SU1373413A1 - Method of preparing oil and water - Google Patents

Abstract

The invention relates to the oil industry, and more specifically to methods for the separation of oil and water, transported together with oil fields. The aim of the invention is to reduce the technological losses of oil and improve the quality of its preparation. In the method of treating oil and water, gravitational separation of oil and water is carried out at a constant level of liquid in a low pressure reservoir with a minimum allowable amount of gas space, and the prepared oil is taken from the level in the reservoir that prevents it from being carbonated (at pressures above the pressure of oil vapor), and it is fed into the discharge pipeline through an elevated pressure tank operating in a connected mode, the maximum allowable level in which is set below the level in ervuare low pressure value, / + hj, where P - pressure in the low pressure zone of the gas tank.; PI is the pressure in the gas zone of the pressurized tank, which is not less than the pressure of the saturated vapor; y is the density of the liquid; h is the hydraulic resistance in the pipeline when oil flows from the low pressure reservoir to the pressure reservoir. 1 il. (L

Description

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with

The invention relates to the oil industry, in particular to methods for the separation of oil and KINDS transported together from oil fields.

The purpose of the invention is to reduce the technological losses of oil and improve the quality of its preparation.

The drawing shows the scheme of the proposed method.

The method is carried out as follows.

The separated water-oil mixture through pipeline 1 through the distribution device, made in the form of the liquor, is fed to the low-pressure process tank 2 below the water level, where, under the optimal hydrodynamic mode, a constant liquid level in the tank providing the minimum allowable volume of the gas space there is a gravitational separation of oil and water. Sucked off water is taken from the reservoir through pipeline 3. Oil is withdrawn through a drain pipe 4, equipped with a defensive device 5, from a zone located at a depth h from the surface level, which eliminates the degassing of the lower oil layers and is determined by the pressure of its vapor density. Level h is located below the surface.

fluid h 7

,

f

where p; - pressure

saturated liquid vapors; Ru is the pressure in the gas zone of the low-pressure tank; fluid density Selected oil is directed to the discharge pipe 6 through a pressure tank 7 operating in a connected mode and playing a role of a buffer tank, the maximum allowable level in which is set below the fluid level in tank 2 by the amount H, which ensures the flow of fluid from tank 2 to tank 7 by gravity and equal

H-- - - + hr,

about

p, is the pressure in the gas zone

low pressure reservoir; P, - pressure in the gas zone

increased pressure tank

0 5

five

0

0 5 0

five

laziness is not less than the pressure of the saturated vapor of the oil; y is the density of the liquid; h is the hydraulic resistance in the pipeline when oil flows from the low pressure reservoir to the pressure reservoir. The connecting tank 7 piping is equipped with an anti-vortex device 8. Tanks 2 and 7 are equipped with safety and breather valves 9 and 10, and tank 2 is also equipped with a level control 11. Oil is transported using a pump 12. When the flow of oil to the tank is exceeded 2 above the pumping out of the rto pipeline 6, it accumulates in the connected pressure tank 7, and when the oil flow decreases from the fields it is taken from the tank 7. This allows the level of the liquid to be kept at tank 2 constant.

By reducing the volume of liquid in the low pressure reservoir, the flow area of the discharge pipe is reduced using a level regulator, and when the flow of liquid is stopped, it completely overlaps. Therefore, the fluid level in the low pressure reservoir remains constant, and the inertia of the system is quenched: using an elevated pressure reservoir.

Most of the oil entering the discharge pipe 6 does not enter the reservoir 7. The same part of the oil that enters the reservoir is most of the time it is under pressure above the pressure of saturated vapor. In addition, the mass transfer between the upper and lower layers is low due to the low velocities of the oil flowing into and out of the tank 7.

The tank 7 has a much smaller evaporation surface than the tank 2.

Maintaining a constant level of fluid in a low pressure reservoir allows you to eliminate large breaths and associated oil losses, and limiting the gas space to the minimum allowable volume

 3137

allows you to minimize the loss of light hydrocarbons from small breaths. The extraction of oil from the level of liquid in the reservoir, which excludes its degassing, significantly reduces the mass exchange between the upper and lower layers of oil, which significantly hinders boiling processes in it, the active

oil and, consequently, increase the degree of dehydration.

Using the proposed method of preparing oil and water provides a lower level of technological loss of oil compared to known methods (according to rough estimates, it is 50-60% lower),

whom evaporation and emission of light fractions higher quality of preparation

into the atmosphere. Implement this

technological reception is possible

only while maintaining a constant

preserving fluid level

rational use of volume

reservoir.

Compensation for the discrepancy between volumes, the flow of well production from the fields to the product preparation and the recovery of fluid through the discharge pipelines is carried out with the help of an elevated pressure tank operating in connected mode. The volume of this reservoir is several times smaller than the volume of the low pressure reservoir, since fluctuations in the difference between the intake and withdrawal of a liquid are usually 10–20%, so its metal consumption is small. The bulk of the oil enters the discharge pipe without planting it into the tank, which eliminates the loss of oil from this volume.

The part of the oil entering the tank is under increased pressure and has an evaporation surface much less than in the low pressure tank, therefore the loss of oil in this tank is an insignificant amount of the total produced oil. The operation of the pressurized tank in the connected mode makes it possible to constantly maintain the same level in the low pressure tank. The maximum allowable liquid level in the pressure tank is established in order to allow the oil to enter it from the low pressure tank by gravity.

A group of pressure tanks can be installed per group of low pressure tanks. The fullest use of the volume of the low pressure tank allows an increase in the residence time in the

oil or higher plant performance with the same quality of produced oil.

The described method of preparing the nave

15 and water is preferable to be used on slowly exfoliating water-borne mixtures, when their stay in process tanks is long and there is a need for

20 large volumes of their one-time download.

Claims (1)

Invention Formula 5 A method of treating oil and water, including the supply of a water-oil mixture to a low-pressure reservoir, a gravitational separation of oil and water in the reservoir, and a separate oil extraction. 30 and water and their withdrawal to the discharge pipelines, which is different from the fact that, in order to reduce the technological losses of oil and improve the quality of its preparation, in a reservoir of low pressure, maintain a constant level of liquid with a minimum allowable amount of gas space , the selection of oil is made from the level that excludes it 40 aeration and located not from the surface of the liquid h-,   R J Well where p is the vapor pressure liquids; p is the pressure in the gas zone of the low-pressure tank; p, is the density of the liquid, and oil is discharged to the discharge pipe by gravity through the pressure reservoir connected to the low pressure reservoir, and the flow area of the oil discharge pipe is changed depending on the volume of the mixture supplied to the low pressure reservoir. . 45 50 oil or higher plant performance with the same quality of produced oil. The described method of oil preparation and water, it is preferable to use on slowly exfoliating water-in-water mixtures, when their stay in process tanks is long and there is a need for large volumes of their one-time download. Invention Formula A method of treating oil and water, including the supply of a water-oil mixture to a low-pressure tank, gravitational separation of oil and water in the tank, separate separation of oil and water, and bringing them to the discharge pipelines, which are different from losses of oil and improving the quality of its preparation; in a low pressure reservoir, a constant liquid level is maintained with a minimum allowable volume of gas space; oil is extracted from a level that excludes its degassing and is located and the depth of the surface of the liquid h-,   R J Well where p is the vapor pressure liquids; p is the pressure in the gas zone of the low pressure reservoir; p is the density of the liquid, and oil is discharged to the discharge pipe by gravity through a pressure reservoir connected to the low pressure reservoir, and the flow cross section of the oil discharge pipe is changed depending on the volume of the mixture fed to the low pressure reservoir. s