryl da, latex, myloneft, etc.). The damping effect of these materials consists in the formation of insoluble precipitates and gels in the water-saturated part of the reservoir due to the interaction with the salts of formation water lj. However, these insulating materials are not applicable for the selective isolation of formation water under conditions of formation temperatures above 60 ° C due to their low heat resistance. A known method of selectively plugging watered zones of the formation, which consists in pumping an aqueous solution of an alkali metal salt, for example sodium carbonate, into the formation, and then injecting liquid glass 2j. An aqueous solution of NajCO, forming water-insoluble compounds CaCOj and MgCOj with calcium ions and magnesium, removes them from the composition of the residual formation water. As a result, the chemical composition of the formation water in the injection zone of the liquid glass varies and consists of the reaction products of the components of the formation WATER with Naj COj - alkali metal chlorides, sulphates and bicarbonates that do not instantly coagulate liquid glass. After injection into the reservoir, liquid glass coagulates in the flooded area due to the diffusion of calcium and magnesium ions from the surrounding reservoir water and thus clogs the flooded areas of the reservoir. Coagulation of liquid glass does not occur in the oil-saturated zone due to the interaction with calcium and magnesium ions. There is practically no source of their input in this zone. The main disadvantage of the known method is the reduction of the permeability of the oil-saturated zones of the reservoir during high temperature formation . Commodity zhtstskoe glass, vyuskae, my industry, and its design. Kbie solutions have a silica module in the range of 2.0-3.5. With this modulus value, at high temperatures, liquid glass coagulates slowly under the action of monovalent metal salts contained in the formation water and in the reaction products of sodium carbonate with the formation water. The purpose of the invention is to prevent a decrease in the permeability of the oil-bearing part of the reservoir and to increase the effectiveness of blocking water channels. The goal is achieved by the method of selectively plugging watered zones of the reservoir, which involves injecting an aqueous solution of an alkali metal salt, such as sodium carbonate, into the reservoir, and subsequently pumping the liquid glass to reduce its silica modulus to the formation of the liquid glass , 3-1.8 and is determined by the formula, 66, K ciHijtcji. 6.45-10 3 K () 1, —concentration of the initial liquid glass, wt.% (Taken from 1.5 to 46 wt.%, Depending on the permeability of the formation); t, cx silica module of the original liquid glass. When commercial liquid glass is used, the silica module is reduced by mixing liquid glass with caustic soda, the amount of which is determined by the formula q; o, + 7.6 - ltf (fK (2-m), where Yatsdon is the amount of caustic soda added to the original liquid glass, d. 6th 510-d |. „- KIS | an aqueous solution of sodium carbonate with a concentration of 4-30 g / l; reducing the silica module of liquid glass to 0.3-1.8 by addition of caustic soda; preparation of liquid glass with a concentration of 4.6-46 wt.%, by adding fresh water to it; injection of an aqueous solution of sodium carbonate to the reservoir and removal of it; in the reservoir for 0.5 h; injection of liquid glass into the reservoir and its holding in the reservoir for 24 hours; the development of the well and its commissioning. For the study of the proposed method, the mixtures prepared are presented in Table 1. Studies of the effect of the prepared mixtures on the permeability of the oil-saturated zone through which the carbonic water solution passed that sodium conducted at a pressure of 30 MPa by the following procedure. Mixed mixtures were pressed into the pore formation model, which was saturated with the products of the reaction of formation water with NajCOj (Table 2), the formation model was kept for 16 hours at 120 ° C and pressure of 30 Sh. By pumping kerosene, the permeability of the formation model was determined before and after the exposure of the prepared mixtures. The results are presented in table. 3, in which, in addition, the results of studies of the interaction of the prepared mixtures with formation water are presented. When considering groups of mixtures 1-5, 6-10, 11-16, 17-20, 21-23, 2426, 27-29, presented in table. 1, and the results of the study of the same groups of mixtures presented in Table 3 show that in each group of mixtures with a decrease in modulus (an increase in the amount of NaOH added to the liquid glass), the multiplicity is reduced to the permeability of the oil-saturated part of the reservoir to 1.0. (no decrease in permeability) for mixtures 5, 10, 16, 20, 23, 26, 29, and the amount of sediment rises, taking the maximum values of dp of the same mixtures 5, 10, 16, 20, 23, 26, 29. The amount of sediment, formed by the interaction of these mixtures with formation water, in the middle m 2.5 times greater than the amount of sediment. resulting from the interaction of commercial liquid glass and its aqueous solutions of low concentration with the same formation water. Mixtures 5, 10, 16, 20, 23, 26, 29 are considered optimal. Table 1

2.00

47.9 2.00 47.9 2.00 47.9 2.00 47.9 2.00 47.9 40.0 2.00

1.00

20.6

52.9 48.0 0.60 57.5 82.3 0.40 61.2 97.0 0.35 61.5 16.6 0.30 63.8 17.2 1.00 45.5

Continuation of table 1

Plastova water

Reaction products of produced water with sodium carbonate

Tayu1 research results (e show, the higher the concentration of the initial liquid glass and its aqueous solutions, the lower the optimal silica modulus of the mixture takes on.

table 2

1.61

65.03

0.28

1.58

74.68

1.58

0.28

To reduce the modulus of the liquid glass, it is possible to use caustic potash.

According to the results of the research, the following dependences of the optimum silica modulus and the amount of caustic soda added to the liquid stack on the concentration and the crusty modulus of the initial liquid glass were obtained. silt rO.Zfe m 5.66K, where tn is the optimum silica module of the liquid glass produced: 5К 6.4510-5К ", (gaish 2 + mi, +1 concentration € 1 of the original liquid glass, in may.% (taken from 4 , 6 to 46 wt.%, Depending on the permeability of the reservoir); m f. Is the silica module of the initial liquid glass. The rms deviation of the actual silica module from that calculated by the formula (1) is 0.0001. 6.10- to (2-t) (3) is the amount of caustic soda where q is added to the initial liquid glass, r. 6 45-10-di "Kitty (tisch-2) m is 1 (4), is the amount of the original liquid glass, q; q "- Chnaon Prim. Industrial implementation of the method. Processable fracture-pore formation 10 m thick, absolute fracture porosity 20%, 50 permeability 270 Md, residual water saturation 44%, pressure 30 Mtta, formation temperature 12 SGS, well depth 3200 m. The lower part of the reservoir is watered with surface water. The main components of the composition of formation water, hl / l: SG 45.2928; 80G 0.8693; HCO 0.2042; 8 Ca 2.6255; Mg 0.4101; Na 25.6696; K 0.7063, Water flow rate - 10 tons / day, oil flow rate 10 tons / day. When testing for injectivity, it was established that the reservoir receives water at a pressure at the mouth of 12 MPa and a flow rate of 8 l / s. It is planned to reduce the permeability of the flooded zone of the reservoir at a distance of 2 m from the bottom of the well. Calculations of quantities of the necessary materials are carried out. For a given depth of isolation of the inflow of formation water into the formation, it is necessary to pump more than one quantity of liquid glass (V ,.): V. .. 3.14 R — depth of isolation of the inflow of formation water, m; h — formation thickness, m; ha - absolute fracture porosity,%; - residual water content,%, 14-2. 10.-: (1100 100 14 mz, According to the table, 4 for treatment of a reservoir with a permeability of 270 MD, it is necessary to apply liquid glass with a concentration of 12Z, T al. 4 Permeability of the reservoir, Concentration MD of liquid glass, wt.% Over 1000 100- 1000 Less than 100 1.5-10 Commercially available liquid glass of silica module 2.8 is available, diluting with water will bring its concentration to the required 12% by weight. Density of diluted liquid glass will be 1.1 g / cm. Weight 14 m times

Claims (2)

1. METHOD OF SELECTIVE TAMPONING OF WATERFLATED ZONE OF THE FORMATION, which consists in injecting an aqueous solution of an alkali metal salt, such as sodium carbonate, into the formation and subsequent injection of water glass, so that, in order to prevent a decrease the permeability of the oil-saturated part of the formation and increase the efficiency of blocking water-saturated channels, before pumping liquid glass into the formation, reduce its siliceous modulus to a value of 0.3-1.8 and it is determined by the formula | u = 5.66 K ' ^0.7S , where 1> 5 K _uc> PE _ix) ^{(C 3} 6,45-10- _IHC K (t + m -O _{Ex Ex} + 1 ' To _ISD - the concentration of the initial liquid glass, wt,% (taken from 1.5 to 46 Mac.Z, depending on the permeability of the formation); w _Ref - siliceous module of the initial liquid glass. 2. The method of pop. 1, characterized in that, in order to use marketable liquid glass, the siliceous module is reduced by mixing liquid glass with caustic soda, the amount of which is determined by the formula, the amount of caustic soda added to the original liquid glass, g, _l <= 6.45-10 ^? d "erKieh ~ 2)% aon ^where Yamona q -> amount of initial liquid glass, g; I am “Chmskh ⁺ Ί Να he · 1 1154438