RU2714347C1 - Apparatus for cleaning oil-field waste water for injection into formation - Google Patents

Abstract

FIELD: technological processes.

SUBSTANCE: invention is intended for production of purified water from oil-field waste water (OWW) and can be used in system of reservoir pressure maintenance at flooding of oil deposits. Plant for cleaning oil-field waste water for pumping into formation consists of hydrocyclone 1 with pipes for feeding initial oil-field waste water 2, removal of upper drain 3 and discharge of lower drain 4 communicated with inlet branch pipe 5 of settler 6, which is also equipped with pipes for discharge of oil emulsion 7, purified water 8, release of residue 9, wherein oil emulsion discharge branch pipe 7 is communicated by means of pipeline with branch pipe of input oil-field waste water 2, hydrocyclone 1 vertically installed relative to settler 6, divided into four communicating chambers by three upper 10 and three lower vertical 11 partitions, wherein each chamber of settler is equipped with conical bottom 12 with discharge branch pipe 9, and purified water discharge branch pipe 8 of settling tank 6 is communicated with inlet branch pipe 13 of additionally installed self-washing sand filter 14, also equipped with cleaned water discharge branch pipe 16 and flushing water discharge branch pipe 15 communicated with feed oil source waste water feed pipe 2 of vertically arranged hydrocyclone 1.

EFFECT: high degree of purification of OWW due to reduced content of oil and mechanical impurities in treated waste water.

1 cl, 1 dwg

Description

The invention is intended to produce purified water from oilfield wastewater and can be used in a system for maintaining reservoir pressure during flooding of oil fields

An analogue of the invention is a device for the purification of oily wastewater (RF Patent No. 2189360 A device for the purification of oily wastewater / A.B. Adelshin, N.I. Potekhin, A.A. Adelshin; registered. 05.23.2000; Publ. 20.09 .2002, Bull. No. 8), which includes a hydrocyclone with nozzles for supplying source water, drainage of the upper and lower drains to a sump equipped with a vertical partition that does not reach its upper part, with nozzles for drainage of oil, purified water and sludge, at the outlet of the upper and lower drains of the hydrocyclone claimed the cylindrical chamber.

The disadvantage of this device is the low effect of oilfield wastewater treatment.

A device for purifying oil-containing wastewater (RF Patent No. 2248327 A device for purifying oil-containing wastewater / A.B. Adelshin, N.I. Potekhin, A.A. Adelshin; registered. 09/11/2003, Published. 03/20/2005 g. .; Bull. No. 8), which contains a pipeline for supplying the initial oil-containing wastewater, a pressure hydrocyclone, at the outlet of the lower discharge of which a cylindrical chamber, a settling tank, and distribution devices are installed. The sump has separation walls, oil collectors, a device for the removal of purified water, oil, and sludge.

This device provides for tangential swirling of the flow in a hydrocyclone in order to destroy the armor shells of oil droplets and hydrodynamic treatment in a cylindrical chamber to intensify the coalescence of oil particles.

The disadvantage of this device is the low effect of oilfield wastewater treatment.

The objective of the invention is to improve the design of the installation for the purification of oil field wastewater (NSW) for injection into the reservoir, ensuring its high performance.

The technical result of the invention is to increase the degree of purification of the LEL by reducing the content of oil and solids in the treated wastewater used in the reservoir pressure maintenance system during waterflooding of oil fields.

The technical result is achieved by the fact that the installation for purification of oilfield wastewater for injection into the reservoir consists of a hydrocyclone with nozzles for supplying the initial oilfield wastewater, a drain for the upper drain and a drain for the lower drain, connected to the inlet of the sump, also equipped with nozzles for the discharge of the oil emulsion, purified water discharge sludge, while the branch pipe for removing the oil emulsion is communicated by means of a pipeline with a branch pipe for supplying the original oil field wastewater, hydrocyclone, vertically installed relative to the sump, divided into four communicating chambers by three upper and three lower vertical partitions, each chamber of the sump equipped with a conical bottom with an outlet pipe, and the outlet pipe of the purified water of the sump is communicated with the inlet pipe of an additionally installed self-washing sand filter, also equipped with a pipe of the outlet for cleaning water and a flushing water outlet pipe connected to a pipe for supplying the initial oilfield waste water vertically laid hydrocyclone.

Reducing the oil content in the treated wastewater is achieved by its partial removal from the pipe outlet of the upper drain of a vertically located hydrocyclone and from the pipe of the discharge of the oil emulsion of the sump. Under the action of centrifugal forces in a vertically located hydrocyclone, the armor shells are destroyed in drops of oil and the intermediate layer of the coarsely dispersed phase at the oil-water interface. As a result, mechanical impurities are released from oil. The released oil droplets coalesce, forming a free-floating oil that floats to the top of a vertically located hydrocyclone due to its lower density compared to water. The vertical arrangement of the hydrocyclone by reducing the diameter in its upper part increases the flow rate of wastewater, which leads to the destruction of the armor shells on small drops of oil.

Reducing the content of mechanical impurities in the treated wastewater is achieved in a vertically located hydrocyclone by releasing them from the intermediate layer of the coarsely dispersed phase and entrainment through the outlet pipe of the lower drain, connected to the inlet of the sump, by the flow of water into the sump, in which mechanical impurities in the form of gravity in the form oil sludge is deposited in the conical bottoms located under each chamber of the sump, after which it is removed through the sludge discharge pipes.

The message of the outlet pipe of the oil emulsion of the sump, divided into four chambers, through a pipeline with a pipe for supplying the source of oilfield wastewater of a vertically located hydrocyclone allows for additional purification of oilfield wastewater, since the passage of oilfield wastewater through the chamber of the settler destroys the armor shells on small drops of oil and oil coalescence, as well as the separation of solids in the form of oil sludge, for collection and disposal where each chamber is equipped with a conical bottom and pipe sediment release.

The message of the outlet pipe of the purified water of the sump to the inlet pipe of the additionally installed self-washing sand filter allows the further movement of partially treated waste water to the sand filter, in which the sewage is treated from oil and mechanical impurities. In a self-washing sand filter there is no compression of sand over time as a result of its constant movement up and down, there is no air purge and there are no clogging nozzles. The filter is able to retain a high content of suspended particles. Flushing water with compacted solid particles leaves through the flushing water outlet pipe, which is in communication with the inlet port of the initial oilfield wastewater of the hydrocyclone, is discharged into a vertically located hydrocyclone, and the treated wastewater is discharged through the outlet of the purified water.

Thus, the combination of essential features allows you to achieve the desired technical result.

The drawing shows the installation for cleaning the NSW for injection into the reservoir, consisting of a hydrocyclone 1 with nozzles for supplying the original oilfield wastewater 2, drain the upper drain 3 and drain the lower drain 4. The lower drain pipe 4 is in communication with the inlet pipe 5 of the sump 6. The sump 6 is provided also the branch pipes of the discharge of oil emulsion 7, purified water 8 and the release of sludge 9. The pipe branch of the oil emulsion 7 of the settler 6 is communicated through a pipe with a pipe for supplying the source of oilfield wastewater 2 vertically installed of the hydrocyclone 1 relative to the settler 6. The settler 6 is divided into four communicating chambers by three upper 10 and three lower 11 vertical partitions. Each sump chamber is equipped with a conical bottom 12 with a sludge discharge pipe 9. The purified water drain pipe 8 of the sump 6 is in communication with an inlet pipe 13 of an additionally installed self-washing sand filter 14. The self-washing sand filter 14 is equipped with a washing water drain pipe 15 in communication with the supply pipe of the original oilfield waste water 2 vertically located hydrocyclone 1, and a pipe for discharging purified water 16.

The inventive installation for cleaning the NSW for injection into the reservoir as follows.

The NSW is fed through the pipe for supplying the initial oilfield wastewater 2 to the hydrocyclone 1. In the hydrocyclone 1, the initial NSW is preliminarily purified by partially removing concentrated oil products and gases released through the branch pipe for the discharge of the upper drain 3. The NSV processing stage consists in the destruction of the armor shells by the centrifugal forces drops of oil and an intermediate layer of a coarsely dispersed phase at the oil - water interface. As a result, mechanical impurities are released from oil. The released oil droplets coalesce, forming a free-floating oil that floats on top of a vertically located hydrocyclone 1 due to its lower density compared to water. Reducing the diameter in the upper part of the hydrocyclone increases the flow rate of wastewater, which leads to the destruction of the armor shells on small drops of oil. Under the action of centrifugal forces in the hydrocyclone 1, NSWs also undergo intensive turbulization, which leads to the release of gases and their removal from the outlet pipe of the upper discharge 3 of hydrocyclone 1. A decrease in the content of mechanical impurities in the treated wastewater is achieved in hydrocyclone 1 by their release from the intermediate layer of the coarsely dispersed phase and ablation through the outlet pipe of the lower drain 4, in communication with the inlet pipe 5 of the sump 6, by the flow of water into the closed sump 6, divided into four chambers by vertical lanes towns 10 and 11, contributing to further destruction of the armoring shells into small droplets of oil and oil coalescing. In the sump 6, under the influence of gravity, mechanical impurities in the form of oil sludge settle in the conical bottoms 12 of each chamber of the sump 6, after which they are removed through the pipes for the discharge of sediment 9. The coalesced oil rises to the upper part of the sump as a trapped oil through the pipe for removing the oil emulsion 7 through a pipeline enters the supply pipe of the source of oilfield wastewater 2 into a vertically mounted hydrocyclone 1. Partially cleaned from mechanical impurities of the NSW further through the pipe ok drainage of purified water 8 of the settler 6 through the pipeline enters through the inlet pipe 13 to a self-washing filter 14, where there is a post-treatment of wastewater from oil and mechanical impurities. In the self-washing sand filter 14, there is no compression of sand over time as a result of its constant movement up and down, there is no air purge and there are no clogging nozzles. Self-washing sand filter 14 holds a high content of suspended particles. From the self-washing sand filter 14, the washing water with compacted solid particles leaves through the pipe for draining the washing water 15 and then through the pipe for supplying the initial oilfield waste water 2 is discharged into a vertically located hydrocyclone 1. The washing of the sand filter 14 is carried out periodically with purified water. Through the outlet pipe for purified water 16, purified water corresponding to quality indicators for oil products and suspended solids that meet the requirements of OST 39-225-88 is fed for injection into the reservoir.

Claims (1)

 Installation for cleaning oilfield wastewater for injection into a reservoir, consisting of a hydrocyclone with nozzles for supplying the original oilfield wastewater, a drain for the upper drain and a drain for the lower drain, connected to the inlet of the sump, also equipped with nozzles for draining the oil emulsion, purified water, and sludge discharge the fact that the outlet pipe of the oil emulsion is communicated through a pipeline with a pipe for supplying the initial oilfield wastewater of a hydrocyclone vertically mounted about the sump, which is divided into four communicating chambers by three upper and three lower vertical partitions, each chamber of the sump is equipped with a conical bottom with a sludge outlet pipe, and the outlet pipe of the purified water of the sump is communicated with the inlet pipe of an additionally installed self-washing sand filter, also equipped with a drain pipe purified water and a branch pipe for flushing water in communication with a pipe for supplying the initial oilfield wastewater of a vertically located hyd cyclone.

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