RU2341651C1 - Method of development of water-flooded deposit with reservoirs of non-uniform permeability - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: method of development of water-flooded deposit with reservoirs of non-uniform permeability consists in pumping into reservoir water solution of hydroxychloride aluminium - waste of production of benzene alkylation with olefins - with successive pressurising of displacement agent, in introducing of oxyethylidendiphosphonic acid at amount of 0.025-0.1% into 15-30% water solution of hydroxychloride aluminium -waste of production of benzene alkylation with olefins.

EFFECT: upgraded efficiency of oil displacement due to formation of water insulating screen in water saturated - washed up zone of reservoir at considerable distance from bottom hole of well.

1 tbl, 10 ex

Description

The invention relates to the oil industry, in particular to increasing oil recovery heterogeneous permeability of water-flooded formations.

There is a method of developing oil deposits by blocking washed channels by injection of aluminum sulfate, which, when in contact with formation water, forms hydroxide crystals (Ibragimov G.I., Fazlutdinov K.S., Khisamutdinov M.I. Reference book. Use of chemical reagents to intensify oil production. M .: Nedra, 1991.S. 168).

The disadvantage of this method is the low efficiency due to the fact that precipitation is associated with pH and low strength.

A known method of developing a water-cut oil reservoir, comprising injecting a portion of water with an additive of 0.02-0.05% concentration of hydroxyethylidene diphosphonic acid as a chemical agent for distillation, followed by injecting a portion of water with an additive of a mixture of acetic acid distillation of hydroxyethylidene diphosphonic acid as a chemical agent the waste of the alkylation process at a ratio of 1: 1 to 1: 3 while maintaining the pH of the portion of water more than 4 (USSR AS No. 1627677, E21B 43/22, 1991).

The disadvantage of this method is the complexity of the injection technology, low efficiency due to the fact that precipitation is associated with pH.

The closest to the proposed technical essence and the achieved result is a method of developing oil deposits by blocking the washed zones by injection of an aqueous solution of aluminum-containing waste from the process of alkylation of benzene with olefins, followed by injection of a displacing agent, the concentration of aluminum-containing waste being 1-30% (RF Patent No. 2042031, Е21В 43/22, 33/138, 1995).

The disadvantage of this method is its low technological efficiency, due to the fact that at high concentrations of waste, its penetration depth decreases due to high reactivity, and at low concentrations, the strength of the precipitate / gel formed decreases.

The basis of the present invention is the task of creating a method of developing an irrigated oil reservoir with heterogeneous permeability reservoirs, which allows to increase the efficiency of oil displacement due to the formation of a water-insulating screen in the water-saturated (washed) zone of the reservoir at a considerable distance from the bottomhole zone of the well.

The problem is solved in that in a method for developing an irrigated oil reservoir with heterogeneous permeability formations, including injecting into the formation an aqueous solution of aluminum hydroxyl chloride by olefin production of alkylation, followed by injection of the displacing agent into a 15-30% aqueous solution of aluminum hydroxyl chloride waste for the production of benzene alkylation with olefins, hydroxyethylidene diphosphonic acid is added in an amount of 0.025-0.1%.

Aluminum hydroxyl chloride (GCA) is taken from the production of benzene alkylation with olefins according to TU 38.302163-94 or TU 2152-005-47773778-2002, hydroxyethylidene diphosphonic acid (OEDPK) according to TU 2439-363-05763441-2002.

A mixture of an aqueous solution of aluminum hydroxychloride and hydroxyethylidene diphosphonic acid is prepared at the factory or directly at the well before use by introducing a calculated amount of hydroxyethylidene diphosphonic acid into an aqueous solution of aluminum hydroxychloride.

To determine the effectiveness of the proposed method with the method of the prototype, an experiment is conducted on reservoir models 1 m long and 0.033 m in diameter with various permeabilities and with a carbonate content of 10%. Saturation of the models is carried out with fresh or mineralized water with a salt concentration of 130 g / l.

Efficiency is estimated by the depth of penetration of the reagent and the increase in the oil recovery coefficient.

The penetration depth of the reagent is determined by the gel-like precipitate formed in the disassembled model after the experiment.

Example 1. An aqueous solution containing 15% GCA and 0.025% HEDPA in the amount of 0.1 pore volume (bp) is pumped into a reservoir model saturated with fresh water. Then a displacing agent, for example water, is pumped. The penetration depth in the high permeability layer is 41.6%, and low permeability - 29.3%, the increase in oil recovery coefficient increases by 9.1%.

Examples 2-7. The experiment is carried out analogously to example 1, changing the concentration of reagents in the mixture.

Example 5. In a reservoir model saturated with mineralized water with a salt concentration of 130 g / l, a 25% aqueous GCA solution containing 0.025% HEDPA is pumped in an amount of 0.1 bp. Then a displacing agent, for example, the same mineralized water, is pumped. The penetration depth in the highly permeable and low permeability layers is 38.7%, 25.5%, respectively, and the oil recovery coefficient growth is 19.0%.

Examples 6-7. The experiment is carried out analogously to example 5, changing the ratio of components in the injected reagent.

Examples 8-10 are carried out according to the specified prototype.

The experimental data are presented in the table.

This method using components in the declared amounts allows to increase the efficiency of oil displacement due to the formation of a water insulating screen in the water-saturated (washed) zone of the formation at a considerable distance from the bottom-hole zone of the well and obtaining the maximum possible gel volume in the amount necessary to fill the permeable sections of the formation with sediment.

As can be seen from the data given in the table, according to the claimed method, the penetration depth increases by 25-30% for high permeability layers and by 20-23.1% for low permeability layers, and the increase in oil recovery coefficient increases by 5-7% compared with the data on the prototype . We give an example of the method in the field. The processing of the oil reservoir is as follows. The estimated amount of reagent is delivered to the wellhead. From the tank, the finished composition is pumped into the well using a pumping unit and squeezed into the reservoir with water in an amount equal to the volume of the tubing and plus 10 m ³ .

The composition is injected until the calculated volume, which depends on specific geological and physical conditions and the tasks to be solved, is pumped into the well and averages 10 m ³ -25 m ^{3 of} composition per 1 meter of effective perforation. At the end of the reagent sales, the well is left for structuring for 24-72 hours.

An example of a specific implementation of the method is the treatment of the wellbore of the Igrinsky oil and gas production department of OAO Udmurtneft in order to align the injectivity profile. The exploited horizon is composed of Bashkir deposits, represented mainly by oil-containing carbonate rocks. The reservoir properties are characterized by the following parameters: total perforated layer thickness - 18 m, porosity - 16.5-24.5%, permeability - 0.62-0.8 μm ² . The basic indicators of well operation prior to waterproofing are as follows: fluid injectivity 88.4 tons / day, oil production rate of reacting production wells 4.6 tons / day, average water cut in the area of 94.7%.

The work was carried out as follows.

Example 1. In injection well No. 308 of the Sundur-Nyazinskoye field, 59 tons of a 22% aqueous solution of aluminum hydroxyl chloride containing 25 liters of HEDPA are pumped at a pressure of 30 atm and 14 cm ^{3 of} water are pushed into the formation (P = 30 atm). Leave for 24 hours for gelation. The success of the process is confirmed by a decrease in injectivity of the well from 720 m ³ per day at 0 atm to 576 m ³ per day at 12 atm.

Example 2. 60 tons of a 25% aqueous solution of aluminum hydrochloride with 0.04% OEDPK at a pressure of 80 atm are pumped into injection well No. 402. Then 14 m ^{3 of} water are pushed into the reservoir (P = 100-110 atm) and the well is stopped for gelation for 36 hours.

As a result of the work carried out, a decrease in water cut of extracted products in the impact area was obtained to 45.6%. Additional oil production over 6 months amounted to about 3,000 tons, with continued technological effect.

Table No.
an example The concentration of reagents,% The permeability of the formation, microns ² The volume of rims, bp Penetration Depth,% Oil recovery factor for water,% Oil recovery coefficient after treatment,% The increase in oil recovery,% GHA OEDFK one fifteen 0,025 3.61
0.24 0.1 41.6
29.3 38.8 47.9 9.1 2 fifteen 0.1 3.68
0.21 0.1 42,4
28.7 40.5 50.3 9.8 3 25 0,07 3.47
0.25 0.1 39.5
26.6 41.2 61.6 20,4 four 25 0.1 3,51
0.23 0.1 40,0
27.1 39,4 59.9 20.5 5 25 0,025 3.56
0.27 0.1 38.7
25.5 39.7 58.7 19.0 6 thirty 0,025 3,54
0.26 0.1 36.8
23.3 40.8 63,2 22.4 7 thirty 0.1 3.60
0.28 0.1 37.0
24.1 41.5 64,2 22.7 According to the prototype 8 fifteen - 3,59
0.26 0.1 13.6
6.1 41.7 46.3 4.6 9 25 - 3.44
0.28 0.1 13
5,6 40.3 53,4 13.1 10 thirty - 3.88
0.23 0.1 12.1
4.0 39.9 55.3 15.4

Claims (1)

A method of developing an irrigated oil reservoir with heterogeneous permeability formations, comprising injecting an aqueous solution of aluminum hydroxyl chloride into the formation - waste from the production of benzene alkylation with olefins, followed by injection of a displacing agent, characterized in that in a 15-30% aqueous solution of aluminum hydroxyl chloride - from alkylation production benzene olefins are introduced hydroxyethylidene diphosphonic acid in an amount of 0.025-0.1%.