RU76971U1 - DEVICE FOR IMPACT ON THE BOTH ZONE - Google Patents

Abstract

The utility model relates to means for generating seismic energy in oil reservoirs. The device contains a storage capacitor, electrodes closed by a metal wire with a cross-sectional area of 0.1 mm ² to 0.9 mm ² . They supply voltage pulses from 2.6 kV to 4.3 kV to the electrodes at intervals of 20 seconds to 70 seconds, thereby providing a wire explosion and the formation of a pressure pulse in the hydraulic medium, while the distance between the electrodes is from 11 mm to 60 mm . Effect: the emergence of resonance phenomena in the elements of the system "well - bottomhole zone - formations", simplification, improving the safety and efficiency of production with minimal impact on the environment.

Description

The technical field to which the utility model relates.

The utility model relates to means for generating seismic energy, for example, elastic vibrations in oil reservoirs, in particular, downhole sources of seismic energy for impacting the bottom-hole zone of wells and oil-saturated formations during the production of hydrocarbons, for example, oil.

State of the art

The prior art there are a large number of means to increase the flow in the well.

The prior art device for influencing the bottomhole zone of a well by creating depressive-repressive pressure pulses of the hydraulic fluid (RU 2276722 C1, published 05/20/2006). The disadvantage is complexity and limited capabilities.

As the closest analogue of the device, a well-known borehole source of seismic energy is selected, comprising a housing, a unit

a high voltage electrode, a low voltage electrode assembly, a spark gap assembly including an electric discharge source (SU 247530 A, G01V 1/02, published 04.11.1969). This spark gap is not suitable for creating an impact with the necessary parameters.

Utility Model Disclosure

This useful model solves the problem of inflow (increase in production) into the well at the production stage, which ensures quick and low-cost output of the well to maximum production rates.

In the course of solving this problem, the following set of technical results is achieved: the occurrence of resonance phenomena in the elements of the "well - bottomhole zone - formations" system, which release pore channels of the bottomhole zone and perforation holes from clogging substances and induce a wave pattern in the formations that ensures an increase in flow rate the entire thickness of the reservoir; improvement of the filtration properties of the bottomhole zone; simplification, increase of safety and production efficiency with minimal impact on the environment.

These technical results are achieved in that the device for influencing the bottom-hole zone (borehole source of seismic energy) contains a housing, a high-voltage electrode, a low-voltage electrode, an electric discharge source, a metal wire feed mechanism, a metal wire has a cross-sectional area from 0.1 mm ² to 0.9 mm ^2, the electric discharge source provides power to the electrodes by the voltage pulses from 2.6 kV to 4.3 kV at intervals of 20 seconds to 70 seconds, whereby races oyanie between the high and low voltage electrodes is from 11 mm to 60 mm.

A distinctive feature of the proposed device is the provision of the formation of directional pressure pulses with an excess pressure at the leading edge significantly exceeding the reservoir pressure, while the pulses have optimal dynamic and energy parameters necessary for the implementation of the above set of technical results.

List of drawings

Figure 1 schematically shows the emitter of the source of the electrohydropulse discharge at the stage of closing the electrodes with a metal wire located opposite the sealed perforation channel.

Figure 2 schematically shows the emitter of the source of the electrohydropulse discharge at the stage of initiation of the explosion, leading to the formation of plasma.

FIG. 3 schematically shows the emitter of an electrohydropulse discharge source at the stage of formation of a shock wave with excess pressure at the leading edge due to the expanding plasma, which penetrates through the perforation channel into the bottomhole zone and further into the formation.

Figure 4 schematically shows the emitter of the source of the electrohydropulse discharge at the stage of compression and cooling of the plasma, which leads to the removal of the mud in the wellbore and cleaning of the perforation channels and increase the permeability of the reservoir.

Figure 5 schematically shows the design of the borehole source of seismic energy.

FIG.6 presents a diagram for determining the duty cycle.

FIG.7 and FIG.8 presents graphs showing the dynamics of changes in the parameters of the well at the stage of operation after applying the method and device.

Information confirming the feasibility of implementing a utility model

In terms of kinetic properties, the oil reservoir in the layered reservoir is a modulus of bulk elasticity, and in terms of its acoustic properties it is a set of vibrational systems where both longitudinal and transverse (shear) waves propagate under pulsed action.

The field of elastic vibrations is determined by the guiding properties of the collector, and its attenuation is determined by the resonant properties of the collector.

When pulsed, a whole set of eigenfrequencies arises in a multilayer medium.

Since the reservoir of the oil reservoir is an anisotropic body, the modulus of longitudinal elasticity and shear modulus take different values in different directions, and their values can vary widely.

Along the resonator layers, it is not the original signal (impulse) that propagates, but the intrinsic oscillation process caused by it, and each resonator layer has its own frequency.

The most important result of the kinetic effect is to take into account the interaction of the shock wave with a group of so-called resonant particles, the speed of which coincides with the speed of wave propagation.

The effect of resonant turbulence, cavitation, appears, the wave vibrational motions of the liquid are transformed into monotonous one-sided directed motions, as well as the wave effects of the spatial shift in highly viscous media. When excited by wave

fields in the treated volume occurs both circulation and the elimination of stagnant zones.

According to the totality of geological, geophysical, hydrodynamic, hydromechanical and other factors, the bottom hole zone of the well with various technologies of primary and secondary drilling of the reservoirs has common characteristics in terms of the structure of clogging substances.

The task of increasing the production rate of the well at the production stage has significant differences from, for example, measures to increase the production rate of the well at the development stage. According to the totality of hydrological, geophysical and other factors, the stage of well operation has significant features due to the laws of formation of the bottom hole zone of the well, for example, compared with the state of the well that occurs during its formation. The geophysical conditions of the bottom-hole zone (filtration properties, etc.), deformation processes, well permeability, structure and rheological properties of the mud, and so on, are significantly different.

This utility model solves the problem of decolmatization of perforation channels in the bottomhole zone of a well with various geological features of an oil reservoir without adding chemicals to the well and causing fluid to flow into the well over the entire working interval. At the same time, the device produces an effective resonant energy pumping of productive formations, which leads to an increase in their permeability.

This utility model solves the problem by creating directed repression-depression elastic waves in the well cavity due to plasma-pulse discharge.

The purpose and result of this utility model is to create in the well cavity a sequence of elastic-wave processes that ensure the occurrence of resonance phenomena both in the bottomhole zone and in more remote sections of the reservoirs. The physical nature of the process

hydrocarbon production is so complicated that it is not possible to carry out adequate mathematical modeling of the elastic-deformation system "bottom-hole zone - well - geological formations" to determine the dynamic properties and perform calculations of oscillatory processes in this system.

As is known from the theory of oscillations and wave processes, the elastic-wave picture that arises in a system is determined mainly by the following indicators:

- vibrational, i.e. dynamic properties of the system itself (inertial, elastic, dissipative properties, rheological characteristics of the medium, etc.)

- parameters of stimulating influences (intensity, frequency, source location, etc.).

The dynamic properties of the system “bottom-hole zone - well - geological formations" at the operational stage have significant differences from the dynamic properties of this system, but which is at the development stage. So, for example, deformations and stresses differ significantly. Wellbore contamination at the development stage is primarily due to the presence of mechanical particles contained in the opening and development fluids with their subsequent swelling, rock fragments, cementitious particles or rock skeleton. All this significantly distinguishes, for example, the task of cleaning the bottom-hole zone at the development stage from cleaning at the operational stage, when the main contamination is alluvial colmatant.

The complexity of solving resonance problems for such a heterogeneous geophysical system, which consists of a well, a bottomhole zone, formations, etc., is also due to the presence of secondary wave and oscillatory processes (reflex waves, i.e. waves reflected from the interfaces between the layers and the bottomhole zone, induced waves and vibrations in individual elements of the system, partial resonances, etc.).

Any problem whose solution is associated with the creation of resonant wave or oscillatory processes in the system is extremely difficult. Not all effects on the elastic-inertial system can cause resonance phenomena. The exposure parameters can be selected so poorly that there will be no resonance, but antiresonance, i.e. a situation where the wave or oscillation process initiated by the subsequent action extinguishes the wave or oscillation process created by the previous effect.

The proposed solution in accordance with this utility model is to provide optimal parameters of stimulating influences (intensity, frequency, source location, etc.) that initiate elastic-wave and oscillatory processes in the well cavity, the propagation of which into the bottomhole zone and geological formations will cause an increase flow rate, cleaning the bottom-hole zone and perforations and improving the filtration properties of the bottom-hole zone.

The initiating effect is characterized by the following parameters:

- the intensity of the pulse effect (pulse energy)

- pulse frequency

- location of the epicenter of the pulsed effect.

The result can be achieved only by determining the optimal combination of all these parameters. The need for an interconnected determination of the intensity of the impact and the frequency of the exciting pulses is explained by the nonlinear dynamic properties of the system "bottom-hole zone - well - geological formations".

The energy parameters of the initiating effect are in correlation with the pulse repetition rate. It has been experimentally established that the pulse energy from 15 MW to 25 MW is optimal. With a lower value, a wave process with the necessary parameters does not occur. A pulse with a higher energy causes a wave that is too intense reflected from the walls of the well, which extinguishes the subsequent

initiated wave. The optimal range of pulse energy values is achieved by the indicated ranges of parameters characterizing the transverse size of the wire and the voltage supplied to the electrodes. If you use a wire with a cross-sectional area of less than 0.1 mm ² , the plasma channel between the electrodes that occurs after its explosion will not allow the electrodes to be closed for the necessary time so that the electric energy stored in the drive is released. The use of a wire with a cross-sectional area greater than 0.9 mm ² will require a greater voltage supply, which will lead to an increase in the size of the entire device.

Pulses are fed at intervals from 20 seconds to 70 seconds. This symptom characterizes the dynamic indicators of the initiating effect. Pulses can be emitted at regular intervals, for example, three times per minute, or at different intervals. The latter option is most effective for adaptive systems, i.e. equipped with a means of measuring the parameters of the hydraulic medium in the well cavity (pressure, etc.) in order to control the moments of the pulse supply, depending on the situation. With a more frequent supply of pulses, the superimposed waves will not allow you to effectively cause the resonance of the elements of the system. With a rarer supply of exciting pulses, it is impossible to ensure overlap, i.e. amplification by the next wave of the previous wave, due to rapid attenuation.

An important parameter is also the duty cycle of the supplied pulses. As you know, the duty cycle is understood as the ratio of the period T of the pulse supply to the duration t of the pulse itself (see FIG. 6). In accordance with the present utility model, the duty cycle characterizes the ratio of the time interval T between pulses to the pulse duration t. Reliability is a dimensionless parameter and its value should be from 10 ⁵ to 10 ⁶ . At a value of less than 10 ⁵ waves are too rare, and a designation above 10 ^{6 is} too often to ensure resonance of the system "bottom-hole zone - well - geological formations".

Thus, the supply of voltage pulses with the indicated parameters causes a wire explosion, the formation of an ion-plasma channel between the electrodes and the zone of increased pressure in the hydraulic medium, which, propagating, forms an elastic-wave process in the well cavity, bottomhole zone and formations. The number of pulses required to process the bottom-hole zone, i.e. the processing time is determined in each case separately depending on the intermediate processing results.

The following is a description of the application of the downhole source.

Depending on the depth of the formation, in order to create a wave front over its entire power, it is necessary to move the source of hydraulic pulses along the well. It is usually advisable to move from bottom to top. However, in a number of special cases, it is optimal to move the source from top to bottom. When generating pulses, the source is moved from 300 mm to 1000 mm. Moving can be carried out both with a constant step, and at various distances depending on the situation. Moving less than 300 mm is impractical due to a slight change in the position of the source. When moving the source of more than 1000 mm, the appearance of shadow zones in the bottomhole zone, which will reduce the effectiveness of the method. This variant of the method assumes that the pulses are formed by a fixed source, which then moves to a specified distance.

To reduce the exposure time, the formation of pressure pulses in the hydraulic medium can be ensured during the movement of the source of the electrohydropulse discharge in the well cavity at a speed of 270 mm / s to 600 mm / s. In this case, the source continuously moves along the well, and pulses are formed during the movement of the source.

The parameters of the movement of the borehole source inside the borehole are not structural parameters of the source itself, since

depend on additional equipment (lifts, etc.) with which the source interacts.

Thus, the optimal range of values of the pulse energy is achieved within the framework of these basic parameters characterizing the cross section of the wire, the distance between the electrodes, the voltage applied to the electrodes, and the time intervals for the formation of pulses.

The supply of voltage pulses with the indicated parameters causes a wire explosion, the formation of plasma between the electrodes and the overpressure zone in the hydraulic medium, which, propagating, forms an elastic-wave process in the bottomhole zone and formations. The number of triggered pulses, i.e. the processing time is determined in each case separately depending on the geological features of the deposit and the depth of the beds, as well as the propagation velocity of the elastic waves in the rocks.

The propagation velocity of elastic waves in rocks is characterized by the following values (m / s):

- gypsum, anhydrite, crystalline 4500-6500

breeds

- rock salt 4500-5500 - hydrocarbon gases 430-450 - oil 1400 - water, drilling mud 1500-1700

Clay, sand and carbonate rocks are characterized by intermediate propagation velocities of elastic waves. The porosity of the rocks helps to reduce, and their cementation - to increase the speed of propagation of elastic waves.

The modulus of elasticity of rocks (E) increases with increasing depth, with the greatest effect on the modulus of elasticity

it has a mineralogical composition, structure, temperature, bedding conditions, the nature of the fluid filling the pore channels.

An increase in sandiness will lead to an increase in E of the rock. With an increase in the carbonate content of sedimentary rocks, the elastic modulus increases. Ceteris paribus, the elastic modulus of fine-grained rocks has higher elasticities than coarse-grained. The elastic moduli for rocks have the following meanings:

Breed Shale Limestone Dolomite Marble Sandstone Quartzite E _s.p · 10 ^-6 , MPa 1.5-2.5 1.3-6.0 2.1-16.5 3.9-9.2 3.3-7.8 7.5-10.0

The downhole seismic energy source for influencing the bottom hole of the well at the development stage, as shown schematically in FIG. 5, comprises a housing 1, a high voltage electrode 2, a low voltage electrode 3, an electric discharge source 4, and a metal wire feed mechanism 5. The metal wire 6 has a cross-sectional area of 0.1 mm ² to 0.9 mm ² . The electric discharge source 4 provides the supply of 2 and 3 voltage pulses to the electrodes from 2.6 kV to 4.3 kV at intervals of 20 seconds to 70 seconds, while the distance L between the high-voltage 2 and low-voltage 3 electrodes is from 11 mm to 60 mm. The electrical components of the source are not the subject of this utility model and can be performed in any known manner, for example, as described in the sources indicated in the prior art section of the present description.

The device operates as follows.

Depending on the distance between the electrodes, the diameter and shape of the cross-section of the wire in the calculated time intervals, a voltage from 2.1 kV to 4.3 kV is applied to the electrodes 2 and 3 (FIG. 1) closed by a metal wire 6 through time intervals from 20 seconds to 70 seconds. As a result of this, an explosion of wire 6 is initiated, leading to the formation of plasma (FIG. 2), the expanding plasma forms a shock wave with an excess pressure at the leading edge significantly exceeding the reservoir pressure (FIG. 3), passing in the bottomhole zone and in the reservoir as a whole a series of successive elastic vibrations. The compression and cooling of the plasma leads to the removal of colmatant into the wellbore, which leads to the cleaning of perforation channels and a significant increase in the permeability of the reservoir (FIG. 4). The emitter of the source of an electrohydropulse discharge, creating pulses with excess pressure in the hydraulic medium, moves along the working perforation interval with a given step or specified speed depending on the power of the oil reservoir and the geological features of the well.

Examples of downhole source applications.

Example 1. Use a source of electrohydropulse discharge, with a wire from 0.7 mm ² . The voltage at the electrodes is 3.8 kV. The pulse sequence is supplied at regular intervals of 60 seconds. The pulse feed rate is 350,000. The change in well parameters after processing is shown in FIG. 7.

Example 2. Use a source of electrohydropulse discharge, with a wire with 0.9 mm ² . The voltage at the electrodes is 4.3 kV. The pulse sequence is supplied at regular intervals of 25 seconds. The pulse feed rate was 410000. The pulses were applied in series of 7 pulses. After each series, the source is moved to a distance of 600 mm. Changing the parameters of the well after processing is shown in FIG. 8.

Example 3. Use a source of electrohydropulse discharge, with a wire with 0.15 mm ² . The voltage at the electrodes is 2.8 kV. The pulse sequence is supplied at regular intervals of 30 seconds. Pulse feed rate 510000. Pulses were applied in series of 10 pulses. The source moves into the well cavity at a speed of 500 mm / s.

Claims (1)

A device for influencing the bottomhole zone, comprising a housing, a high voltage electrode, a low voltage electrode, an electric discharge source, a metal wire feed mechanism, characterized in that the metal wire has a cross-sectional area of from 0.1 to 0.9 mm ² , the electric discharge source provides supplying voltage pulses from 2.6 to 4.3 kV to the electrodes at time intervals from 20 to 70 s, while the distance between the high-voltage and low-voltage electrodes is from 11 to 60 mm.