SU937712A1 - Method of mine working of oil deposit - Google Patents

Description

The invention relates to the oil industry, and more particularly to methods for mine development of oil fields with high viscosity oils.

A known method for developing an oil reservoir is to displace oil from the formation by injecting coolant into the formation through wells and draining oil through production wells [1].

However, the known method is not effective enough, since during the development of the mine method, there are large losses of coolant in the roof and bottom of the formation.

There is also known a method of mine development of oil deposits by heating the treated area of the reservoir by cyclically alternating injection of steam and hot water through injection wells and ¹ periodic selection of oil through production wells [2].

The disadvantage of this method is the insufficiently high rate of oil withdrawal from the reservoir and the low efficiency of the heat treatment process.

The purpose of the invention is to increase the rate of oil recovery and increase the efficiency of the process of thermal exposure to the formation.

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This goal is achieved by the fact that according to the method after injection of steam, air is injected.

The essence of the method is as follows.

In the development of an oil reservoir, including the injection of steam and hot water, alternating the supply of these agents to the reservoir, the air is injected after the injection of steam. This is due to the fact that _{10 the} use of steam to displace oil in excess of the norm necessary for heating the formation increases the specific consumption of steam and reduces the efficiency of the mine development process. An increase in the injection pressure of the injected steam leads to breakthroughs of 15 steam into the mine workings, and long-term continuous injection of steam at a low injection pressure causes significant heat loss through the roof and the bottom of the formation, and breakthroughs of steam into production wells ₂₀ . Closing these wells reduces oil production.

The rate of selection and the efficiency of the process of thermal action on the formation increases due to air injection with a partial reduction in the volume of injection of steam and hot water.

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Ceteris paribus, choosing the amount of coolant at the level necessary for technological purposes, and replacing part of the coolant that is used only for the selection (displacement from the reservoir) of oil, with a cheaper agent - 5 air, increases the efficiency of the process, i.e. less heat carrier is consumed per unit of oil produced.

Additional air supply to the formation over a certain period of time allows increasing the rate of oil extraction from the formation.

Air entering the heated reservoir expands, creating an additional pressure drop in the reservoir, which helps to move oil to production wells. In this case, first of all, the saturating fluid is displaced from large cracks and pores.

Hot water injected after this displaces oil due to capillary impregnation from small pores and microcracks.

The alternation of air, hot water, again steam, air and hot water into a preheated formation reduces the flow rate of the coolant, increases the rate of fluid withdrawal from the formation and at the same time maintains the temperature of the formation at a technologically necessary level.

The method is carried out as follows.

A mining system is being built above the reservoir or in its 30th roof. Through the slope and walker, the supra-layer horizon of mining is connected to the expatriation gallery, which is located in the lower part or below it.

From the drilling chambers located above or in the top of the formation, ³⁵ injection wells are drilled.

Upstream or horizontal production wells are drilled from the production chamber (gallery).

Through a system of injection wells 40, the reservoir is heated by injecting steam to the desired temperature.

Then, air is pumped into the oil reservoir through injection wells. The duration of air injection cycle is determined from fiziches- FIR properties of oil ⁴⁵ and oil reservoir geologic characteristics: thickness, porosity, fracture, oil and vodonasptsennosti and other parameters. The amount of injected air should not · ₅₀ exceed the volumes, · at which spontaneous combustion of oil in the oil-bearing formation may occur.

Next, hot water is pumped through injection wells into the oil reservoir. The duration of water injection is also determined depending on the geological characteristics of the formation.

The cycles of injecting steam, air and hot water into the oil reservoir repeat the technologically necessary number of times.

Simultaneously with the cyclic injection of steam, air and hot water, periodic selection of oil (liquid) from production wells is carried out.

The inclusion of air injection in the technological cycle leads to a decrease in the flow of coolant and to the possibility of using it in new areas. Heat loss through the roof and sole is reduced.

For injection into the reservoir, hot water simultaneously produced from production wells can be used.

Thus, the heat that is irrevocably lost with the produced water, which was previously pumped from the mine to the surface, is also included in the cycle.

This also leads to an increase in the efficiency of the steam-thermal treatment process.

The cost of production and injection into the reservoir of 1000 m ^{3 of} compressed air is 4.99 rubles. 1000 m ^{3 of} hot water with a temperature of 75 ° C - 40 rubles, 1 t. Steam - 2 rubles.

The injection of 1000 m ^{3 of} air at a pressure of 5 atm with a temperature of 10-15 ° C will lead to the expansion of this volume to 1250 m ³ with an increase in temperature to 75-80 ° C or to an increase in pressure by 25% with a constant volume.

The savings from pumping 1000 m ^{3 of} air will be about 45 rubles. As a result of this, along with a reduction in the volume of coolant pumped into the formation, conditions are created that can maintain high temperature in the formation for a longer time. Due to this, the coverage of the reservoir increases by displacement and, as a result, oil recovery increases.

Claims (1)

Claim The method of mine development of oil deposits by heating the treated area of the reservoir by cyclically alternating injection of steam and hot water through injection wells and periodic selection of oil through production wells, characterized in that, in order to increase the rate of oil extraction and increase the efficiency of the process of thermal exposure to the reservoir, steam injections pump air.