RU2712980C1 - Method of increasing oil production efficiency - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: group of inventions relates to a combined electrohydraulic oil recovery method for increasing efficiency of oil output from conventional oil deposits, which consist of water- and oil-containing geological formations. Electrohydraulic method of increasing oil production efficiency from oil fields with water- and oil-containing geological formations, in which at least one structure of steel pipes, fixed in a conventional production well located in a pumping mode, is used as an electrode and a power line, and at least one metal structure under ground is used as opposite electrode. At that, production zones of liquid inflow of drilling production well are installed with at least one water-and oil-bearing geological formation. Electrode formed from the lower part of the steel pipe structure of the drilling production well comprises a surface of electrical contact with the electrolytic current conducting liquid mixture from water/oil in the borehole and above liquid inflow zone is surface of electric contact with geological formation. Between the earth surface and the electrode from the upper part of the structure from the steel pipes of the drilling production well, an electric connecting pipeline is formed. At that, electric insulation of connecting pipeline in direction is provided by means of air filled annular space present between drilling production well and structure of steel pipes, and in outward direction to rocks – by means of existing high-resistance area of cement filling in annular space between structure of steel pipes and borehole wall. There are at least one electrical contact terminal in the drilling head of the steel pipe of the drilling production well and at least one electrical contact terminal on the opposite electrode. Alternating-current source is installed on the earth's surface with current rectifier fixed on it and connection of electric cables is provided between current rectifier and electric contact leads. In the pressure line of the drilling production well, a pressure pump is actuated, which is electrically isolated from the pressure pipeline and is electrically isolated from the hydraulic flow in the pump due to the intermittent pumping mode divided into parts by volume. Hydraulic volume flow of water/oil in geological formation is continuously created by means of pump mode in drilling well. During phase of action on formation electric alternating field is applied on hydraulic flow field. Current rectifier generates electric variable field in a controlled manner, wherein continuous functional AC passage in the low frequency spectrum through the electrode and the opposing electrode is provided, and as a result, oscillation electric currents of positive and negative charge carriers are initiated in water- and oil-containing geological formation. In fine-porous mainly oil-rich areas of geological formation by means of oscillating motion of carriers of positive and negative charges provide increase in surface density of charges, which in turn leads to reduced viscosity of interface and surface tension, as well as increased electric repulsion between oil droplets and main mass of rock, while improving permeability and fluidity. In high-permeable mainly water-containing zones of flow of geological formation due to oscillatory movement of carriers of positive and negative charges there is a process of mixing, with increase in contact surface and diffusion of water and oil, which provides creation of high-viscosity water/oil emulsions, which provide blocking of highly permeable zones. By blocking high-permeability flow zones in connection with volume flow, driven by pressure, and electric action on the formation, additional crude volumes not previously developed are used, and at the same time new flow paths for transportation are created.

EFFECT: higher efficiency of oil production.

9 cl, 2 dwg

Description

The present invention relates to a combined electro-hydraulic method for extracting oil to increase the efficiency of oil recovery from conventional oil fields, which consist of water and oil containing geological formations. At the same time, existing drilling production wells are used as electrodes and opposite electrodes to supply controlled, functionally alternating low-frequency current to the production layers simultaneously during pump production. Due to the interaction of various within formation processes, additional volumes of oil are involved, in particular from areas of finely porous rock. The method can, in particular, be applied in the case of progressive watering during production.

Conventional oil fields consist of permeable porous rocks, which in their porous cellular structure (pores, cracks, karst channels) contain salt water in addition to oil. For decades, general experiments have shown that from such geological formations only 20–40% of the total oil available there can be extracted using conventional oil recovery operations, such as primary production through natural reservoir pressure and pump production, as well as secondary production through injection of additional water into the well.

To increase the oil recovery coefficient, traditional tertiary oil recovery operations are used, such as, for example, thermal, chemical and microbiological methods, as well as a gas injection method, all of which require the creation of additional injection wells.

In addition, for example, from WO 2012/074510 A1 or US 4084638 A1, tertiary electrical methods are known in which a direct current or current pulse is used to reduce the viscosity of heavy oil by resistive heating and, at the same time, improve the plastic deformation ability. This requires additional elements of the well in the form of separate electrodes and cable leads, immersed in the production layers. In the method known from US Pat. No. 4,662,438 A1, alternating current is supplied to the electrode pair inside a hotel drill production well, more specifically, it passes into the depths of individual holes through the electrodes to the production layers.

The aim of the present invention is the provision of an electro-hydraulic method and device, which or which can increase the efficiency of oil production from oil fields with water and oil-containing geological formations.

This goal is achieved through the features of an independent claim.

The dependent claims indicate preferred embodiments of the present invention.

In the electro-hydraulic method of increasing the efficiency of oil production from oil fields with water- and oil-containing geological formations:

a) at least one steel pipe structure, mounted in a conventional borehole operating in a pumping mode, is used as an electrode and a power line, and at least one metal structure underground is used as an opposing electrode,

b) the production zones of the fluid inflow of the production well establish electrical communication with at least one water and oil-containing geological formation,

c) a water / oil production stream comprising a portion of the volume of water and a portion of the volume of oil flows through a discharge pipe that is electrically isolated from the structure from steel pipes,

d) the electrode formed from the lower part of the structure from steel pipes of the borehole, contains the surface of electrical contact with the electrolytic conductive liquid mixture of water / oil in the borehole and above the zone of fluid flow, the surface of electrical contact with the geological formation,

e) an electrical connecting pipe is formed between the earth’s surface and the electrode from the top of the structure from steel pipes of the production well bore, while the electrical insulation of the connecting pipe inward is provided by the air-filled annular space present between the drilling production well and the steel pipe structure, and outward towards the rocks - through the existing high-resistance annular cement filling area a space of between the structure of the steel pipe and the borehole wall,

f) at least one electrical contact terminal in a drill head of a steel pipe of a production well bore and at least one electrical contact terminal on an opposing electrode are provided,

g) an AC source with a rectifier mounted thereon is mounted on the earth's surface and the electrical cables are connected between the rectifier and the electrical contact terminals, and

h) in the pressure line of the production well, an injection pump is activated, electrically isolated from the injection pipeline and electrically isolated from the hydraulic production flow in the pump due to the discontinuous volumetric pumping mode,

i) by means of a pumping mode in a production well, a pressure-driven hydraulic hydraulic flow of water / oil in a geological formation is continuously generated,

j) during the formation phase, an electric alternating field is superimposed on the hydraulic field of the flow,

k) the current rectifier in a controlled manner generates an electric alternating field, while ensuring the continuous passage of functionally alternating current in the low-frequency spectrum, in particular in the frequency spectrum from more than 0 Hz to 500 Hz, through the electrode and the opposite electrode, and as a result into oil-containing geological formation is the initiation of oscillatory electric currents of carriers of positive and negative charges,

l) in finely porous, predominantly oil-rich areas of the geological formation by means of oscillatory motion of carriers of positive and negative charges, they increase the surface density of charges, which, in turn, leads to a decrease in the viscosity of the interface and surface tension, as well as an increase in the electrical repulsion between oil droplets and the bulk of the rock, while improving permeability and fluidity,

m) in highly permeable predominantly water-containing zones of the flow of the geological formation due to the oscillatory movement of carriers of positive and negative charges, a mixing process occurs, with an increase in the contact surface and diffusion of water and oil, which ensures the creation of highly viscous water / oil emulsions that block high-permeability zones,

n) by blocking highly permeable flow zones due to the volumetric flow driven by pressure and electrical stimulation of the reservoir, additional previously undeveloped volumes of oil are used, and at the same time, new flow paths for transportation are created.

The achieved advantages are, in particular, in that, in comparison with the traditional tertiary method of oil recovery, labor-intensive and costly drilling of wells for injection and additional infrastructure are not required, there is no adverse effect on the environment and there are no restrictions on depth. Compared to other electric tertiary methods, in addition to an improved oil recovery factor, there is also no need for additional deep drilling and additional well elements in production wells. Accordingly, the new method can prevent production losses that occur during the period of deepening, implementation and construction. Additional advantages are flexible operation during vertical, inclined and horizontal drilling of various recesses and structures, as well as quick and low-cost installation and execution. In general, a significant economic benefit is provided, which, on the one hand, is to increase oil production and save money on pumping water compared to exclusively pumping production (primary and secondary production), and, on the other hand, at a significantly lower unit cost volume of oil produced compared to other tertiary methods.

The electro-hydraulic method of oil recovery compared to traditional pump production provides an increase in oil production due to the supply of low-frequency alternating current to the water and oil-containing geological formations of oil fields. At the same time, existing rigs of drilling production wells are used as electrodes and opposite electrodes, as well as an electric wire, and during pump production they provide an electric impact on the formation. An electrical impulse is caused simultaneously with the processes of mixing and activation in the place of occurrence, as well as the creation of new flow paths, while it is possible to extract additional volumes of oil, in particular from areas of finely porous rock.

The present invention will be described in more detail below using an embodiment with reference to the accompanying drawings.

On graphic materials:

FIG. 1 is a schematic illustration of a sectional view of components of a device according to the present invention, as well as the principle of operation of the method, and

FIG. 2 is a graph of a portion of oil versus time with an image of the result of applying the method.

In accordance with FIG. 1 in a production drilling production well 1, an existing steel pipe structure is used as an electrical connecting pipe 11 and an electrode 10, as well as a spaced metal structure 2 as an opposing electrode for supplying a low-frequency electric alternating current through a salt electrolytic conductive liquid mixture 9b from water / oil to borehole and zone 3 of fluid flow in water and oil-containing formations 4 oil fields, resulting in oscillatory the movement being in salt water carriers 20 positive and negative charges. In this case, a functionally and frequency alternating current, based on a three-phase power supply unit 16, passes through a current rectifier 15 located on the earth's surface 12, which is connected by connecting 17 electrical cables to the electrical terminals 14 on the drill head of a production well 1 and the head of a metal anchor / opposite electrode. For the functional suitability of the method, electrical insulation of the following three components is required: a connecting pipe 11 of steel pipes, a discharge pipe 5 and a production stream 9a. This is achieved using the following existing components: a high-resistance annular space / area 13 of cement filling between the connecting pipe 11 of steel pipes and the wall of the borehole for rocks, air-filled annular space 8 between the discharge pipe 5 and the connecting pipe 11 of steel pipes, plastic or rubber O-ring 6, insulation 7 of the outer pipe between the discharge pipe 5 and the drill head of the steel pipe, as well as the insulation injection pump 18. It has an effect, on the one hand, due to individual plastic components as an insulating rupture of the electronic conductivity of the metal discharge pipe 5, and, on the other hand, due to the pumping mode itself, while the electronic conductivity of the operating fluid flow 9a is interrupted by interruptions in air-divided parts by volume, so the hydraulic operating flow 9a on top of the discharge pump 18 can no longer t conduct electric current. Due to the simultaneous operation of the discharge pump 18 and the rectifier 15 in the production geological formation 4, the hydraulic field of the flow is superimposed on the electric alternating field, respectively, on the volumetric flow of water / oil with an oscillating current contained in the carrier 20 of positive and negative charges. In highly permeable predominantly water-containing zones of the flow of the geological formation, this leads to the mixing of water and oil and, as a result, to the formation of highly viscous water / oil emulsions, which contribute to the blocking of highly permeable zones. In finely porous, predominantly oil-rich areas of the geological formation, due to the electrical impact on the reservoir, oil droplets are simultaneously activated. In general, due to the interaction of both effects, previously undeveloped volumes of oil are involved, and at the same time, new flow paths for transportation are created.

In FIG. 2 shows the time variation of the measured portion of the oil volume of the water / oil production stream 9a that was pumped from the production well 1 and before, during and after the stimulation phase 21, during which an electrical impulse was applied according to the method of the present invention. By the beginning of the stimulation phase, curve 22 of the oil portion data tends to decrease, which is typical due to increasing water cut in the primary and secondary oil recovery operations. This trend can be statically shown in the form of a dashed line 24 of regression, which on the zero line indicates the theoretical completion in time of oil production using exclusively a pumping element, from which we can calculate the maximum volume of pumping oil (oil production) from medium- and highly permeable areas of the geological formation 4 Due to the electrical impact on the formation during and after phase 21 of the impact on the formation, part of the oil of the total production water / oil flow is increased compared to the regre line 24 these, in particular compared to the zero line. From the corresponding difference of 23 parts of oil, after multiplying by an unchanged total water / oil production coefficient, an additional volume of oil production per unit time is obtained, which is essentially characteristic of finely porous and low-permeability areas of the geological formation.

Reference designations

1. Drilling production well

2. Metal construction

3. The zone of fluid flow

4. Geological formation

5. Pressure line

6. O-ring

7. Insulation of the outer pipe

8. The annular space

9a operating flow

9b Liquid mixture

10. The electrode

11. Connecting pipeline

12. Earth's surface

13. Cement filling area

14. Contact conclusion

15. Rectifier

16. Three-phase power supply

17. Connection of electric cables

18. Pressure pump

19. The volumetric flow of water / oil

20. Media

21. Formation phase

22. Oil data curve

23. The difference in parts of oil

24. The regression line

Claims (30)

1. The electro-hydraulic method of increasing the efficiency of oil production from oil fields with water and oil-containing geological formations, in which: a) at least one steel pipe structure fixed in a conventional borehole production well (1) in pumping mode is used as an electrode and a power line, and at least one metal structure (2) underground is used as an opposing electrode , b) the production zones (3) of the fluid inflow of the production well (1) establish electrical connection with at least one water and oil-containing geological formation (4), c) a water / oil production stream (9a) containing a part of the water volume and a part of the oil volume flows through the discharge pipe (5), which is electrically isolated from the structure from steel pipes, d) the electrode (10) formed from the lower part of the structure from steel pipes of the borehole (1) contains an electric contact surface with an electrolytic conductive liquid mixture (9b) from water / oil in the borehole and over the liquid inflow zone (3) - surface of electrical contact with the geological formation, e) between the earth's surface (12) and the electrode (10) from the upper part of the structure from steel pipes of the production well (1), an electrical connecting pipe (11) is formed, while the electrical insulation of the connecting pipe (11) inward is provided by an air filled annular space (8) present between the production borehole (1) and the steel pipe structure, and outward to the rocks - through the existing high-resistance region (13) filling ment in the annular space between the structure of the steel pipe and the borehole wall, f) at least one electrical contact terminal (14) in the drill head of the steel pipe of the production well (1) and at least one electrical contact terminal on the opposing electrode are provided, g) an alternating current source with a rectifier (15) mounted on it is mounted on the earth's surface and a connection (17) of the electric cables between the rectifier (15) and the electrical terminals (14) is provided, and h) in the pressure line of the production well (1), an injection pump (18) is activated, electrically isolated from the injection pipe (5) and electrically isolated from the hydraulic production flow in the pump due to the intermittent volume-divided pump mode, characterized in that i) by means of a pumping mode in a production well (1), a pressure-driven hydraulic volumetric flow (19) of water / oil in a geological formation (4) is continuously generated j) during phase (21) of stimulation of the formation, an electrical alternating field is superimposed on the hydraulic field of the flow, k) the rectifier (15) in a controlled manner generates an electric alternating field, while ensuring the continuous passage of functionally alternating current in the low-frequency spectrum through the electrode (10) and the opposite electrode, and as a result, initiation in the water and oil-containing geological formations (4) occurs vibrational electric currents of carriers (20) of positive and negative charges, l) in finely porous, predominantly oil-rich regions of the geological formation (4), through the oscillatory motion of the carriers (20) of positive and negative charges, they increase the surface charge density, which, in turn, leads to a decrease in the viscosity of the interface and surface tension, as well as an increase electrical repulsion between drops of oil and the bulk of the rock, while improving permeability and fluidity, m) in highly permeable predominantly water-containing zones of the flow of the geological formation (4) due to the oscillatory movement of carriers (20) of positive and negative charges, the mixing process occurs, with an increase in the contact surface and diffusion of water and oil, which ensures the creation of highly viscous water / oil emulsions that block highly permeable zones n) by blocking highly permeable flow zones due to the volumetric flow driven by pressure and electrical stimulation of the reservoir, additional previously undeveloped volumes of oil are used, and at the same time, new flow paths for transportation are created. 2. The method according to p. 1, characterized in that through the pumping mode in the production well (1) from the geological formation (4) additional volumes of oil are used, which are involved in the place of occurrence, during and after the electrical phase (21) of the impact on the formation while the percentage part (22) of the volume of oil in the volumetric flow (19) of water / oil is increased when comparing the difference (23) with the curve (24) of the decrease in part of the oil, in particular with the zero line, while the curve of the decrease in part of the oil is determined based available data with us exclusively meat production during electrical stimulation by a regression analysis. 3. The method according to p. 1 or 2, characterized in that the additional volume of oil production per unit time is determined by the difference (23) of the oil parts, multiplied by the unchanged total coefficient of water / oil production, and by activating the additional volume of oil from areas of finely porous geological Formations (4), the total volume of oil production and the oil recovery coefficient are increased in comparison with exclusively pumping production. 4. The method according to p. 1, characterized in that the alternating current is supplied in the frequency spectrum from more than 0 Hz to 500 Hz through the electrode (10) and the opposite electrode. 5. A device for implementing the method according to claim 1, comprising: a) at least one ordinary drilling production well (1) in pumping mode with an existing steel pipe structure fixed therein, which is made as an electrode (10) and a power line, and at least one metal structure working as an opposing electrode (2) underground, while the production well (1) contains production zones (3) of fluid flow for electrical communication with at least one water and oil-containing geological formation (4), while the non-heating pipeline (5) of the production well (1) is made electrically isolated from the structure of steel pipes, b) at least one electrode (10) formed from the lower part of the structure from steel pipes of a borehole (1), which contains an electric contact surface with an electrolytic conductive fluid mixture (9b) from water / oil in the borehole and over the zone ( 3) fluid flow - the surface of electrical contact with the geological formation (4), c) at least one electrical connecting pipe (11) between the earth's surface and the electrode (10), which is formed from the upper part of the structure from steel pipes of a production well (1) and is electrically insulated, d) at least one electrical contact terminal (14) in the drill head of the steel pipe of the borehole (1) and at least one electrical contact terminal on the opposite electrode, e) an AC source mounted on the earth’s surface with a current rectifier (15) fixed to it and a connection (17) of electric cables between the current rectifier (15) and the electrical terminals (14), and f) an injection pump (18) in the pressure line of the production well (1), which is electrically isolated from the injection pipeline (5) and electrically isolated from the hydraulic production flow in the pump due to the intermittent volume-divided pump mode. 6. The device according to p. 5, characterized in that the opposite electrode is part of the construction of the steel pipes of an additional drilling production well. 7. The device according to claim 5, characterized in that the production well (1) by means of an annular seal (6), insulation (7) of the outer pipe and air-filled annular space (8) is electrically isolated relative to the structure of steel pipes. 8. The device according to p. 5 or 7, characterized in that the liquid mixture (9b) from water / oil is located in the borehole section under the annular seal (6). 9. The device according to p. 5, characterized in that the rectifier (15) current is connected to a source (16) of power supply, made in the form of a three-phase AC source.

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