RU2568451C2 - Self-regulation method within preset limits for separating of gas-oil and oil-water phases in sealed flowing water tanks at changing phase parameters and device for its implementation - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: self-regulation method within preset limits for separating of gas-oil and oil-water phases in sealed flowing water tanks at changing phase parameters is characterised by the fact that phase interfaces are fixed by constructions at the preset levels and they cannot be changed essentially in height at change in parameters as to the height of the respective preset level of gas-oil phase separating the oil overflow tube is mounted and the above tube guides dehydrated oil to oil discharge chamber equipped with a float valve opening the oil pipeline when oil is delivered and closing the oil pipeline when oil is unavailable, at that the upper oil level in a sealed flowing water tank is regulated by height of the oil overflow tube, from the lower part of the sealed flowing water tank from zone placed below the preset level of oil-water phase separating settled water is supplied through water overflow pipe to water discharge chamber equipped with a float valve opening the drain pipeline when settled water is delivered and closing the drain pipeline when settled water is unavailable, at that water level in the sealed water flowing tank is regulated by height of water overflow tube thus forming hydraulic seal, and gas coming from the sealed water flowing tank is supplied to gas pipeline placed above the level of gas-oil phase separating through gas regulating valve, which maintains the preset gas pressure in the sealed water flowing tank, oil discharge chamber and water discharge chamber.

EFFECT: increased reliability and quality of separation.

3 cl, 2 dwg

Description

The invention relates to the automation of technological processes, in particular to devices for regulating the process of separation of a gas-oil mixture with the possibility of using reservoir pressure and (or) hydraulic energy of a pump supplying a mixture for transporting separated products and pumping water to maintain reservoir pressure, and can be used in oil fields and at the complex oil treatment facilities.

There is a method of controlling the level of the water-oil phase separation in dehydrators, in which the level of the phase separation is measured with a discrete sensor, by which the degree of opening of the regulatory body is changed, the level is measured using a two-position sensor with a zero deadband and in each control cycle the current values of the degree of opening of the regulatory body, on the basis of which the average value of its opening is determined, and at the time of switching the specified sensor measure the degree of opening the regulatory body to an average value [description of the invention to the patent of the Russian Federation No. 2065195 of 02.26.1991, IPC6 G05B 11/28, publ. 08/10/1996].

This method provides high quality adjustment of the level of the water-oil phase separation, but only if the oil density is constant. But in practice, as you know, it happens that the density of oil changes significantly during the day.

A known method of automatically controlling the process of sludge oil emulsion by adjusting the level of the phase separation of oil and water depending on the difference in hydrostatic pressure between two points located in the upper and lower parts of the sump, by taking into account the hydrostatic pressure of water in the emulsion phase of the oil, the density of water discharged from sedimentation tank, determine the average density of the oil emulsion between the given points from the measured density of the discharged water, determine the relationship of the measured value I drop the hydrostatic pressure and the density difference of the discharged water and the oil emulsion, and depending on the ratio found, they regulate the oil-water phase separation [description of the invention to USSR author's certificate No. 722936 of 07.25.1978, M.kl.2 C10G 33/00, G05D 27/00, publ. March 25, 1980, Bulletin No. 11].

The method solves the technical problem of improving the accuracy of regulating the level of the phase separation of oil and water.

A known method of regulating the process of sludge oil-water mixture by regulating the drainage of water from the separator-sump, while measuring the proportion of water in the oil-water mixture by comparing the hydrostatic pressure of the oil-water mixture in the separator-sump and the hydraulic pressure of the water in the water pipe located in the separator-sump, compare the measured the value of the difference of hydrostatic pressures with a given value of the pressure difference and the difference of these values form a control signal to regulate rd valve in the drainage line [specification of a patent RF №226,2528 on 26.05.2004, MPK7 C10G 33/08, publ. 10.20.2005].

A known method of regulating the level of the oil-water phase separation in sealed flowing vessels, including determining the level of the oil-water phase separation depending on the difference in hydrostatic pressure between the control points located in the upper and lower parts of the flow tank, with the subsequent formation of a control action on the water discharge rate , characterized in that in the volume of the flow tank there are three control points, two of which are located at the top and bottom of its oil part, and the third in the lower water of the second part, after which the hydrostatic pressure is measured between the control points in the oil part and between the control points at the top of the oil part and the lower water part, and the control action on the water drainage rate is formed based on the value of the current water level (patent No. 2328518 from 07/10/2008. )

In practice, as mentioned above, the density of oil can vary significantly during the day. Therefore, the disadvantage of the methods is the lack of influence on the control system of changes in the density of oil, which leads to low accuracy of measuring the level of phase separation, especially at a low water level. In practice, this manifests itself as the presence of residual water in dehydrated oil or the presence of oil in discharged water.

Closest to the claimed is a device for regulating the process of separation of the oil-water mixture containing a water level sensor connected via a regulator to a control valve on the water drainage line from the separator-settler, characterized in that the water level sensor is installed in a vertical expanded section of the water pipe, the lower end which is located in the zone of water accumulation, and connected to the regulator, the second input of which receives a signal of a set value of the water level in the water pipe, and its output is connected with a control valve on the water drainage line, in addition, the upper part of the water pipe by a gas equalization line is connected to the gas zone of the separator-settler [description of the invention to the patent of the Russian Federation No. 2268285 of 06.15.2004, IPC7 C10G 33/08, publ. January 20, 2006].

The disadvantage of these methods and devices is the low quality of regulation of the process of separation of the oil-water mixture due to the reduced accuracy of measuring the level of the oil-water phase separation, the complexity of the process of separation of the oil-water mixture when changing phase parameters and the low reliability of regulation due to the oversaturation of the device with sensors, measuring instruments, actuators, pumps, as well as the need for electrical networks and electrical equipment.

A common drawback of such devices is that over time, the sensitive elements of the sensors are coated with resinous substances and other contaminants, which significantly reduces the accuracy of their readings, and numerous sensors, measuring instruments and actuators, pumps, electrical networks and electrical equipment reduce the reliability and time of trouble-free operation.

Unreliability of regulation of the phase separation levels and regulation of the process of separation of the gas-oil mixture in sealed flow tanks when using numerous sensors, measuring instruments and actuators, pumps with changing phase parameters.

Also, these methods and devices do not provide for the use of reservoir pressure energy and (or) pressure created by the pump delivering the gas-oil mixture to separate and further transport phases through the corresponding pipelines and inject water to maintain reservoir pressure.

The objective of the invention is to improve the quality of separation of the gas-oil mixture due to the stabilization of adjustable parameters - the specified levels of phase separation and to increase the reliability of regulation of the process of separation of the gas-oil mixture in pressurized flow tanks with varying phase parameters and the use of reservoir pressure and hydraulic flow energy.

The method solves the technical problem of increasing the accuracy of the regulation of the levels of the gas-oil and oil-water phase sections under varying phase parameters using the energy of the reservoir pressure and (or) the pressure created by the pump delivering the gas-oil mixture to separate and further transport the phases through the corresponding pipelines and pump water to maintain reservoir pressure.

Technical result:

- increasing the purity of the separated components of the gas-oil mixture in sealed flow tanks with any changes in phase parameters;

- improving the reliability and cost of the cost of the device and the terms of the maintenance-free period due to the refusal of extra sensors, measuring instruments, actuators, control pumps, electrical networks and electrical equipment;

- the possibility of using the energy of the reservoir pressure or the pressure generated by the pumping unit, supplying the gas-oil mixture to the sealed flow tanks, for separation and transportation of the separated phases through pipelines and pumping water to maintain reservoir pressure;

- the ability to control the quality of the process of separation of the gas-oil mixture and the purity of the separation products by changing the supply volume of the gas-oil mixture in the supply pipe;

- reducing the cost of the process of separation and transportation of the separated phases through pipelines and pumping water to maintain reservoir pressure through the use of reservoir pressure energy or pressure created by a pumping unit that delivers a gas-oil mixture in a sealed flow tank;

- the possibility of reconstruction and equipping existing devices with a device;

- the possibility of combining, without loss of pressure, the separated oil and gas for transporting the gas-oil mixture to the points of complex processing of petroleum products through one pipeline;

- the ability to supply the settled water to maintain reservoir pressure directly to the nearest injection wells in oil fields or to the reservoir pressure maintenance system without unnecessary transportation and without additional pumping equipment by using reservoir pressure energy or pressure created by a pumping unit supplying gas-oil mixture to pressurized flow tanks ;

- the ability to equip any section of the pipeline with a device since it does not require either electrical networks or maintenance personnel;

- the ability to reduce the load and (or) the diameter of the pipeline from the place of formation water discharge to the preliminary oil treatment plants;

- the device operates autonomously in self-regulation mode.

Figures 1 and 2 show examples of options for external and internal design of devices for self-regulation within the specified limits of the levels of gas-oil and oil-water phases in sealed flow tanks with varying phase parameters.

The technical result that can be obtained by implementing the proposed method is achieved as follows.

The technologically optimal levels of gas-oil and oil-water phase divisions and the necessary internal pressure for a specific sealed flow tank and gas-oil mixture supply mode are calculated and set.

An oil overflow pipe (1) is installed to the height of the specified gas-oil phase separation level, which directs the dehydrated oil to the oil discharge chamber (2), equipped with a valve (3), for example, a float valve that opens the oil pipeline (4) when oil enters and closes the oil pipeline (4) when her absence. In this case, the upper level of oil in a sealed flow tank is regulated by the height of the oil overflow pipe to obtain a given level of height of the gas-oil phase separation.

From the bottom of the sealed flow tank from the zone located below a predetermined level of the oil-water phase separation, the settled water is supplied to the water discharge chamber (5), the water level in which is regulated by the preset design height of the water overflow pipe (6). As a result, the oil-water and gas-oil phase separation levels are structurally fixed with a water-hydraulic shutter at predetermined levels with insignificant fluctuations in the oil-water phase separation level in height in proportion to changes in the specific gravities entering the sealed oil and water flow tank for any changing phase parameters. The water unloading chamber (5) is equipped with a valve (7), for example, a float valve, which opens the waste water pipe (8) upon receipt of the settled water and closes the waste water pipe (8) if it is absent.

The incoming gas from the sealed flow tank is fed into a gas pipeline (10) located above the gas-oil phase separation through a gas control valve (9) that maintains a predetermined gas pressure in a sealed flow tank, oil discharge and water discharge chambers.

Valves that open pipelines when fluid enters and lock pipelines if it is absent provide sealing of water and oil discharge without pressure loss in a sealed flow tank.

The device is easy to implement, since gas and liquid valves of various designs are mastered by industry.

The reliability of the device depends on the reliability of the valves - the only moving parts of the device.

The process of separation of gas-oil mixture proceeds under a common predetermined pressure in a sealed flow tank, oil discharge and water discharge chambers. The pressure in the waste gas, oil and water pipelines behind the valves automatically decreases and equalizes to the operating pressures of each of these systems. The specified pressure in the device is created by using the energy of the reservoir pressure and (or) the pressure created by the pumping unit, which supplies the gas-oil mixture to the sealed flow tanks. Pressure energy can be used to transport separated petroleum products through pipelines without additional pumping equipment. If necessary, it is possible to combine, without loss of pressure, the separated oil and gas for transporting the gas-oil mixture to the points of complex processing of oil products through one pipeline.

The device makes it possible to supply the settled water to maintain reservoir pressure directly into the nearest injection wells in oil fields without unnecessary transportation and without additional pumping equipment due to the use of reservoir pressure energy and (or) pressure created by the pumping unit, which supplies the gas-oil mixture to the sealed flow tanks.

When considering a closed sealed system operating under total pressure and consisting of a well supplying a gas-oil-water mixture to a sealed flow tank and an injection well supplying settled water to maintain reservoir pressure, it should be noted that at equal pressures and piezometric heights, the piezometric head of the well with water significantly more than the piezometric pressure of a well with a gas-oil-water mixture due to different density of liquids. That is, heavier water from the device can by gravity enter the injection well, which is under reservoir pressure.

Claims (3)

1. The method of self-regulation within the specified limits of the levels of the phases of the gas-oil and oil-water phases in sealed flow tanks with varying phase parameters, characterized in that the phase sections are structurally fixed at predetermined levels and cannot significantly change in height when the phase parameters change that an oil overflow pipe is installed to a height of a predetermined level of gas-oil phase separation, directing dehydrated oil to an oil discharge chamber equipped with a float valve that opens the oil pipeline when oil enters and shuts off the oil pipeline in its absence, while the upper oil level in the sealed flow tank is controlled by the height of the oil overflow pipe, from the bottom of the sealed flow tank from the zone below the specified oil-water phase separation, the settled water is fed through the water overflow pipe to a water unloading chamber equipped with a float valve that opens the waste water pipe upon receipt of the settled water and closes the waste water pipe if it is absent, when this, the water level in the sealed flow tank is regulated by the height of the overflow pipe, forming a hydraulic shutter, and the incoming gas from the sealed flow tank is fed into a gas pipeline located above the gas-oil phase separation through a gas control valve that maintains a given gas pressure in the sealed flow tank, oil discharge and water discharge chambers. 2. A device for self-regulation within the specified limits of the levels of the gas-oil and oil-water phases in sealed flow tanks with varying phase parameters, comprising a hydraulic water shutter for stabilization within the specified limits of the phases of the phases and an unloading gas valve that regulates the gas pressure in the sealed flow tanks, characterized in that an oil overflow pipe is installed to the height of the specified gas-oil phase separation level, which directs the dehydrated oil to the oil discharge chamber, equipped with a float valve that opens the oil pipeline when oil enters and closes the oil pipeline when it is absent, a water overflow pipe is installed to the height of the specified water level, made with the possibility of taking water from the bottom of the sealed flow tank from the zone below the specified oil-water phase separation, this water overflow pipe, forming a hydraulic shutter, is configured to supply water to a water discharge chamber equipped with a float valve that opens the waste water However, upon receipt of the settled water and locking the waste water supply system in its absence, moreover, a gas pipeline having a gas control valve supporting a predetermined gas pressure in the sealed flowing tank is connected to the oil discharge chamber and the water discharge chamber with the upper part of the sealed flow tank above the gas-oil interface, oil discharge and water discharge chambers. 3. The device according to claim 2, in which water from the water discharge chamber, which is under a given pressure, is supplied to the well or reservoir pressure maintenance system for injection into the reservoir due to this pressure.

Images