The invention relates to the field of oil production, in particular to the field gathering and transportation of gas and oil products of oil wells during single-pipe transportation to a central oil collection and preparation point.
Also, the invention can be used in other sectors of the economy for pumping and transportation of multiphase mixtures.
A known system for collecting and transporting oil and gas from the fields to the central collection and preparation center, including separators for separating the well’s production from water-cut oil and gas, followed by separation of water from oil at the central collection point (CPC) and transporting water to the reservoir pressure maintenance system (see ed. certificate of the USSR No. 623049, class F 17 D 1/00 of 1976).
The disadvantage of this system is that the production of the well is transported due to the energy of the formation or deep pumps, which imposes a limit on the productivity of the wells and reduces the overhaul period.
To eliminate these shortcomings in subsequent years, systems were proposed for collecting and transporting oil well products, including booster pumping stations (BPS). So, for example, traditional oil and gas gathering and transportation systems are known, including wells, group metering units connected by collectors with BPS, pressure pipelines for transporting oil and gas to BPS to the DSP, water to the RPM system (see RD 39-01-0148311-605 -86). Traditional DNS in known systems, as a rule, is equipped with a pump, separators, sedimentation tanks, tanks, and a flare device. As a pump in the CSN known systems are used:
- volume displacement pumps (see ed. certificate of the USSR No. 989230, class F 17 D 1/00 of 1981);
- screw pumps (see RF patent No. 2020371, class F 17 D 1/00 of 1992);
- centrifugal pumps (Booster pump - compressor for liquidation of an oil gas flare. I.V. Belykh et al. / Oil industry. - 1994. - No. 9. - P. 60).
The disadvantage of the collection and transportation system, equipped with CSN with a volume displacement pump, is the presence of a large number of pipelines with valves and cumbersome equipment, which reduces the reliability of the system and does not ensure the stability of the mode of transportation of multiphase liquid.
The disadvantage of a system for collecting and transporting well products equipped with a pump with a screw pump is that this system allows you to transport only a strictly defined volume of gas-oil mixture per unit time, equal to the capacity of the pump, and with a gas phase content of not more than 60%, which makes In general, the operation of the system is extremely sensitive and unreliable. This eliminates the possibility of using this system in wells with any flow rate, as well as high gas content.
The system for collecting and transporting the products of wells equipped with CS with a centrifugal pump also has limitations in application, namely: it can transport a gas-oil mixture only with a small gas factor.
In addition, the common significant drawback of all these known collection and transportation systems with traditional BPSs is cumbersome, the need for significant areas for equipment, which causes difficulties with the construction of systems in agricultural areas, on wetlands and lands of the state forest fund.
Closest to the proposed technical solution in terms of technical nature is an installation for collecting and transporting oil well products, including a network of prefabricated pipelines from wells, a pressure pipeline to an oil treatment unit, and a pump installation located between the network of prefabricated pipelines and a pressure pipeline. The pump installation was performed using a multiphase sucker rod pump mounted on a tubing and installed in a sump equipped with a large diameter pipe with a plug at the lower end and wellhead equipment at the upper end. The lateral branch of the sump connected to the annular space is connected to the network of prefabricated pipelines through an expansion chamber, and the lateral branch of the wellhead equipment is a linear branch of the wellhead equipment that communicates with the internal cavity of the tubing and is connected to the pressure pipe through an ejector, which is connected to the gas space via a gas line expansion chamber. A rocking machine was used as a drive for a multiphase sucker-rod pump, a polished rod of which is connected to the sucker-rod pump (see RF patent No. 2160866, class F 17 D 1/00 from 1999).
However, this known installation does not provide a stable and constant mode of transportation of the gas-oil mixture from wells with high production rates, as well as with a high gas factor and a high content of solids, because The sucker rod pump used for transportation, which passes all the transported liquid through itself, has a limited capacity, determined by the capabilities of the rocking machine. Moreover, such a pump can only pump liquid with a small gas factor. Therefore, to ensure reliable operation in a known installation, it is always necessary to additionally install a buffer tank, which makes the installation inefficient, cumbersome and inconvenient in operation.
In addition, since the known installation contains two stages of pumping (sequentially by a sucker rod pump and a jet pump), in the event of failure of one of the pumping stages, the transportation of well products stops completely, the wells themselves are stopped, and for restarting the installation, in addition to additional material costs , and also additional time costs, which leads to an increase in the cost of the transportation process, as well as to its discrete mode, as a result of which frequent outputs of the equipment are possible Bani down.
Along with this, the known installation does not allow equipping it with a remote control, because during its operation, it is impossible to single out any single control indicator characterizing the operation of the installation as a whole. This disadvantage complicates the operation of the entire known installation.
Another disadvantage of this installation is the need to pump through the sucker rod pump the entire volume of oil well production, which leads to unreasonably high energy consumption and increased wear of equipment.
The proposed invention solves the problem of ensuring a stable and constant mode of transportation of single-phase multiphase products of both low- and high-rate oil wells with any gas factor and any content of impurities, as well as eliminating transportation stop when the pump is turned off, while reducing energy consumption and ensuring environmental friendliness .
An additional technical objective of the invention is ease of use due to the possibility of remote maintenance of the system.
This problem is solved by the proposed system for collecting and transporting oil well products, including a network of prefabricated pipelines from wells, a pressure pipe to an oil treatment unit, an ejector and a pump mounted on a tubing and placed in a sump that is equipped with a pipe with a plug at the lower end and wellhead equipment at the upper end, the drainage of the annulus of the sump and linear drainage of the wellhead equipment, communicating with the internal cavity of the tubing, in which The new one is that the system is additionally equipped with a separation unit having taps for gas-oil and water-oil separation products, an ejector is placed between the network of prefabricated pipelines and the pressure pipe, while the pipe for introducing the transported liquid into the ejector is connected to the network of prefabricated pipelines, the ejector nozzle is through a linear wellhead outlet the equipment is connected to the cavity of the tubing, and the ejector diffuser is connected to the inlet of the separation unit, the discharge of gas-oil separation products which the ohm is connected to the pressure pipe, and the discharge of the oil and water separation products is connected by the bypass pipe to the discharge of the annulus of the sump, while the system contains an electric centrifugal pump as a pump.
The bypass pipe can be optionally equipped with a filter of mechanical impurities.
As a separation installation, it is preferable to use a tube phase divider.
The sump of the proposed system can be equipped with an additional pipe installed coaxially with the first pipe, while the wellhead equipment of the sump is made common to these pipes.
The achievement of the technical result is achieved due to the proposed layout of the system nodes and their relationship.
Due to the fact that the ejector is located between the network of prefabricated pipelines and the pressure pipe, and also because of the output of the ejector (diffuser) is connected to the input of the separation unit additionally introduced into the system, the output of which is connected to the pressure pipe, the primary transportation of all oil well products through one pressure pipe is provided the pipeline to the installation of oil treatment. The introduction of a separation unit allows the separation of multiphase products into components: gas-oil and water-oil. Oil and gas products are diverted to the pressure pipeline, and the oil and water component through the bypass pipeline, the annulus of the sump is received by the electric centrifugal pump (ESP) installed in the sump, ensuring its operating mode. In turn, the ESP installed in the sump is intended for forming a working (ejecting) fluid flow in the ejector to provide an ejected ejector effect. To do this, it is proposed that the internal cavity of the tubing, on which the pump is fixed, be connected to the ejector nozzle by means of a linear outlet in the wellhead equipment. The submersible electric centrifugal pump provides a constant volume of liquid and constant pressure to the ejector nozzle. As a result, the workflow emerging from the ejector nozzle with high speed causes a vacuum in the mixing chamber of the ejector, thereby ensuring the suction of well products from prefabricated pipelines in a constant mode, regardless of the flow rate of the wells and gas content, as well as the presence of solids in the well production. The mixture consisting of the working fluid and the pumped liquid carried by it in the ejector diffuser reduces the speed and increases the pressure to the required value to ensure the delivery of fluid to the separation unit and then to the pressure pipe. All this allows you to create a stable and reliable mode of transportation of production of both low- and high-yield wells. At the same time, the gas factor of well production does not impose any restrictions on the operation of the proposed system, due to the proposed connection of the ejector, and also due to the fact that practically degassed water-oil component will always be supplied to the ESP after leaving the separation unit. Moreover, due to the fact that the ejector is “not afraid” of mechanical impurities, it can work even with a large number of them.
Thanks to the proposed connection of the ejector between the network of prefabricated pipelines and the pressure pipe, and also due to the introduction of a separation unit on the pressure pipe line, the system ensures reliable operation without stopping the wells and without stopping the transportation process even when the ESP is switched off, since a flow system is formed from the wells to the pressure pipe.
Thanks to the proposed connection in the proposed system, namely: wells - ejector - separation unit - ESP - ejector, a closed cycle of operation of these system nodes is provided, which provides:
firstly, the operational reliability of the system;
secondly, the environmental friendliness of the system;
thirdly, the possibility of establishing the main control parameter of the system, ensuring its constant and reliable mode, namely: the pressure of the fluid supply by the electric centrifugal pump to the ejector nozzle to create an ejected effect, which makes it possible to remotely control the entire system by this parameter, which greatly simplifies its operation;
and fourthly, the compactness of the system, the ease of replacing failed nodes.
The invention is illustrated in the drawing, which shows a process diagram of a system for collecting and transporting oil well products.
The system for collecting and transporting oil well products contains a network of prefabricated pipelines 1 connected to the wells 2 through group metering units (GZU) 3, an ejector 4, a separation unit 5 and an electric centrifugal pump (ESP) 6.
The ejector 4 is placed between the network of prefabricated pipelines 1 and the pressure pipe 7. The prefabricated pipelines 1 are connected to the pipe 8 of the transported fluid ejector 4, which through the mixing chamber 9 of the ejector enters the diffuser 10, which is connected to the input 11 of the separation unit 5.
The separation unit 5 can be performed, for example, in the form of a tube phase divider. It is equipped with a branch 12 of gas and oil products and a branch of 13 water-oil separation products.
ESP 6 is installed in sump 14, equipped with a pipe 15 with a plug 16 at the lower end and wellhead equipment 17 - at the upper. The ESP 6 is mounted on a tubing 18 located in the sump 14 and connected to the wellhead equipment 17, while the inner space 19 of the tubing 18 is connected to the nozzle 21 of the ejector 4 through a linear outlet 20 of the wellhead 4. The annular space 22 of the sump 14 is connected bypass pipeline 24 with branch 13 of oil and water separation products. The outlet 12 of the separation unit 5 is connected to a pressure pipe 7, which is connected to an oil treatment unit (UPN) 25.
Bypass pipe 24 is additionally equipped with a filter 26 of mechanical impurities.
In order to ensure electrical safety of the ESP operation in the proposed system, the sump 14 can be equipped with an additional pipe 27 mounted coaxially to the pipe 15, while the wellhead equipment 17 of the sump 14 is made common to both pipes. Pipes 15 and 27 are isolated from each other.
The system operates as follows.
Multiphase gas and oil products of oil wells 2 are supplied through a gas supply unit 3 to a network of prefabricated pipelines 1, then to an ejector 4 through a nozzle 8 of an input to a mixing chamber 9 and a diffuser 10, where the fluid flow increases pressure and enters the input 11 of the separation unit 5, where separation occurs multiphase fluid to the gas-oil fraction, discharged through the outlet 12 into the pressure pipe 7, and to the oil-water fraction. The latter through the outlet 13 is fed through the bypass pipe 24 and the outlet 23 into the annular space 22 of the sump 14 and then to the reception of the electric centrifugal pump 6. ESP 6 supplies liquid through the internal cavity 19 of the tubing 18 to the nozzle 21 of the ejector 4. The working fluid flows from the nozzle 21 s high speed into the mixing chamber 9 and creates a vacuum in it. Due to the rarefaction in this chamber 9 of the ejector 4, the production of oil wells 2 is sucked through the input pipe 8 into the mixing chamber 9. Then, the products selected from the wells 2, carried away by the working fluid stream from the nozzle 21, rush into the diffuser 10, where the mixture of these flows reduces the speed but increases the pressure to the value of the required transportation pressure, and is fed to the input 11 of the separation unit 5. At the same time, there will always be a flow with the required transportation pressure at the outlet of the diffuser, regardless of which characteristic ie production well (flow rate, gas content, the presence of mechanical impurities). After passing through the separation unit, the gas-oil part of the separation product enters the pressure pipe 7 and then to UPN 25, and the oil-water part bypass pipe 24 enters the annulus 22 to receive the pump 6, which supplies the nozzle 21 of the ejector 4 with the required amount of liquid to create an ejected effect. Such a closed loop underlies the work of the proposed system.
The use of the filter 26 reduces the energy load of the ESP, and thereby facilitates its operation upon receipt of products heavily contaminated with mechanical impurities.
The separation unit 5 in the form of a tube phase divider allows you to create a fluid flow for the ESP to form a working (ejection) flow in the nozzle 21 of the ejector 4 in the quantity and necessary condition that will ensure the operation of the entire system in a closed cycle.
Thus, the inventive system for collecting and transporting oil well products has the following advantages:
- provides a stable and constant mode of transportation of the production of any wells (both low- and high-yield) with any gas factor (up to 100%) and with any content of solids (up to sludge);
- eliminates the shutdown of transportation, and therefore eliminates the shutdown of wells when the electric centrifugal pump is stopped, which ensures an economical mode of operation of the system and operational reliability;
- provides environmental friendliness by creating a closed loop;
- ease of operation due to the possibility of remote control of the system by pressure parameter.