CA2398393A1 - Method for wave processing mainly productive strata - Google Patents
Method for wave processing mainly productive strata Download PDFInfo
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- CA2398393A1 CA2398393A1 CA002398393A CA2398393A CA2398393A1 CA 2398393 A1 CA2398393 A1 CA 2398393A1 CA 002398393 A CA002398393 A CA 002398393A CA 2398393 A CA2398393 A CA 2398393A CA 2398393 A1 CA2398393 A1 CA 2398393A1
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- 238000000034 method Methods 0.000 title claims abstract description 52
- 239000007788 liquid Substances 0.000 claims abstract description 51
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 26
- 230000015572 biosynthetic process Effects 0.000 claims description 54
- 238000005755 formation reaction Methods 0.000 claims description 54
- 239000000463 material Substances 0.000 claims description 54
- 230000009471 action Effects 0.000 claims description 46
- 239000011148 porous material Substances 0.000 claims description 15
- 239000002002 slurry Substances 0.000 claims description 11
- 238000005056 compaction Methods 0.000 claims description 9
- 235000019353 potassium silicate Nutrition 0.000 claims description 9
- 239000004576 sand Substances 0.000 claims description 9
- 230000002528 anti-freeze Effects 0.000 claims description 8
- 239000004568 cement Substances 0.000 claims description 8
- 239000004567 concrete Substances 0.000 claims description 8
- 230000008014 freezing Effects 0.000 claims description 8
- 238000007710 freezing Methods 0.000 claims description 8
- 239000003350 kerosene Substances 0.000 claims description 7
- -1 for instance Substances 0.000 claims description 5
- 239000011435 rock Substances 0.000 claims description 5
- 239000002699 waste material Substances 0.000 claims description 3
- 239000000126 substance Substances 0.000 claims description 2
- 230000000694 effects Effects 0.000 abstract description 7
- 230000008569 process Effects 0.000 abstract description 5
- 230000005540 biological transmission Effects 0.000 abstract description 3
- 229930195733 hydrocarbon Natural products 0.000 abstract description 2
- 150000002430 hydrocarbons Chemical class 0.000 abstract description 2
- 229910052500 inorganic mineral Inorganic materials 0.000 abstract 2
- 239000011707 mineral Substances 0.000 abstract 2
- 230000005855 radiation Effects 0.000 abstract 1
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- 238000005243 fluidization Methods 0.000 description 4
- 239000003502 gasoline Substances 0.000 description 4
- 229920006395 saturated elastomer Polymers 0.000 description 4
- 239000003795 chemical substances by application Substances 0.000 description 3
- 238000006073 displacement reaction Methods 0.000 description 3
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- 238000013459 approach Methods 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 239000004927 clay Substances 0.000 description 2
- 125000004122 cyclic group Chemical group 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 238000013461 design Methods 0.000 description 2
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- 241000566515 Nedra Species 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
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- 230000008020 evaporation Effects 0.000 description 1
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Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/25—Methods for stimulating production
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/003—Vibrating earth formations
Landscapes
- Geology (AREA)
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Mining & Mineral Resources (AREA)
- Environmental & Geological Engineering (AREA)
- Fluid Mechanics (AREA)
- Physics & Mathematics (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Investigation Of Foundation Soil And Reinforcement Of Foundation Soil By Compacting Or Drainage (AREA)
- Geophysics And Detection Of Objects (AREA)
- Variable-Direction Aerials And Aerial Arrays (AREA)
- Liquid Crystal Substances (AREA)
Abstract
The invention relates to geotechnical processes for extracting mineral products, in particular to methods for effecting productive strata by controlled physical waves and can be used for extracting liquid and gaseous hydrocarbons, water and other liquid and gaseous mineral products from the interior of the earth and also for geophysical studies. The aim of the invention is to increase the transmission efficiency for a vibroseismic sign al sent from the source thereof arranged on the earth surface to a productive stratum by increasing the density, specific mass and the rigidity of a groun d in the volume of the added mass thereof. The inventive method consists in a wave effect performed on the productive strata with the aid of a seismic vibration source whose radiation platform is arranged on the surface of the ground, and means modifying physical and mechanical properties of the ground in the volume of the added mass thereof.
Description
METHOD OF WAVE TREATMENT, PREDOMINANTLY OF PRODUCING
FORMATIONS
Field of the Art The contemplated invention relates to the field of geotechnical processes, particularly to methods of acting by controllable physical waves on producing formations, and may be used in the recovery of liquid and gaseous hydrocarbons, water and other liquid and gaseous useful products from the interior of the Earth, as well as in geophysical investigations.
State of the Art Known in the art is a method of treating producing formations with longitudinal waves from a vibroseis source (the latter consisting of a seismic generator, an emitting platform with a system for matching with the ground and a mass of the ground added thereto) installed on the ground surface (see, e.g., N.P.Ryashentsev et al., Controlled Seismic Action on Oil Deposits. Preprint, 1989, No. 31. Novosibirsk, Academy of Sciences of the USSR, Special Design Office of Applied Geophysics (in Russian)). It has been established that the average volume density of the wave energy in sedimentary rocks (sandstone, clay) is proportional to the density of the ground.
In the method described above the effectiveness of seismic signal transmission from the signal source to the producing formation is low, and there are no means which allow varying the parameters of action on the formation. The mass of the ground added to the emitting platform (base plate) damps the vibrations, and this leads to the absorption of the energy which does not reach the producing formation.
Also known is a method of developing flooded oil field according to Inventor's Certificate No. 1596081, Cl. E21B 43/00, published in Bulletin of Inventions No. 36, 1990, which comprises the steps of developing a formation with wells, recovering formation fluid via a cluster of producing wells, acting on the formation with vibroseis signals from a ground source of vibrations, determining the frequency of effective action by searching frequencies of the emitted vibrations, determining the composition and quantity of the recovered fluid prior to and after the action. A flooded field area with a stationary oil phase is found, a vibroseis source is installed within this area on a cluster of producing wells, a seismic detector is lowered into one of the producing wells to the reservoir depth, the microseis background is measured during a period of two or three days with determining simultaneously the percentage of oil in the well fluid, and a vibroseis action is carried out with frequency search. On completion of the action, the amplitude spectrum of the microseis background is measured, and from the revealed additional frequencies in the spectrum a dominant frequency is found, an action at this frequency is carried out, the source is shifted alternately for half the wavelength till the content of oil in the well fluid ceases to increase, and the radius of the effective zone of the source action is determined, additional sources are installed and spaced from one another so that the distance between them is equal to the diameter of the effective zone of the source action, and vibroseis action at the dominant frequency is carried out.
The above-discussed method is also disadvantageous in view of energy losses in the added mass of the ground, since the ground, because of the presence of pores and cracks, damps wave oscillations, and the effectiveness of the action on the producing formation is lowered, in spite of using the dominant frequency of vibrations.
Besides, the process of oil production is complicated owing to the necessity of shifting the vibroseis source for half the wavelength.
The analog nearest in the technical essence and the attained effect to the method of the present invention is the method of development of oil-gas deposit according to RF
Patent No. 2078913, CI. E21B 43/18, published in Bulletin of Inventions No.
13, 1997.
This method comprises injecting a displacement agent via injection wells, recovering a formation fluid via producing wells, carrying out cyclic vibroseis action with frequency search on a producing formation from ground vibration sources, determining, prior to and after carrying out the action, the amount of the recovered fluid, revealing dominant frequencies of the formation from the response of its microseis background to the vibroseis action, and carrying out an additional vibroseis action at the dominant frequency. The cyclic vibroseis action with frequency search is carried out with a simultaneous stepwise lowering, with a step OP, of the formation pressure in each cycle by varying the rates of injecting the displacement agent and recovering the formation fluid. Then the value of lowering the formation pressure is determined, which ensures maximum response of the formation to the vibroseis action at the dominant frequency, and an additional vibroseis action with this value of the lowered formation pressure is carried out. After that the formation pressure is restored to the value that ensures optimum formation development conditions, and an additional vibroseis action on the formation is carried out again.
A disadvantage of the method under consideration is the loss of energy in the added mass of the ground, since the latter, due to the presence of pores and cracks, damps the oscillations, the effectiveness of the vibroseis action being thus lowered.
Furthermore, this known method is difficult to implement because of the necessity to vary the rate of injecting the displacement agent.
Essence of the Invention S The technical problem solved by the proposed invention is to raise the effectiveness of transmitting a vibroseis signal from a source thereof, installed on the ground surface, to a producing formation, by increasing the density, specific gravity and rigidity of the ground in the volume of its added mass.
This problem is solved by that in a method of wave treatment, predominantly of producing formations, consisting in a wave action on a producing formation with the help of a vibroseis source installed with an emitting platform on the ground surface, according to the technical solution, the physico-mechanical properties of the ground are varied within the volume of its added mass. Such a combination of operations makes it possible to increase the efficiency of transmitting the vibroseis signal from the source thereof installed on the ground surface to the producing formation. This is accomplished by reducing losses of this signal in the added mass of the ground, since it is possible to reduce the pores and cracks in the latter by varying the physico-mechanical properties of the ground and, consequently, it is possible to increase the rigidity of the added mass of the ground, its specific gravity and density.
It is expedient to vary the physico-mechanical properties of the ground within the volume of its added mass before or after the wave action on the producing formation. In this case the operation of varying the physico-mechanical properties is simplified, since it can be earned out at any convenient time, irrespective of the time of carrying out the wave action on the producing formation. The operation carried out before the wave action enables the effect to be obtained upon this particular wave action on the producing formation. The operation carried out after the wave action enables the effect to be obtained upon next wave action on the producing formation.
It is possible to vary the physico-mechanical properties of the ground within the volume of its added mass in the course of wave action on the producing formation. Such solution makes the action on the formation more effective, since the process of ground relaxation and evaporation (leakage) of liquid from pores and cracks is ruled out.
It is expedient to vary the physico-mechanical properties of the ground within the volume of its added mass by filling pores and cracks in the ground with a practically incompressible liquid. Such solution makes it possible to increase the rigidity, specific gravity and density of the added mass of the ground. Furthermore, energy losses for Rayleigh waves are reduced. We shall explain this fact. In the course of surface excitation of the medium there originate several types of waves. The energy spent for their excitation is approximately as follows: longitudinal wave, 8%; Rayleigh wave, 70%; C-wave, 20%. It is known also that in an ideal fluid Rayleigh waves are not excited. The proposed method provides a heterogeneous medium which is close to an ideal fluid; therefore, there occurs a redistribution of energy for the excitation of different types of waves. For the excitation of longitudinal waves, which are of interest to us, 7 to 10 times more energy is spent. This, ultimately, contributes to increasing the effectiveness of transmitting the vibroseis signal to the producing formation.
It is expedient to use water as a practically incompressible liquid. This simplifies the implementation of the proposed method.
It is also expedient to use, as a practically incompressible liquid, a substance in the liquid aggregate state, for instance, liquid glass. Such solution substantially increases the rigidity, density, and specific gravity of the added mass of the ground, which, in turn, enhances the transmission of the vibroseis signal to the producing formation.
Furthermore, liquid glass after transition to the solid phase under the effect of the ambient temperature does not evaporate and does not flow into the ground beyond its added mass, so that longevity of the acquired properties is ensured.
It is also expedient to use, as a practically incompressible liquid, a liquid with a low freezing point, e.g., kerosene or antifreeze. Such solution makes it possible, while providing an increase in the rigidity, density and specific gravity of the added mass of the ground, to use the proposed method in winter conditions.
In winter conditions, it is expedient to heat the practically incompressible liquid before filling the pores and cracks with it. This will make it possible to use the proposed technical solution when the frost penetration into the ground is not deep, so that the scope of application of the invention under different climatic conditions is broadened.
It is expedient to heat water till steam formation: this broadens the range of potential applications of the proposed method, since steam penetrates into smaller pores and cracks than liquid does (in the course of time steam under the effect of the temperature of the surrounding ground becomes converted into liquid). In addition, steam heats the thin, frozen layer of the ground more intensively, insuring the penetration of moisture through it.
It is expedient to vary the physico-mechanical properties of the ground within the volume of its added mass by means of in-depth compaction of the ground by driving at 5 least one well and subsequent introducing a filling material into it. Such combination of operations makes it possible to raise the effectiveness of transmitting the vibroseis signal from the vibroseis signal source installed on the ground surface to the producing formation due to the filling of pores and cracks with the ground displaced in a radial direction in the course of driving wells.
It is expedient to use a liquid, e.g., water, as the filling material. This will make it possible, in addition to increasing the specific gravity, density, and rigidity of the ground within the volume of its added mass, to reduce losses of wave energy, because in the liquid medium surface waves (Rayleigh waves, Love waves) are not formed. In the case under consideration, the medium, on addition of water to it, approaches in its properties a liquid medium. Therefore, here a reduction of expenditures caused by the formation of Rayleigh and Love waves is involved, rather than their complete ruling out, since the medium is actually not a liquid.
It is also expedient to use loose material, e.g., rock waste or sand, as the filling material. Such solution is more effective than the preceding one in increasing the density, specific gravity, and rigidity, since the specific gravity of the filling material (rock waste or sand) is greater than the specific gravity of water.
In such cases it is expedient to moisten loose material. Such solution increases still further the effectiveness of transmitting the vibroseis signal, because the probability of origination of surface (Rayleigh, Love) waves decreases, and the specific gravity, density, and rigidity of the ground within the volume of its added mass increase considerably, since the spaces between particles of loose material filling the well, as well as pores and cracks around the well in the ground mass, are filled with water.
It is also expedient to use cement slurry as the filling material. This provides an increase in the effectiveness of transmitting the vibroseis signal and simplifies the technology of carrying out jobs, because the well is filled in one operation with loose material and water comprised in the cement slurry.
It is also expedient to use concrete slurry as the filling material. This contributes to a still higher increase in the weight and density of the ground within the volume of its added mass than with the use of water, loose material or cement slurry (concrete slurry being heavier), and, after concrete setting, this contributes to an increase in the rigidity of the added mass.
It is expedient to use liquid glass as the filling material. Being more dense than water, liquid glass contributes to a greater extent to an increase in the density and specific gravity of the ground within the volume of its added mass, and after the change of the aggregate state the rigidity of the ground increases sharply.
It is also expedient to use a liquid having a low freezing point as the filling material. Such technical solution makes it possible to broaden the scope of application of the method with respect to climatic conditions, i.e., to work at low temperatures.
It is expedient, after introducing filling material into the well, to drive additional wells in the added mass of the ground. This will make it possible to compact both the ground and material found in the well, whereby the density and rigidity of the added mass of the ground will be increased.
It is expedient after introducing the filling material into the well, to displace water from the filling material into the added mass of the ground by driving the well with the filling material again, and then again introducing the filling material into the resulting spaces. Such solution increases the effectiveness of the proposed method, since the density, specific gravity and rigidity of the added mass of the ground increases to a still greater extent because of the greater amount of the filling material that has entered the added mass.
It is expedient to moisten the newly introduced filling material. This operation will contribute to increasing the density, specific gravity and rigidity of the added mass of the ground. Furthermore, in subsequent running along the well with the filling material, the liquid will penetrate into the added mass of the ground to a greater depth.
It is expedient also before commencing the wave action on the producing formation to carry out preliminary wave treatment of the added mass of the ground. Such operation makes it possible to obtain optimal parameters of the added mass of the ground, providing for the most effective transmission of the vibroseis signal. This may be attained through the agency of different parameters in the preliminary wave treatment (resonance frequency) and in the wave action on the producing formation (dominant frequency).
Brief Description of the Drawings The essence of the proposed technical solution will be better understood from an example of a particular embodiment thereof and the accompanying drawings, in which:
FORMATIONS
Field of the Art The contemplated invention relates to the field of geotechnical processes, particularly to methods of acting by controllable physical waves on producing formations, and may be used in the recovery of liquid and gaseous hydrocarbons, water and other liquid and gaseous useful products from the interior of the Earth, as well as in geophysical investigations.
State of the Art Known in the art is a method of treating producing formations with longitudinal waves from a vibroseis source (the latter consisting of a seismic generator, an emitting platform with a system for matching with the ground and a mass of the ground added thereto) installed on the ground surface (see, e.g., N.P.Ryashentsev et al., Controlled Seismic Action on Oil Deposits. Preprint, 1989, No. 31. Novosibirsk, Academy of Sciences of the USSR, Special Design Office of Applied Geophysics (in Russian)). It has been established that the average volume density of the wave energy in sedimentary rocks (sandstone, clay) is proportional to the density of the ground.
In the method described above the effectiveness of seismic signal transmission from the signal source to the producing formation is low, and there are no means which allow varying the parameters of action on the formation. The mass of the ground added to the emitting platform (base plate) damps the vibrations, and this leads to the absorption of the energy which does not reach the producing formation.
Also known is a method of developing flooded oil field according to Inventor's Certificate No. 1596081, Cl. E21B 43/00, published in Bulletin of Inventions No. 36, 1990, which comprises the steps of developing a formation with wells, recovering formation fluid via a cluster of producing wells, acting on the formation with vibroseis signals from a ground source of vibrations, determining the frequency of effective action by searching frequencies of the emitted vibrations, determining the composition and quantity of the recovered fluid prior to and after the action. A flooded field area with a stationary oil phase is found, a vibroseis source is installed within this area on a cluster of producing wells, a seismic detector is lowered into one of the producing wells to the reservoir depth, the microseis background is measured during a period of two or three days with determining simultaneously the percentage of oil in the well fluid, and a vibroseis action is carried out with frequency search. On completion of the action, the amplitude spectrum of the microseis background is measured, and from the revealed additional frequencies in the spectrum a dominant frequency is found, an action at this frequency is carried out, the source is shifted alternately for half the wavelength till the content of oil in the well fluid ceases to increase, and the radius of the effective zone of the source action is determined, additional sources are installed and spaced from one another so that the distance between them is equal to the diameter of the effective zone of the source action, and vibroseis action at the dominant frequency is carried out.
The above-discussed method is also disadvantageous in view of energy losses in the added mass of the ground, since the ground, because of the presence of pores and cracks, damps wave oscillations, and the effectiveness of the action on the producing formation is lowered, in spite of using the dominant frequency of vibrations.
Besides, the process of oil production is complicated owing to the necessity of shifting the vibroseis source for half the wavelength.
The analog nearest in the technical essence and the attained effect to the method of the present invention is the method of development of oil-gas deposit according to RF
Patent No. 2078913, CI. E21B 43/18, published in Bulletin of Inventions No.
13, 1997.
This method comprises injecting a displacement agent via injection wells, recovering a formation fluid via producing wells, carrying out cyclic vibroseis action with frequency search on a producing formation from ground vibration sources, determining, prior to and after carrying out the action, the amount of the recovered fluid, revealing dominant frequencies of the formation from the response of its microseis background to the vibroseis action, and carrying out an additional vibroseis action at the dominant frequency. The cyclic vibroseis action with frequency search is carried out with a simultaneous stepwise lowering, with a step OP, of the formation pressure in each cycle by varying the rates of injecting the displacement agent and recovering the formation fluid. Then the value of lowering the formation pressure is determined, which ensures maximum response of the formation to the vibroseis action at the dominant frequency, and an additional vibroseis action with this value of the lowered formation pressure is carried out. After that the formation pressure is restored to the value that ensures optimum formation development conditions, and an additional vibroseis action on the formation is carried out again.
A disadvantage of the method under consideration is the loss of energy in the added mass of the ground, since the latter, due to the presence of pores and cracks, damps the oscillations, the effectiveness of the vibroseis action being thus lowered.
Furthermore, this known method is difficult to implement because of the necessity to vary the rate of injecting the displacement agent.
Essence of the Invention S The technical problem solved by the proposed invention is to raise the effectiveness of transmitting a vibroseis signal from a source thereof, installed on the ground surface, to a producing formation, by increasing the density, specific gravity and rigidity of the ground in the volume of its added mass.
This problem is solved by that in a method of wave treatment, predominantly of producing formations, consisting in a wave action on a producing formation with the help of a vibroseis source installed with an emitting platform on the ground surface, according to the technical solution, the physico-mechanical properties of the ground are varied within the volume of its added mass. Such a combination of operations makes it possible to increase the efficiency of transmitting the vibroseis signal from the source thereof installed on the ground surface to the producing formation. This is accomplished by reducing losses of this signal in the added mass of the ground, since it is possible to reduce the pores and cracks in the latter by varying the physico-mechanical properties of the ground and, consequently, it is possible to increase the rigidity of the added mass of the ground, its specific gravity and density.
It is expedient to vary the physico-mechanical properties of the ground within the volume of its added mass before or after the wave action on the producing formation. In this case the operation of varying the physico-mechanical properties is simplified, since it can be earned out at any convenient time, irrespective of the time of carrying out the wave action on the producing formation. The operation carried out before the wave action enables the effect to be obtained upon this particular wave action on the producing formation. The operation carried out after the wave action enables the effect to be obtained upon next wave action on the producing formation.
It is possible to vary the physico-mechanical properties of the ground within the volume of its added mass in the course of wave action on the producing formation. Such solution makes the action on the formation more effective, since the process of ground relaxation and evaporation (leakage) of liquid from pores and cracks is ruled out.
It is expedient to vary the physico-mechanical properties of the ground within the volume of its added mass by filling pores and cracks in the ground with a practically incompressible liquid. Such solution makes it possible to increase the rigidity, specific gravity and density of the added mass of the ground. Furthermore, energy losses for Rayleigh waves are reduced. We shall explain this fact. In the course of surface excitation of the medium there originate several types of waves. The energy spent for their excitation is approximately as follows: longitudinal wave, 8%; Rayleigh wave, 70%; C-wave, 20%. It is known also that in an ideal fluid Rayleigh waves are not excited. The proposed method provides a heterogeneous medium which is close to an ideal fluid; therefore, there occurs a redistribution of energy for the excitation of different types of waves. For the excitation of longitudinal waves, which are of interest to us, 7 to 10 times more energy is spent. This, ultimately, contributes to increasing the effectiveness of transmitting the vibroseis signal to the producing formation.
It is expedient to use water as a practically incompressible liquid. This simplifies the implementation of the proposed method.
It is also expedient to use, as a practically incompressible liquid, a substance in the liquid aggregate state, for instance, liquid glass. Such solution substantially increases the rigidity, density, and specific gravity of the added mass of the ground, which, in turn, enhances the transmission of the vibroseis signal to the producing formation.
Furthermore, liquid glass after transition to the solid phase under the effect of the ambient temperature does not evaporate and does not flow into the ground beyond its added mass, so that longevity of the acquired properties is ensured.
It is also expedient to use, as a practically incompressible liquid, a liquid with a low freezing point, e.g., kerosene or antifreeze. Such solution makes it possible, while providing an increase in the rigidity, density and specific gravity of the added mass of the ground, to use the proposed method in winter conditions.
In winter conditions, it is expedient to heat the practically incompressible liquid before filling the pores and cracks with it. This will make it possible to use the proposed technical solution when the frost penetration into the ground is not deep, so that the scope of application of the invention under different climatic conditions is broadened.
It is expedient to heat water till steam formation: this broadens the range of potential applications of the proposed method, since steam penetrates into smaller pores and cracks than liquid does (in the course of time steam under the effect of the temperature of the surrounding ground becomes converted into liquid). In addition, steam heats the thin, frozen layer of the ground more intensively, insuring the penetration of moisture through it.
It is expedient to vary the physico-mechanical properties of the ground within the volume of its added mass by means of in-depth compaction of the ground by driving at 5 least one well and subsequent introducing a filling material into it. Such combination of operations makes it possible to raise the effectiveness of transmitting the vibroseis signal from the vibroseis signal source installed on the ground surface to the producing formation due to the filling of pores and cracks with the ground displaced in a radial direction in the course of driving wells.
It is expedient to use a liquid, e.g., water, as the filling material. This will make it possible, in addition to increasing the specific gravity, density, and rigidity of the ground within the volume of its added mass, to reduce losses of wave energy, because in the liquid medium surface waves (Rayleigh waves, Love waves) are not formed. In the case under consideration, the medium, on addition of water to it, approaches in its properties a liquid medium. Therefore, here a reduction of expenditures caused by the formation of Rayleigh and Love waves is involved, rather than their complete ruling out, since the medium is actually not a liquid.
It is also expedient to use loose material, e.g., rock waste or sand, as the filling material. Such solution is more effective than the preceding one in increasing the density, specific gravity, and rigidity, since the specific gravity of the filling material (rock waste or sand) is greater than the specific gravity of water.
In such cases it is expedient to moisten loose material. Such solution increases still further the effectiveness of transmitting the vibroseis signal, because the probability of origination of surface (Rayleigh, Love) waves decreases, and the specific gravity, density, and rigidity of the ground within the volume of its added mass increase considerably, since the spaces between particles of loose material filling the well, as well as pores and cracks around the well in the ground mass, are filled with water.
It is also expedient to use cement slurry as the filling material. This provides an increase in the effectiveness of transmitting the vibroseis signal and simplifies the technology of carrying out jobs, because the well is filled in one operation with loose material and water comprised in the cement slurry.
It is also expedient to use concrete slurry as the filling material. This contributes to a still higher increase in the weight and density of the ground within the volume of its added mass than with the use of water, loose material or cement slurry (concrete slurry being heavier), and, after concrete setting, this contributes to an increase in the rigidity of the added mass.
It is expedient to use liquid glass as the filling material. Being more dense than water, liquid glass contributes to a greater extent to an increase in the density and specific gravity of the ground within the volume of its added mass, and after the change of the aggregate state the rigidity of the ground increases sharply.
It is also expedient to use a liquid having a low freezing point as the filling material. Such technical solution makes it possible to broaden the scope of application of the method with respect to climatic conditions, i.e., to work at low temperatures.
It is expedient, after introducing filling material into the well, to drive additional wells in the added mass of the ground. This will make it possible to compact both the ground and material found in the well, whereby the density and rigidity of the added mass of the ground will be increased.
It is expedient after introducing the filling material into the well, to displace water from the filling material into the added mass of the ground by driving the well with the filling material again, and then again introducing the filling material into the resulting spaces. Such solution increases the effectiveness of the proposed method, since the density, specific gravity and rigidity of the added mass of the ground increases to a still greater extent because of the greater amount of the filling material that has entered the added mass.
It is expedient to moisten the newly introduced filling material. This operation will contribute to increasing the density, specific gravity and rigidity of the added mass of the ground. Furthermore, in subsequent running along the well with the filling material, the liquid will penetrate into the added mass of the ground to a greater depth.
It is expedient also before commencing the wave action on the producing formation to carry out preliminary wave treatment of the added mass of the ground. Such operation makes it possible to obtain optimal parameters of the added mass of the ground, providing for the most effective transmission of the vibroseis signal. This may be attained through the agency of different parameters in the preliminary wave treatment (resonance frequency) and in the wave action on the producing formation (dominant frequency).
Brief Description of the Drawings The essence of the proposed technical solution will be better understood from an example of a particular embodiment thereof and the accompanying drawings, in which:
FIG. 1 shows an operation of injecting a practically incompressible liquid into the added mass of the ground;
FIG. 2 shows an operation of in-depth compacting the ground by driving wells;
FIGS. 3--4 show an operation of filing the driven wells with a loose material and a liquid;
FIG. 4 shows an operation of broadening the driven wells in the added mass of the ground;
FIG. 5 shows an operation of filling broadened wells with a loose material and a liquid;
FIG. 6 shows seismograms of fluidizing drift sands in dynamic probing with a cone having the cross-sectional area of 100 cm2, wherein 4-8 are the numbers of experiments;
FIG. 7 shows distribution curves Pp of loess-like rocks according to the dynamic probing data, wherein 1 denotes water-saturated foams, 2 denotes solid and semi-solid foams occurring above the groundwater level;
FIG. 8 shows the attenuation of the vibration amplitude A of drift sand as one recedes from the excitation source to distance l, wherein 1 is the distance before the fluidization, 2 is the distance after the fluidization, 9, 12-16 are the numbers of experiments;
FIG. 9 shows the amplitude-frequency characteristic of drift sands (A is the vibrational amplitude. Vibration frequencies: fo - of driving force , f - of drift sand subjected to dynamic action. Numerals in the plots denote the numbers of experiments).
Description of the Preferred Embodiments of the Invention It has been established (see Dwgs. 1---4 of the Appendix) that under seismic action on dry and moisture-saturated ground the signal transmission is different: in moisture-saturated ground the signal parameters 3 to 8 times exceed those of the signal obtained under the action on dry ground (see, e.g., A.Ya.Rubinshtein, B.LKulachkin, Dynamic Ground Probing, Moscow, "Nedra", 1984, pp. 33, 35, 70 (in Russian)). For instance, FIG.
6 shows a seismogram of fluidization of drift sands in dynamic probing.
Judging from the positive pulse, in moisture-saturated sand it exceeds seven-fold the signal obtained in the case of dry sand; judging from the negative pulse, the difference is ten-fold.
FIG. 7 shows the distribution .curves of the complex index of the mechanical properties of the ground, this index being the conventional dynamic resistance Pp that determines the character of the ground variability and the degree of the inhomogeneity of the mechanical properties of isolated layers with the help of the known mathematical relationships for the qualitative evaluation of their variability.
The frequency of vibrations of moisture-saturated foams is twice that of dry foams;
FIG. 8 shows the curve of damping of vibrational amplitude A of drift sand, as one recedes from the excitation source for distance 1. From the plots it is seen that after the fluidization (shown with dotted lines) the vibrational amplitude is 2-3 times that of dry sand; FIG. 9 shows the amplitude-frequency characteristic of drift sands, from which it is seen that constant vibrations of the driving force of a definite frequency, with each subsequent pulse, cause all the greater destruction of the ground and diminution of the vibration frequency of the latter.
This process goes on until the vibrational frequency fo of the driving force approaches the frequency f of natural vibrations of the ground. Then the amplitude of the ground vibrations sharply increases, and the ground becomes fluidized.
The essence of the proposed method of wave treatment, predominantly of producing formations, consists in increasing artificially the specific gravity and density of the added mass of the ground, and, consequently, also the weight of the added mass of the ground, and the rigidity thereof by introducing into the pores and cracks of said mass a filling (loose or moistened) material or practically incompressible liquid.
This can be accomplished by two different methods. The driven well and, consequently, also the added mass of the ground, can be filled with a practically incompressible liquid (water, kerosene, antifreeze or well fluid comprising a mixture of oil and water). Another, more rational method is mechanical, in-depth compaction of the ground within the volume of its added mass by driving at least one well and subsequent introducing therein a filling material, such as water, loose material, cement or concrete slurry, liquid glass, a liquid having a low freezing point, and the like. The well with loose material disposed therein may be filled with water which seeps into the added mass of the ground surrounding the well.
We shall now consider these methods.
A vibrator 1 (Fig. 1 ) is installed on an emitting platform (not shown in the Figure) which is usually deepened into ground 2 from the surface. Added mass 3 of the ground 2, shown in Fig. 1 with a dotted line, is defined by the zone of action of the vibrator 1. The latter may be of any design and operate on any principle, i.e., it may comprise rotating masses or a striker moved by a pneumatic or hydraulic drive and striking against the emitting platform, etc. Before the commencement of the vibroseis action on a producing formation, a liquid which is practically incompressible is injected into the added mass of the ground 2 through injectors 4, 5. Water, liquid glass, kerosene, gasoline, antifreeze may be used as such liquid, Fig. 2 shows the operation of in-depth compaction of the ground 2 by driving wells 6-8. The injectors 4, 5 and the wells 6-8 may be located around the vibrator 1 and even under it (usually before installing thereof). The wells 6-8 may be vertical or inclined and filled with a loose material 9 (Fig. 3) or with a practically incompressible liquid, cement or concrete slurry. The wells may be driven in several steps, when use is made of a pneumodrift with a comparatively small impact energy.
For this to be done, first small-diameter wells 6-8 are driven, whose diameter is equal to the diameter of the pneumodrift body (the pneumodrift is not shown in the Figure, because it is a well-known device for driving wells by ground compaction). Then the wells 6-8 are broadened by repeated driving (in Fig. 4 the well 8 is shown partially broadened, i.e., in the course of broadening). Then into the driven wells 6-8 a filling material is introduced (loose material, practically incompressible liquid, cement or concrete slurry, etc.).
Increasing the density, specific gravity and rigidity of the added mass 3 of the ground 2 can be accomplished prior to or after the wave action on the producing formation.
In this case the operations of wave action on the producing formation and of varying the physico-mechanical properties of the ground 2 within the volume of its added mass 3 are carried out separately. If the latter operation takes place after the wave action, it is necessary to provide openings in the emitting platform of the vibroseis source for installing the injectors 4, 5 in these openings or for inserting the pneumodrift through these openings into the ground 2. It is also possible to drive inclined wells 6-8 around the emitting platform of the vibrator 1 or to insert the injectors 4, 5 into the ground 2 with a tilt (driving of the wells 6-8 brings about compaction of the ground 2 around them). This predetermines first of all the filling of pores and cracks with the displaced ground 2, and this leads to increasing the rigidity of the added mass 3 of the ground 2.
Subsequent filling of the wells 6-8 with the loose material 9, practically incompressible liquid, etc., (Figs. 3, 5) leads to an increase in the specific gravity, density and rigidity of the added mass 3 of the ground 2.
When the vibrator 1 is switched on, vibroseis pulses are transmitted via the added mass 3 of the ground 2 to the producing formation more effectively, because more rigid added mass 3 of the ground 2 promotes it. It should be taken into account that the chosen liquid is practically incompressible (within the range of built up pressures).
Thereby, the liquid strengthens the ground skeleton. In the case of using a heated liquid (water), the proposed method is effective in winter conditions, when the temperature of air is below zero, and a superficial frozen crust of the ground 2 has already formed. The heated liquid warms up this crust and seeps into the depth of the added mass 3 of the ground 2.
5 As the liquid is heated, steam is formed. In winter conditions this contributes to more intensive warming-up of the frozen crust of the ground 2. Furthermore, a new effect appears due to the fact that steam fills fine pores and cracks inaccessible to the liquid. As a result, the added mass 3 of the ground 2 is filled with the liquid more completely (with time, the steam which has entered the micropores and microcracks transforms into water, 10 and this is just what is necessary for increasing the specific gravity, density and rigidity of the added mass 3 of the ground 2).
When working under the conditions of low temperatures, it is necessary to use liquid with a low freezing point, for instance, kerosene, gasoline or antifreeze: this will make the added mass 3 of the ground 2 not sensitive to freezing and, consequently, give an opportunity to work in winter conditions. Using the now existing vibroseis sources with an emitting platform under the conditions of low temperatures leads to breakage of the platform.
This phenomenon is associated with that the water present in the connected mass 3 of the ground 2 freezes and is displaced at the edges of the emitting platform. As a result, the emitting platform hangs at the periphery. The disturbing force which originates at the center of the emitting platform causes bending and breakage of the emitting platform. This phenomenon does not occur, if non-freezing liquids (antifreeze, kerosene, gasoline) are used, and the service life of the emitting platform is increased. From the ecological standpoint, local fouling of the ground 2 within the volume of its added mass 3 (when using, e.g., antifreeze) is insignificant.
As the practically incompressible liquid it is possible to use water, antifreeze, gasoline, kerosene, liquid glass, which, as the temperature changes, change their aggregate state, passing into the solid phase. It is also possible to use, as the filling material, concrete or cement slurry containing a liquid component and a solid component. In this case the transition into the solid phase is time-dependent. Setting, these materials in the added mass 3 of the ground 2 increase the rigidity, density and specific gravity of the added mass 3, so that the mass of the emitting platform may be made smaller (proofs are presented hereinbelow).
FIG. 2 shows an operation of in-depth compacting the ground by driving wells;
FIGS. 3--4 show an operation of filing the driven wells with a loose material and a liquid;
FIG. 4 shows an operation of broadening the driven wells in the added mass of the ground;
FIG. 5 shows an operation of filling broadened wells with a loose material and a liquid;
FIG. 6 shows seismograms of fluidizing drift sands in dynamic probing with a cone having the cross-sectional area of 100 cm2, wherein 4-8 are the numbers of experiments;
FIG. 7 shows distribution curves Pp of loess-like rocks according to the dynamic probing data, wherein 1 denotes water-saturated foams, 2 denotes solid and semi-solid foams occurring above the groundwater level;
FIG. 8 shows the attenuation of the vibration amplitude A of drift sand as one recedes from the excitation source to distance l, wherein 1 is the distance before the fluidization, 2 is the distance after the fluidization, 9, 12-16 are the numbers of experiments;
FIG. 9 shows the amplitude-frequency characteristic of drift sands (A is the vibrational amplitude. Vibration frequencies: fo - of driving force , f - of drift sand subjected to dynamic action. Numerals in the plots denote the numbers of experiments).
Description of the Preferred Embodiments of the Invention It has been established (see Dwgs. 1---4 of the Appendix) that under seismic action on dry and moisture-saturated ground the signal transmission is different: in moisture-saturated ground the signal parameters 3 to 8 times exceed those of the signal obtained under the action on dry ground (see, e.g., A.Ya.Rubinshtein, B.LKulachkin, Dynamic Ground Probing, Moscow, "Nedra", 1984, pp. 33, 35, 70 (in Russian)). For instance, FIG.
6 shows a seismogram of fluidization of drift sands in dynamic probing.
Judging from the positive pulse, in moisture-saturated sand it exceeds seven-fold the signal obtained in the case of dry sand; judging from the negative pulse, the difference is ten-fold.
FIG. 7 shows the distribution .curves of the complex index of the mechanical properties of the ground, this index being the conventional dynamic resistance Pp that determines the character of the ground variability and the degree of the inhomogeneity of the mechanical properties of isolated layers with the help of the known mathematical relationships for the qualitative evaluation of their variability.
The frequency of vibrations of moisture-saturated foams is twice that of dry foams;
FIG. 8 shows the curve of damping of vibrational amplitude A of drift sand, as one recedes from the excitation source for distance 1. From the plots it is seen that after the fluidization (shown with dotted lines) the vibrational amplitude is 2-3 times that of dry sand; FIG. 9 shows the amplitude-frequency characteristic of drift sands, from which it is seen that constant vibrations of the driving force of a definite frequency, with each subsequent pulse, cause all the greater destruction of the ground and diminution of the vibration frequency of the latter.
This process goes on until the vibrational frequency fo of the driving force approaches the frequency f of natural vibrations of the ground. Then the amplitude of the ground vibrations sharply increases, and the ground becomes fluidized.
The essence of the proposed method of wave treatment, predominantly of producing formations, consists in increasing artificially the specific gravity and density of the added mass of the ground, and, consequently, also the weight of the added mass of the ground, and the rigidity thereof by introducing into the pores and cracks of said mass a filling (loose or moistened) material or practically incompressible liquid.
This can be accomplished by two different methods. The driven well and, consequently, also the added mass of the ground, can be filled with a practically incompressible liquid (water, kerosene, antifreeze or well fluid comprising a mixture of oil and water). Another, more rational method is mechanical, in-depth compaction of the ground within the volume of its added mass by driving at least one well and subsequent introducing therein a filling material, such as water, loose material, cement or concrete slurry, liquid glass, a liquid having a low freezing point, and the like. The well with loose material disposed therein may be filled with water which seeps into the added mass of the ground surrounding the well.
We shall now consider these methods.
A vibrator 1 (Fig. 1 ) is installed on an emitting platform (not shown in the Figure) which is usually deepened into ground 2 from the surface. Added mass 3 of the ground 2, shown in Fig. 1 with a dotted line, is defined by the zone of action of the vibrator 1. The latter may be of any design and operate on any principle, i.e., it may comprise rotating masses or a striker moved by a pneumatic or hydraulic drive and striking against the emitting platform, etc. Before the commencement of the vibroseis action on a producing formation, a liquid which is practically incompressible is injected into the added mass of the ground 2 through injectors 4, 5. Water, liquid glass, kerosene, gasoline, antifreeze may be used as such liquid, Fig. 2 shows the operation of in-depth compaction of the ground 2 by driving wells 6-8. The injectors 4, 5 and the wells 6-8 may be located around the vibrator 1 and even under it (usually before installing thereof). The wells 6-8 may be vertical or inclined and filled with a loose material 9 (Fig. 3) or with a practically incompressible liquid, cement or concrete slurry. The wells may be driven in several steps, when use is made of a pneumodrift with a comparatively small impact energy.
For this to be done, first small-diameter wells 6-8 are driven, whose diameter is equal to the diameter of the pneumodrift body (the pneumodrift is not shown in the Figure, because it is a well-known device for driving wells by ground compaction). Then the wells 6-8 are broadened by repeated driving (in Fig. 4 the well 8 is shown partially broadened, i.e., in the course of broadening). Then into the driven wells 6-8 a filling material is introduced (loose material, practically incompressible liquid, cement or concrete slurry, etc.).
Increasing the density, specific gravity and rigidity of the added mass 3 of the ground 2 can be accomplished prior to or after the wave action on the producing formation.
In this case the operations of wave action on the producing formation and of varying the physico-mechanical properties of the ground 2 within the volume of its added mass 3 are carried out separately. If the latter operation takes place after the wave action, it is necessary to provide openings in the emitting platform of the vibroseis source for installing the injectors 4, 5 in these openings or for inserting the pneumodrift through these openings into the ground 2. It is also possible to drive inclined wells 6-8 around the emitting platform of the vibrator 1 or to insert the injectors 4, 5 into the ground 2 with a tilt (driving of the wells 6-8 brings about compaction of the ground 2 around them). This predetermines first of all the filling of pores and cracks with the displaced ground 2, and this leads to increasing the rigidity of the added mass 3 of the ground 2.
Subsequent filling of the wells 6-8 with the loose material 9, practically incompressible liquid, etc., (Figs. 3, 5) leads to an increase in the specific gravity, density and rigidity of the added mass 3 of the ground 2.
When the vibrator 1 is switched on, vibroseis pulses are transmitted via the added mass 3 of the ground 2 to the producing formation more effectively, because more rigid added mass 3 of the ground 2 promotes it. It should be taken into account that the chosen liquid is practically incompressible (within the range of built up pressures).
Thereby, the liquid strengthens the ground skeleton. In the case of using a heated liquid (water), the proposed method is effective in winter conditions, when the temperature of air is below zero, and a superficial frozen crust of the ground 2 has already formed. The heated liquid warms up this crust and seeps into the depth of the added mass 3 of the ground 2.
5 As the liquid is heated, steam is formed. In winter conditions this contributes to more intensive warming-up of the frozen crust of the ground 2. Furthermore, a new effect appears due to the fact that steam fills fine pores and cracks inaccessible to the liquid. As a result, the added mass 3 of the ground 2 is filled with the liquid more completely (with time, the steam which has entered the micropores and microcracks transforms into water, 10 and this is just what is necessary for increasing the specific gravity, density and rigidity of the added mass 3 of the ground 2).
When working under the conditions of low temperatures, it is necessary to use liquid with a low freezing point, for instance, kerosene, gasoline or antifreeze: this will make the added mass 3 of the ground 2 not sensitive to freezing and, consequently, give an opportunity to work in winter conditions. Using the now existing vibroseis sources with an emitting platform under the conditions of low temperatures leads to breakage of the platform.
This phenomenon is associated with that the water present in the connected mass 3 of the ground 2 freezes and is displaced at the edges of the emitting platform. As a result, the emitting platform hangs at the periphery. The disturbing force which originates at the center of the emitting platform causes bending and breakage of the emitting platform. This phenomenon does not occur, if non-freezing liquids (antifreeze, kerosene, gasoline) are used, and the service life of the emitting platform is increased. From the ecological standpoint, local fouling of the ground 2 within the volume of its added mass 3 (when using, e.g., antifreeze) is insignificant.
As the practically incompressible liquid it is possible to use water, antifreeze, gasoline, kerosene, liquid glass, which, as the temperature changes, change their aggregate state, passing into the solid phase. It is also possible to use, as the filling material, concrete or cement slurry containing a liquid component and a solid component. In this case the transition into the solid phase is time-dependent. Setting, these materials in the added mass 3 of the ground 2 increase the rigidity, density and specific gravity of the added mass 3, so that the mass of the emitting platform may be made smaller (proofs are presented hereinbelow).
In-depth compaction of the ground can be carried out in two ways: a) by repeated drivings of one well with introducing filling material thereinto (after each driving or at the end, after the maximum-diameter well has been driven); b) by driving a plurality of wells (a network of wells) and introducing filling material thereinto.
In the case of low-power pneumodrifts, compaction of the ground 2 is carried out by repeated drivings of vertical or inclined wells 6-8 (Figs. 4, 5) in the added mass 3 of the ground 2. First, small-diameter wells 6-8 are driven by in-depth compacting the ground 2 owing to its radial shifting. A small volume of the ground 2 is thus displaced in a radial direction, whereby filling of pores and cracks with the displaced ground 2 is predetermined. Then the driven wells (Fig. 4) are broadened by additional drivings, using the same pneumodrift. It is possible to introduce into the wells 6-8 a filling material (loose material 9, wet or dry with subsequent humidification) after each driving or after the final broadening of the wells. In the latter case the pneumodrift will travel along the filled well 6-8, moving radially the loose material 9 with water and the ground 2 which is beyond the wells 6-8.
An increase in the specific gravity of the added mass 3 of the ground 2 makes it possible to obtain an additional effect which consists in reducing the mass of the vibroseis source. We shall illustrate this by examples, when the added mass 3 of the ground 2 has different density and specific gravity.
Let us consider the action of a vibroseis source on a producing deposit with the thickness of the producing formation h = 75 m; velocity of propagation of elastic waves directed perpendicular to the producing formation, V = 600 m/s; disturbing force of the vibrator 1 P = 100 t, the vibrator being installed on an emitting platform deepened from the surface into the ground 2 consisting of loamy sand with clay, with' the following characteristics: the density of the ground 2 after and before compaction p, =
2.5 t/m3; pz =
1.87 t/m3; modulus of elasticity E = 10' 103 t/m3; coefficient of transverse elastic deformation ~. = 0.25.
Let us find the resonance frequency of the producing formation c~res.fo~. = h k with the repeatability factor k of passage of the generated seismic waves equal to 1, 2, 3, 4 (as an example, let k = 1):
In the case of low-power pneumodrifts, compaction of the ground 2 is carried out by repeated drivings of vertical or inclined wells 6-8 (Figs. 4, 5) in the added mass 3 of the ground 2. First, small-diameter wells 6-8 are driven by in-depth compacting the ground 2 owing to its radial shifting. A small volume of the ground 2 is thus displaced in a radial direction, whereby filling of pores and cracks with the displaced ground 2 is predetermined. Then the driven wells (Fig. 4) are broadened by additional drivings, using the same pneumodrift. It is possible to introduce into the wells 6-8 a filling material (loose material 9, wet or dry with subsequent humidification) after each driving or after the final broadening of the wells. In the latter case the pneumodrift will travel along the filled well 6-8, moving radially the loose material 9 with water and the ground 2 which is beyond the wells 6-8.
An increase in the specific gravity of the added mass 3 of the ground 2 makes it possible to obtain an additional effect which consists in reducing the mass of the vibroseis source. We shall illustrate this by examples, when the added mass 3 of the ground 2 has different density and specific gravity.
Let us consider the action of a vibroseis source on a producing deposit with the thickness of the producing formation h = 75 m; velocity of propagation of elastic waves directed perpendicular to the producing formation, V = 600 m/s; disturbing force of the vibrator 1 P = 100 t, the vibrator being installed on an emitting platform deepened from the surface into the ground 2 consisting of loamy sand with clay, with' the following characteristics: the density of the ground 2 after and before compaction p, =
2.5 t/m3; pz =
1.87 t/m3; modulus of elasticity E = 10' 103 t/m3; coefficient of transverse elastic deformation ~. = 0.25.
Let us find the resonance frequency of the producing formation c~res.fo~. = h k with the repeatability factor k of passage of the generated seismic waves equal to 1, 2, 3, 4 (as an example, let k = 1):
-_ 3. 5600 = 25.13 1/s or f = 4 Hz.
res.fonn.
The disturbing force being known, F = 100 t, let us find the area S of the emitting platform with the specific dynamic load q = 2.8 t/m2:
S=-- =35.7 m2.
q 2.8 The equivalent reduced radius of the emitting platform r = S/~c = 35.7/3.14 = 3.37 m.
The added mass 3 of ground 2 is determined from the formula mg, = 1. l7p~ro3.
For grounds 2 with densities pi and p2, respectively, we shall have mgrs = 1.17'2.5'3.373 = 112 t mgr2 = 1.17'1.873.373 = 83.7 t.
Let us find the rigidity of the added mass of ground 2 from the formula C - 2Ey - 2'10'103 35.7 =12.73104 t/m.
1-,u2 1-0.252 Let us find the mass m,,;br.s. of the vibration source c 12.73'104 = 0.02-104 = 200 t.
m~~br.s. = Z - 2 ~res.Jorm. 25.13 Let us find the mass of vibrator 1 and of the emitting platform for grounds 2 with densities p1 and p2 from the formula m,,;br. = mvibr.s.- mgr:
mvibr.l = 200 - 112 = 88 t m,,;br.2 = 200 - 83.7 = 116.3 t.
As a result, we shall obtain that as the specific gravity of the added mass 3 of the ground 2 increases, the mass of the vibrator 1 and of the emitting platform decreases (in the case under consideration by 28.3 t).
The physico-mechanical properties of the ground within the volume of its added mass may be varied in the same regime as the vibration action on the producing formation (at the dominant frequency).
However, the added mass and the producing formation are located at different depths, have different physico-mechanical properties and, accordingly, the resonance and N Y-dominant frequencies of their treatment may differ substantially. Therefore, it is expedient first to perform the operation of varying the physico-mechanical properties within the volume of the added mass of the ground, having carried out its preliminary wave treatment at the resonance frequency and then to carry out the vibration action on the producing formation at the dominant frequency, optimal from the standpoint of increasing the oil recovery.
res.fonn.
The disturbing force being known, F = 100 t, let us find the area S of the emitting platform with the specific dynamic load q = 2.8 t/m2:
S=-- =35.7 m2.
q 2.8 The equivalent reduced radius of the emitting platform r = S/~c = 35.7/3.14 = 3.37 m.
The added mass 3 of ground 2 is determined from the formula mg, = 1. l7p~ro3.
For grounds 2 with densities pi and p2, respectively, we shall have mgrs = 1.17'2.5'3.373 = 112 t mgr2 = 1.17'1.873.373 = 83.7 t.
Let us find the rigidity of the added mass of ground 2 from the formula C - 2Ey - 2'10'103 35.7 =12.73104 t/m.
1-,u2 1-0.252 Let us find the mass m,,;br.s. of the vibration source c 12.73'104 = 0.02-104 = 200 t.
m~~br.s. = Z - 2 ~res.Jorm. 25.13 Let us find the mass of vibrator 1 and of the emitting platform for grounds 2 with densities p1 and p2 from the formula m,,;br. = mvibr.s.- mgr:
mvibr.l = 200 - 112 = 88 t m,,;br.2 = 200 - 83.7 = 116.3 t.
As a result, we shall obtain that as the specific gravity of the added mass 3 of the ground 2 increases, the mass of the vibrator 1 and of the emitting platform decreases (in the case under consideration by 28.3 t).
The physico-mechanical properties of the ground within the volume of its added mass may be varied in the same regime as the vibration action on the producing formation (at the dominant frequency).
However, the added mass and the producing formation are located at different depths, have different physico-mechanical properties and, accordingly, the resonance and N Y-dominant frequencies of their treatment may differ substantially. Therefore, it is expedient first to perform the operation of varying the physico-mechanical properties within the volume of the added mass of the ground, having carried out its preliminary wave treatment at the resonance frequency and then to carry out the vibration action on the producing formation at the dominant frequency, optimal from the standpoint of increasing the oil recovery.
Claims (21)
1. A method of wave treatment, predominantly of producing formations, consisting in a wave action on a producing formation with the help of a vibroseis source installed with an emitting platform on the ground surface, wherein the physico-mechanical properties of the ground are varied within the volume of its added mass.
2. The method of claim 1, wherein the physico-mechanical properties of the ground within the volume of its added mass are varied prior to or after the wave action on the producing formation.
3. The method of claim 1, wherein the physico-mechanical properties of the ground within the volume of its added mass are varied prior to or during the wave action on the producing formation.
4. The method according to one of claims 1-3, wherein the physico-mechanical properties of the ground within the volume of its added mass are varied by filling pores and cracks in the ground with a practically incompressible liquid.
5. The method of claim 4, wherein water is used as the practically incompressible liquid.
6. The method of claim 4, wherein a substance in the liquid aggregate state, for instance, liquid glass, is used as the practically incompressible liquid.
7. The method of claim 4, wherein a liquid with a low freezing point, for instance, kerosene or antifreeze, is used as the practically incompressible liquid.
8. The method of claim 4, wherein the practically incompressible liquid is heated before filling pores and cracks therewith.
9. The method of claim 5, wherein water is heated till steam formation.
10. The method according to one of claims 1-3, wherein the physico-mechanical properties of the ground within the volume of its added mass are varied by in-depth compaction of the ground by driving at least one well and subsequently introducing a filling material thereinto.
11. The method of claim 10, wherein a liquid, for instance, water is used as the filling material.
12. The method of claim 10, wherein a loose material, for instance, rock waste or sand is used as the filling material.
13. The method of claim 12, wherein the loose material is moistened.
14. The method of claim 10, wherein cement slurry is used as the filling material.
15. The method of claim 10, wherein concrete slurry is used as the filling material.
16. The method of claim 10, wherein liquid glass is used as the filling material.
17. The method of claim 10, wherein a liquid with a low freezing point is used as the filling material.
18. The method according to one of claims 10-17, wherein after introducing the filling material into the well, additional wells are driven in the added mass of the ground.
19. The method according to one of claims 11, 13-17, wherein after introducing the filling material into the well, water is displaced from the filling material into the added mass of the ground by driving the well with the filling material again, and then again introducing the filling material into the resulting spaces.
20. The method of claim 19, wherein the again-introduced filling material is moistened.
21. The method according to one of claims 1-20, wherein before the commencement of the wave action on the producing formation a preliminary wave treatment of the added mass of the ground is carried out.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| RU2000130962 | 2000-12-09 | ||
| RU2000130962/03A RU2196225C2 (en) | 2000-12-09 | 2000-12-09 | Method of wave treatment, mainly, producing formations |
| PCT/RU2001/000425 WO2002046578A1 (en) | 2000-12-09 | 2001-10-17 | Method for wave processing mainly productive strata |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2398393A1 true CA2398393A1 (en) | 2002-06-13 |
Family
ID=20243261
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|---|---|---|---|
| CA002398393A Abandoned CA2398393A1 (en) | 2000-12-09 | 2001-10-17 | Method for wave processing mainly productive strata |
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|---|---|
| CN (1) | CN1398321A (en) |
| CA (1) | CA2398393A1 (en) |
| GB (1) | GB2377956A (en) |
| MX (1) | MXPA02007706A (en) |
| NO (1) | NO20023710L (en) |
| RU (1) | RU2196225C2 (en) |
| WO (1) | WO2002046578A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2008083471A1 (en) * | 2007-01-08 | 2008-07-17 | University Of Regina | Methods and apparatus for enhanced oil recovery |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EA030026B1 (en) * | 2015-11-23 | 2018-06-29 | Республиканское Унитарное Предприятие "Производственное Объединение "Белоруснефть" | Method for development of a saline low-permeable oil formation |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| RU2001254C1 (en) * | 1990-07-13 | 1993-10-15 | Институт горного дела СО РАН | Method for wave treatment of strata |
| RU2063507C1 (en) * | 1992-12-28 | 1996-07-10 | Акционерное общество закрытого типа "Биотехинвест" | Method for gas production from a seam with a trap |
| US5396955A (en) * | 1993-11-22 | 1995-03-14 | Texaco Inc. | Method to selectively affect permeability in a reservoir to control fluid flow |
| RU2107814C1 (en) * | 1997-06-17 | 1998-03-27 | Общество с ограниченной ответственностью Научно-технический центр "Новые технологии" | Method and device for pulsing action on productive bed |
-
2000
- 2000-12-09 RU RU2000130962/03A patent/RU2196225C2/en not_active IP Right Cessation
-
2001
- 2001-10-17 CA CA002398393A patent/CA2398393A1/en not_active Abandoned
- 2001-10-17 CN CN 01804496 patent/CN1398321A/en active Pending
- 2001-10-17 WO PCT/RU2001/000425 patent/WO2002046578A1/en active Application Filing
- 2001-10-17 MX MXPA02007706A patent/MXPA02007706A/en unknown
- 2001-10-17 GB GB0218277A patent/GB2377956A/en not_active Withdrawn
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2002
- 2002-08-06 NO NO20023710A patent/NO20023710L/en not_active Application Discontinuation
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2008083471A1 (en) * | 2007-01-08 | 2008-07-17 | University Of Regina | Methods and apparatus for enhanced oil recovery |
| US8534352B2 (en) | 2007-01-08 | 2013-09-17 | University Of Regina | Methods and apparatus for enhanced oil recovery |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1398321A (en) | 2003-02-19 |
| RU2196225C2 (en) | 2003-01-10 |
| NO20023710L (en) | 2002-09-04 |
| MXPA02007706A (en) | 2002-10-11 |
| WO2002046578A1 (en) | 2002-06-13 |
| GB2377956A (en) | 2003-01-29 |
| NO20023710D0 (en) | 2002-08-06 |
| GB0218277D0 (en) | 2002-09-11 |
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