RU2303161C1 - Underwater pumping station for transfer of multicomponent gas-containing mixture - Google Patents

Abstract

FIELD: oil and gas producing industries.

SUBSTANCE: invention relates to underwater pumping sets (stations) for transfer of multicomponent gas-liquid mixtures and it can be used for pumping multicomponent products of sea wells with high and unstable gas content. In proposed underwater pumping station containing at least one screw pump installed on pipe whose inlet is connected with liquefaction main line through electromagnetic valve electrically coupled through control unit with thermocouple installed at pump outlet, liquefaction main line communicates with sea water surrounding the station.

EFFECT: provision of restoration of pump efficiency and elimination of overheating.

2 cl, 1 dwg

Description

The present invention relates to underwater pumping stations for pumping multicomponent gas-liquid mixtures, mainly products of offshore oil wells.

A known method of pumping oil wells, including the separation of a multicomponent gas-containing mixture before entering the pumping station [Oilfield equipment. Directory. Ed. E.I. Bukhalenko. - M .: Nedra, 1990, p. 425].

The disadvantage of this method is the need for complete removal of gas from the liquid fraction during separation (the complexity of the process), as well as the loss of gas and negative environmental consequences when it is burned in a flare unit.

The use of multiphase pumping stations has several advantages: 1) a simplified and completely sealed system for transporting well products from the production site to the central oil (gas) treatment point, regardless of its distance; 2) increasing the flow rate of the well (oil recovery) by reducing pressure at the wellhead; at the same time submersible borehole pumps are operated in more favorable technological conditions; 3) reduction of harmful effects on the environment; 4) reduction of capital expenditures for the development of the field (abandonment of the construction of long oil collectors and a gas pipeline); 5) the ability to operate wells, as well as the field as a whole in economically profitable modes by automatically maintaining the pressure at the pump inlet; 6) inclusion in the general system of field development of zones or individual wells (clusters), geographically remote or located in remote places; 7) the possibility of one hundred percent gas utilization, starting from the first day of field operation.

There are various technical solutions for pumping a gas-liquid mixture: pumping units containing metering and booster piston pumps, interconnected by means of a pipeline and valve [a.s. USSR No. 1339297, class F04B 23/00, publ. 09/23/87; A.S. USSR No. 1585545, class F04B 23/00, publ. 08/15/90], pumping stations with preliminary separation of the production of oil wells in front of the station into oil, water and gas, followed by separate injection and mixing after the station [a.s. USSR No. 623049, class F17D 1/00, publ. 1978; A.S. USSR No. 653481, class F17D 1/00, publ. 1979, US Pat. RF №2007659, class F17D 1/00, publ. 1994].

The disadvantages of the known technical solutions are the design complexity, low reliability and high cost of pumping stations that implement these technical solutions.

Also known is a pumping station for pumping multiphase mixtures, containing a screw pump mounted on the pipeline [P.E. Amosov and other screw compressor machines. L .: Engineering, 1977, p. 13].

The well-known screw pump-based station is simple in design and operation, reliable in operation, and economical (efficiency up to 75%). However, at high gas contents (60 ... 100 vol.%) And large degrees of pressure increase (5 ... 10 times or more), its efficiency decreases to 20 ... 30% and an unacceptably high overheating of the screw pump occurs due to the lack of liquid sealing and cooling at the points of contact between the screws and the pump casing.

The closest in technical essence and the achieved result is the selected as a prototype pump station for pumping multiphase mixtures, containing at least one screw pump installed on the pipeline, the inlet of which is connected by a line with an additional liquefaction tank filled with a water-oil mixture, and an adjustable valve is installed on the line configured to open when a gas plug or mixture with a high gas content enters the pump inlet, for example, made in de electromagnetic valve electrically connected through the control unit with a thermocouple installed at the pump outlet [RF Patent No. 2239122, cl. F17D 1/00, publ. 10/27/2004].

The disadvantages of the known pumping station are the design complexity and limited application possibilities (can only be used at shallow depths of the offshore zone of the sea).

To eliminate these drawbacks, an underwater pumping station for pumping a multicomponent gas-containing mixture is proposed, containing at least one screw pump installed on the pipeline, the input of which is connected to the liquefaction line through an electromagnetic valve electrically connected through a control unit to a thermocouple installed at the pump outlet, in which according to the invention, the liquefaction line is in communication with the seawater surrounding the station.

To reduce the corrosive effects on the working parts of a screw pump, the liquefaction line can be communicated with sea water through a desalination unit made, for example, in the form of a filter of ion-exchange resins.

A comparative analysis of the inventive pumping station with the prototype and with other solutions in the art shows that the set of features set forth in the patent formula is unknown from the existing level of technology, on the basis of which it can be concluded that it meets the criteria of the invention of “novelty”.

According to the applicant and the authors, the totality of the essential features set forth in the patent formula does not follow explicitly from the prior art, as it does not show the effect on the technical result obtained - a new property of the object - the totality of the features of the patent formula, which allows us to conclude compliance of the proposed solution to the second criterion of "inventive step".

The compliance of the proposed solution with the criterion of the invention "industrial applicability" is evident from the following example of a specific embodiment of an underwater pump station.

The invention is illustrated in the drawing, which shows a functional diagram of an underwater pumping station with desalination unit (dependent paragraph 2 of the patent formula).

Items shown in the diagram:

1 - pipeline;

2 - screw pump;

3 - liquefaction line;

4 - desalination unit;

5 - adjustable valve;

6 - electromagnet;

7 - electronic control unit;

8 - thermocouple.

The underwater pumping station includes a screw pump 2 mounted on the pipeline 1, the input of which is connected to the liquefaction line 3 through an adjustable (electromagnetic) valve 5, the electromagnet 6 of which is electrically connected via an electronic control unit 7 to a thermocouple 8 located at the output of pump 2.

The work of the underwater pump station is as follows.

When the screw pump 2 is turned on, the gas-oil mixture is pumped through pipeline 1. If a gas plug or gas-oil mixture with a high (60 ... 90 vol.%) Gas content gets to the inlet of the screw pump 2, the mixture is heated due to adiabatic gas compression and reduce liquid cooling of the pump 2. This heating is detected by a thermocouple 8 at the outlet of the pump 2 and leads to the operation of the electronic control unit 7, the electric control signal from which is supplied to the electromagnet 6 of valve 5. Valve 5 opens. Seawater surrounding the pumping station passes sequentially through the desalination unit 4 and then through the open solenoid valve 5 through line 3 to the inlet of the screw pump 2. This ensures the recovery of the pump efficiency and eliminates its overheating. The ingress of a relatively small volume of water into pipeline 1 does not significantly affect the quality of the pumped products of the subsea oil well (it initially contains a certain percentage of water), and the flow of fluidizing pump 2 to the inlet occurs only for a relatively short transit time of the gas plug. After passing the gas plug, the electronic control unit 7 is triggered (from the thermocouple signal 8), the electric control signal from which is supplied to the electromagnet 6 of valve 5. Valve 5 closes.

The use of the claimed invention allows to significantly simplify the design of an underwater pump station, reduce energy costs for pumping multicomponent oil and gas mixtures with screw pump stations (almost to the energy costs of separate transportation of the gas fraction), while retaining the advantages of screw pumps (simplicity, the ability to pump mixtures with a gaseous fraction from 0 up to 100%, high reliability, durability and ease of use). Distinctive features of the pumping station are low capital and operating costs.

Claims (2)

1. An underwater pumping station for pumping a multicomponent gas-containing mixture, containing at least one screw pump mounted on the pipeline, the input of which is connected to the liquefaction line through an electromagnetic valve electrically connected through the control unit to a thermocouple installed at the pump outlet, characterized in that the liquefaction line is connected to the surrounding sea water. 2. Underwater pumping station according to claim 1, characterized in that the liquefaction line is in communication with sea water through a desalination unit, made, for example, in the form of a filter of ion-exchange resins.