CC BY
9
electrodes, or react with the electrodes or diluent. The chemical reactions that take neutralize ions form a secondary reaction. Products of secondary reactions at the electrodes are allocated or go into solution.
Thus, the current flow through the electrolyte to the electrodes accompanied by the release components electrolyte electrode system - a typical electrolyte occurs acid-reduction reaction. Occurs at the cathode recovery process -Transfer electron action from the solution, and the anode oxidation process occurs - electron anions returns. Therefore, the cathode is the reducing agent, anode-oxidant.
As is well known, mineralized water oil fields are typical electrolytes - aqueous solutions of salts and composition are calcium chloride, magnesium chloride, and hydrocarbonatrium water.
Oil, consisting mainly of a mixture ofvarious hydrocarbons, is a dielectric. However, some oil formation conductivity different from the conductivity of the same oil to the surface. In situ oil is in equilibrium with the buried water, partially saturated with moisture and gas.
Oil-water-gas in the pores are in dynamic equilibrium. Because of the large oil resistance, can not be electrolyzed.
When electro processing layers converts electrical energy into heat, which is accompanied by changes in temperature, evaporation and condensation, chemical reactions (electrolysis), electro osmosis, electrophoresis and mechanical deformations of the rock matrix.
When electro processing formation around the current conductor, a magnetic field acting on the charged particles, and exerts a force on adjacent current-carrying conductors.
Liquid particles that are in the low-permeability in-terlayers will experience than the pressure forces the action of electric and magnetic forces. The electric current excites the magnetic field, ie, has a magnetizing force is numerically equal to the most current.
The magnetic field acts on the magnetic substance dissolved in a liquid and a solid dielectric; last magnetizing reinforce the magnetic field. Especially enhanced field, when the ferromagnetic material and contains cause additional mechanical strength.
Thus, arising electroprocessing seams magnetic and electric forces can effectively drain the reservoir heterogeneity and remove residual oil from non-performing layers.
References:
1. Gaiman M. A., Namikov A. G. Application of electro-osmotic exposure to oil field. Tr. Institut of oil. - Volume 3, - M. - 1955. - 955. 138-144.
2. Brodsky A. I. Physical chemistry G. P.M.-L, - 1948.
3. The electro kinetic properties of capillary systems. Proceedings of the USSR Academy of - M-L. - 1956.
4. Polivanov K. M. and others. The use of electro and hydraulic structures. Magazine ''Electricity № 8'', - 1951.
5. Endel K. Electrochemical binding clays - P. 18, 226, - 1935.
6. Titkov N. I., Korzhuev A. S., Nikitkina V. A., Smolyaninov V. About applying an electric current to the exercise of rocks on the walls of wells. Proceedings of the Institute of oil of the USSR Academy, t. H1, - 1958.
7. Devlikamov V. V. and others. Enhanced oil recovery using electro osmosis. News of Higher Schools. Series of Oil and Gas, - 1958.
DOI: http://dx.doi.org/10.20534/AJT-17-3.4-22-26
Hajan Hajiyev,
PhD in Petroleum Engineering, Associate Professor SRI of "Geotechnological problems of oil gas, and chemistry"
E-mail: [email protected] Nazim Nasibov,
PhD in Petroleum Engineering Khazar University
Baku, Azerbaijan E-mail: [email protected]
Wave device for near wellbore zone treatment
Abstract: Near wellbore zone treatment using pressure impulse creating device is considered. Proposed a new high frequency wave creating devicethat provides the possibility of strengtheningcreated pressure impulses.
Thus, as it becomes obvious, adding the jet-pump to the construction of the device and aligning its useful work together with other constructive elements leads to the increasing frequency and strengthening ofthe waves created by the device because extra part of the borehole liquid directed to the device through the jet-pump.
Keywords: layer, device, wave, jet-pump, hydrodynamic radiator, nozzle, diffuser, check valve, throttle, frequency.
Introduction. In the oil industry waves are used widely for treatment of reservoir. The spread of waves in the porous media and its impact on filtration of oil and gas allow achieve many positive results. Existing developed technologies in this area based oncreating disperse liquid systems using theoretical and experimental investigations conducted in the laboratories and injecting these systems into the near wellbore zone of reservoirs using special devices. Along with the developed technologies in this area a number of devices able to create oscillation and vibrating waves have been created for implementing these technological operations [1-3]. But it is necessary to note that the majority of the waves creating devices are able to create low frequency waves and their ability to create high frequency waves is rather limited. It reduces their efficiency and results in their limited practical application [1-3].
It is well known that the wave emerged from periodical forcing function gradually covers the whole system and after some time oscillating waves with stable amplitude are established. Wave spread in porous media, besides the rock and liquid physical properties also depends on interaction of the hard and liquid phases [1]. When the low frequency waves begin to spread in the porous media, the vibrations of the wave and rock skeleton become co-phased.With the increase of the frequency the spread of the wave in the liquid phase lags behind its spread in the rock as a result of the inertial and viscous forces.
The researches evidence [1] that the increase in the frequency of waves and of their amplitude in some cases have a positive impact on pushing the oil from the pore and on washing the collimated particles.
However, there is a great need for the development and implementation of new technologies and new devices based on improved mechanism of acoustic wave's impact on the technological processes.
Statement of the problem. As it was noted above, in many casesphysical field creating devices are widely used in the oil industry for increasing the efficiency of theworks conducted forregulating the key performance indicator ofthe reservoirs and wells and for increasing their productivity. Such devices may include vibrators for near wellbore zonetreatment [4], devices for wells startup (flow initiation) [5], devices for perforation
[6], devices for the near wellbore treatment and washing [7].
Disadvantages of these devices are their capability to create only waves of limited frequency (up to 500 Hz), low reliability because of the moving mechanical parts, weak parameter ofproduced waves due to non-synchron-ic work of the some main devices and low efficiency of work because of the said.
Therefore, there is a need inovercoming above-mentioned disadvantages, developing more effective oscillating wave devices and applying them appropriately to the production processes. Taking all this into account, a new type of wave device is proposed.
The goal in the development of the device is to increase the efficiency of the device by increasing liquid rate which passes through the hydrodynamic radiator (wave generator) achieved byaligning the work of the hydro-dynamic radiator (wave generator) and the jetpump.
The set forth goal is achieveddue to proposed new near wellbore zone treatment and well start up device consisting of the jet pump which inlet connected with tubing, hydro-dynamic radiator (wave generator) located below jet pump and transmitting pipes connecting space under the packer and annulus with jet pump and with hydro-dynamic radiator (wave generator). Jet pump's diffuser outlet connected with inlet of hydro-dynamic radiator (wave generator) and with the annulus. The throttle is installed at the outlet of transmitting pipe to the annulus and the check valve is installed at the entry of transmitting pipe from space under the packer into the reception camera of jet pump.
The main point in the work of the device may be described like this: during the near wellbore zone treatment the liquid sucked by the jet-pump from the annu-lus is added to the liquid pumped to the pipes from the surface, it passes through the hydro-dynamic radiator (wave generator) and as a result it strengthens created waves (but in the existing devices the liquid only from the surface passes through the hydro-dynamic radiator). Installation of a throttle at the exit of transmitting pipe into the annulus is aimed at regulating the work of the hydro-dynamic radiator (wave generator) during the well start up and reducing the pressure in the annulus.
The scheme of the proposed device is given below (Fig. 1). The device consists of the following parts: a jet-pump 2 connected to the tubing 1, its inlet nozzle 3, mixing 4 and reception 5 cameras, diffuser 6, its outlet 7, hydro-dynamic radiator (wave generator) 8, its tangential inlet 9, the canal 10 which connects the outlet 7 of diffuser 6 with the inlet 9 of hydro-dynamic radiator (wave generator) 8, transmitting pipes 13,14 connecting the outlet of the canal 10 with the annulus 11 and with the space under the packer 12, the check valve 15 installed on transmitting pipe 13 at the inlet of the reception camera 5 of the jet-pump and the throttle 16 installed at the outlet of transmitting pipe 14 into the annulus.
The wave device is lowered into the borehole with tubing and allows begin the operation in two cases:
when the absorption ability of the layer is sufficiently enough.
The device operates as it is described below:
When the absorption ability of the treated layer is sufficiently enough, the outlet of the annulus to the surface is closed at the wellhead. To begin the operation the reagent for the treatment is pumped into the layer through the tubing 1, jet-pump and when it is limited.
2, canal 10 and hydro-dynamic radiator (wave generator) 8. When the reagent passes through the inlet nozzle 3 of the jet pipe 2 and through the reception camera 5 and enters the mixing camera 4, then through the transmitting pipe 13 the liquid is sucked from under packer space 12, passes through the tubing 1 and mixes with the liquid which enters the mixing camera 4 through the nozzle 3.
Figure 1. Device for the treatment of reservoir's near wellbore zone.1 -Tubing; 2-Jet-pump; 3-Inlet nozzle; 4-Mixing camera; 5-Reception camera;6-Diffusor; 7-Diffusor outlet;8-Hydro-
dynamic radiator (wave generator); 9-Tangential inlet of generator (radiator); 10-Canal which connects the diffusor with the annulus and with the generator (radiator); 11 -annulus; 12-Underpacker space; 13, 14-Transmitting pipes; 15-Chech valve; 16-Throttle element
The volume of liquid passed from diffuser 6, canal 10 and hydrodynamic radiator (wave generator) 8, is the total of the liquid volume pumped from the surface through the tubing 1 and through the nozzle 3 and the liquid volume sucked from underpacker space 12 through the transmitting pipe 13, and it will increase the power of
the wave. In this case, for comparison, the power of the wave created by the existing devices will be based only on water pumped through the pipeline 1, because this time the jet-pump will not work.
When the absorption capacity of the borehole is limited, the outlet of the annulus at the wellhead is opened,
liquid pumped through the tubing 1 passes through the jet-pipe2, entersinto annulusll through the transmitting pipe 13 and throttle element 16, a part of this liquid will be directed to the surface, the rest will mix with the liquid by passing through the tubing 1, enter through the nozzle 3 to the mixing camera 4 and together again will be transmitted to under packer space 12 by passing through hydrodynamic radiator (wave generator). In this case again the volume of the liquid, which passes through the hydrodynamic radiator, will be equal to the total of the working liquid pumped from the surface and the liquid sucked from the under packer space. In the known existing devices all the liquid sucked by the jet-pump from the under packer space is transmitted through the annulus to the surface, so less liquidvolume passes through the generator.
7
Thus, as it becomes obvious, adding the jet-pump to the construction of the device and aligning its useful work together with other constructive elements leads to the increasing frequency and strengthening of the waves created by the device because extra part of the borehole liquid directed to the device through the jet-pump.
Experimental researches results. To determine the impact of the added jet-pump to the device, special stand experiments have been conducted in laboratory conditions. The tests have been conducted by determining the hydraulic resistance in both cases, that is, when the device was put into operation with the addition of the j et-pump and without it. For this purpose at different rate ofwater pumped with the washing unit pressure loss has been measured by precise manometers. The results of the stand tests have been shown in Fig. 2:
AP, MPa
y = 124165-x2;045 R2 = 0,995 o
y = 4 13048-x2 .356
R2 = 0,998
0.001 0.002 0.003 0.004 0.005 0.006
0.007 0.008 Q, m3/sec
O - with a jet-pump; x - without a jet-pump Figure 2. Pressure loss vs. liquid rate with and without working jet-pump
As it is seen from Fig.2, when the j et-pump is at work, the power of the device and the frequency of generated waves grow significantly.
The experimental dependences shown in Fig.2 may be described by the following equations:
AP1 = 124165Q045 (1)
AP = 413048-Q6
(2)
Here AP1 and AP2 - pressure loss with and without working jet-pump correspondingly, MPa, Q- liquid rate which has passed through the device, in cubic meter per second.
In both cases evaluating pressure loss is possible by dividing equation (1) to equation (2):
AP1/AP2 = 0.3-Q-0'311 (3)
The calculations using equation (3) show that according to the conducted experiments pressure loss varies within 27-47%.
Thus, the application of the proposed device in all the cases allow create intensive pressure waves during the near wellbore zone treatment.
Results: For near wellbore zone treatment new pressure impulse creating device has been proposed and described its advantages in comparison with the existing ones.
The stand tests of the device showed that the rise of pressure loss in the jet-pump and hydrodynamic radia-torwhich are the main parts of the device and the growth of liquid rate that passes through the device, power and frequency of the pressure waves sufficiently increase.
References:
1. Гадиев С. М. Использование вибрации в добыче нефти. - М., Недра, - 1977, - 160 с. (S. M. Hadiyev. Application ofvibration in oil production. Publishing House "Nedra", - M., - 1977, - 160 p., in Russian).
2. Устройство для перфорации и обработки призабойной зоны скважины. Патент РФ № 2072421, опубл. 19.01.1996. (Device for perforation and processing of the hole-bottom of the borehole, Patent of RF No 2072421, published in 19.01. 1996, in Russian).
3. Устройство для обработки и освоения скважин. Патент РФ № 1522817, опубл. 20.01.1996. (Device for the development and assimilation of boreholes, Patent of RF, No 1522817, published in 20. 01. 1996, in Russian).
4. Устройство для перфорации и обработки призабойной зоны скважины. ПатентРФ № 2072421, опубл. 19.01.1996. (Device for perforation and processing of the hole-bottom of the borehole, Patent of RF No 2072421, published in 19.01. 1996, in Russian).
5. Устройство для обработки и освоения скважин. Патент РФ № 1522817, опубл. 20.01.1996. (Device for the development and assimilation of boreholes, Patent of RF, No 1522817, published in 20. 01. 1996, in Russian)
6. Сургучев М. Л., Кузнецов О. Л., Симкин Г. М. Гидродинамическое, акустическое, тепловое циклические воздействия на нефтяные пласты. - М., Недра, - 1975 г., - 185 с. (Surguchev M. L., Kuznetsov O. L., Sim-kin G. M. Hydrodynamic, acoustic thermo-cyclic action on the oil layer, Publishing House "Nedra", - M., - 1975,
- 185 pp., in Russian).
7. Кузнецов О. Л., Ефимова С. А. Применение ультразвука в нефтяной промышленности. - М. Недра, - 1983 г.,
- 192 с. (Kuznetsov O. L. Application of ultra-sound in oil industry. Publishing House "Nedra", - M., - 1983, -192 p., in Russian).
8. Временная инструкция по эксплуатации скважинных гидродинамических генераторов колебаний (СГГК). Нижневартовск, - 1986 г., - 26 с. (Temporary instruction for the exploitation of the hydrodynamic generators of waves, Nizhnevartovsk, - 1986, - P. 26, in Russian).
9. 9liyev Y. M., Rahimov C. 9. Layin quyudibi sahasinin reagent ilai§lanmasitisulu//AR patenti. Sanaye mtilkiyyati. Rasmi btilleten. -2004. - № 4. (Aliyev Y. M., Rahimovs. A. Method of reagent development of the holebottom of the borehole. Officalbulkleten, - 2004, - No 4 in Azerbaijani).
10. Kamilov M. A., Sliyev Y. M., Rahimov C. 9. Layin quyudibi sahasina tasir etmak va quyulari yumaq ti^tin qurgu//AR patenti. Sanaye mtilkiyyati. -2003. - № 3. (Kamilov M. A., Aliyev Y. M., Rahimov S. A. Device for action into the bottomhole of the borehole of the layer and for the wash of the holebottom, Patent of RA, Industry property, - 2003, - No 3, in Azerbaijani)
