SU1574799A1 - Method of thermochemical processing of near-face zone of seam - Google Patents

Abstract

This invention relates to the petroleum industry. The purpose of the invention is to increase the efficiency of thermochemical treatment of the bottomhole formation zone (PPP) due to more complete use of reagents in the reaction zone, increasing the thermal effect and reducing the contamination of the PPP. A suspension of aluminum (magnesium) (10 wt.%) In a hydrocarbon fluid is pumped into the well and forced into the reservoir with water so that water does not enter the reservoir. Water is removed from the well by air and a portion of air is introduced into the formation to evenly distribute the slurry in the PPP. Then 15-27% hydrochloric acid is injected into the formation in an amount sufficient to react with aluminum and is forced into the formation by air. The well is crushed with water and held to react the acid with aluminum and oxygen from the air with oil. After that, a 0.5-2.0% solution of caustic soda is pumped into the formation in an amount sufficient to saponify the fatty acids formed in the formation. The well was commissioned. As a result of processing, the value of the increase in the permeability of the PPP increases by 5 times, and the duration of the effect by 2.6 times. 1 hp f-ly, 2 ill., 1 tab.

Description

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Calculate the required amount of reagents and portions of air. A calculated portion of the suspension of aluminum (magnesium) in the hydrocarbon fluid is pumped into the well and forced into the reservoir with water so that water does not enter the reservoir. Then, with the open annulus, water is removed from the well by blowing tubing with air and introducing a portion of air into the formation in order to achieve a uniform distribution of the suspension in the bottomhole formation zone, minimal displacement from the reaction zone and creating initial gas saturation. After that, 15 - hydrochloric acid solution is injected into the well and forced into the reservoir by air with the annulus closed. The concentration of hydrochloric acid is determined by the conditions of its delivery to the oil fields (maximum concentration of supplied hydrochloric acid is 27%), its corrosivity and thermal efficiency of the process. At a high initial reservoir temperature (50–60 ° C), it is recommended to use 15% acid. Lower concentration is undesirable due to the high content of ballast water which reduces the thermal efficiency of the process. The well is caught in water and held until aluminum (magnesium) is completely reacted with hydrochloric acid and oxygen and air and hydrocarbons are oil. If necessary, several cycles of the described operations are possible. To do this, water in the well is replaced with a suspension with an open annulus and a new well treatment cycle is carried out in the specified sequence.

Since the oxidation of petroleum hydrocarbons with oxygen by oxygen produces organic acids that can partially interact with the carbonate part of the reservoir, in order to improve the washing of the near-abdominal zone of the formation from acFalt-resinous compounds, after keeping the well to the reaction, the formation of 0.5-2.0% is carried out. a sufficient amount of caustic soda (caustic soda) in an amount sufficient to saponify the organic acids formed 1 in the formation and the formation of surfactants, which, when extracting products from the well, will contribute chshemu launder bottomhole

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zone. After processing the wellbore zone, the well is put into operation.

In the initial period of the well operation, additional cleaning of the bottomhole zone occurs due to removal of insoluble reaction products with nitrogen and carbon dioxide.

The laboratory unit contains model 1, thermal insulation 2, acid tank 3, tank 4 with oil, separator 5, measuring tank 6, valve 7, pressure gauges 8, gas meter 9, gas cylinder 10, pressure regulator 11, heater 12, thermocouple 13, potentiometer 14.

Example. The formation is treated using, in the first case, a suspension of aluminum powder in a hydrocarbon fluid with a density of 800 kg / m with an aluminum concentration of 10% by weight. In the second case, magnesium is used instead of aluminum at the same concentration. The thickness of the formation is h4 m, the formation temperature is Tmelt 20 C, the total heat capacity of the reservoir and the fluids С fa

2380 kJ / m. Air injection pressure is 10 MPa. It is necessary to conduct thermochemical treatment of the bottomhole formation zone in radius R

1 m in order to increase its temperature to 150 ° C. Before processing, calculate the required amount of reagents for portions of air. The specific consumption of aluminum (magnesium) per 1 m of the effective thickness of the layer is calculated by the formula

CfcnfiVmSp m ------

100 -K

ye

where m S,

TO

S8

0,2 - reservoir porosity;

0.8 - saturation of the near-abdominal zone with the suspension;

1.2 - coefficient of increase in the volume of the treated zone. The specific volume of the suspension is

.., M 100 vco / c

The specific volume of 15% hydrochloric acid to fully react aluminum (magnesium) is calculated from stoichiometric ratios.

The temperature increase due to the reaction of aluminum (magnesium) with hydrochloric acid is

H Cl m KJLeIL-

515

where H is the thermal effect of the reaction.

The temperature of the bottomhole formation zone is

T, TT + 4T,.

To raise the temperature in the bottomhole formation zone with a thickness of 1 m to 150 ° C, due to the reaction of oxygen with oil, it is necessary to inject a specific volume of air (per 1 m thickness of the formation)

SrOZO-T) FR

6

The actual response time at RF 10.0 MPa is

Faculty

C, 8

where Co 0.12 is the average oxygen concentration in the reaction zone. Nefgen is srt ssten assumed equal to 0.5. Average rate of air injection

veel

0.21 fe Hcrt0l

t uj

where (150 -T,) is a necessary

temperature increase due to the reaction of acid-type air with oil, ° С;

- thermal effect of this reaction;

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0.8 - oxygen utilization factor |

p „is the air density. ) and 1 / z kg / m.

The total air volume required for injection is

VeoSA ™ V g03A h,

Of this volume, the share of the buffer portion of air per 1 m of productive thickness is

T.FRVSr-fl ...

where S is the saturation of the bottom zone with air; p0 a 0.1 MPa - atmospheric pressure.

The reaction time of the injected portion of air with oil from T to 150 ° C is determined from the solution of the heat balance equation (excluding heat loss)

, I exp (E / RT) JdT

t "

Och5n nN A0Row / S} t67462 with (46.5 h),

where E 69000 kJ-mole;

A-Pd 1279 kg 0 / kg-s are the kinetic constants of a specific reservoir oil (determined experimentally).

The time is calculated for the experimental conditions, sg.y PO f 0.039 MPa.

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The response time D to increase the safety of the treatment takes

t #on OjS t „KT.

In tab. Table 1 shows the results of calculating the technological parameters of the process of thermochemical treatment of the formation and the quantities of reagents when using aluminum or magnesium in the technology of processing.

There are no fundamental differences in the parameters of well treatment using magnesium and aluminum. When processing with magnesium, the required volume of hydrochloric acid is reduced, and the rate of reaction of magnesium with hydrochloric acid decreases than aluminum. Therefore, when using magka, the rate of increase in temperature is higher, and the proportion of heat loss in real conditions due to a decrease in the reaction time is less. As a result, the heating of the formation in real conditions will be approximately the same as when using aluminum.

The method is tested on a reservoir model.

A suspension of aluminum powder is introduced into the oil-water-saturated model and heated to reservoir temperature, which is controlled by thermocouples installed outside and inside the model. The model is combined with a tank containing 27% hydrochloric acid. Acid in the quantity required for its reaction with aluminum in the reservoir model is supplied to the model by pumping gas (nitrogen — by simulating the prototype method or air — by the proposed method) into the acid tank at a pressure of 0.7 -1.0 MPa.

In tab. 2 shows the amount of aluminum and acid required for

heating the reservoir model to a predetermined temperature.

The beginning and end of the reaction are monitored by the indications of an internal thermocouple. After nitrogen or air is pumped through the model, oil is pumped back at a constant pressure drop, measuring its flow. In tab. 3 shows the results - experiments.

Experiments to determine changes in core permeability on a linear reservoir model have been carried out to determine the effectiveness of the thermal alkaline treatment of the formation by pumping alkali after oxidizing oil with oxygen. To do this, in the first experiment, the oil in the reservoir model is oxidized in a stream of air at a rate of 30 l / h for 30 minutes until the temperature of the reservoir reaches 150 ° C. After that, a 2% sodium hydroxide solution is pumped through the model, and then a reverse flow of oil is carried out at 100 ° C and at a constant pressure drop of 0.2 MPa (operation phase). In a parallel experiment, the flow of alkali and the reverse flow of oil are identical. conditions, but without prior oxidation.

Board 4 shows the results of the experiment.

The results obtained (Table 4) prove the improvement of the effect of washing off the rock after the injection of alkali into a model of a porous medium saturated with water and high resin oil, with its preliminary oxidation. The temperature at the beginning of both experiments is the same (100 ° C) and the productivity obtained at this moment is also the same, which indicates that the effect of elevated temperature is identical. Then, when the temperature drops to the reservoir (the effect of a decrease in the viscosity of the oil disappears), the filtration occurs in the model where the surfactants are generated by saponification of the oxidized oil with alkali

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Ba 15 in FIG. 2). Due to the introduction of alkali and its interaction with oxidized oil, the productivity of the reservoir increased 1.4 times as compared with the known method of affecting reservoir oil (curve 16 in Fig. 2). Thus, the effect of the treatment according to the proposed method consists of two components: an increase in temperature and purification from reaction products. Due to the higher heating of the model, the effect during thermochemical processing is 2.6 times higher than in the prototype. The oxidation of oil with oxygen from the air produces oxygenated hydrocarbon compounds, which are solvents and surfactants, as well as carbon dioxide, nitrogen and water vapor. This creates additional conditions for better purification of the porous medium from insoluble reaction products. Due to this, the permeability of the core increases by 5 times, and the duration of the effect - by 2.6 times compared with the prototype. .

Claims (2)

1. Thermochemical treatment method of the bottomhole formation zone, which includes sequential injection of aluminum or magnesium suspensions into the formation, hydrochloric acid thief, holding their in the reservoir and the extraction of reaction products, characterized in that, in order to increase processing efficiency due to more complete use of reagents in the reaction zone, increase the thermal effect of the process and reduce contamination of the bottomhole zone, before and after the injection of hydrochloric acid into the bottomhole zone t air. 2. The method according to claim 1, characterized in that, before removing the reaction products, a 0.5-2.0% alkali solution is pumped into the formation. Indicators Maximum temperature of the model, ° C Duration of effect due to temperature increase, min. Pressure drop, MPA The degree of increase in the permeability of the formation model with respect to the prototype Table 1 Table 2 Table3 Method Prototype Proposed 175 26 0.3 eleven 1574799 // vЈ § 1-2 Table Xj 14 1 g, SP3 min 75 5Q 01 2345 6789 10 111Z 13 14 15 FIG. 2Times A l