RU2741296C1 - Unit set for cluster separation - Google Patents

Abstract

FIELD: oil and gas industry.SUBSTANCE: invention relates to oil industry and can be used for separation of well products at oil fields of late development stage. Block unit of cluster separation includes oil-water emulsion (OWE) supply system from collector well head or AGMU, separation unit, water removal system from separation unit into MRP system, system for removal of dehydrated water-oil emulsion from separation unit, reagent supply system, gas collection and supply system. In the separation unit there installed in parallel are two tubing strings of different length, inlet of shorter tubing string in upper part is hydraulically connected to outlet of OWE feed system pipeline, and the output of the longer tubing string in the upper part is hydraulically connected to the water removal system from the separation unit to the MRP system. Separation unit is made in the form of well in conservation, and on lower part of longer string of tubing there is submersible pump. Output of separation unit is hydraulically connected with inlet to ejector, outlet of which is hydraulically connected to inlet of collection system. Gas collection and supply system includes a gas separator hydraulically connected to the inlet to the ejector chamber.EFFECT: increased efficiency of cluster separation due to use of well in conservation, located on cluster platform, without additional construction of new wells and capital structures.1 cl, 1 dwg

Description

Technology area

The invention relates to the oil industry and can be used to separate the production of wells into oil and water in oil fields of a late stage of development.

State of the art

There is a known method of dumping the produced water (RF patent No. 106845, IPC E21B 43/00, published on 07/27/2011), containing a well plugged with a packer, a pipe insert and an inner string are located in the well, the lower end of the inner string is located at or deeper the lower end of the pipe insert, the inlet pipe for water-in-oil emulsion (VNE) is connected to the wellhead or pipe insert, the water outlet pipe is connected to the inner string, the oil outlet pipe is connected to the pipe insert or well. The water outlet is connected by a bypass to the oil outlet, valves are made on the bypass and on the water outlet after connection with the bypass, and the water outlet is equipped with a sampler before being connected to the bypass. Regulating valves are located on the water outlet to the bypass and on the oil outlet. The disadvantage of this device is its low efficiency due to insufficient purification of the discharged water from mechanical impurities.

There is a known method of cluster discharge and utilization of produced water (patent RU No. 2588234 C1 IPC E21B 43/20, published on June 27, 2016), according to which the injectivity of an injection well is measured, the products of one or more production wells are fed into a well or a well for preliminary discharge water. Measure the amount of crude oil and gas, as well as the water cut of crude oil, the density of oil and water entering the well or pit for preliminary water discharge. Well products are divided into partially dehydrated oil, gas and water. Partially dehydrated oil and gas are sent to the collection header. The discharged water is fed into the injection well. Determine the compatibility of the discharged water with the formation water. If the waters are compatible, the injection well is equipped with a device for creating a water pressure sufficient for pumping water into the formation, configured to change the flow rate, including the minimum flow rate. If the quality of the discharged water is unsatisfactory, it is sent to the collecting collector. If the quality of the discharged water is satisfactory, it is sent to the injection well. The amount of discharged water entering the injection well is measured. The disadvantage of this device is that the amount of water discharged into the collecting collector is not constant, which significantly reduces the efficiency of the technology.

Known separation plant (RF Patent No. 2252312, class IPC E21B 43/38, published date 20.05.2005), containing a column with pipelines for supplying an oil-water emulsion and removing water and oil, while the column is located in a well, the pipeline for supplying an oil-water emulsion is connected tangentially to the top of the column, the bottom of the column is open. The oil withdrawal pipeline, made in the form of a pipe with a smaller diameter than the string, is located inside the string, and the water withdrawal pipeline is connected to the wellhead. The axes of the string and the oil withdrawal pipeline are made coaxial or parallel, the water withdrawal and oil withdrawal pipelines are equipped with control devices. The disadvantage of the device is that the effective separation of the water-oil emulsion is not ensured, in particular, a sufficiently effective water purification is not provided, while part of the oil droplets is carried away with the water. Separation takes place in a limited annular space, as a result of which there are no conditions for water purification and sedimentation of mechanical impurities. Another drawback is the high metal consumption during the construction of a pit on a well cluster and insufficient equipment of the technology with control, management and automation means.

The closest technical solution in terms of a set of essential features to the claimed invention and selected as a prototype is a method for dumping associated water and gas separately on the well pads of an oil field (RF patent No. 2713544, class IPC E21B 43/34, published date 05.02 .2020), implemented through the installation, including the installation located on the well cluster, containing a vertical pipe, plugged from below, with a sealed inner cavity, immersed to its full depth in the ground, shut-off valves, pressure regulator, inlet and outlet pipelines, water conduit, gas outlet, which, being located vertically, parallel to each other, tightly pass from above through the wellhead fittings into the installation.

The disadvantage of this installation is the complexity of running three parallel pipe strings into the well, the absence of additional water purification from mechanical impurities and the complexity of the installation with a low gas factor of well production.

The essence of the invention

The proposed invention is aimed at increasing the efficiency of cluster separation through the use of a conservation well located on the cluster site, without additional construction of new wells and capital structures.

The technical result, which consists in increasing the efficiency of well product separation and reducing the influence of the gas factor on the operation of the unit, is achieved due to the fact that the cluster unit of cluster separation includes wellhead equipment, a gas collection and supply system, a control station, a system for supplying water-oil emulsion from a collection well or AGZU into the separation block, the water drainage system from the separation block to the pressure maintenance system, the drainage system of dewatered VNE from the separation block, while inside the separation block, two tubing strings are installed in parallel in such a way that the shorter tubing string in the upper part is hydraulically connected to the outlet of the supply pipeline VNE, a longer tubing string in its upper part is hydraulically connected to the water drainage system from the separation unit to the reservoir pressure maintenance system, the upper part of the separation unit through the wellhead valve is connected to the inlet to the collection system (UPPN, BPS), with the separation unit made in the form of a law a torn well with a production casing, a submersible pump is located on the lower part of a longer tubing string, and the upper part of the separation unit is connected to the entrance to the collection system (UPPN, BPS) through an ejector, and the cluster separation unit also includes reagent supply system.

The specified technical result is also achieved by the fact that the block installation of cluster separation includes: a reagent supply system, a system for collecting and supplying gas to the ejector, as well as a control station.

Brief Description of Drawings

FIG. 1 shows a diagram of a block installation of cluster separation Implementation of the invention

A block-type installation for cluster separation includes: a system for supplying VNE from a collecting collector of wells or AGSU to a separation unit, a separation unit (pit or mothballed well), a water drainage system from a separation unit to a pressure maintenance system, a system for draining dewatered VNE from a separation unit, a reagent supply system gas collection and removal system, control station BUKS.

The system for supplying VNE from a prefabricated reservoir of wells or AGZU to a borehole or a mothballed well includes pipeline 1 for supplying VNE with AGZU through a filtration unit 2 to a gas separator 3, which is hydraulically connected by pipeline 4 to the inlet of pump 5. The outlet of pump 5 is hydraulically connected by pipeline 6 to the inlet to separation unit 7.

The separation unit 7 includes a suspended well 8 with a production casing diameter (146/168 mm), in which tubing strings 9 and 10 are installed in parallel (for example, 40 mm in diameter). The inlet of the shorter tubing string 9 in the upper part is hydraulically connected to the outlet of the pipeline 6 of the VNE supply system. The outlet of the longer tubing string 10 in the upper part is hydraulically connected to the water drainage system from the separation unit 7 to the reservoir pressure maintenance system. A submersible pump 11 is located on the lower part of the tubing string 10.

The water drainage system into the reservoir pressure maintenance system includes a pipeline 12, hydraulically connecting the outlet of the tubing string 10 with the inlet to the filter unit 13, as well as a pipeline 14 connecting the outlet of the filter unit 13 with the inlet to the reservoir pressure maintenance 15.

The drainage system for dewatered VNE includes a pipeline 16, which hydraulically connects the outlet of dewatered oil from the upper part of the separation unit 7 to the inlet to the ejector 17, as well as a pipeline 18 connecting the outlet of the ejector 17 to the inlet to the collection system (BPS).

The reagent supply system includes a reagent supply unit 19, hydraulically, by pipeline 20, connected to the pipeline 6, and electrically connected to the ESP 21 control station.

The gas collection and supply system includes a gas separator 3, hydraulically by a pipeline 22, connected to the inlet to the ejector chamber 17. The gas separator 3 is designed to reduce the effect of the released gas on the separation process and the operation of the block installation.

The control station 21, which ensures the automated operation of the installation, has three control levels.

Implementation of the invention

Block installation of cluster separation works as follows.

To implement the method of cluster separation and utilization of produced water, the device operates as follows. The unit, housed in a box-type casing, is delivered to an oil treatment facility, for example, a well cluster. The ground equipment of a block-type installation for cluster separation includes: filtration units for preliminary and fine cleaning from mechanical impurities, a gas separator, a horizontal pump, an ejector, and a reagent supply unit. Installation is carried out on a prepared site with a hard surface. This design provides mobility and ease of transportation and installation of the unit. The unit is connected to the wells collection header or the outlet from the AGZU through a flange or quick-disconnect connection. A sampler is located at the entrance to the installation. To the wells connected to the AGSU or the collection header, through the pipeline 1, the production of production wells is sent, which is a direct emulsion with a high water cut (more than 70%). The dispersed phase is oil in the form of finely crushed droplets, the dispersion medium is produced water.

The oil-water emulsion from the collecting header through the pipeline enters through the valve into the gas separator 3, designed to reduce the effect of the released gas on the separation process and the operation of the installation. The incoming VNE pressure is monitored through a pressure sensor.

Due to the parallel arrangement of tubing strings 9 and 10 for the introduction of the product by the well and the removal of separated water, the possibilities and boundaries of the technology applicability are expanded in terms of the volumes of water withdrawal after separation. Due to the limitation of the ESP diameter (146/168 mm), with the coaxial arrangement of tubing strings 9 and 10 in the separation unit 7, there is no possibility of running ESPs of sizes 3 and more, which have disadvantages in cost and energy saving in front of pumps of serial sizes.

The water-oil and gas mixture is directed through the tubing string 9 with a diameter of 40 mm, taken out to a predetermined injection depth and directed into the annulus between the tubing strings 9 and 10 with a diameter of 40 mm and the production casing with a diameter of 146/168 mm, where mixing and creation of an unstable emulsion occurs. Due to the difference in densities, the separated oil accumulates in the upper part of the well of the production casing 8 of the separation unit 7, and then, along the annular space and is discharged through the branch pipe for oil outlet into the pipeline 16. The water separated after settling accumulates in the lower part of the production casing 8. Remaining in water, oil droplets float in a descending stream of water, while the droplets participate in the process of phase separation, provided that oil droplets are created and enlarged while moving to a submersible pump 11. A submersible pump 11 of the ESP type raises water to the surface, directing it to pipeline 12. Partially dehydrated oil rises from the well into pipeline 16 due to the line pressure of the producing wells.

The demulsifier reagent is fed to the VNE from the reagent supply unit 19 through the pipeline 20 to increase the separation efficiency.

The gas separated in the gas separator 3 is directed through the pipeline 22 to the inlet of the ejector 17, with the help of which the gas is pumped into the flow of liquid leaving the separation unit, and the degassed VNE is fed to the intake of a horizontal pump, on which the pressure required for the movement of the liquid in the well is reached. When the pressure in the collecting manifold is sufficient for the operation of the installation, the pump is turned off, and the VNE is sent to the bypass.

The separated water, through the pipeline 12, enters the filtration unit 13 to purify the discharged water. The filtration unit 13 on the water outlet line allows to reduce the size and content of mechanical impurities in the water, allowing it to meet the conditions of STP and OST 39-225-99. The flow meter measures the amount of discharged water. To control the quality of water, samples are taken at the inlet and outlet of the filtration unit 13. If the quality meets the requirements of OST, water is sent to the reservoir pressure maintenance system.

Partially dehydrated oil enters the oil outlet line 16. A moisture meter and a flow meter determine the flow rate and water cut of the oil. The pressure is controlled via a pressure transducer. After that, the oil is fed to the intake of the ejector 17 for pumping the previously separated associated gas from the gas separator 3 through the pipeline 22. At the outlet of the ejector 17 there is a sampler.

The automated operation of the unit is provided by three control levels: the lower level - sensors and actuators (Pt pressure sensors, Ft flow meters). The middle level includes controllers that receive and process information from sensors and issue control signals to regulate the parameters of the separation process (VFD), as well as indication sensors. The upper level - automated workstations (AWP) of the operator, providing collection and storage of information, and issuing remote control commands.

The piping of all technological elements of the surface part of the installation is made in such a way that it allows directing the flow of oil-containing liquid through the bypass without the intake of VNE if there is no need. With an inclined profile of the well in conservation, an additional separation of oil from water occurs, since the inclined design allows the presence of a larger surface (the walls of the production string) for the accumulation and enlargement of oil droplets contained in the emulsion, thereby characterized by an increased efficiency of the installation compared to the vertical profile.

Improving the reliability of well operation regulation includes measuring the amount of supplied water-oil emulsion and associated gas, as well as water cut, determining the amount of incoming dewatered oil, withdrawing partially dewatered oil and associated gas from the annulus of the well, removing discharged water through the tubing string, measuring the amount of discharged water, measuring the pressure of the water-oil emulsion at the well inlet, the pressure of partially dehydrated oil at the outlet of the annular space of the well and the pressure of the discharged water at the outlet of the inner string. The operation of the installation is controlled by means of shut-off and control valves at the entrance to the separation unit, at the exit from the annulus and at the exit from the tubing string, and the amount of dehydrated oil is determined and compared with the amount of crude oil entering the well. Lift pipes are subject to pressure testing before being put into operation.

Claims (2)

1. Block installation of cluster separation, including a system for supplying water-oil emulsion (VNE) from a collecting header of wells or AGZU, a separation unit, a water drainage system from a separation unit to a reservoir pressure maintenance system, a system for removing dewatered water-oil emulsion from a separation unit, a reagent supply system, a collection system and gas supply, while two tubing strings of different lengths are installed in parallel in the separation block, the inlet of the shorter tubing string in the upper part is hydraulically connected to the outlet of the pipeline of the VNE supply system, and the outlet of the longer tubing string in the upper part is hydraulically connected to the water drainage system from separation unit into the reservoir pressure maintenance system, characterized in that the separation unit is made in the form of a well in conservation, and a submersible pump is located on the lower part of the longer tubing string, while the outlet of the separation unit is hydraulically connected to the inlet to the ejector, the outlet of which is hydraulically connected to the inlet into the collection system, while the gas collection and supply system includes a gas separator, a guide Equally connected with the entrance to the ejector chamber. 2. Block installation of cluster separation according to claim 1, characterized in that the separation block is made in the form of a pit.

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