SU1661379A1 - Method of control of oil deposit exploitation - Google Patents

Abstract

The invention relates to an oil producing industry. The goal is to increase the efficiency of the method by improving the insulation of the water conducting formations while increasing the heat resistance of the insulating material. To do this, a composition having a pH of 1–3 containing the following components with their ratio, wt.%, Is injected into the productive layers: water-soluble polymer 0.005-5.0

single-cation chromate 0.002-0.04

polyfunctional organosilicon compound 0,002-12,0

water the rest. As a polyfunctional organosilicon compound, orthosilicic acid esters, oligoorganoethoxy-chloro siloxanes, glycol esters of organosilicon compounds, sodium alkyl silicates, or a mixture thereof are introduced into the composition. The use of this method allows to improve the quality of insulation works to limit the water inflow into oil wells, and used to regulate the development of deposits during water flooding. 1 hp ff, 1 tab.

Description

The invention relates to the oil industry, in particular, to methods and compositions for regulating the development of oil fields, which allow changing the injectivity profile of injection wells and (or) isolating water inflows of oil wells.

The aim of the invention is to increase the efficiency of the method by improving the isolation of the water-conducting formations while increasing the heat resistance of the insulating material.

The method of regulating the development of oil fields is that a composition having a pH of 1-3, containing components with their ratio, wt.%, Is pumped into productive layers: Water-soluble polymer 0.005-5.0

Monovalent cation chromates0, 002–0.04 Polyfunctional silicon-organic compound 0, 002–12.0 WaterOstalal Hydrolyzed polyacrylamide and cellulose derivatives, for example, carboxymethylcellulose, are used as a water-soluble polymer; chromates and dichromates monovalent are used as the polymer;

about

with XI

4D

for example, potassium and sodium chromates and bichromates, as a polyfunctional organosilicon compound — orthocrystic acid alkyl esters (ethyl silicate 40, product 119-126), oligoorganic ethoxy (chlorine) siloxanes (product 119-204), g Silicon compounds icol esters (BTS-1, JBTC-2), sodium alkyl silicates (NGL-10) or their mixture (mixture ETS-40 with product 119-204 in a 2: 1 ratio, mixture of product 119-296 with product 119-204 in the ratio of 2: 1). In addition, a pH of 1-3 compositions is controlled by the addition of inorganic acids, for example hydrochloric or sulfuric.

In the compositions, trivalent chromium is also obtained from chromates, but using a reducing agent — organosilicon compounds at pH 1-3 by the following reaction equation using the example of ortho-silicate acid, potassium dichromate and hydrochloric acid:

i

n

S2n5-o - & - o- s2n / gggo-gsgn5on + but | -5 | -o + n

ogn5 / „

oad

ZSNz-CH20N + 5K2SG20 + 40HCI - - KNEP-COOH + 10KCI + 10CgCl3 + 6H20

As a result of the reaction at pH 1-3, hydroxyalkoxyloxanes, dicarboxylic acid and trivalent chromium are formed, which in the presence of a water-soluble polymer, for example, hydrolyzed polyacrylamide, with increasing pH above 3, react with each other to form a cross-linked polymer modified with hydroxy-silver organic compounds and dicarboxylic acid. As laboratory studies have shown, the modified cross-linked polymer has better insulating properties and heat resistance than the known compositions, due to the improved spatial structure of the gel and silicon content in it.

For the preparation of the composition used in the proposed method, use 0.005-5.0% aqueous solutions of the polymer with the content of carboxyl groups of 5-30%, 1-2% salic acid solutions

a monovalent cation chromate with an organosilicon compound in an amount sufficient to reduce hexavalent chromium to trivalent,

having a pH of 0.5-1.5. Both solutions are mixed in the required ratio, the pH of the resulting composition is 1-3. The prepared composition is stored for as long as desired, without crosslinking. but

when the composition is injected into the oil reservoir, when the pH rises above 3 due to the acid reacting with the rock and mixing with the formation fluids, the polymer is crosslinked, the hydroxy-silicon organic combines the dicarboxylic acid with trivalent chromium to form a viscoelastic gel. The latter blocks the porous medium in which it was formed from penetration of the water injected or extracted from the reservoir through it, changing the direction of the injected water into the poorly developed oil-saturated zones, i.e. allows you to regulate the development of oil field by flooding. Besides,

Silicon polymer gels are more thermostable than known. This ensures a longer preservation of its insulating properties in high temperature formations.

Example. For the preparation, a polyacrylamide (PAA) molecular weight of 16 ppm and a hydrolysis level of 25% and carboxymethylcellulose (CMC), sodium bichromate (BHN) and potassium chromates (BHC) are taken as the polymer, polyfunctional organosilicon compounds separately and in a mixture of the following brands: ETS-40, product 119-296, GKZH-10, VTS-1, VTS-2,

product 119-204, a mixture of ETS-40 with the product 119-204 in the ratio of 2: 1.

Of these components, a 0.001–5.0% aqueous polymer solution and a 1–2% aqueous hydrochloride solution are prepared.

sulfuric acid solution of chromates and organosilicon compounds (CBS). Before examining the compositions, a solution of chromates and KOS is introduced into the aqueous polymer solution and, if necessary, an additional KOS solution is added.

mixing, the test compounds with a pH of 1-3 are prepared and the insulating properties are determined by the following method (the compositions according to a known method are prepared in the same way, but without hydrochloric and sulfuric acids and KOS, with sodium sulfite).

The reservoir model (core) with a length of 9 and a diameter of 2.5 cm, represented by quartz sand and 3% of its weight of calcium carbonate - marble (CaCO3) with a permeability of 4.6-26.2 μm2, is saturated with water with a total salt content of 12%, then create bound water by pumping 2-3 pore volumes of oil core with a viscosity of 9.3 MPa C and residual oil saturation by pumping fresh water through the core at a constant speed of 7.18 m / day. Kern is ready to study the compositions. Through the core with residual oil saturation, the pore volume of its test composition is pumped at the same rate, allowed to hold for 16 h to form a cross-linked polymer, and then 5 pore volumes of fresh water core are pumped. The maximum pressure of the water injection before and after the composition is determined by a manometer at the intermediate point of the core (4.5 cm from the entrance) and the mobility of the water to the composition (Le) and after

composition (L), and by their mobility they calculate the residual resistance factor (Howl) at the intermediate point of the model using the formula

Rd d - g

Av

L

According to the ROCT value, the insulating properties of the composition are judged: the greater the ROCT, the higher its insulating properties.

To evaluate the insulating properties of low polymer concentrations, the screen factor (Sf) is determined on the screen viscometer with respect to the expiration time of 50 ml of the test composition from the screen viscometer to the expiration time of the same volume of solvent. The more Sf, the higher the insulating properties of the composition.

The table shows the data on the compositions for regulating the development and their technological properties.

The heat resistance of the compositions is determined as follows.

The investigated composition in a volume of 100 ml is placed in a steel bomb with a capacity of 100 ml, sealed with a screw cap and placed in a drying cabinet in which the temperature is maintained with an accuracy of ± 2 ° C. The composition is heated at a given temperature for four hours, starting at 80 ° C, thereafter, they are rapidly cooled, the cap is unscrewed, and the presence or absence of syneresis is visually determined (gel aging with the release of solvent). In the absence of syneresis, the heating temperature is increased by 10 ° C and the above procedure is repeated. The temperature is 10 ° C lower than the temperature at which

Syneresis was detected, assumed to be heat resistant.

The table shows that the proposed compositions (pH 1-3) in its insulating

properties are significantly superior (several times) known (pH 7-9), for example, compounds 1 with 10.3 s 11.7 s 12. However, compositions with a polymer content below 0.005, chromate below 0.002 and silicone

compounds below 0.002 wt.% exhibit the same technological properties with the known (for comparison, the compositions 14 and 18 with the composition 17). Thus, the lower limit of the content of the components in the proposed composition is 0.005 for the polymer, 0.002 for chromates, and 0.002 wt.% For organosilicon compounds, and the upper limit for the content of components is, respectively, 5.0; 0.04 and 12.0 wt.%, As above

These concentrations of the components of the gel are formed by mixing them, which makes it impossible to use it in field conditions. The proposed compositions have not only high insulating properties as compared with the known ones, but also a higher thermal stability (table, for comparison, compositions 3 with 11, 7 with 12), which provides a longer effect in relatively high-temperature formations.

The process of applying the compositions is simple and consists in injecting them into the reservoir before reducing the injection capacity of the well by 20-50%, displacing the composition from the wellbore into the reservoir with water, exposing the reservoir to

16-24h and commissioning of a well for oil wells or water injection for injection wells.

The invention allows to improve the quality of insulation works to limit

inflow into oil wells and can be used to regulate the development of oilfields during water flooding, which leads to an increase in oil production (with a simultaneous decrease in water production)

for each well operation.

Claims (2)

1. A method of controlling the development of oil fields, comprising pumping a composition containing a water-soluble polymer, a monovalent cation chromates, a reducing agent, and water, characterized in that into reservoirs. that, in order to increase the efficiency of the method by improving the isolation of the water-conducting layers while increasing the heat resistance of the insulating material, the pH of the composition is adjusted to 1-3 before being pumped into the layers, and a polyfunctional organosilicon compound is introduced into the composition, the following ratio of components, wt.%: Water-soluble polymer0,005-5.0 Monovalent cation chromate0,002-0,04 Polyfunctional silicon-organic compound0 value0,002-12,0 WaterEverything 2. The method according to claim 1, characterized by the fact that as a polyfunctional organosilicon compound orthosilicon alkyl esters are introduced acids, oligoorganoethoxy (chloro) siloxanes, glycol organosilicate esters, sodium alkyl silicates or mixtures thereof. On reservoir model 1.5 3.0 2.2 1.0 3.0 9139 "408 2939 2045 3967 120 110 110 120 675 6.5 48.7 90 80 2- 7220 2-737.5 790 75.0 7-2,0  2.0