RU2191896C2 - Method of treating bottom-hole formation zone - Google Patents

Abstract

FIELD: oil and gas producing industry. SUBSTANCE: method may be used in cleaning of bottom-hole formation zones from colmatage materials in completion, reanimation and increase of productivity of wells operated under complicated conditions, inclined and horizontal wells and side holes of operating wells, in water wells, and also in mineral borehole mining. Claimed method includes vibrowave treatment of bottom-hole formation zone with use of vibration hydrodynamic generator, reduction of bottom-hole pressure to below formation pressure with simultaneous vibrowave treatment and increase of pressure in absence of treatment. Pressure is reduced and raised by cycles. Hydrodynamic testing of bottom-hole zone is performed in initial, final and at least in one intermediate cycles. Treatment conditions are adjusted by testing results. In cycle of pressure reduction, treatment conditions are corrected. Set of obtained parameters is used for adoption of decision on necessity of reagent; injection or ceasing of treatment cycles. EFFECT: increased economic efficiency of well treatment due to optimization of treatment hydrodynamic conditions, improved quality of cleaning, reduced power and production expenditures. 20 cl, 1 ex

Description

 The invention relates to the oil and gas industry and can be used to clean the bottom-hole formation zone (PZP) from clogging materials during development, resuscitation and increasing productivity of wells, in particular wells operating in difficult development conditions, as well as horizontal and horizontal wells and second shafts of existing wells , water wells, in addition, can be used in the mining industry to initiate and intensify downhole hydraulic mining of minerals, glands s ores, molybdenum, diamond, and others.

 A known method of multi-cycle pulsed impact on the reservoir with the cleaning of the borehole zone (RF Patent 2136874, CL E 21 B 43/25, publ. In B. I. 25, 1999). The disadvantage of this method is the low cleaning efficiency of the bottomhole zone in complicated operating conditions of the wells due to the short duration of the cycles of repression and depression and their strong attenuation over time.

 Closest to the proposed invention is a method of processing the bottom-hole formation zone (RF Patent 2128770, class E 21 B 43/25, published in B.I. 10, 1999), according to which at the initial stage of the treatment cycle increase the pressure on the bottom wells, limiting it to the hydraulic fracturing pressure, and support it for the time necessary to establish a piezometric curve. After repression, they quickly reduce the pressure on the face below the reservoir, while producing a vibro-microwave effect by a hydrodynamic generator. The disadvantage of this method is the not very high processing efficiency associated with the inconsistency of the repression, depression and vibration exposure to the change in the state of the bottom-hole zone that occurs during processing, which does not allow to make the necessary corrections to the technological modes, to optimally assign any additional operations, rationally limit processing time and carry out effective commissioning of a well after it, reduce energy consumption you. It also narrows the scope of the method for objects and reservoir conditions.

 The objective of the invention is to increase the efficiency of the method by controlling the processing regimes, providing optimal indicators of depression and microwave exposure based on controlled parameters characterizing changes in the filtration properties of the bottomhole zone, expanding the scope of application by categories of wells and reservoirs, reducing energy costs.

 The problem is solved in that in the method for processing the bottom-hole zone of the formation, including vibrating the wave using a hydrodynamic generator, reducing the pressure at the bottom of the well below the formation with simultaneous vibration and the pressure in the absence of exposure, according to the invention, the pressure is reduced and increased cyclically, with in the initial, final and at least one intermediate pressure increase cycles, hydrodynamic testing of the bottom-hole zones is carried out wells, for example, by a stepwise change in pressure and fluid flow rate, on the basis of which the treatment regime is set, for example, flow-pressure and time parameters of the cycles, in the pressure reduction cycle, the treatment regime is adjusted, for example, according to the volume balance of the injected and output fluids, the difference their costs and the parameters of the latter, based on the totality of all the above parameters, decide on the need for the injection of reagents in at least one of the pressure increase cycles and / or judge the appropriateness of terminating processing cycles.

Moreover, it is possible that:
a) during processing, additionally measure the thermodynamic downhole parameters, such as pressure and temperature;
b) control the physico-chemical parameters of the outgoing fluid, for example, the content and composition of mechanical and liquid muds, the content of oil and / or gas phases;
C) additionally carry out the adjustment of the amplitude-frequency processing parameters;
d) pressure reduction at the bottom is carried out by a jet pump, the geometric parameters of which are determined depending on the depth of the formation, its hydraulic conductivity, the flow rate of the fluid through the generator, the density and viscosity of the working and formation fluids, and the structural parameters of the well;
d) the pressure at the bottom is reduced by filling the well with gas-liquid foam obtained at the bottom when using a generator of mixtures of liquids with gases, the gas content of which is determined depending on the depth of the formation, its thickness, formation pressure, the permissible degree of decrease in bottom hole pressure;
e) the vibrating microwave action is carried out by a hydrodynamic generator based on vortex centrifugal nozzles with at least two pressure steps of the opposite twist;
g) use a hydrodynamic generator, in which the amplitude and frequency of the generated oscillations varies depending on the pressure drop;
h) before processing the well, determine the depth, opening and number of previously created or already existing in the near-wellbore zone of cracks or channels that have hydraulic connection with the well, conduct a study of the properties of the well fluid, determine its density and compressibility, and perform a microwave exposure to elastic vibrations in the perforation interval with a resonant frequency calculated from the totality of the above parameters depending on the diameter of the well, its depth and depth of installation of the packer;
i) preliminary determine the coefficients of porosity, density, compressibility, shear moduli of the rock material, compressibility of the porous skeleton of the rock, density, dynamic viscosities and compressibility of saturating fluids for oil-saturated and host rocks, and the microwave action is carried out at the frequency of waveguide propagation of elastic waves in the reservoir, which calculated using the above parameters;
j) the frequency change is carried out in the range of 5-800 Hz with oscillation amplitudes at the boundary of the effective impact zone in the depth of the formation of at least 0.01 MPa;
k) as a reagent use aqueous solutions of surfactants, chemicals with an acidic or alkaline reaction, hydrocarbon solvents or their compositions;
m) in carbonate formations in a sequence of pressure reduction and pressure increase cycles, sequential multiple injections of hydrochloric acid or its solutions and / or oil acid emulsion and solvent are performed;
m) in the final cycle of increasing pressure, sediment-forming or gelling compositions are pumped;
n) well treatment is completed by filling the well with a reverse oil-water emulsion prepared at the bottom or at the wellhead when pumping water-oil mixtures through a vortex hydrodynamic generator;
o) in one of the cycles of increasing pressure by pumping a working fluid through an oscillation generator, hydraulic fracturing is performed with the possibility of fixing cracks from closing;
p) continuously monitor the hydrodynamic parameters over time using an automated multi-channel recording device, for example, based on microprocessor technology;
c) the vibrating microwave effect is carried out by a hydrodynamic generator mounted on a flexible pipe lowered into the well.

 The essence of the invention consists in cyclically repeating repression, depression, and microwave exposure, while to ensure optimal performance of these effects at the beginning of processing, information is obtained on the current state of the bottomhole zone of the well. Hydrodynamic testing, carried out, for example, by stepwise increasing the injection pressure, allows you to determine indicator charts and, using automated systems and computer technology, quickly evaluate the filtration characteristics, for example, productivity coefficient and / or hydraulic conductivity of the well, and change the pressure and flow parameters of the working fluid injection to configure work hydrodynamic generator for optimal operation. In addition, the levels of absorption and inflow are estimated, which allows us to determine the optimal values of the created cycles of repression and depression on the reservoir, the duration of these cycles and to provide the most complete coverage of the bottomhole zone in depth with the required level of depression.

 With the optimal operating mode of the generator, resonant excitation of the borehole and reservoir systems and the most complete transfer of elastic vibrational energy to the reservoir occur. Along with the deep coverage of the bottom-hole zone in depth with the necessary level of depression, this leads to the most profound and effective impact on the formation.

In terrigenous reservoirs, the following occurs:
- reducing the strength of the "fillers" of the porous medium, the clogging material, clay inclusions and cleaning the pore channels of the reservoirs, eliminating the blocking effect of the residual phases of gas, oil and water, initiating the filtration of fluids in unreached layers and zones, increasing the coverage of the formation both in thickness and in thickness strike;
- improving the filtration characteristics of sealed reservoirs,
- faster and deeper penetration of solutions of chemicals, foams and emulsions into the reservoir,
- equalization of reaction rates in zones with different phase saturation,
- effective dissolution and removal of carbonate cement and clay, as well as secondary reaction products from the bottomhole zone,
- increasing the efficiency of the interaction of solvents with the surface of the skeleton of the rock and cleaning the bottom-hole zone of asphalt-resinous-paraffin deposits.

In carbonate reservoirs occurs:
- faster and deeper penetration of solutions of chemical reagents, foams and emulsions into the formation, while due to the acceleration of their penetration into the pores and cracks of the productive rocks, an increase in the depth and efficiency of processing the formation occurs without the use of special chemical inhibitors of the reaction;
- equalization of reaction rates in water and oil zones;
- expansion of existing and the creation of new microcracks in the bottomhole zone;
- effective interaction of reagents and solvents with the surface of the skeleton of the rock;
- cleaning the bottom-hole zone of asphalt-resinous-paraffin deposits;
- dissolution and removal of the carbonate component without the accumulation of insoluble secondary reaction products in the pores of the formation;
- alignment of the inflow profile and throttle response.

 When creating the necessary level of depression, the polluting components are effectively carried out by the filtration flow into the well and removed with the fluid flow at the wellhead. A maximum radius radius of effective well treatment is achieved.

 During processing in pressure reduction cycles, the described processing parameters are adjusted, for example, according to the volume balance of the injected and discharged fluids, the difference in their flow rates and the estimated parameters of the fluid exiting the well. This correction quickly takes into account the changes occurring in the bottom-hole zone and allows optimal control of the treatment for based on the "response" of the well to the impact. To clarify the incoming information, hydrodynamic testing can be repeated. The information obtained during processing allows us to make a conclusion about the need for injection of the reagent, at least in one of the pressure increase cycles and to judge by the achievement of certain filtration indicators of the bottomhole zone on the advisability of terminating the processing cycles.

 The combination of the above operations allows you to expand the scope of the method for the categories of wells and the conditions of occurrence of productive formations. Wells can be effectively processed for which geological and technological information on the status of the reservoir is incomplete or absent, exploratory wells, water wells, wells revealing deposits of solid minerals, iron ore, etc.

 Thanks to the optimal assignment of cycle times and the control completion of processing, energy costs for its implementation are significantly saved.

 It is advisable during the processing to additionally measure thermodynamic downhole parameters, such as pressure and temperature. The information obtained allows us to more fully evaluate the performance of the repression and depression cycle, as well as to carry out accurate hydrodynamic testing. The change in temperature assesses the change in the nature of the influx or absorption of the formation and judges the presence of contaminated zones in the near-wellbore region.

 It is also advisable to control the physico-chemical parameters of the effluent, for example, the content and composition of mechanical and liquid muds, the content of oil and / or gas phases. This allows us to judge the state, degree and nature of the contamination of the bottom-hole zone, on the basis of which to determine the feasibility of injecting reagents, their physico-chemical purpose and the required volumes.

 An additional implementation of tuning the amplitude-frequency processing parameters is possible. During processing, depending on the condition of the bottom-hole zone, it may be necessary to change the depth of the impact or conduct a new stage, for example, reagent injection into the formation, in this case, the design characteristics of the generator are tuned for optimal amplitude-frequency characteristics of the generation of elastic vibrations in new conditions.

 It is advisable to reduce the pressure at the bottom with a jet pump, the geometric parameters of which are determined depending on the depth of the formation, its hydraulic conductivity, the flow rate of the fluid through the generator, the density and viscosity of the working and formation fluids, and the design parameters of the well.

 Downhole pressure can be reduced by filling the well with gas-liquid foam obtained at the bottom when using mixtures of liquids with gases as the working fluid of the generator, the gas content of which is determined depending on the depth of the formation, its thickness, formation pressure, and the permissible degree of decrease in bottomhole pressure. This is especially useful when processing wells where there are difficulties due to the design features of the wells.

 Based on the aforementioned, known before processing and controlled parameters obtained during it, the optimal geometric characteristics of the jet pump are calculated, which works in conjunction with a hydrodynamic generator, allowing to produce specified amplitude-time levels of pressure reduction at the bottom. The calculation is made according to a special computer program available to the inventors. The program takes into account changes in the operating conditions of the jet pump depending on the depth of the formation, its filtration properties, physical properties of the working and reservoir fluids, the flow rate of the fluid through a hydraulic generator, the sizes of the well design and the injection lines used. Operational adjustment of the jet pump. Correction of its work can be done by changing the pressure-flow characteristics of the injection of the working fluid or a stepwise change in its geometric characteristics.

 An important advantage of the use of gas-liquid foams is the possibility of applying the method in deviated horizontal, horizontal wells and second wellbores, where the technical operations of landing the packer are impossible or extremely difficult, which eliminates the use of a jet pump to create depression on the formation. In addition, the elastic properties inherent in foam systems, as well as their increased viscosity and retention ability, make it possible to very effectively, in combination with the action of elastic vibrations, clean the production interval of horizontal wells from drilling mud in the gap between the cementless filter and the wall of the open hole, as well as remove clay cake formed on the wall of the well, highly densified due to adsorption and molecular bonds between clay particles. It is possible to control the magnitude of the depression and create a predetermined depression at adjustable time intervals, to take into account the weak cementation of the collectors, the location of the bottom water or gas cap. One of the properties of the foam is its elasticity. Due to the compression of the gas phase, the foam column has a large reserve of elastic energy, which manifests itself in the phenomenon of foam self-spill. An important advantage of using foam systems is the ability to pump foam and create depression on the formation under conditions of high absorption. The level of depression created is regulated by changing the degree of gas supply to the injected working fluid. The mixture of gas and water supplied via the injection line passes through a hydrodynamic generator, and a finely dispersed foam is formed at its outlet, filling the well space, which is responsible for the formation of hydrostatic pressure on the formation. Gas injection parameters for specific well treatment conditions, taking into account the characteristics controlled during processing — formation thickness and the permissible degree of depression — are calculated using the computer program available to the inventors.

 It is advisable to carry out a vibrating microwave action with a hydrodynamic generator based on vortex centrifugal nozzles with at least two pressure steps of the opposite twist. Such a generator has increased generation efficiency in a wide range of changes in the pressure-flow rate parameters of the working fluid injection, works stably, starting from the relatively small initial values of these parameters, and has a high hydraulic-acoustic efficiency. This allows you to very effectively use this design for a wide range of technological operations of the microwave action when working together with other devices that consume hydraulic energy, for example, jet pumps, while the equipment parameters can be adjusted using the computer program for optimal operation for each well-formation system. The relatively small working flow rate and pressure drop when producing sufficiently powerful oscillations make it possible to efficiently use this generator to regenerate filters for water wells and increase their productivity using simple pumps or pumping units, and at a lower total cost to carry out a depressive effect using a jet pump.

 With the appropriate settings, the amplitude and frequency of the generated oscillations can vary depending on the pressure drop, which allows targeted control of the parameters of the microwave exposure and depression when processing the bottom-hole zone depending on the degree and depth of its contamination.

 Before treating a well, one should determine the depth, opening and number of previously created or already existing in the near-wellbore zone of cracks or channels that have hydraulic connection with the well, conduct a study of the properties of the well fluid, determine its density and compressibility, and perform a microwave exposure to elastic vibrations in the perforation interval with resonant frequency, calculated from the combination of the above parameters, depending on the diameter of the well, its depth and depth of installation of the packer. In this case, the processing efficiency increases due to the improvement of the filtration characteristics of the bottomhole zone, associated with the occurrence of intense resonant flow pulsations in the channels or cracks.

 The coefficients of porosity, density, compressibility, shear moduli of the rock material, compressibility of the porous skeleton of the rock, density, dynamic viscosities and compressibility of saturating fluids should be determined for oil-saturated and host rocks, and the microwave exposure should be carried out at the waveguide frequency of elastic waves in the reservoir, which is determined according to the patterns of spatial-energy distribution of the field of elastic vibrations in the reservoir, calculated by a special computer program IU, available to the inventors, using the above parameters. In this case, the depth and effectiveness of the action of elastic vibrations significantly increase.

 The most noticeable manifestation of the effect of cleaning the porous medium from mechanical and clay muds is observed in the frequency range of the microwave action of 5-800 Hz, while the amplitudes of elastic vibrations should not be less than 0.01 MPa. Original experimental studies of the authors found that outside the proposed frequencies, the cleaning efficiency is significantly reduced, and decolmating mechanisms in porous media begin to appear when the threshold level of fluctuations of 0.01 MPa is exceeded.

 As chemical reagents it is useful to use solutions of surface-active substances (surfactants), solutions of acids, alkalis, salts with an acidic or alkaline reaction, hydrocarbon solvents or their composition. The use of these chemicals for processing is based on their interaction with the minerals of the solid phase of the reservoir and the liquid and solid colmatants deposited in the bottomhole zone. The action of solvents leads to a change in the properties or state of oil and heavy and solid components - resins, asphaltenes and paraffin, which, when the thermodynamic state changes, form deposits in the pore channels such as paraffin, asphalt, resin and paraffin. By liquefying, dissolving and washing them off the surface of the minerals, an increase in the permeability of the collector is achieved and the effectiveness of the chemical acid or alkaline effect is increased. When diluting the working fluid - oil, its viscosity decreases and dissolving activity increases, as well as the pressure loss on the equipment decreases, which leads to a decrease in hydraulic power, lower fuel consumption or increased efficiency of use of pumping units. To increase the efficiency of solvents or oil as active agents, oil-insoluble surfactants can be dissolved in them.

 The action of surfactants is quite multifaceted, aimed at changing and regulating the molecular-surface properties of the oil, water, gas and reservoir in contact with each other and significantly increases the efficiency of the method. The surfactants used are selected according to heat resistance in accordance with reservoir temperature and physico-chemical compatibility with the reservoir and the working fluid. They are also used as additives in the working fluid to improve bottom hole cleaning and reduce hydraulic pressure losses on the suspension of tubing, as well as in compositions with acidic, alkaline and other reagents.

 The use of specific chemical reagents depends on the geological and physical conditions, the category of wells, lithological characteristics, type, clay and carbonate of the reservoir, the degree of colmatization of the bottomhole zone, the nature of the mud, etc.

 For the treatment of producing wells revealing carbonate formations, it is advisable to sequentially repeatedly inject hydrochloric acid or its solutions and / or oil acid emulsion and solvent in a sequence of pressure reduction and pressure increase cycles. Such operations cause effective cavern accumulation in the near-wellbore zone of the formation and a significant increase in oil production. Along with the initiation of the extraction of colmatizing materials and reaction products from the reservoir, the vibratory microwave action here introduces a regulatory function: due to the intensification of the filtration processes, the depth of the reaction zone and the coverage of the formation by the thickness increase simultaneously increase. During the aforementioned cyclic operations, the cavity formation process occurs uniformly in the entire volume of the bottomhole formation zone, including in its regions remote from the well, which leads to a noticeable increase in processing efficiency.

 For wells that open up stratified heterogeneous oil deposits (terrigenous or carbonate reservoirs), where water breaks out quickly during flooding or gas breaks out of the gas cap through interlayers with increased permeability, it is advisable to pump sediment-forming or gel-forming compositions in the final cycle of increasing pressure when pumping components through the generator. At the same time, effective isolation of gas manifestations in wells is achieved. The microwave action contributes to the disintegration of particle aggregates in the pore channels and initiates the filtration of suspensions of these particles. Therefore, the penetration into the pore channels of sediment-forming mixtures and compositions containing dispersed particles is intensified, the processes of particle integration, the formation of impermeable “crusts” on the surface of perforation channels and “blockage” of the porous medium in the near-barrel zone are slowed down. Along with this, elastic vibrations have a positive effect on gelation, reduce premature viscoelasticity, and improve the adhesion of the insulating material to the rock surface. In addition, the decrease in the amount of bound water in the PZP pores that occurs during vibrational stimulation intensifies the course of chemical reactions and significantly strengthens the “screens” formed during processing.

 The combination of mixing agents and the microwave action during the injection of insulating mixtures makes it easier to introduce them into the formation with a more uniform and deeper filling of the pore space and the reservoir structure, in addition, the pressure on which the agents are pumped by pumping units and the injection rate increase. Due to the manifestation of a combination of effects in this combination, it becomes possible to combine compositions and save basic insulating materials.

 It is advisable at production wells, in particular on carbonate formations, to complete the treatment by filling the barrel with reverse oil-water emulsion, prepared at the bottom or at the wellhead when pumping water-oil mixtures through a vortex hydrodynamic generator. This allows you to significantly reduce the negative effects of jamming, to ensure high quality subsequent commissioning of the well.

On reservoirs with low permeability of the order of 10 ^-2 μm ² and lower and / or with reservoir properties close to the conditioning limit, it is advisable in one of the pressure increase cycles to produce hydraulic fracturing by pumping a working fluid through an oscillation generator with the possibility of fixing cracks from closing. The formed cracks can be fixed using known methods, for example, by pumping a suspension of sorted sand fraction. The pressure fluctuations excited by the generator at the bottom of the well create elastic deformations in the near-wellbore zone, which contribute to the formation of microcracks and the primary hydraulic fracture at significantly lower pumping fluid injection pressures, when the crack is fixed, the sand fraction is transported deeper and more evenly distributed in it, thereby there will be more of their residual openness and hydraulic fracturing efficiency.

 It is most preferable to continuously monitor in time the hydrodynamic and other (for example, density, temperature, viscosity of the working fluid) process parameters using an automated multi-channel recording device based on microprocessor technology. This allows you to document the work on the well, to automatically calculate the hydrodynamic parameters of the bottomhole formation zone, energy and time costs, reduce the cost of processing by reducing the number of hydrodynamic and geophysical studies.

 The vibrating action by a hydrodynamic generator mounted on a flexible pipe allows continuous movement of the generator to efficiently process formations, zonal intervals of large thickness, as well as extended sections of horizontal wells.

 The method is as follows. For the selected well, an analysis of the geological and technical characteristics and production data is performed and the method of creating depression on the formation, for example, using a jet pump, is selected. A hydrodynamic generator, for example, made on the basis of vortex centrifugal nozzles with two steps of the opposite twist, is chosen as a generator for vibrating microwave action. They calculate depending on the depth of the formation, its hydraulic conductivity, the flow rate of the fluid through the generator, the density and viscosity of the working and formation fluids, the design parameters of the well, the permissible depression on the formation, and other geometric parameters and the range of operating modes of the jet pump. Prepare and adjust the jet pump and generator before they are lowered into the well. An oscillation generator, a jet pump, a packer and, if necessary, documentation of downhole parameters, an autonomous multi-day depth device, for example, a manometer-thermometer-densitometer, are lowered into the well in the interval of the formation on tubing (tubing). Packer is planted and wellhead or preventer installed. From the annular valve, a flow line is laid in a container with a working fluid, for example a groove tank. A pumping unit is connected to the tubing with the help of the discharge pipe, in which the end of the receiving sleeve with the filter is lowered into the groove tank. On the discharge and discharge lines, flow meters of injected and discharged liquid are installed, as well as pressure and annular pressure sensors, which are connected to an automated multi-channel recording device, which may include a microcomputer. Surfactants are added to the working fluid.

First, at medium speeds of the pumping unit, the wells are topped up until circulation appears. The reservoir pressure is determined from the expended fluid volume V [m ³ ], density ρ [kg / m ³ ], known well depth N [m] and specific volume of the internal space of the well Vc [m ^{3 /} pog.m] by the formula:
Rpl = ρg (HV / Vc) • 10 ^-6 [MPa],
where g = 9.81 m / s ² is the acceleration of gravity.

Then the annulus is closed and hydrodynamic testing is carried out by 3-5 step injection while maintaining Q [m ³ / day] or wellhead pressure Rust [MPa] for 5-10 minutes at each stage, starting from the lowest to the highest possible flow rate pump unit or to the maximum allowable pressure on the strength of the production string or wellhead fittings. According to the measured pressure values at each stage, the repression dP on the reservoir is calculated by the formula:
dP = ρgH • 10 ^-6 + Pyst-Ppl [MPa],
build an indicator chart as a function of dP = f (Q) and calculate the productivity coefficient by the formula:
KPR = tan α = Q / dP [m ³ / day • MPa],
where α is the angle of inclination on the indicator line.

 After that, the injection is stopped and the dynamics of the pressure drop is monitored for a qualitative assessment of the filtering properties of the PPP. Using well-known methods of processing the measurement results, a graph is plotted in the coordinates dP-Ln t, where t is the time, and other parameters of the bottomhole formation zone are evaluated (hydraulic conductivity, piezoconductivity, permeability of the borehole zone, etc.). The data obtained are the source for subsequent testing.

Once again, injection into the reservoir is started at the maximum permissible pressure (repression cycle), and after stabilization of the flow rate, the annulus is opened and the pump unit is brought to the injection mode at pressure P ₁ and flow rate Q ₁ , which corresponds to the minimum of the calculated range of pressure-flow rate parameters of the jet pump and generator.

 In order to increase the efficiency of PZP treatments, it is useful to carry out a vibrating microwave effect in combination with exposure to heat and / or physical fields, for example magnetic, electric. The thermal effect should mainly be used for deposits in the bottom-hole zone of paraffin, asphalt-resinous substances or “oxidized” oil, as well as in the treatment of formations with increased oil viscosity and low formation temperature. In these cases, it is useful to combine with exposure to an electric field. The magnetic field is useful for treating formations with increased clay content and in the deposition of salts and paraffin. When combined with physical and vibrational fields, along with “field” and vibrational fields, additional mass transfer and thermodynamic effects will occur that contribute to improving the efficiency of cleaning PZP from clogging materials of various nature and increase the overhaul period.

 Under certain conditions, it is advisable to put the well into operation through a generator installed on the bottom. This can be done, for example, in the event of a danger or transition of the well to gushing during or after development after drilling, as well as when treating a layered formation with several interlayers separated by clays, when killing with water is undesirable, and a previously undeveloped formation or interlayers increased reservoir pressure. The generator left in the well will not have a significant effect on its fountain operation. Subsequently, it is possible to re-stimulate the operation of the well without carrying out tripping operations. The need can also arise when there is an increased likelihood of deposition of asphalt-resinous substances, salts and paraffin, as well as when processing injection wells to maintain injectivity at an acceptable level and / or a microwave exposure to the formation. To increase the efficiency of work, the resonant properties of the generator-well-reservoir system can be realized.

The volume of the annular gap between the column and tubing (annulus) V _to and the flow rate Q ₁ calculate the time t = V _to / Q ₁ when the first portions of the bottomhole fluid will reach the mouth and it will be possible to take the first sample of the outflowing fluid. Subsequent samples are taken every 10-30 minutes depending on the intensity of inflow and outflow of colmatant. The color and component composition of the liquid (the presence of solid and soft particles, emulsion, gas, etc.) and the amount of sediment are visually assessed in the selected samples. It is advisable to use a chemical laboratory field kit and use a centrifuge to perform an express analysis of the amount of suspended particles (EHF) and evaluate its mineral composition.

 The flow difference dQ from the reservoir is estimated by the difference in the costs flowing from the annulus and the pumped fluid or by a change in the level in the trough. In the absence of inflow and outflow, the mode is adjusted by incrementally increasing the flow rate of the pump unit.

 When stabilizing the inflow from the reservoir and decreasing the EHF in a row, in the last two of the series of samples, taking into account the achieved value of the inflow, a decision is made to conduct a repression cycle. With a sufficiently large increase in the inflow and outflow of colmatant, the repression cycle can be combined with hydrodynamic testing. The obtained value of the pick-up coefficient is compared with the initial one to estimate the rate of its increase, and by comparing with the maximum value, the degree of PZP cleaning is estimated by the operation history. Based on this, they decide on the continuation of the cycles or the need for the injection of reagents, their types and quantities.

 After the injection of reagents, cycles of depression and repression are performed according to the procedure described above. At the final stage, hydrodynamic testing is carried out. Then, the final work is carried out to extract the downhole equipment and put the well into operation. After extracting the deep device, the readings are decrypted and, using well-known techniques, the PPP parameters are estimated.

An example of the method
The injection well with a depth of 1745 m reveals a sand-siltstone heterogeneous in permeability in the perforation interval of 1701-1706 m. The reservoir pressure is 16 MPa. The reservoir temperature is 30 ^o C. Production string 146 mm (2.5 ").

After development for the injection of wastewater over 4 years, the injectivity of the well decreased from 500 m ³ / day to 100 m ³ / day at an injection pressure of 6 MPa, respectively, the injection rate from 59.84 to 11.94 m ³ / day • MPa. A decision is made to produce a microwave exposure to a generator of the type GD2V-3, having a working flow rate of 3 dm ³ / s, and to create depression with the help of a jet pump of the type IS-3. The working fluid is wastewater with the addition of surfactants of type AF9-12 according to TU38.507-63-171-91 in an amount of 5 kg / m ³ . The geometrical and operational parameters of the jet pump, generator are calculated according to a computer program, and their preparation and adjustment are carried out before being launched into the well.

 An oscillator with a two-vortex centrifugal nozzle type GD2V-3, a jet pump and a mechanical packer type PV-M-118-350 are lowered into a well at 73 mm (2.5``) tubing (tubing) to a depth of 1703 m. Packer is planted and wellhead piping is installed. From the annulus, a flow line is laid in a container with a working fluid (gutter tank). Using the discharge pipe, a pump unit of the SIN-31 type is connected to the tubing, at which the end of the receiving sleeve is lowered into the groove tank. On the discharge and discharge lines, flow meters of injected and discharged liquid are installed, as well as discharge and annular pressure sensors, which are connected to an automated multi-channel recording device, which includes a microcomputer.

First, at medium speeds of the pumping unit, wells are added. Spent fluid volume V = 2.5 m ³ . According to the fluid density ρ = 1100 kg / m ³ , the known well depth N and the specific volume of the internal space of the well (for 146 mm production casing and 73 mm tubing Vc = 0.01175 m ^{3 /} pog.m), the reservoir pressure is determined by the formula:
Rpl = ρg (HV / Vc) = 1100 • 9.81 (1701-2.5 / 0.01175) • 10 ^-6 = 16.06 MPa,
which turns out to be close to field data.

Then the annulus is closed and hydrodynamic testing is carried out by stepwise injection while maintaining flow rates of 100, 130, 170 and 200 m ³ / day for 5-10 minutes at each stage, while the wellhead pressure Rust amounted to 6.5, 9, 12.5, respectively and 15 MPa. The calculated productivity coefficient Knp = tg α = Q / dP = 11.31 m ³ / day • MPa, where α is the angle of inclination on the indicator line, dP = ρgH • 10 ^-6 + Pyst-Ppl is repression to the formation, which is slightly less indicated in the characteristics of the well, and this could happen due to additional mudding of the bottomhole zone by particles during tripping and washing the face during preparation for processing. After that, the injection is stopped and the dynamics of the pressure drop is monitored for a qualitative assessment of the hydraulic conductivity of the PPP. The data obtained are the source for subsequent testing.

The injection is again switched on at a pressure of 15 MPa (repression cycle), and after stabilization of the flow, the annulus is opened and the pump unit is put into discharge mode at a pressure of P = 15 MPa and a flow rate of Q = 9.5 dm ³ / s, which corresponds to the minimum of the calculated pressure-flow range operating parameters of the jet pump and generator. With the volume of the annular gap between the column and tubing (annulus) Vc = 15.3 m ^{3, the} first portions of the bottomhole fluid will come to the mouth after a time t = V _to / Q = 15300 / 9.5 = 1615 s = 27 min, so the first test Leaking fluid is taken after 30 minutes and subsequent samples every 15 minutes. By the change in the liquid level in the gutter tank and the difference in the discharge flow rates, the fluid inflow from the formation is estimated at 10 dm ³ / min. In sample 2, a black precipitate was found with a reddish tint in an amount of about 0.5%. In subsequent samples 3 and 4, the sediment gradually increased to 1.5%, and in samples 5 and 6 it gradually decreased to 0.5%. The inflow from the reservoir after 1 h 45 min of exposure increased to 12 dm / min and stabilized. Based on these data, a conclusion is drawn on the need for a repression cycle and adjustment of the treatment regimen. With a closed annulus, injection is carried out at a flow rate of 250 m ³ / day until the wellhead pressure is established for 15 minutes, while the pressure is 15 MPa and the estimated pick-up coefficient is 14.5 m ³ / day • MPa, the increase of which indicates the cleaning of the near-trunk zone. After another 15 min of injection, the annulus opens and the pump unit is brought to the discharge mode with a flow rate of 10 dm ³ / s at a pressure of P = 16 MPa. After 30 min, sample 7 is taken, the precipitate is 1.5%. The flow of fluid increases to 16 DM ³ / min. In subsequent samples 8, 9 and 10, the sediment consistently increased to 3.5%, in samples 11 and 12 it decreased to 3%, and in sample 13 it was 0.5%, while in the samples the color of the precipitate acquired a reddish-gray tint and appeared film of "oxidized" oil. The inflow from the reservoir in 1 h 45 min of exposure increased to 21 dm ³ / min and stabilized. A prolonged yield of colmatant and a significant increase in inflow indicate that the treatment regime is close to optimal, and a color change indicates the extraction of drilling fluid and / or clay material from the reservoir and the residual oil from the less permeable layers bypassed by injection.

Hydrodynamic testing is carried out by step injection with flow rates of 170, 200, 250 and 300 m ³ / day, while the pressure was 1.4, 2, 3.2 and 4.3 MPa, respectively. The calculated average pick-up coefficient is 45.1 m ³ / day • MPa. Since the injectivity value, which was after being developed for water injection, was not reached, a decision was made to inject the solvent and hydrochloric acid at 0.5 m ³ per 1 meter of formation thickness, i.e., 2.5 m ³ . The basis for such a solution is the appearance of an oil film and the presence of iron oxides introduced by injected water and deposited on the surface of the sandstone. The solvent is designed to remove the oil film from the surface of the pore channels, and as a result, a soluble salt is formed in the chemical reaction of hydrochloric acid with iron oxides. Since the volume of the inner space of the tubing is 5.1 m ³ , and the total volume of the reagents is 5 m ³ , the solvent and acid can be sequentially pumped into the tubing without fear of their entry into the annulus, and then pushed into the formation in one go. The oil solvent Nefras-A-150/330 is used in accordance with TU 38-1011049-87E and an aqueous solution of 12% concentration of hydrochloric acid inhibited in accordance with TU 39-06765670-OP-212-95.

With an open annulus, nefras is pumped using a pumping unit, then an acid solution is used with an acidic unit such as Azinmash-30A. The annulus closes and water is pushed into the reservoir in a volume of 5.5 m ³ with a flow rate of 300 m ³ / day. The initial selling pressure is 4.5 MPa, the final 3.1 MPa, and the recorded dynamics of the process showed at first an increase in pressure to 5.5 MPa, and by the end of the injection, a rapid decrease in pressure, which indicates the success of the operation. The well is left to react for 4 hours. After that, the annulus is opened and the pump unit is brought to the discharge mode with a flow rate of Q = 11 dm ³ / s at a pressure of P = 16.5 MPa. After 30 minutes, sample 14 was taken. A black precipitate of approximately 1% was detected. In subsequent samples 15 and 16, the precipitate increased to 1.5% and flakes appeared, characteristic of the acid reaction products. In sample 17, the sediment decreased to 0.5%, and in 18 and 19, water bleached gradually and a nephras film with dissolved oil appeared. The inflow from the reservoir increased from 21 to 32 dm ³ / min and stabilized at this level. A stable flow-pressure mode of operation of the pumping unit, a stabilized inflow, water clarification and the appearance of nefras in the samples serve as the basis for completing the treatment, but for the final decision, hydrodynamic testing is required, which is carried out according to the above procedure. With a stepwise change in the flow rate of 300, 400, 500 and 600 m ³ / day, the injection pressure was 1.8, 3.2, 4.6 and 6 MPa, respectively. The calculated pick-up coefficient was 71.5 m ³ / day • MPa. Thus, as a result of complex processing, the injectivity was not only restored, but even exceeded the initial one after development for water injection due to the high-quality cleaning of the PPP from the clogging materials introduced into it during a long injection, extraction of drilling mud residues, i.e. retrofitting, and connecting to work low-permeability layers not covered by filtration. A study carried out after equipment extraction by flow metering showed that the injectivity profile was 100%, i.e. the entire thickness of the formation became covered by the injection.

 The use of the invention allows to significantly increase the profitability of well treatments by optimizing the hydrodynamic regimes in the process, improving the quality of cleaning, reducing hydrodynamic and geophysical studies, energy and labor costs, the timing of repair of wells, as well as optimizing the consumption of chemicals, increasing productivity and working conditions. In addition, the quality of putting production wells into operation improves, the coverage of the impact zone increases, and the efficiency of hydraulic mining of minerals increases.

Claims (20)

 1. The method of processing the bottom-hole zone of the formation, including vibrating the wave using a hydrodynamic oscillation generator, reducing the pressure on the bottom of the well below the formation with simultaneous microwave exposure and increasing the pressure in the absence of exposure, characterized in that the pressure is reduced and increased cyclically, while the initial, final and at least in one of the intermediate pressure increase cycles, hydrodynamic testing of the bottom-hole zone of the well, for example, By changing the pressure and flow rate of the liquid, on the basis of which the processing mode is set, for example, flow-pressure and time parameters of the cycles, the processing mode is adjusted in the pressure reduction cycle, for example, according to the volume balance of the injected and exhausted liquids, the difference in their flow rates and the parameters of the latter , based on the totality of all the above parameters, decide on the need to pump the reagent in at least one of the pressure increase cycles, and / or judge whether shortening of processing cycles.  2. The method according to claim 1, characterized in that during processing, additionally measure the thermodynamic downhole parameters, such as pressure and temperature.  3. The method according to claim 1 or 2, characterized in that the physicochemical parameters of the outgoing liquid are controlled, for example, the content and composition of mechanical and liquid colmatants, the content of oil and gas phases.  4. The method according to any one of claims 1 to 3, characterized in that it further adjusts the amplitude-frequency processing parameters.  5. The method according to any one of claims 1 to 4, characterized in that the pressure at the bottom is reduced by a jet pump, the geometric parameters of which are determined depending on the depth of the formation, its hydraulic conductivity, the flow rate of the fluid through the generator, the density and viscosity of the working and formation fluids , design parameters of the well.  6. The method according to any one of claims 1 to 5, characterized in that the pressure at the bottom is reduced by filling the well with gas-liquid foam obtained at the bottom when using a generator of mixtures of liquids with gases, the gas content of which is determined depending on the depth of the formation , its thickness, reservoir pressure, the permissible degree of downhole pressure reduction.  7. The method according to any one of claims 1 to 6, characterized in that the microwave action is carried out by a hydrodynamic generator based on one or twin centrifugal vortex nozzles with at least two pressure steps of the opposite twist.  8. The method according to any one of claims 1 to 7, characterized in that the microwave action is carried out by a hydrodynamic generator, in which the amplitude and frequency of the generated oscillations vary depending on the pressure drop.  9. The method according to any one of claims 1 to 8, characterized in that before processing the well, the depth, opening and number of cracks or channels previously created or already existing in the near-wellbore zone having hydraulic connection with the well are determined, a study of the properties of the well fluid is carried out, determine its density and compressibility, and the vibrating microwave effect by elastic vibrations is carried out in the perforation interval with a resonant frequency calculated by the totality of the above parameters depending on the diameter of the well, its depth and depth of installation of the packer.  10. The method according to any one of claims 1 to 9, characterized in that the coefficients of porosity, density, compressibility, shear modulus of the rock material, compressibility of the porous rock skeleton, density, dynamic viscosities and compressibility of saturating fluids are preliminarily determined for oil-saturated and enclosing rocks, and the microwave action is carried out at the frequency of the waveguide propagation of elastic waves in the reservoir, which is determined by the patterns of spatial-energy distribution of the field of elastic vibrations in the reservoir, calculating using the above parameters.  11. The method according to any one of claims 1 to 10, characterized in that the frequency change is carried out in the range of 5-800 Hz with oscillation amplitudes at the boundary of the effective impact zone in the depth of the formation of at least 0.01 MPa.  12. The method according to any one of claims 1 to 11, characterized in that solutions of surfactants, chemicals with an acid or alkaline reaction, hydrocarbon solvents or their compositions are used as a reagent.  13. The method according to any one of claims 1 to 12, characterized in that in the carbonate formations in a sequence of pressure reduction and pressure increase cycles, sequential multiple injections of hydrochloric acid or its solutions and / or oil acid emulsion and solvent are performed.  14. The method according to any one of claims 1 to 13, characterized in that in the final cycle of increasing the pressure, sediment-forming or gel-forming compositions are pumped.  15. The method according to any one of claims 1 to 14, characterized in that the well treatment is completed by filling the well with a reverse oil-water emulsion prepared at the bottom or at the wellhead while pumping water-oil mixtures through a vortex hydrodynamic generator.  16. The method according to any one of claims 1 to 13, 15, characterized in that in one of the cycles of increasing pressure by pumping fluid through an oscillation generator, hydraulic fracturing is performed with the possibility of fixing cracks from closing.  17. The method according to any one of claims 1 to 16, characterized in that they continuously monitor in time the hydrodynamic and other parameters, for example, density, temperature, viscosity of the working fluid, using an automated multi-channel recording device, for example, based on microprocessor technology.  18. The method according to any one of claims 1 to 17, characterized in that the microwave action is carried out by a hydrodynamic generator mounted on a flexible pipe lowered into the well.  19. The method according to any one of claims 1 to 18, characterized in that the microwave exposure is carried out in combination with exposure to heat and / or physical fields, for example, magnetic, electric, electromagnetic.  20. The method according to any one of claims 1 to 19, characterized in that the well is put into operation through a generator installed on the bottom.