Well jet device

For extracting oil from wells, pipe string, packer with axial through hole and support with axial channel with seat for jet pump mounting. Bypass channel with return valve is in support wall. Pump has cylindrical body with annular shoulder, for support seat mounting. Body has channel for supplying active medium to the pump nozzle, channels for supplying pumped out medium and removing media mixture and through channel with sealing unit. The channel couples to unit downstream channel. The unit has axial channel passing and displacing a logging cable/instrument. Mixing chamber with diffuser connected to the pipe string cavity upstream of pump positions axially to the nozzle. Channel diameter of support downstream of seat is equal to or greater than packer hole. The invention makes it possible to extend the device functionalities due to the possibility of disconnecting the in-tube space and casing annulus when the pump is stopped.

FIELD OF THE INVENTION

This invention relates to the field of pump engineering and in particular to well jet devices for producing oil from wells.

BACKGROUND OF THE INVENTION

A well jet device is known, which comprises a pipe string with a jet pump installed on the flow string in a well and a geophysical instrument arranged below the jet pump in the flow string (see: RU Patent No. 2059891 C1, FO4F 5/02, 10.05.1996).

This known device enables to pump a variety of produced media, e.g., oil, out of a well, while simultaneously treating a produced medium and the formation near-well area, but this device provides for supplying an operating fluid into the nozzle of the jet pump via the pipe string, which a number of cases narrows the field of use of this device.

The closest to the invention as to the technical essence and the achieved result is a well jet device comprising a packer, a pipe string with a support wherein drain openings are made and whereon a jet pump is installed in the body of which a channel for supplying an active fluid to the nozzle of the jet pump, a channel for supplying a medium pumped out of a well and a channel for removing a medium mixture from the jet pump are made, and a through channel with a mounting seat for installing a sealing unit is made in the body above the channel for supplying a pumped out medium. An axial channel is made in the sealing unit with the possibility of passing a logging cable through it and through the channel for supplying a pumped out medium, which logging cable is used for installing bottomhole instruments on it and below the jet pump with the possibility of moving them along the well hole when the jet pump is or is not in operation, the channel for supplying an active medium to the jet pump nozzle being in communication with the drain openings and, through the latter, with the space surrounding the pipe string, and the channel for removing a medium mixture being in communication with the inner cavity of the pipe string above the jet pump (see: RU Patent No. 2188970, F04F 5/54, 10.09.2002).

The above well jet device enables to carry out various process operations in a well below the jet pump installation level, also when a pressure differential above and below the sealing unit exists. But this device does not enable to use its possibilities to the fullest extent due to the impossibility of pumping chemical reagents to a producing formation with the use of the jet pump without preliminarily installing a special insert, which separates the pipe inner space and the annular space in the jet-pump through channel; and, consequently, the functional capabilities of the well jet device are reduced.

SUMMARY OF THE INVENTION

The objective of this invention is to develop a well jet device with the possibility of separating the pipe inner space and the annular space when a jet pump is not in operation.

The technical effect of using the proposed well jet device consists in expanding the functional capabilities of the well jet device.

The stated technical problem can be solved, and the technical effect can be achieved, due to the fact that the proposed well jet device comprises a pipe string provided with, from bottom to top, a packer with an axial through opening and a support with an axial channel having a mounting seat intended for installing a jet pump on it, wherein the support wall includes a drain channel with a check valve, and the jet pump includes a cylindrical housing which outer surface is provided with an annular shoulder intended for installing the jet pump onto the mounting seat in the support, and the housing is provided with a channel for supplying an active fluid into the nozzle of the jet pump, a channel for supplying a medium pumped out of a well into the jet pump, a channel for removing a medium mixture from the jet pump, and a through channel with a sealing unit installed in its upper part, the through channel being connected to the channel for supplying a medium pumped out of a well below the sealing unit, the sealing unit having an axial channel for passing a logging cable intended for installing a logging instrument for measuring physical parameters of a well, e.g., pressure and temperature, and treating producing formations, e.g., with ultrasound, through that channel, with the possibility of moving the said instrument along the well hole when the jet pump is or is not in operation, and the channel for supplying an active fluid into the nozzle of the jet pump being connected to the support through channel and, via the latter, to the space surrounding the pipe string, a mixing chamber with a diffuser being in alignment with the nozzle, and the diffuser outlet being connected to the pipe inner cavity above the jet pump via the channel for removing a medium mixture from the jet pump, and the diameter of the support axial channel below the mounting seat is not less than the diameter of the axial through opening in the packer.

An analysis of operation of the proposed well jet device shows that there exists the possibility of expanding the functional capabilities of the well jet device through enlarging a range of operations that may be carried out in a well without lifting the jet pump up to the surface and without installing additional equipment on the jet pump.

The proposed well jet device enables to create several differential pressure drawdown values at a given differential pressure and use a logging instrument for registering pressure, temperature and other physical parameters of a well itself and a medium pumped out of it, surveying and testing a well, and register a formation pressure-restoration curve in the under-packer space of a well without using a special functional insert. However, in a number of cases where only a survey is conducted or a producing formation is treated with the use of a logging instrument, e.g., in a case of treating a producing formation with physical fields, in particular with ultrasound, it is insufficient for intensifying an inflow from a producing formation. Providing the support wall with a through channel having a check valve, in combination with making the diameter of the support through channel below the mounting seat not less than the diameter of the axial through opening of the packer, enables to supply chemical reagents or a hydrofracturing fluid via the pipe string without using any additional tools or functional inserts on the pipe string and improve the work efficiency, and the check valve prevents a medium pumped into a producing formation from entering into the well annular space above the packer during pumping operations. The above-said relation between the diameters of the support axial channel and the axial through opening of the packer is very important. Making the diameter of the support axial channel not less than the diameter of the axial through opening of the packer is necessary for obtaining the possibility of lowering a logging instrument into the well under-packer area for the purposes of treating a formation with physical fields (treating with ultrasound or creating, e.g., a thermal field) and reducing hydraulic resistance both when pumping various media into a producing formation and for pumping treatment products and a produced medium out of a producing formation after a differential pressure drawdown on such a producing formation is created. At the same time, it becomes possible to monitor a differential pressure drawdown value by controlling the rate of supplying an active operating fluid. During testing formations it is possible to adjust pumping modes by changing the pressure of an active operating fluid supplied to the active nozzle of the jet pump. Also, a spontaneous backflow of an operating fluid into the under-packer area is precluded both when the jet pump is operated and is not operated.

Through creating pulsed differential pressure drawdown on producing formations in combination with acting on producing formations with, e.g., ultrasound fields created by a bottomhole instrument it is possible to carry out works on intensifying an inflow from producing formations.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The proposed well jet device comprises a pipe string1provided with, from bottom to top, a packer2with an axial through opening3and a support4with an axial channel5having a mounting seat6intended for installing a jet pump7on it. The support wall4includes a drain channel8with a check valve9, and the jet pump7includes a cylindrical housing10which outer surface is provided with an annular shoulder11intended for installing the jet pump7onto the mounting seat6in the support4, and the housing10is provided with a channel12for supplying an active fluid into the nozzle13of the jet pump7, a channel14for supplying a medium pumped out of a well into the jet pump7, a channel15for removing a medium mixture from the jet pump7, and a through channel16with a sealing unit17installed in its upper part. The through channel16is connected to the channel14for supplying a medium pumped out of a well below the sealing unit17. The sealing unit has an axial channel18for passing a logging cable19intended for installing a logging instrument20for measuring physical parameters of a well, e.g., pressure and temperature, and treating producing formations, e.g., with ultrasound, through that channel, with the possibility of moving the said instrument along the well hole when the jet pump7is or is not in operation. The channel12for supplying an active fluid into the nozzle13of the jet pump7is connected to the through channel8of the support4and, via the said channel8, to the space surrounding the pipe string1. A mixing chamber21with a diffuser22is in alignment with the nozzle13. The diffuser outlet is connected to the pipe inner cavity above the jet pump via the channel15for removing a medium mixture from the jet pump7, and the diameter D1of the axial channel5of the support below the mounting seat6is not less than the diameter D2of the axial through opening3in the packer2.

The pipe string1is lowered into a well together with the packer2and the support4, and the packer2is arranged over a producing formation (not shown). The packer2is brought into its operative position, thus separating the well space surrounding the pipe string1. A hydrofracturing fluid or an acid solution is supplied under pressure via the pipe string1to the producing formation, after which and the jet pump7is lowered into the pipe string1together with the sealing unit17, as installed in the through channel16, and the logging instrument20arranged on the logging cable19below the body10of the jet pump7. The body10of the jet pump7is installed on the mounting seat6. An operating (active) fluid, e.g., water, a salt solution, oil, etc., is pumped into the annular space surrounding the pipe string1. The operating fluid comes through the drain channel8and the check valve9into the channel12for supplying an active fluid into the nozzle13of the jet pump7. Within a few seconds after pumping the operating fluid through the nozzle13a stable jet is formed at its outlet, which, while exiting the nozzle13, draws a surrounding medium into the mixing chamber21, which results in a reduced pressure first in the channel14for supplying a pumped out medium and then in the well under-packer space also. A value for which pressure is reduced depends on the flow rate of the operating (active) fluid in the nozzle13, and the flow rate, in its turn, depends on supply pressure of the operating (active) fluid through the well annular space above the packer2. Then, the hydrofracturing fluid or products of chemical treatment of the producing formation are pumped out of the producing formation, and then a formation fluid is pumped out of the producing formation and comes to the mixing chamber21via the pipe string1, the through channel16and the channel14for supplying a pumped out medium, where it is mixed with the operating (active) fluid, and into the diffuser22. Then the mixture comes from the well to the surface through the pipe string1due to the energy of the operating (active) fluid. During pumping out of a formation fluid the logging instrument, as installed on the cable19, is used for monitoring parameters of the pumped out fluid as well as for acting on the producing formation with physical fields, e.g., with ultrasound fields, for the purpose of intensifying an inflow from the producing formation. According to a specific task, it is possible to move the logging instrument20along the well hole. At the same time, several values of differential pressure drawdown on the producing formation are created by changing the pressure of the operating (active) fluid, and parameters of the pumped out fluid inflow from the producing formation are registered with the use of the logging instrument20. After the well survey and the treatment of the producing formation are completed, the logging instrument20is lifted up with the use of the logging cable19, is used for acting on the housing10of the jet pump7. Then the jet pump7is extracted from the well with the use of the logging cable19, and the well is transferred into the operation mode.

INDUSTRIAL APPLICABILITY

The proposed invention may be used for testing, developing and operating oil and gas-condensate wells as well as during well-workover operations.