SU1645475A1 - Method of exploitation oil field - Google Patents

Description

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(21) 4485050/03

(22) 08/15/88

(46) 04.30.91. Bul P 16

(71) Kazakh interdisciplinary scientific and technical center of SVS

(72) G.I. Ksandogtulo, V.A. Ivanov, A.A.Sagindykov, Yu.V.Antnpo, V.A.Simonov, I.A.Koshkinov and A.Murzagpev

(53) 6.22.276 (088.8)

(56) Mannzer T.Ya. Review of patents on thermal methods of oil extraction, Ser. Mining, Moscow: VNIIOENG, 1970, p. 42-43.

(54) METHOD FOR DEVELOPING OIL FIELDS

(57) The invention relates to an oil producing industry. The goal is to increase oil recovery and increase the stability of the combustion front. In reservoir

initiate the combustion front. Through the injection wells pumped air and heat-transfer fluid, which is used as a 50-65% aqueous solution of ammonium nitrate. The combustion front is moved from the injection wells to the producing ones. The decomposition of ammonium nitrate begins to occur at i-pe above 210 ° C, which is always achievable under the conditions of the scorched zone of the thermal wave of the super-humid intra-layer combustion. The effect of using this method is due to an increase in the number of produced oil due to the reagent intensification of in-situ combustion during injection into the reservoir as a coolant ammonium nitrate solution. 1 tab.

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The invention relates to the oil industry and can be used to increase the coefficient of oil recovery in the development of deposits by the method of intra-layer combustion of oil.

The aim of the invention is to increase oil recovery and increase the stability of the combustion front.

The essence of the method lies in the fact that it is advisable to use the heat-scorched zone of the reservoir from a physico-chemical point of view not only to evaporate water (purely heat engineering technique), but also to start the reaction of ammonium nitrate decomposition, followed by heat release, and Most importantly, substances that accelerate the in situ combustion of nitrogen monoxide and oxygen (physico-chemical method).

The decomposition of ammonium nitrate begins to occur at temperatures above 210 ° C, which is always achievable under the conditions of the scorched zone of the thermal wave of the super-humid intralayer combustion. Since the decomposition of ammonium nitrate occurs in the burned area immediately near the combustion front

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or in the combustion front, the oxygen and nitrogen oxides that are released with it actively act on the burning tone, which is expressed in an increase in the stability of the propagation of the combustion front, the temperature of which is much higher than in the case of water injection in the same amount. Maintaining the air / water ratio at the same level. The air pressure in the core holder allowed the heat to be transferred efficiently from the burned zone to the area ahead of the combustion front, which allows the oil saturated rock to be warmed up at a considerable distance from the front of the burning front.

The possibility of this method is confirmed by laboratory experiments. In the laboratory, the experiments were constant for all experiments and were 2.0 MPa. The use of an aqueous solution of ammonium nitrate with a concentration below 50% as a heat carrier leads to a deterioration of the process performance — the temperature of the combustion front and the oil displacement coefficient decrease (see table). The use of a solution of ammonium nitrate with concentrates used oil 20 above 65% is difficult due to poor

reservoir collector. The oil saturation of core material was 41.2%. Oil characteristics: density 943 kg / m3, viscosity 1100 mPa-s (20 ° С).

The rock is a mixture of uncemented sandstones, sands and siltstones with the main content (90 wt.%) Of the fraction 0.05-0.25 mm. Mineralogical composition, wt.%: Quartz 30, feldspar 25, rock fragments 45.

The experiments were carried out in a laboratory high-pressure installation, the main part of which is a core holder, made in the form of a tube-in-tube heat exchanger. The core holder is a thin-walled tube with an inner diameter of 50 mm (wall thickness of 1.5 mm), which is placed in a thick-walled casing. The pressure in the shell and inside the core holder is kept the same. The thin wall of the formation model and the air gap between the core holder wall and the casing significantly reduces heat loss from the combustion front to the model wall, and this, in turn, eliminates the preliminary heating of the collector material to form and propagate the combustion front. The packing length of oil-saturated rock is 700 mm. The core holder is provided with an axial thermocouple pocket. Core holder was loaded with oil-saturated rock. The initiation of the combustion process was carried out with the help of solid fuel placed in the upper part

keriroderzhatel. Coke or carbon dioxide reagent was used as a solid fuel. Solid fuel ignition was performed using chemical reagents. The temperature of the heat wave and its velocity of propagation were fixed with the help of four stationary thermocouples.

was constant for all experiments and was 2.0 MPa. The use of an aqueous solution of ammonium nitrate with a concentration below 50% as a heat carrier leads to a deterioration of the process performance — the temperature of the combustion front and the oil displacement coefficient decrease (see table). Application of ammonium nitrate solution with concentration 0

five

five

0

five

0

five

solubility of the reagent with a further increase in its content in the solution.

Example 1. A core holder was packed with collector material. A charge of solid fuel and a chemical reagent were placed at the top of the core holder to initiate the combustion process. Air was then introduced into the formation model at a flow rate of 0.36 m3 / h. During the pumping of a certain portion of water, a vigorous release of heat was observed, which led to the ignition of the charge of solid fuel with the further initiation of the center of combustion in the oil-saturated porous medium. After the formation of a stable combustion front, water was injected into the model as a heat carrier. The water ratio was 1.25-10 5 m3 / nm3. The high-temperature front formed at the beginning of the process with a temperature of 490-520 ° C as the water is pumped into the model has a decay character and the temperature at the end of the experiment was 120-200 ° C. Experiments carried out in parallel indicate an extremely unstable combustion regime with large amplitudes of temperature fluctuations in a thermal wave. The utilization rate of oxygen does not exceed 45%. The rate of heat wave propagation also varies significantly during the course of the experiment. The achieved oil displacement rate from the formation model is 24.5-42.0%.

Example 2. The experiment was carried out analogously to example 1. Instead of

516

water and modem and the quality of the coolant iodine nale 50% aqueous solution of ammonium nitrate. The ratio of the volume of the injected ammonium nitrate solution to the volume of injected air was 1.25-10 3 m3 / nm3. During the experiment, a stable combustion front with a temperature of 505–520 ° C was observed. There was a decrease in temperature fluctuations in the heat wave and stabilization of the velocity of the combustion front. Oxygen utilization rate wounded 74.6%. The oil displacement ratio was 70.0%.

Example 3. The experiment was carried out similarly to examples 1 and 2. In this case, a 65% aqueous solution of ammonium nitrate was injected into the formation model with a ratio of the volume of the injected solution to the volume of injected air of 1.50-10 e m3 / m 2. A stable combustion front is formed with a temperature of 515-520 ° C. The oxygen utilization rate was 88%, with the oil displacement coefficient being 76.9%.

Examples 4-7. The experiments were carried out similarly to examples 1 and 2 with the difference that aqueous solutions of ammonium nitrate of various concentrations were used as the heat transfer medium. The results of the experiments are shown in the table.

Thus, laboratory experiments indicate the possibility of increasing the stability of the front of the in-situ combustion and the intensification of oil production.

Thus, the proposed method in comparison with the prototype allows

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to produce oil without reducing the total amount of coolant injected into the reservoir, which ultimately will determine the rate of development of the oil field. At the same time, the introduction of a sufficiently large amount of coolant to the process does not reduce the temperature of the combustion front, which is observed when carrying out the process of super-wet oil burning and allows oil to be produced with a high displacement ratio (70.0-76.9%)

The effect is caused by an increase in the amount of produced oil due to reagent intensification of intra-plate combustion when injected into the reservoir as a coolant ammonium nitrate solution, the decomposition of which in the combustion front results in the release of additional heat and the formation of oxygen and nitrogen oxides, which have a catalytic effect on the combustion process.

Claims (1)

Invention Formula A method of developing an oil field, including initiating a combustion front in a formation, injecting air and a liquid heat carrier through injection wells, moving the combustion front from injection wells to producing wells, extracting oil through producing wells, characterized in that, in order to increase oil recovery and increase stability combustion front, as a liquid coolant using 50-65% aqueous solution of ammonium nitrate. The effect of the concentration of the injected ammonium nitrate solution on the indicators of the in-situ combustion of oil in the field ten 20 30 40 40.0 burning process in progress 430-440 49.0 470-500 52.4 510-520 59.4