RU79936U1 - DEVICE FOR SEPARATION OF GAS AND MECHANICAL IMPURITIES FROM OIL IN A WELL - Google Patents

Abstract

A device for separating gas and solids from oil in a well. It can be used in the process of oil production using electric centrifugal pump installations (ESP). The device is adapted to be connected to the pump, it contains a housing with openings for the entrance of a gas-liquid mixture and a slurry container for sedimentation of mechanical impurities, and differs in that the device comprises a suction pipe attached to the pump placed in the housing, the upper part of the housing in contact with the suction pipe , perforated, and the lower one, located under the nozzle, is a slurry container. The claimed design creates such a change in the speed of the upward flow of the produced fluid, which allows you to simultaneously separate from the produced oil and gas and mechanical impurities. The gas-liquid mixture coming from the reservoir using the ESP, passing through the perforation holes of the body, picks up speed and when it reaches the end of the suction pipe, it sharply changes the flow direction by 180 °. At the same time, the flow rate in the cavity of the sludge container decreases by 2-3 times due to an increase in its bore. This creates the conditions for the deposition of solids according to the Stokes formula, and solids are deposited on the bottom of the sludge container. Moreover, the design of the device does not contain separate from each other complex nodes for gas separation and separation of impurities. A new technical result achieved by using the claimed device is to increase the efficiency of separation of both gas and mechanical impurities from oil with a significant simplification of the design.

Description

The utility model relates to the oil industry and can be used in the process of oil production using electric centrifugal pump units (ESP).

The content of solid mechanical impurities and gas in the produced products from the wells adversely affect the ESP performance. So, as a result of the destructive effect of mechanical impurities on the working parts of the ESP pump, the overhaul period of its operation is significantly reduced, and often leads to accidents (flights) due to breakdown of the ESP sections. Due to destruction by mechanical impurities and clogging of the working parts of the ESP pumps, more than 20% of the ESP premature failures occur. The increased gas content in the produced products leads to a disruption of the ESP operation mode, a decrease in flow rates, and most often to a pump outage. Large amounts of money are spent on eliminating these complications.

In the practice of oil production, in order to combat the harmful effects of gas, various types of gas separators are used, which are included in the ESP unit, and to combat the increased content of mechanical impurities in the produced products, wear-resistant working elements of ESP pumps are produced, various types of sludge traps, filters are used.

A device for separating sand and gas from oil in a well (RU 2006574, publ. 1994) / 1 /. The principle of operation of this device is based on the use of the properties of gravitational forces during gas separation and sand deposition in borehole conditions using deep-well sucker-rod pumps (SHGNU). The objective of this device is to separate sand and gas from a multiphase well fluid in order to increase the overhaul

period of the sucker rod pump. The known device comprises a lifting pipe for a pump, placed in a pipe with radial holes and a bottom, rigidly connected with the pipe, and forming an annular cavity with it, a coupling in the upper part of the pipe, made with channels communicating the annular cavity with the external environment. In this case, the nozzle provides a pressure drop in oil of 1-2.5 MPa, and the channels are blocked by check valves. The lifting pipe with the lower end is installed at a distance of 1 / 7-1 / 15 of the length of the pipe from its bottom.

Check valves create additional resistance in the channels, which does not allow sufficient separation of gas from the well fluid, while the filling factor of the SHGNU valves and, accordingly, its performance are reduced. According to the authors of the device / 1 /, the sedimentation of sand along the annulus to the bottom of the well occurs at the moment the formation fluid moves from the formation to the device with a lifting speed of about 1.7 m / min. However, it is known that the sedimentation rate of sand particles according to the Stokes formula Vzh ≤1.2 m / min, and therefore the bulk of the sand will rush together with the reservoir fluid through the radial holes of the device to receive a sucker rod pump. Due to the fact that the flow velocity will decrease to a value of 1.2 m / min, as you approach the lower part of the nozzle, sand will settle to the bottom of the nozzle.

Considering the fact that the distance between the bottom of the nozzle and the intake of SHGNU is 1/7 ÷ 1/15 of the length of the nozzle, which is 80 ~ 90 cm, such a small volume of the chamber for the accumulation of sand significantly reduces the period of operation of the SHGU and after 1-2 months of operation there will be a full filling of the chamber, clogging with sand in the intake of the pump and its stop.

In addition, there is a well-known gas-liquid mixture separator (RU 72015, publ. 2008) / 2 /, designed for phase separation of a gas-liquid mixture at the inlet of a sucker rod pump (SHGU) in order to increase the filling ratio of the pump valves, i.e.

increase in its productivity and the overhaul period. The known separator comprises a housing with openings for the entrance of a gas-liquid mixture, a preliminary gas separation unit and a gravitational gas separation unit, a mechanical impurity separation unit with a channel for removing them into a collector, a channel for removing purified liquid, and the preliminary gas separation unit is made in the form of covering the body glasses facing each other with the bottom, while the holes for the entrance of the gas-liquid mixture are located at the bottom of the glasses, open on top, and at the open end of the glasses.

Due to preliminary gas separation in the bottom of the glasses, despite the fact that the most complete gas separation occurs in the gravitational gas separation unit, due to an increase in the flow rate of the gas-liquid mixture and its screw movement, gas bubbles under the action of centrifugal forces move to the wall of the separator body and are carried away the upper part of the gas separator, and then into the annulus. This ensures a high degree of gas separation from the produced multiphase well products. The disadvantage of this model is the low degree of separation of sand from well products, because the basic condition is not satisfied under which the sedimentation of sand particles Vzh / W≤2.5, where

Vzh - fluid velocity at which sand separation occurs;

Vzh ≤1.2 m / min;

W is the sand deposition rate.

The borehole fluid, passing through the inlet openings, picks up speed, and when passing through the gravity separation unit, the flow velocity is multiplied, and the borehole fluid, separated from the gas, but not freed from sand, rushes to receive a sucker rod pump. The increased sand content in the produced fluid will inevitably lead to premature wear of the valve steam of SHGNU and its failure. In addition, separate pre-assembly

gas separation, made in the form of cups covering the case, facing each other with the bottom, as well as a gravitational gas separation unit, made in the form of a hollow screw, the separation of mechanical impurities contained in the known separator, complicate its design.

The claimed device for separating gas and solids from oil in the well, as well as the known separator, is configured to connect to the pump. The device comprises a housing with openings for entering the gas-liquid mixture and a slurry container for sedimentation of mechanical impurities. The difference between the claimed device and the known one / 2 / is that the device comprises a suction nozzle connected to the pump, placed in the housing, the upper part of the housing in contact with the suction nozzle is perforated, and the lower one, located under the nozzle, is a slurry container.

The claimed design creates such a change in the speed conditions of the upward flow of the produced fluid, which allows you to simultaneously separate from the produced oil and gas and mechanical impurities. The gas-liquid mixture coming from the reservoir using the ESP, passing through the perforation holes of the body, picks up speed and when it reaches the end of the suction pipe, it sharply changes the flow direction by 180 °. At the same time, the flow rate in the cavity of the sludge container decreases by 2-3 times due to an increase in its bore. This creates the conditions for the deposition of solids according to the Stokes formula, and solids are deposited on the bottom of the sludge container. Moreover, the design of the device does not contain separate from each other complex nodes for gas separation and separation of impurities.

A new technical result achieved by using the claimed device is to increase the efficiency of the Department

from oil, both gas and mechanical impurities with a significant simplification of the design.

The utility model is illustrated in the figure, which shows an electric centrifugal pump 1, which is connected through a transfer clutch 3 to a suction pipe 4 placed in a housing 5. The upper part of the housing 5 in contact with the suction pipe 4 is perforated with holes 6, and the lower one located under the pipe 4 , one-piece, is a slurry container 7 with a plug 8.

When installing the ESP, the casing 2 is attached to the input module of the ESP pump 1, to which the claimed device is connected via the transfer clutch 3, and then the ESP is fully installed and put into the well by tubing (tubing).

The gas-liquid mixture coming from the reservoir using the ESP through the lower perforation holes 6 of the housing 5 enters the sludge container 7, and due to a sharp decrease in the speed and direction of the gas-liquid mixture flow, gas is separated and freely released. Bubbles of gas rise up and through the upper perforated holes of the housing 5 enter the annulus of the well. With a decrease in the fluid flow rate, mechanical impurities are deposited in the sludge container 7 due to gravitational forces, where they accumulate. Degassed liquid, purified from mechanical impurities and gas, through the suction pipe enters the receiving module of the ESP pump and rises to the surface through the elevator of the tubing. The claimed device allows the simultaneous separation of mechanical impurities and gas from the produced oil using ESP. In addition, it is compatible with the standard casing included in the ESP unit, is easily modeled depending on the pump performance, gas factor and the content of solids in the produced products from the well, and is also simple, not requiring significant installation time.

Claims (1)

A device for separating gas and mechanical impurities from oil in the well, made with the possibility of attaching to the pump, comprising a housing with openings for the entrance of a gas-liquid mixture and a slurry container for sedimentation of mechanical impurities, characterized in that the device comprises a suction pipe connected to the pump placed in the housing , the upper part of the housing in contact with the suction pipe is perforated, and the lower, located under the pipe, is a slurry container.