SU1765364A1 - Compound for selective reduction at permeability of high-permeable seam layers in wells - Google Patents

Abstract

The composition for selectively reducing the permeability of the highly permeable formation intervals in the well contains, in wt%: Deman — polymethyl methacrylate modified with monoethanolamine in an aqueous medium, 0.2–1.0; bentonite 0.2-1.0; water the rest. 2 tab.

Description

This invention relates to the petroleum industry.

A composition based on polyacrylamide and waste water is known to limit the water flow.

The disadvantage of this composition is low efficiency for highly permeable formations.

A composition based on a hypoformaline mixture and saline water is known.

The disadvantages of this composition are the difficulty in preparation, high toxicity, as well as the rapid removal of the composition with the production of wells, which significantly complicates the operation of oil treatment facilities.

The closest in technical essence and the achieved effect is a composition based on PAA and clay suspension.

A disadvantage of the known composition is the insufficiently high efficiency associated with a small penetration of PAA and clay slurry into the bottomhole zone and the depth of the formation.

The purpose of the invention is to increase the efficiency of well treatments by increasing the selectivity of

and increasing the processing depth of the high permeable intervals.

This is achieved by using the Deman reagent - polymethyl methacrylate modified with monoethanolamine in the aqueous phase as the polymer in the following ratio of components, wt.% - Deman 0.2-1.0

Clay suspension 0.2-1.0 - Water Else

Above the upper and lower limits, the composition loses effectiveness due to a decrease in the isolation selectivity of the highly permeable formation.

Deman polymer is a water-soluble high-molecular compound of the general formula

with

WITH

 about ate

co o

and produced by the domestic industry according to TU 6-01-8-73-83.

In the petroleum industry, Deman is used to increase oil recovery.

An unexpected positive effect is achieved due to the formation of polymer-clay dispersions capable of selectively isolating highly permeable formation intervals without clogging up low-permeability, which is associated with the size of the clay particles formed by the polymer, as well as by increasing the processing depth of high-permeability intervals.

For experimental testing, the deposition rate of polymer-clay suspensions of the proposed composition and prototype was determined under comparable conditions, and the degree of isolation of highly permeable zones during filtration was determined on a model of uncooperative inhomogeneous water-saturated formations.

Example 1. Preparing 100 ml of a solution containing 0.2% Déman in fresh water, add 0.2% bentonite clay, mix quickly, and then place the glass on a table installed in an analytical balance, and lower the plate in the glass. area of 1 cm2, attached to the beam of the scales. By increasing the mass of the plate, the rate of deposition of the polymer-clay suspension is determined. For 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10 minutes, 0.043 was besieged; 0.086; 0.160; 0.275; 0.307; 0.324: 0.331, 0.335; 0.337; 0.338 g of sediment, respectively. The remaining results are shown in Table 1.

Example 2. A bulk model of non-communicating heterogeneous reservoirs with permeabilities of 0.120 µm2 and 1.08 µm, a length of 500 mm and a diameter of 30 mm is saturated with water until stabilization of flow rates corresponding to the permeability of water models, after which Déman rim is pumped in 0.15 Vnop) and bentonite (0.15 Vnop) with a concentration of 0.2%. The average filtration rate of water and reagent solutions is 1800 m / year. Then

QB

R distribution:

QH

- where QB is the quantity

fluids filtered through a highly permeable formation; QH is the amount of fluid filtered through a low-permeable formation. In this case, R was 3.4 or 2.7 times better than water distribution. The results of the remaining experiments are shown in Table 2.

As can be seen from the results of Table 1, the sedimentation rate of clay particles with Déman solution is approximately twice as low as in the case of PAA, which provides deeper processing of high-permeability intervals.

As can be seen from Table 2, the optimal ratio of the components of the composition is Deman 0.1-0.2 wt.%, Clay suspension 0.1-0.2 wt.%. Above the upper limit, the use of the composition is impractical due to technical and economic considerations (since the efficiency practically does not change with an increase in the concentration above 0.2% with a component ratio of 1: 1). Below the lower limit, the composition loses the property of selectively reducing the permeability of a highly permeable formation.

Experiments 16-21 (Table 2) show that the proposed composition will be most effective under conditions of elevated temperatures and large pressure drops. The prototype under such conditions loses its effectiveness, which is associated with low PAA stability in hydrodynamic and temperature fields.

Industrial implementation of the invention does not require the development of additional equipment and technical operations and can be carried out in accordance with RD 39-23-1187-84, prepared for polymer-clay suspensions for polyacrylamide.

Claims (1)

Composition for selectively reducing the permeability of highly permeable formation intervals in a well, containing water-soluble polymer, bentonite and water, characterized in that, in order to increase the efficiency of well treatment by increasing the selectivity of the action while simultaneously increasing the penetrating ability of the composition, it contains as a water-soluble polymer Deman-polymethyl methacrylate, modified monoethanolamine in the aqueous phase, in the following ratio of ingredients, wt.%: Deman-polymeta methacrylate, modified with monoethanolamine in aqueous srede0,2-1,0; bentonite 0.2-1.0; water rest. Polymer-clay suspension deposition rate ate No Composition, wt.% 1PAA 0.1 Bentonite 0.1 2PAA 0.05 Bentonite 0.2 3 Freshwater Bentonite 4Deman 0.1 Bentonite 0.2 5Deman 0.2 Bentonite 0.1 6 Deman 0.2 Bentonite 7Deman 0.1 Bentonite . As PAA, a Japanese reagent of the DKZ ORFF 40 NT brand, Idling, was used. The precipitation time (min) and the amount of precipitated sediment (g) ... 1 2A01.3 0Lf} A0 5A0 6D0 7A0 8A0 §40 lOA0. 0.0530.0920.1610.1860.1870.1870.1870.1870.1870.187 0,0920,1700,20 j0,2180,2240,227 .0,2270,2270,2270,227 0,0010,0020,00250,00300,00340,0037 0.00400,00420,00440,0046 0,0380,0700,0920,1200,1360,1490,1610,1750,1890,201 0.0410.0810.1160.13.35.1580.17.20.1890.20.20.2110.217 0,0430,0860,1600,2750,3070,3240,3310,3350,3370,338 0.0330,0640,0870,1180,1310,1430,1580,1640,1720,175 -j SP ate Cj sp jb SP 71765364 Table 2 Dependence of the filtration flow distribution in heterogeneous reservoirs depending on the ratio of the components of the composition Idle experience   The experiments were carried out taking into account the mechanical degradation while mixing with a high-speed (2000 rpm) agitator for 20 minutes and thermo-oxidative degradation (temperature control of the polymer solution at 60 C for 48 h,  As the PAA-used reagent Leninsk-Kuznetsk plant. 176536410 Continued tabl, 2