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A METHOD FOR APPLYING PHYSICAL FIELDS OF AN APPARATUS IN THE HORIZONTAL END OF AN INCLINED WELL TO PRODUCTIVE HYDROCARBON BEDS

Summary

This Project is aimed at meeting the demand on the hydrocarbon production market for an inexpensive, effi-cient and environmentally perfect technology to improve production in horizontal wells. The market analysis shows that there is a demand from companies for a technology having the following characteristics: profitabil-ity, high mobility, extremely precise selective action pattern and environmental friendliness. The plasma impulse excitation method is a method providing a way to find all these items that satisfy the above-mentioned re-quirements. The experience existing in the application of this method in vertical oil wells, as well as laboratory research on cores of different types, provide proof of high technological and economic potential of the devel-opment.

Technology Benefits

Key advantages of the Project Participant's solution over analogous solutions presented on the market and being under development (including a statement of the rationale therefor):
• Retention of natural geological structure
• No adverse environmental impact
• Agents are not used
• Explosive substances are not used
• There is no breakdown of cement column
• Rapid deployment
• Integration into scheduled and routine well work

Technology Application

Oil&Gas, EOR

Detailed Technology Description

Energy consumption: Power supply – 220V, Input power - 500W. Voltage stored on capacitors unit – up to 6000V. Strength of current at the moment of discharge - up to 500 kA.
The accumulated energy is discharged through the calibrated metallic conductor. At the moment of the explosion of the metallic calibrated conductor a great amount of energy is generated within a short period of time (see Picture).
The pulse pressure is formed in liquid by means of the explosion of the calibrated conductor in the following way:
The wire is pulled in the discharger of the downhole generator. A powerful electric pulse is fed to the wire, which leads to the melting of the wire followed by its evaporation and the metallic plasma formation. This process is characterized by a high temperature (up to 4·104 K), a great number of particles ~4·1020 units (8,4·1022 cm−3) and a high pressure (~4·1010 Pa). The pressure generated by the metallic plasma formation penetrates into the surrounding medium through the liquid that fills the discharger.
Water near the electrodes is heated and evaporated under the impact of the discharge of the passing current. As a result, a gas channel is formed between the electrodes, and then the breakdown of the interelectrode gap occurs.
After the gas channel is formed, a strong discharge current (up to 500 kA) heats the plasma up to the temperature of 104 K at the initial stage of the discharge. At the time of the discharge, while the current is flowing, the plasma temperature slightly changes and goes down after the end of the discharge.
The plasma heating causes an increase in pressure in the channel, as a result of which the channel extends. At the initial stage of the discharge, the pressure in the channel carries on increasing, despite the continued extension of the channel. In the course of the discharge, the pressure in the channel reaches its maximum. After the energy is no longer generated, the extension of the channel still goes on, first, under the pressure which is higher as compared to the hydrostatic pressure, and then due to the inertia of the spreading fluid flow.
At the end of the discharge, the channel turns into a gas bubble. The extension of the gas bubble continues until the kinetic energy of the spreading flow is completely transformed into the potential energy of the bubble, whose pressure is much lower than the hydrostatic pressure. Under the hydrostatic pressure, the liquid begins to move in the opposite direction. The potential energy is again transformed into the kinetic one. The pressure formed as a result of this process throws the liquid out, and this is repeated several times as a range of consecutive damping pulsations (depression-repression). The extension of the channel at the stage of the discharge followed by the consecutive bubble pulsations is accompanied by the emission of compression and tensile waves. The compression waves initiated at the stage of the discharge and during the following bubble pulsations, characterized by a high pressure in the channel and then in the compressed bubble, lead to the tightening of the neighboring fluid layers. The compression waves are altered with the quite long rarefaction waves generated when the bubble pressure is lower than the hydrostatic pressure.
Because of the fact that the short, but powerful impulse, accompanied by pressure pulsation (depression-repression), is initiated in a confined space, the elastic shock wave goes through the perforation holes into the stratum. The determined number of pulses is repeated at one point of the wellbore interval at regular time intervals. The first series of pulses cleans the perforation from the colmatant; the next pulses propagate into the stratum producing the effect of acoustic cavitation, which cleans the natural fractures and capillaries existing in the stratum and leads to the formation of an abnormal system of microfractures. As a result, the permeability of the bottomhole zone increases.
The operation is carried out in one running-in and pulling-out of the equipment. The metallic conductor restores automatically without pulling-out of the equipment. The generator can produce up to 1000 pulses in one run depending on the plan of works.
The radius of effective action accounts for several hundred meters and depends on the whole range of geophysical and technological factors, such as, for instance, type of reservoir, number and power of pulses. The reaction to the Plasma-Pulse Action (gas emission) was caught on the video camera installed in a well at a distance of 200 meters from the well with the source of excitation. The official research carried out by JSC “Lukoil” in the well before and after the Plasma-Pulse Treatment has shown that as a result of the treatment the external reservoir boundary extended from 150 to 250 meters.

Application Date

24-Jan-2014

Patent Information

РСТ/RU 2014/000060

Others

The invention relates to the field of the oil and gas industry for intensifying the rate of inflow of oil. The method comprises delivery and arrangement at a horizontal end of a well bore of an apparatus which is equipped with an electrical-energy storage unit and an emitter with two electrodes which, upon an operator's command, are connected by a calibrated metal wire, which leads to the latter exploding and to the formation of a directed, localized, high-pressure impact wave propagating radially from given points of the horizontal well borehole with the aim of increasing the permeability of the bottom region of working sections of the horizontal hole. The invention makes it possible to exploit an obliquely directed well bore with a horizontal end to maximum effect and in an ecologically flawless manner.

Country/Region

Russia