CN103742124A - Production fluid re-separation method for downhole oil-water separation and injection-production well - Google Patents

Abstract

The invention relates to the technical field of oil extraction engineering, and belongs to a method for re-separating produced liquid of an underground oil-water separation same-well injection-production well by using a hydrocyclone. The invention relates to a method for overcoming the defect that the water content reduction range of an ultrahigh water-containing well is small, which is realized by the following devices: the system consists of an injection pump 1, an underground hydrocyclone 2, a production pump 3, a casing 4, an oil pipe 5, a casing four-way 6, an oil pipe four-way 7, a liquid outlet pipeline 8, a ground hydrocyclone 9 and a liquid return pipeline 10, and finally oil-water separation is carried out twice through an underground well and a wellhead; the invention has the advantages of greatly reducing the liquid quantity and the water content of the produced liquid of the oil well under the condition of not reducing the crude oil yield of the oil well, improving the water quality of the reinjection water after separation, and the like.

Description

Production fluid re-separation method for downhole oil-water separation and injection-production well

Technical field: The present invention relates to the technical field of oil production engineering, and belongs to a method for re-separating production fluid from injection and production wells using hydrocyclones to separate downhole oil and water.

Background technology: When the oil field enters the period of ultra-high water-cut production, the increase of water content not only increases the lifting cost, but also requires a corresponding increase in ground treatment facilities to meet the processing requirements of huge liquid volume, which greatly increases the cost of crude oil production and is economical. Benefits are significantly reduced. The downhole oil-water separation and injection-production process can separate oil and water downhole, reduce the water content of the produced fluid, and at the same time directly reinject the separated water into the formation, shortening the oil-water treatment process of the produced fluid.

Summary of the invention: The purpose of the present invention is to invent a kind of downhole oil-water treatment system that further reduces the volume of produced fluid and water content, increases the injection volume, and improves the water quality of the reinjection water after separation without reducing the oil production volume. A method for re-separation of produced fluid from injection and production wells in the same well.

The present invention is realized by the following devices: it consists of injection pump, downhole hydrocyclone, production pump, casing, oil pipe, casing cross, oil pipe cross, liquid outlet pipeline, surface hydrocyclone and return Liquid pipeline composition, the present invention is realized through the following steps:

a. First, connect the injection pump, downhole hydrocyclone, production pump, and tubing sequentially from bottom to top and lower them into the well;

b. Connect one end of the liquid outlet line to an outlet of the tubing cross, the other end to the liquid inlet of the surface hydrocyclone, one end of the return line to the bottom flow port of the wellhead hydrocyclone, and the other end to the casing four One outlet of the hydrocyclone, the overflow port of the hydrocyclone is connected to the pipeline entering the pumping station;

c. After the original well fluid enters the oil casing annulus from the oil layer, it enters the downhole hydrocyclone, and the separated water is injected into the formation through the injection pump of the system, and the oil-water mixture is lifted to the ground by the production pump of the system;

d. After the oil-water mixture reaches the ground, it passes through the outlet of the wellhead oil pipe cross, flows through the outlet pipeline, enters the wellhead hydrocyclone, and is separated again, and the separated oil-water mixture passes through the overflow of the surface hydrocyclone mouth, and finally into the pumping station;

e. The separated water passes through the return line, flows back to the casing through the casing spool, mixes with the original well fluid provided by the production layer, and the mixed fluid enters the downhole hydrocyclone for oil-water separation, and finally realizes that the original well fluid enters the pumping station before Oil-water separation twice.

Compared with the prior art, the present invention has the following advantages:

1) Well fluid with high water content can achieve better oil-water separation in the downhole and wellhead, further reducing the volume of produced fluid and water content, and effectively reducing the pressure of surface water treatment.

2) Through two separations, the amount of reinjection water is increased, and the oil displacement capacity of reinjection water is improved.

3) The bottom hole flow pressure is increased, the energy consumption of downhole equipment is reduced, and the service life of the equipment is prolonged.

4) The water content of the inlet liquid flow of the downhole hydrocyclone increases, and the water quality of the reinjection water after oil-water separation will be improved, which can prevent it from clogging the injection layer.

BRIEF DESCRIPTION OF THE DRAWINGS: Figure 1 is a schematic diagram of the field application of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS: The present invention will be described in further detail below in conjunction with the accompanying drawings. The present invention is realized by the following devices: it consists of injection pump 1, downhole hydrocyclone 2, production pump 3, casing 4, oil pipe 5, casing cross 6, oil pipe cross 7, liquid outlet pipeline 8 , surface hydrocyclone 9 and liquid return line 10, the present invention is achieved through the following steps:

a. First connect the injection pump 1, the downhole hydrocyclone 2, the production pump 3, and the tubing 5 sequentially from bottom to top and lower them into the well;

b. Connect one end of the liquid outlet line 8 to an outlet of the oil pipe cross 7, the other end to the liquid inlet of the surface hydrocyclone 9, and one end of the return line 10 to the bottom flow port of the wellhead hydrocyclone 9, and the other One end is connected to an outlet of the casing cross 6, and the overflow port of the hydrocyclone 9 is connected to the pipeline entering the pump station;

c. After the original well fluid enters the oil casing annulus from the oil layer, it enters the downhole hydrocyclone 2, and the separated water is injected into the formation through the injection pump 1 of the system, and the oil-water mixture is lifted to the ground by the production pump 3 of the system;

d. After the oil-water mixture reaches the ground, it passes through the outlet of the wellhead oil pipe cross 7, flows through the outlet pipeline 8, enters the wellhead hydrocyclone 9, and is separated again, and the separated oil-water mixture passes through the surface hydrocyclone 9's overflow port, finally enters the pumping station;

e. The separated water passes through the return line 10, flows back to the casing 4 through the casing spool 6, mixes with the original well fluid provided by the production layer, and the mixed fluid enters the downhole hydrocyclone 2 for oil-water separation, and finally realizes the original well fluid Oil and water are separated twice before entering the pump station.

Claims (1)

1. pair downhole oil-water separation same-well injection is adopted the Produced Liquid separation method again of well, the present invention is by realizing with lower device: it is comprised of injection pump (1), downhole hydraulic cyclone (2), extraction pump (3), sleeve pipe (4), oil pipe (5), four-way junction of casing (6), oil pipe four-way (7), fluid pipeline (8), ground hydrocyclone (9) and liquid back pipe line (10), it is characterized in that: the present invention realizes by following steps:

A. first from bottom to top injection pump (1), downhole hydraulic cyclone (2), extraction pump (3), oil pipe (5) are connected successively and G.I.H;

B. by an outlet of one end connected pipes four-way (7) of fluid pipeline (8), the other end connects the inlet of ground hydrocyclone (9), the underflow opening of one end connecting well mouth hydrocyclone (9) of liquid back pipe line (10), an outlet of other end splicing sleeve four-way (6), the overfall of hydrocyclone (9) connects the pipeline that enters pumping plant;

C. original well liquid is entered after oil jacket annular space by oil reservoir, enters downhole hydraulic cyclone (2), and isolated water is injected into stratum by the injection pump (1) of system, and oil-water mixture arrives ground through extraction pump 3 liftings of system;

D. oil-water mixture arrives behind ground, by the outlet of well mouth oil pipe four-way (7), the fluid of flowing through pipeline (8), enter well head hydrocyclone (9), again separate, oil-water mixture after again separating, by the overfall of ground hydrocyclone (9), finally enters pumping plant;

E. the water after separating is through reflux pipeline (10), by four-way junction of casing (6), be back to sleeve pipe (4), the original well liquid providing with extraction layer mixes, mixed liquor enters downhole hydraulic cyclone (2) and carries out water-oil separating, finally realizes original well liquid and enters front twice water-oil separating of pumping plant.

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