Method of determining weight concentration of polymer penetrating porous medium

FIELD: chemistry.

SUBSTANCE: method comprises drying a polymer solution until complete evaporation of water; heating the polymer formed after drying the polymer solution, and determining the temperature range of active decomposition of the polymer at a given heating rate, as well as the degree of decomposition of the polymer in said temperature range; drying, performing thermal analysis in the temperature range which includes the temperature range of active decomposition of the polymer, and calculating weight loss of a weighed amount of the sample of porous medium and a weighed amount of the same sample of porous medium after pumping the polymer solution; determining the weight concentration of the polymer that has penetrated the porous medium based on the obtained values.

EFFECT: high accuracy of the obtained data and rapid analysis.

6 cl, 3 dwg

 

The invention relates to methods of analysis of samples of porous materials, in particular it can be used for a quantitative study of the deterioration of the bottomhole zone oil/gas reservoirs due to the ingress of the polymers contained in the mud.

The problem of damage of the bottomhole zone of the formation under the influence of the penetrating component of the drilling fluid (or mud) is very important, especially for long horizontal wells since the completion of most of them is in an open state, i.e. without cemented and perforated production string.

Drilling fluids are complex mixtures of polymers, particles (ranging in size from hundreds of microns to less than one micron), clays and other additives contained in the "carrier" fluid "basis" of the drilling fluid, which may be water, oil or any synthetic fluid.

In the process of drilling under the influence of excess pressure of the mud filtrate, and contained fine particles, polymers and other components penetrate into kalokairinou zone of the reservoir and cause a significant reduction in its permeability (for characterization of this phenomenon is typically used the term "damage to the bottomhole zone of the formation, or about the fact, "formation damage"). In addition, the borehole wall is formed external filtration cortex, consisting of the filtered solids and other components of the drilling fluid.

During the process of cleaning procedures well (by the gradual withdrawal of extraction) external filtration cortex is destroyed, and penetrated components of the drilling fluid partially washed away from the vicinity of the zone, and its permeability is partially restored. However, some components remains irreversibly retained in the pore space of rocks (adsorption on the pore surface, engagement in the pore narrowing and so on), which leads to a considerable difference between the initial permeability and permeability are restored after the technological procedure cleanup (usually restored permeability does not exceed 50-70% of the initial).

Common laboratory method of testing the quality of the drilling fluid is a filtration experiment on its injection into the core sample with subsequent reverse pumping (i.e., displacement penetrated the mud of the original reservoir fluid), which measured the dynamics of degradation / restoration of the permeability as a function of the number of injected pore volumes of fluids (drilling fluid or formation fluid).

However, the generally accepted laboratory shall priori method allows to measure only the integral hydraulic resistance of the core sample (the ratio of the current pressure drop across the core to the current flow), the change which is due to the growth/destruction of the outer filter cover on the side of the core and the accumulation/removal of a component of the drilling fluid in the rock.

The depth of penetration and concentration of the polymers and other components of the drilling fluid, held in the pore space after reverse pumping, represents an important information for understanding the mechanism of formation damage and select the appropriate method of increasing the productivity index of the well (minimizing damage to the bottomhole zone of the formation). These parameters are not measured under the above traditional procedures for checking the quality of the mud.

Quantitative analysis of the mechanisms of formation damage associated with penetration during drilling of polymers is of great interest because of their wide use of polymers (such as xanthan gum, carboxymethylcellulose, and so on) in modern types of drilling fluids. Technical problem relates to the difficulty of measuring small weight concentration of the polymer in a porous medium.

In U.S. patent No. 4540882 and No. 5027379 claimed methods of determining the depth of penetration of the drilling fluid using x-ray computed tomography core with the addition of a contrast agent. But the use of contrast agent, the solution is considered as the "carrier liquid", does not allow to estimate the penetration depth and the concentration of polymers and other low-contrast additives contained in the mud, because the penetration depth of the mud filtrate and these additives are in General different.

In U.S. patent 5,253,719 a method of diagnosing the mechanisms of formation damage by analyzing the radially oriented core samples taken from wells. The core samples are analyzed using a set of different analytical methods to determine the type and extent of formation damage, as well as the depth of the damage zone. Among the analytical methods listed x-ray diffraction analysis (XRD), local x-ray analysis, scanning electron microscopy (SEM), electron microscopy backscattering, petrographic analysis, optical microscopy. However, listed in the above patent methods are not applicable to change the weight concentration of polymer. On the other hand, the polymers have a weak contrast to the x-ray radiation and therefore cannot be detected using x-ray computed microtomography without the use of contrast agents.

A widespread method of measuring the amount of irreversibly retained polymer in the sample of the porous medium based on sledovatelei injection of several fringes of the polymer and the registration of their front at the exit of the sample by measuring the dynamics of the concentration in the resulting solution (see, for example, Zaitoun, A., N. Kohler Two-phase flow though porous media: effect of an adsorbed polymer layer, SPE 18085, or Zaitoun, A., Kohler N. The role of adsorption in polymer propagation through reservoir rocks, SPE-seam 16274). On the other hand, the number of retained polymer can be estimated using a mass balance is uploaded and published polymers.

The disadvantage of these methods is the need to re-upload the rim of the polymer and the measurement of the concentration of the polymer (or a special tracer, see, for example, Zaitoun, A., Kohler N. The role of adsorption in polymer propagation through reservoir rocks, SPE-seam 16274) at the exit of the sample. This significantly lengthens the time of the experiment, and for measuring the concentration of output requires periodic sampling of expiring solution or the complexity of the design of the installation.

Another significant disadvantage of the method consists in determining the total amount of irreversibly retained polymer in the entire sample of the porous medium. This value is suitable for the quantitative description only mechanism for reducing the permeability of the porous medium that is associated with the adsorption of polymer molecules on the pore walls, as in this case, if a sufficiently large volume injection (when the concentration of the polymer at the outlet of the sample constant) held the polymer is evenly distributed on the sample of porous medium.

However, if the size of the macromolecules of the polymer becomes commensurate with the Hara, the characteristic pore size of the porous medium (or in the solution are the microgels) starts to operate and a different mechanism of retention polymer macromolecules trapped in the pore narrowing, see, for example, Zitha, P. L. J., G. Chauveteau, L eger L. Unsteady-State Flow of Flexible Polymers in Porous Media, Journal of Colloid and Interface Science. 2001. Vol.234, pp.269-283. When this charged polymer is unevenly distributed along the length of the sample of the porous medium. The total number of irreversibly retained polymer in the entire sample of the porous medium in this case is not a parameter for the quantitative description of the mechanism of reducing the permeability of the porous medium.

The technical result achieved by the invention is to enable simple, fast and efficient measurement of the weight concentration of the polymer penetrated into the pore space during injection of the polymer-containing solution, without using re-download the fringes of the polymer, which significantly reduces the time of the experiment and does not require measuring the concentration at the exit of the sample. In addition, the implementation of the invention allows to measure the profile of the distribution of the weight concentration of the polymer along the sample.

In accordance with the proposed method are prepared in an aqueous solution of the polymer and dried prepared solution of the polymer at a temperature not exceeding the decomposition temperature of the polymer, until complete evaporation of water. Heat the polymer formed after drying of the polymer solution, and determine the range of those which of peratur active decomposition of the polymer at a given rate of heating, as well as the degree of decomposition of the polymer δFSin this temperature range as

δpandCl=ΔMpMp0,

where Δp- weight loss of the polymer in the temperature range of active decomposition,Mp0- the original weight of the polymer before heating.

Then dried not containing the polymer of the first sample of the porous medium at a temperature not exceeding the decomposition temperature of the polymer, until complete evaporation of pore moisture, and carry out thermal analysis of the sample of the first sample of the porous medium in the temperature range including the temperature range of active decomposition of the polymer at a given rate of heating. Calculate the mass loss of the sample of the first sample of the porous medium when reached during thermal analysis reference temperature, not lower upper boundary temperature in the temperature range of active decomposition of the polymer at a given rate of heating.

Carry out pumping solution containing a specified polymer through a second sample of the porous medium, similar to the first, and dried a second sample of the porous medium to full the nd evaporation of pore moisture and at the same temperature, the first sample. Performed thermal analysis of the sample in the second sample of a porous medium under the same heating rate as that for the sample of the first sample, and in the temperature range including the temperature range of active decomposition of the polymer at a given rate of heating and the reference temperature. Calculate the mass loss of the sample in the second sample of the porous medium when reached during thermal analysis reference temperature.

The weight concentration of the polymer is defined as

Cp=ΔMpaboutint-ΔMKaboutntpδpandCl,

where ΔREPthe weight loss of the sample in the second sample of the porous medium, Δcounterthe weight loss of the sample of the first sample of the porous medium, δFSthe degree of decomposition of the polymer.

The weight loss of the sample of the first sample of the porous medium and the weight loss of the sample in the second sample of the porous medium when reaching the reference temperature, not lower upper boundary temperature in the temperature range of active decomposition of the polymer at a given rate of heating can be determined relative to the source is elicina:

ΔMKaboutntp=100*(MKaboutntp0-MKaboutntp*)/MKaboutntp0,

where Δcounterthe weight loss of the sample of the first sample of the porous medium,MKaboutntp*- the weight of the portion of the first sample of the porous medium at the reference temperature,MKaboutntp0- the initial mass of a sample of the first sample of the porous medium.

ΔMpaboutinp=100*(Mpaboutint0-Mpaboutint*)/Mpaboutint0,

where ΔREPthe loss in sample mass vtoro what about the sample of the porous medium, Mpaboutint*- the weight of the portion of the second sample of the porous medium at the reference temperature,Mpaboutinp0- initial mass of the sample in the second sample of the porous medium.

In accordance with one embodiments of the invention, the first and second samples of porous material using a core of rock, and the solution containing ukazanny polymer - drilling mud.

In accordance with another embodiment of the invention through a second sample core advanced pumped stratiform liquid, the injection reservoir fluid is carried out from an end face opposite the end face, which was carried out by pumping drilling mud.

In accordance with another embodiment of the invention after priming solution containing a specified polymer through a second sample of the porous medium, the second sample is divided at least into two parts, calculate the mass loss of the sample and determine the weight concentration of polymer for each part, the result of which determine the distribution profile, the weight concentration of the polymer along the sample.

Izopet the tion is illustrated by drawings, where in Fig.1 shows thermal curves for the first sample, Fig.2 thermal curves for the second sample, Fig.3 - distribution profile, the weight concentration of the polymer along the sample.

The physical basis of this method is due to degradation (decomposition) of the polymer upon reaching a certain temperature. For example, xanthan gum begins to decompose at a temperature of about 250-300°C. Intensive decomposition of the polymer leads to a decrease in mass of the sample that is registered instruments for thermal analysis (for example, derivatograph, thermogravimetric analyzer, and others). The total mass loss is proportional to the mass concentration of the polymer contained in the sample.

As an example of the method describes the measurement of the residual polymer (xanthan gum) in the sample Castlegate Sandstone permeability MD 690 water (1.2 L gas) and porosity of 25.5%. Thermal analysis was carried out using derivatograph Q-1500D (country of origin - Hungary).

Was prepared with 1% solution of xanthan resin in water with a salt content of NaCl and 18 g/l Sample polymer solution was dried at a temperature Tdrying=105°C until complete evaporation of water.

By heating in derivatograph Q-1500D defined temperature range of the active decomposition of the polymer, T1≈220°C, T2≈400°C, and Stephen is its decomposition δ FS=0.675 at heating rate 20°C/min

The first (containing no polymer) sample Castlegate Sandstone was dried at a temperature Tdrying=105°C for 24 hours and pulverized in a mortar. Was taken the sample of the first sample with a mass of aboutMKaboutntp0470.2mg(corresponds to the characteristics of derivatograph Q-1500D) for conducting thermal analysis (see, for example, the Axe N. D., Ogorodova L. P., Melchakova L. C. Thermal analysis of minerals and neorganicheskoi compounds. M MSU Publishing house, 1987, S. 6-23).

Conducted thermal analysis of the sample in the temperature range from room temperature to 1000°C, thermal curves shown in Fig.1. On the curve DTA (differential heating curve) indicates the endothermic effect in the area of 575°C, corresponding to a phase transformation of the α-β quartz. The curves DTG (differential thermogravimetric curve) and TG (thermogravimetric curve) in the range of 400-700°C recorded weight loss of the characteristic thermal behaviour of clay minerals, including kaolinite.

The calculated weight loss of the sample of the first sample (relative to the initial value) Δcounterin the temperature range from 105° to the Ref who annoy temperature T*=400°C, the corresponding upper boundary temperature of a previously defined temperature range of the active decomposition of the polymer at a given rate of heating, Δcounter=0.13%.

Been downloading this polymer solution (1% solution of xanthan resin in water with a salt content of NaCl and 18 g/l) in the second sample core, similar to the first, and subsequent injection of NaCl solution (18 g/l) in water from the end opposite the end from which were injected polymer to remove the rolling of the polymer.

A second sample of the Castlegate Sandstone dried at a temperature Tdrying=105°C for 24 hours and pulverized in a mortar. Taken linkage of the second sample weightMpaboutint0=457mg(corresponds to the characteristics of derivatograph Q-1500D) for conducting thermal analysis.

Led thermal analysis of the sample in the second sample in the temperature range from room temperature to 1000°C, thermal curves shown in Fig.2. In addition to the described above for the control sample there is loss of mass in the region of lower temperatures (220-400°C). On the curve DTG (differential thermogravimetric curve) this area is indicated by the ellipse and corresponds intensive is Oteri in sample mass due to decomposition of the polymer.

The calculated weight loss of the sample in the second sample (relative to the initial value) Δthe xin the temperature range from 105° to the reference temperature T*=400°C, Δthe x=0.25%.

Calculated weight concentration of polymer Withp(in percent):

Cp=ΔMpaboutinp-ΔMKaboutntpδpandCl=0.25%-0.13%0.6750.18%.

The second example in the initial stages similar to the previous example used a similar sample of the Castlegate Sandstone, carried out by the injection of 1% solution of xanthan resin in water with a salt content of NaCl and 18 g/l and subsequent injection of NaCl and 18 g/l from the opposite end. Unlike the first example, after pumping the drilling fluid a second sample core was divided into 4 parts and the further procedure was carried out for each part of the core. As a result, was built the profile distribution of the weight concentration of the polymer along the sample in the direction from the end of the used polymer injection. Given the profile shown in Fig.3.

1. The method of determining the weight concentration of the polymer penetrated into the porous medium, according to which:
- prepare an aqueous solution of the polymer and dried prepared solution of the polymer at a temperature not exceeding the decomposition temperature of the polymer, until complete evaporation of water,
- heat the polymer formed after drying of the polymer solution, and determine the temperature range of active decomposition of the polymer at a given rate of heating and the degree of decomposition of the polymer δFSin this temperature range as a
δpandCl=ΔMpMp0,
where Δp- weight loss of the polymer in the temperature range of active decomposition,Mp0- the original weight of the polymer to heat,
- dried not containing the polymer of the first sample of the porous medium at a temperature not exceeding the decomposition temperature of the polymer, until complete evaporation of pore moisture,
- carry out thermal analysis of the sample of the first sample of the porous medium in the temperature range including the temperature range of active decomposition of the polymer at specified is the rate of heat
- calculate the mass loss of the sample of the first sample of the porous medium when reached during thermal analysis reference temperature, not lower upper boundary temperature in the temperature range of active decomposition of the polymer at a given heating rate,
- carry out pumping solution containing a specified polymer through a second sample of the porous medium, similar to the first, and dried a second sample of the porous medium to full evaporation of pore moisture at the same temperature as the first sample,
- carry out thermal analysis of the sample in the second sample of a porous medium under the same heating rate as that for the sample of the first sample, and in the temperature range including the temperature range of active decomposition of the polymer at a given rate of heating and the reference temperature,
- calculate the mass loss of the sample in the second sample of the porous medium when reached during thermal analysis reference temperature, and
determine the weight concentration of the polymer penetrated into the porous medium, as
Cp=ΔMpaboutint-ΔMKaboutntpδpandCl,
where the M REPthe weight loss of the sample in the second sample of the porous medium, Δcounterthe weight loss of the sample of the first sample of the porous medium, δFSthe degree of decomposition of the polymer.

2. The method according to p. 1, according to which the mass loss of the sample of the first sample of the porous medium and the mass loss of the sample in the second sample of the porous medium when reaching the reference temperature determined relative to the initial value:
ΔMKaboutntp=100*(MKaboutntp0-MKaboutntp*)/MKaboutntp0,
where Δcounterthe weight loss of the sample of the first sample of the porous medium,MKaboutntp*- the weight of the portion of the first sample of the porous medium at the reference temperature,MKaboutntp0- the initial mass of a sample of the first sample of the porous medium, ΔMpaboutinp=100*(Mpaboutint0-Mpaboutint*)/Mpaboutint0,
where ΔREPthe weight loss of the sample in the second sample of the porous medium,Mpaboutint*- the weight of the portion of the second sample of the porous medium at the reference temperature T*,Mpaboutinp0- initial mass of the sample in the second sample of the porous medium.

3. The method according to p. 1, whereby the first and second samples of porous material using a core of rock, and the solution containing the polymer - drilling mud.

4. The method according to p. 3, whereby through the core sample is additionally pumped stratiform liquid, the injection reservoir fluid is carried out from an end face opposite the end face, which was carried out by pumping drilling mud.

5. The method according to p. 1, soo what, according to which after the pumping of the solution through a second sample of the porous medium, the second sample is divided at least into two parts, calculate the mass loss of the sample and determine the weight concentration of polymer for each part of the sample, the result of which determine the distribution profile, the weight concentration of the polymer along the sample.

6. The method according to p. 5, whereby the first and second samples of porous material using a core of rock, and the solution containing the polymer - drilling mud.



 

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3 cl, 2 dwg

FIELD: oil and gas industry.

SUBSTANCE: invention refers to the oil and gas industry and can be used in particular to prolong anhydrous operation conditions of oil producers. The substance of the invention: a device comprises a pipe string lowered into a well, a packer with a sealing member and a flow shutdown mounted therein; a hollow body comprises a pipe concentric with its axis. From above, this pipe is rigidly connected to the pipe string, and from below - to a piston. The pipe and piston are axially movable in relation to the hollow body from the flow shutdown. The hollow body from the flow shutdown is blind off from below; its holes are inclined at 120° to each other in three vertical planes along the perimeter of the hollow body. The first vertical plane comprises two holes above and below the sealing element of the packer, respectively. One hole is formed in the second vertical plane below the sealing element of the packer. The third vertical plane has one hole above the sealing element of the packer. The piston has a slot configured to provide an alternative connection of the holes of the vertical planes to the pipe inside when the pipe string and piston move axially and rotate about the hollow body of the flow shutdown. The hollow body of the flow shutdown is provided with an outer long slot inside from below, while the piston at the bottom has three inner long grooves inclined at 120° to each other along the perimeter; the outer long slot of the hollow body of the flow shutdown can be fixed in any of the three inner long grooves of the piston.

EFFECT: simplifying the operational structure of the device, improving its reliability and enhancing the same.

3 dwg

FIELD: oil and gas industry.

SUBSTANCE: invention refers to chemical and thermal treatment of a bottom-hole formation zone in developing high-viscosity oil deposits. A hollow cylinder rod is connected to a line of hollow pumping rods. A unit has also a working substance supply unit. This unit is stationary and isolated from a well production gathering line. An inside below an intake screen of the pump, between the cylinder wall and the surface of the hollow rod is divided into two sections. The cylinder rod is common for both sections and extends through a cylinder rod packing. The packing is provided between the sections. The bottom of the cylinder is connected to a tail piece with outlet holes. The tail piece comprises a hollow discharge rod. It is connected to the hollow rod of the pump. A non-return spring-loaded valve is arranged on the outlet of the hollow discharge rod of the pump.

EFFECT: unit comprises the differential sucker-rod pump, a cylinder of which is connected to a flow column; it ensures more reliable operation of the bore-hole sucker-rod pump unit and reducing serviceability.

1 dwg

FIELD: oil-and-gas industry.

SUBSTANCE: invention relates to recovery of said well located at multihorizon field. Proposed process comprises injection of isolating composition via well tubing string and fitting of "liquid" packer below tubing string shoe. Then, flow tubing above "liquid" packer is filled with killing fluid. Tubing string is withdrawn from the well. Deflector wedge is fitted inside tubing string. Lateral opening is cut in tubing string above overlaying high-pressure productive bed. Side hole is bored through said bed to extend through its entire depth to make side hole face occur nearby said high-pressure productive bed. Casing string with filter is lowered into bored side hole. Casing string is cemented above filter to the roof of top high-pressure productive bed and said wedge is withdrawn. Hanger with latch joint arranged at its inner surface is lowered on temporary string. Said hanger is fitted inside flow string under side opening. Oil string provided with side opening is lowered into flow string till interaction with latch device so that side openings of both strings are located opposite each other. Then, influx from lateral hole is initiated to remove killing fluid from the well. Then, liner with centring funnel at its shoe and packer hanger at its top is lowered on flexible pipe inside oil string to "liquid" packer. Solvent is injected via said liner. Said solvent destructs said "liquid" packer its residues falling on the face. Now liner is lowered to bottom holes of perforation interval of the bottom low-pressure productive bed. Liner is suspended in oil string above side opening of oil string. Flexible pipe is withdrawn from the well to place the well in operation.

EFFECT: efficient recovery.

7 dwg

FIELD: transport.

SUBSTANCE: method for installation of rapid-moving eduction column includes passing the rapid-moving column into a well, engagement of key for interaction with occlusion with nipple occlusion, extending interacting with profile key on rapid-moving column to interact with corresponding stopping profile in well shaft wall and thus supporting the rapid-moving column. In this method, interaction of the key with nipple occlusion causes extending the key interacting with profile into engagement with stopping profile.

EFFECT: higher reliability of holding the rapid-moving column while keeping relatively large flow diameter of the column.

29 cl, 8 dwg

FIELD: oil and gas industry.

SUBSTANCE: method involves dilution of salt rock with fresh or subsaline water by cyclic action on the formation, each of which includes pumping of a working agent to the saline oil formation through a well, closure of the well for the time of salt rock dilution, extraction of liquid from the formation through the same well. Cycles of action on the deposit are repeated till full coverage of the saline formation by action before opening of oil deposits contained in it and production of all the extracted oil deposits. Water pumping to the formation is performed at maximum possible constant bottom-hole pressure till reduction of the well water intake capacity by 2-8 times in comparison to its value at the pumping beginning, and extraction of liquid from the formation is performed at minimum possible constant bottom-hole pressure before the liquid with volume of at least 1.1-1.5 volumes of the fresh or subsaline water pumped to the formation earlier is removed to the surface.

EFFECT: increasing permeability of a saline formation throughout the area of its propagation, increasing productivity of production wells, increasing the coverage of the formation by action, volume of the removed oil deposits and acceleration of development rates.

4 cl, 1 tbl

FIELD: oil and gas industry.

SUBSTANCE: invention relates to submersible pumping units for operation of wells, where it is necessary to increase the differential pressure drawdown, without deepening of submersible pumping unit, and/or with unsealed production casing. The unit for oil-well operation includes the tubing string, electric submersible cable, electric submersible pump, the hydroprotection and submersible electric motor of which are encapsulated in the pressure-tight housing, which is tightly closed on the housing of the input unit of the electric submersible pump, the liner consisting from the pipe string the top part of which through the bushing is tightly connected to the bottom part of the pressure-tight housing, and in the bottom part of the liner the branch pipe with external sealing elements is located. The unit contains at least one packer with internal through passage channel with the diameter allowing to pass through the packer the tool, equipment and instruments, without extracting the packer. The sealing unit for the tight connection with the branch pipe of the liner is located either in the packer housing, or in the device below or above the packer.

EFFECT: improvement of performance of recovery of formation fluid from the wells.

1 dwg

FIELD: oil and gas industry.

SUBSTANCE: unit includes the wellhead equipment, concentrically located tubing strings of two diameters with electrocentrifugal and jet pumps in the production casing of the well. There is a separating camera located in the bottom part of the well bore under the centrifugal pump, equipped with the sealing housing. The unit has the channel for passing of the separated oil connecting the annular space above the pump with the separating camera, and inlet holes for entering the separated water. The sealing housing of the electric centrifugal pump from below in the interval of the separating camera is equipped with the inlet device made as the liner damped from below. The liner is divided into sections with the inlet holes. At the level of each inlet hole the liner is equipped with a glass used as a hydraulic lock for petroleum drips and inlet of water from the separating camera. The inlet holes are located in a single row along the liner and are made with the diameters diminishing in each subsequent section upwards. The gap between the housing and production casing of the well is used as a channel for passing of petroleum drips. The tubing string of the greater diameter in the wellhead equipment is connected to the water line, and tubing string with the smaller diameter - with the oil line. The bottom of the string with the smaller diameter is tightly installed in the upper cylindrical camera of the commutator installed in the tubing string with the greater diameter at the depth below the working level of fluid in the well. The commutator has vertical peripheral channels for passing through them of the upward flow of water and bottom cylindrical camera for placement of plug-in jet pump, the output of which is interconnected with the upper cylindrical camera. Meanwhile the possibility of supply of working fluid into the jet pump from the centrifugal pump, and pumped off fluid - along the side channel of the commutator from the annular space of the well through the check valve located from the external party of the commutator is provisioned.

EFFECT: downhole separation of oil from extracted product of the well and separate lifting of oil and water to the surface during inter-well pumping-over of water for maintaining of formation pressure.

2 cl, 3 dwg

FIELD: oil extractive industry.

SUBSTANCE: method includes lowering a tail piece into well with temperature, electric conductivity and pressure sensors placed on tail piece along its length. Pressure sensors are used in amount no less than three and placed at fixed distances from each other. After that, continuously during whole duration of well operation between maintenance procedures, temperature, conductivity of well fluid, absolute value of face pressure and difference of pressures along depth of well in area of productive bed are recorded. Different combinations of pairs of pressure sensors are used for determining special and average values of well fluid density. When absolute pit-face pressure is lower then saturation pressure for well fluid by gas and/or when average values of density deviate from well fluid preset limits and/or when its conductivity deviates from preset limits, adjustment of well operation mode is performed.

EFFECT: higher efficiency, higher safety.

2 cl

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