RU2118447C1 - Method for development of oil deposit - Google Patents

Abstract

FIELD: oil and gas production industry. SUBSTANCE: according to method, injected into clay-bearing reservoir through injection wells is magnetized water, and oil is recovered through producing wells. Water is magnetized by magnetic field with intensity of 300-450 Oe. Added to water before and after its magnetization are salts of polyvalent metals with concentration of 3-10 g/t. EFFECT: higher efficiency. 1 tbl

Description

 The invention relates to the oil and gas industry, and in particular to methods for developing oil fields.

 A known method of developing an oil field, in which the permeability of the formation with clay-containing reservoirs is achieved by adding chemicals containing salts of multivalent metals, such as aluminum oxide, with a concentration of 4 to 10 kg / t [1].

 The disadvantage of this method is that with its help only stabilizes, but does not increase the permeability of the reservoir rock.

 Closest to the proposed invention in technical essence is a method of developing an oil field, which includes injecting magnetized water through an injection well into a clay-containing reservoir and taking oil through production wells. Water magnetization is carried out at an electromagnetic field strength of about 1250 Oe [2].

 The disadvantage of this method is its low efficiency due to a small increase in permeability by 20-30%.

 The aim of the invention is to increase the efficiency of the method.

 This goal is achieved by the fact that in the method of developing an oil field, which includes injecting magnetized water through a clay well into a clay-containing collector and extracting oil through producing wells, polyvalent metal salts with a concentration of 3-10 g / t are added to the magnetized water, and the magnetization of the water is magnetic field strength 300 - 450 E. Salts of polyvalent metals can be introduced into the water before it is magnetized.

 The implementation of the method is illustrated by examples of its implementation.

 As salts of polyvalent metals, ferric chloride and aluminum chloride were used.

 The method was experimentally implemented on a linear model of the reservoir, which was used as a pipe model with a length of 250 mm, with an inner diameter of 30 mm and a porosity of 35-37%.

Water samples and core material taken at the Novolodyozhne oil field in Western Siberia were used. In all examples, the initial value of permeability (K _o ) was close to 0.12 μm ² .

где
K_o - начальное значение проницаемости;
K - значение проницаемости после добавления соли многовалентного металла и магнитной обработки.As a porous medium, an analogue of the clay-containing reservoir, crushed core material with clay minerals (concrete and montmorillonite) from 0.5 to 15% was used. As a measure of change in permeability (K), a value relative to a change in permeability was used.

Where
K _o - the initial value of permeability;
K is the permeability value after the addition of a multivalent metal salt and magnetic treatment.

 Water was magnetized by permanent magnets with a magnetic field strength of 300 - 450 E.

в данном примере составила 33% ± 2%.Example 1 (control)
Water was treated with a magnetic field of permanent magnets, the magnitude of which amounted to 850 Oe. Then magnetized water was pumped into the reservoir model from one end of it, simulating an injection well, and this water was taken from the other end of the model, simulating a producing well. Value

in this example, it was 33% ± 2%.

 Example 2

 Aluminum chloride in an amount of 1 g / t was added to water as a salt of a multivalent metal. Then the solution was pumped from one end of the reservoir model and fluids were taken from the other end of the model.

составила 20% ± 2%.Then the value

amounted to 20% ± 2%.

 Example 3

составила 90% ± 3%.Aluminum chloride was added to the water in an amount of 3 g / t and pumped through a reservoir model (as in Example 2). Value

amounted to 90% ± 3%.

 Example 4

 Water was pretreated with a magnetic field of 500.. Then, ferric chloride was added to water in an amount of 1 g / t as a salt of a multivalent metal. After that, the magnetized solution was pumped through the reservoir model.

составила 83% ± 3%.Value

amounted to 83% ± 3%.

 Example 5

, которая составила 238%.Aluminum chloride was preliminarily introduced into the water in an amount of 3 g / t. Then, the water with the additive was treated with a magnetic field of 300 Oe. After that, the magnetized water with the additive was pumped through the model and the value was calculated

, which amounted to 238%.

 Example 6

 Perform, as example 5, but the amount of aluminum chloride was 7 g / t, and the magnetic field treatment was carried out with a strength of 400 E.

 Example 7

 Perform, as example 4, but ferric chloride is added to the amount of 10 g / t in water magnetized with a magnetic field of 450 Oe.

 The results of the experiments are summarized in a table, from which it can be seen that the value of the relative change in permeability increases especially strongly when multivalent metals with a concentration of 3-10 g / t are added to water and magnetized by a magnetic field of 300-450 e.

 Thus, the maximum effect when treating a porous medium with water with the addition of salts of multivalent metals (analogue) was 90%, while treating with magnetized water only was 33%. The sum of these effects is 123%.

 However, as can be seen from the table, the effect of the total application of these technical solutions reaches 241%, which exceeds the sum of the effects by almost 2 times.

 The result is explained by a change in the colloidal composition and a decrease in the size of the colloidal particles contained in the solution, which contributes to a decrease in the decay rate of the chemical reagent.

 Thus, this method, in addition to a significant increase in permeability, also allows the use of magnetic fields of lower intensity when processing water than in the prototype.

 The economic effect of the implementation of the invention is determined by the increase in the rate of water injection into injection wells.

 An increase in the injection rate correlates well with an increase in rock permeability; therefore, it can be considered that an increase in permeability, for example, by 50% will lead to an increase in injection rates by 50%. If we take the average water cut of 50% and the annual oil production of 200 thousand tons, then as a base figure we can assume that as a result of applying this technology production can be increased without changing the pressure in the injection well system to 400 thousand tons (increased 100%). This will lead to an increase in the amount of selected oil by 100 thousand tons. Multiplying the cost of oil 60 thousand rubles / ton by the additional amount of oil produced 100 thousand tons, we obtain the value of the additional income of 60 thousand rubles / ton to 100 thousand tons = 6 billion . rub. The cost of magnetic devices with their installation at an appropriate water consumption of 1200 thousand rubles. m about 5-10 million rubles. The cost of the reagent is approximately 1000 rubles / kg or 100 rubles. 300 tons of water, or 4 million rubles. Thus, at a cost of about 15-20 million rubles, the income will be approximately 5980 million rubles.

Sources of information:
U.S. Pat. 166-272, N 3621913.

 L.A.Demchuk, B.M. Leibert, I.K. Marhasin, R.A. Shestakova. The influence of a magnetic field on the filtration properties of water. Improving the processes of well drilling and oil recovery. Collection of scientific papers., Kuibyshev KPTI, 1984, p. 93-98 (prototype).

Claims (1)

 \\\ 1 A method of developing an oil field, including magnetizing water, pumping it through injection wells into a clay-containing reservoir, and taking oil through production wells, characterized in that polyvalent metal salts with a concentration of 3-10 g / t are added to water before or after magnetization , and the magnetization of water is carried out by a magnetic field with a strength of 300 - 450 E.

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