RU2232935C2 - Oil well products complex treatment system and method of its implementation - Google Patents

Abstract

FIELD: oil producing and refining industries.

SUBSTANCE: in proposed system of complex treatment of oil well products consisting of pipelines, heat exchangers, oil heater, tank-settler and stock-oil tank, tank-settler is furnished with inner individual separating unit built in its upper zone and connected through vertical drain branch pipe with mother-distributor providing complete separation of gas and getting of stock oil and clean formation water in one tank-settler. According to proposed method of complex treatment of oil well products including separation of gas and formation water from oil, delivery o gas-water-oil emulsion into separation unit is provided tangentially to form effect of hydrocyclone and ensure uniform distribution of separated liquid through drain branch pipe in mother-distributor located under layer of water.

EFFECT: improved quality of oil treatment.

3 cl, 1 tbl, 2 dwg

Description

The invention relates to the oil and oil refining industry, and in particular to devices and methods for the preparation and processing of gas-oil emulsions coming from wells, and is intended primarily for use in systems for the preparation of oil in oil fields with a complete cycle, including those producing high-sulfur oil .

A well-known unified scheme for collecting and preparing oil well products, including wells, automatic metering unit, demulsifier reagent dosing unit, 1st stage separator, oil pre-dewatering tank, crude oil pump, heat exchanger, crude oil heating unit, fresh dehydrated oil mixer water, a deep desalination unit (electric dehydrator), a separator of the 2nd (hot) stage, a tank for salable oil, a pump for pumping salable oil.

Hot oil after the deep desalination unit, passing the heat exchanger, heats the crude oil and, when cooled, enters the commodity tank from which it is pumped to the consumer.

The produced water that separated during the destruction of the crude oil emulsion and the fresh flushing water used to desalinate the dehydrated oil, after the above recycles, are mixed in the oil pre-dehydration tank, from where they are supplied to the water treatment and treatment unit for its subsequent use in the reservoir pressure maintenance system.

Petroleum gases separated in the 1st stage (high pressure gas) and the 2nd - hot stage (low pressure gas) are sent to a gas processing plant for processing [1].

A well-known oil field treatment scheme consisting of separators, sump tanks equipped at the top with oil collectors (drain pipes), product tanks, an oil heater, a tank (treatment facilities) for collecting and treating water and a metering pump, and sump tanks operate in parallel alternately and for the collection of persistent oil emulsion that has not decomposed in the settling tanks for re-preparation, an emulsion collection tank is additionally used, where each of the tanks is sludge Ikov is connected with the possibility of communication through the oil collectors in the upper part with any of the commodity tanks and through the acceptance pipes with the emulsion collection tank, and the water treatment tank (treatment facilities) with the upper part equipped with an oil collector (drain pipe) is connected to the collection tank emulsions [2].

The disadvantage of unified technological schemes for the collection, preparation of oil, gas and water in oil-producing regions is that these technological schemes designed for equipping oil fields proved to be unacceptable for the preparation of high-sulfur, residual gas factor, oils, as well as the difficulty of their operation, due to the presence of large the number of sedimentation tanks, reservoirs and multi-stage oil treatment.

With the development and implementation in the oil industry of light fraction capture systems (SFM) (development of the TatNIPIneft Institute and the supply of Tatex CJSC), great opportunities have appeared for the effective use of RVS tanks not only as buffer tanks for receiving raw materials and storing commercial oil and oil products , but also as technological apparatus-settlers for the preparation of oil and associated formation water, including for the production of wells that produce sour oil.

However, in tanks where there is no excess pressure, the oil preparation process occurs with intensive separation of the residual gas dissolved in the oil. Bubbles of gas, rising vertically up the entire section of the reservoir through a layer of water and oil, carry with them to the upper zone part of the already separated water. At the oil-gas phase boundary, large gas bubbles burst, and part of the water, not having time to precipitate, passes through the overflow pipe to the tank of commercial oil, and part of the water with gas in the form of smaller bubbles (foam) slips into the gas extraction system, where subsequently falls into condensate.

At the same time, the hydrostatic column of liquid (oil, water), which is constant in the settling tank, does not allow for complete separation of gas from oil with direct input of raw materials into the mother-distributor located in the lower zone of the tank. As a result, the oil that is not completely separated from the gas is transferred to the tank of commercial oil, where a similar process is repeated. Thus, the process of gas separation from oil in the tank, accompanied by bubbling of the liquid, leads to a deterioration in the quality of the preparation of oil, produced water and gas.

With the maximum use of the in-tube demulsification effect, oil preparation to commercial conditions is possible at a temperature of no higher than 30-35 ° С. However, at this process temperature the requirement of one of the parameters presented to the quality of marketable oil according to GOST 9965-76 “Oil. Degree of training for oil refineries. Technical conditions ”, - elasticity of saturated vapors. To ensure the fulfillment of this quality parameter, a process temperature of 40-45 ° C is required. And with an increase in the process temperature, the heavier part of hydrocarbons evaporates (C ₃ and higher), as well as more intensive evaporation of water. Thus, the higher the oil heating temperature, the deeper the degree of gas separation. However, an increase in temperature leads to the opposite effect of oil demulsification associated with more intensive bubbling of liquid in the tank, i.e. increase in ballast content in commercial oil (water, salt).

Based on the foregoing, the basis of the invention was the task to develop a device and method that would allow the process of preparing sour oil and to separate gas and produced water from oil directly in the settling tank, and to eliminate the effect of bubbling and its negative impact on the quality of oil and water, increasing the depth of gas separation from oil at lower temperatures of the oil preparation process (30-35 ° C), a method for deep separation of residual gas from oil is proposed directly in the upper zone of the settling tank.

The technical result of the invention is: improving the quality of oil preparation, accelerating the natural decay of gas-oil emulsions into their constituent ingredients (oil, water, gas) when supplied to the settling tank and sludge at low temperatures.

This is achieved in a device consisting of pipelines, heat exchangers, an oil heater, a settling tank and a commodity tank due to the fact that the settling tank is equipped with an internal individual separation unit integrated in the upper zone and connected through a vertical drain pipe to a mother liquor distributor that ensures complete gas separation and obtaining marketable oil and clean produced water in the same sump tank.

This is also achieved in a method for the comprehensive preparation of well products, including the separation of gas and produced water from oil due to the fact that the gas-oil emulsion is introduced into the separation unit tangentially with the aim of obtaining the effect of a hydrocyclone and uniform distribution of the separated liquid through the drain pipe through the mother liquor-distributor located under a layer of water.

What is new is that the sump tank is equipped with an individual separation unit integrated in the upper zone, which provides a deep degree of gas and oil separation and eliminates the negative effect on the dehydration and desalination of the residual gas entering the sump tank.

The process of separation of gas from oil occurs in the upper zone of the settling tank in the absence of excess pressure, and to eliminate the effect of sparging, the mixture completely separated from gas and destroyed by oil and water flows under the layer of produced water through the mother liquor, where the mixture is naturally completely separated into water and oil phase, and not through a layer of water and oil with the formation of gas bubbles with water moving vertically up the entire section. The completed oil treatment cycle occurs at a heating temperature of not more than 30-35 ° C and with the previous quality indicators of commercial oil, water and gas.

The above new significant features are the hallmarks of the invention in relation to the solution known from the prototype, they ensure the achievement of a new technical result of the claimed invention.

From publicly available sources of patent and scientific and technical information, we do not know devices or methods for the preparation of oil and associated formation water with a complete completion cycle, which, together with well-known features, would generally include the above-mentioned combination of new essential features, characterized in that:

- new structural elements have been introduced: the settling tank is equipped with a hollow separation unit;

- a new form of execution of the elements has been proposed: the input of the inlet pipe is located tangentially, and the gas-oil emulsion is supplied to the upper zone of the settling tank;

- a new mutual arrangement of the elements has been completed: the hollow separation unit is integrated in the upper zone of the settling tank.

The essence of the invention is illustrated by drawings, on which:

figure 1 - the proposed system for the preparation of well products;

figure 2 - diagram of the tank-settler according to the proposed system, a section along aa.

At the end of the description is a comparative table of some technical and economic indicators before and after implementation.

The integrated well production preparation system and the method for its implementation (Fig. 1) comprises a raw material pipe 1, a heat exchanger 2, a furnace 3, a settling tank 4, an integrated individual separator (hollow separation unit) 5, a tank 6, a commercial oil pump 7, a cleaned pump water 8, the installation of ULF 9.

The sump tank 4 (FIG. 2) includes a receiving pipe 10 with a tangential entry vertically rising to a height H ₂ , a hollow separation unit 5 of height H with upper and lower cones with baffle plates located in the upper conical part of the hollow separation unit 5, a gas pipe 11, a drain pipe 12, a commodity oil pipe 13 located at a height of H ₃ , and a purified water pipe 14.

The system of integrated preparation of well products is as follows.

An emulsion preliminarily destroyed by oil and water with a residual gas content of 0.2-0.6 m ³ / t is fed through a nozzle pipe 10 through a nozzle (to create a swirl speed) to a hollow separation unit 5 located in the upper zone of the settling tank 4 at a distance H ₁ from the roof. The hollow separation unit 5, made of a pipe of large diameter (⌀ 500-1000 mm) with a height N with upper and lower cones for the exit of gas and oil, consists of two parts:

- actually built-in individual oil, gas and water separator (hollow separation unit) 5, which is an element of a hydrocyclone;

- fenders from gas and water bubbles located in the upper conical part of the hollow separation unit 5.

The destroyed water-gas-oil emulsion through the nozzle is tangentially introduced into the upper part of the hollow separation unit 5 of the hydrocyclone. A certain vacuum is achieved in the hydrocyclone, which contributes to the efficient evolution of dissolved gas. Rotational movement in a spiral from top to bottom around the wall circumference of the hollow separation unit 5 due to the tangential input causes the effect of centrifugal forces sufficient to separate the gas-liquid mixture into three phases. Light - gas - in the center rushes to the upper conical part with bump plates, where it is freed from small bubbles (foam) and water. Water flows down the walls. Closer to the wall is the aqueous phase, behind it is oil, which under the influence of gravitational forces freely flows through the drain pipe 12 into the mother liquor-distributor located in the lower part of the settling tank 4 under a layer of produced water. The mixture, completely separated from gas and destroyed by oil and water, enters under the layer of produced water through the mother liquor-distributor located at a height of H ₄ , where there is a natural complete separation into the water and oil phases.

The working (liquid) volume of the settling tank 4 at the same time serves only for deep dehydration of oil, because there is no negative effect of bubbling the mixture with residual gas. Thus, a deeper separation of gas and produced water from oil at low temperatures is achieved.

This design of the hollow separation unit 5 can also be used in horizontal sumps and dehydrators.

The table for comparison presents data characterizing the achieved quality of commercial oil, and the main technological parameters of the existing oil treatment system (UPVSN NGDU “Yamash-oil”), operating according to the well-known technological scheme, and a system for the comprehensive preparation of well products using the same oil using the proposed technical solutions.

The system is simple to manufacture and install, reliable in operation, does not require qualified maintenance and does not depend on other technical and technological factors, i.e. a positive effect is achieved with any changes in the technological regime.

Due to the proposed presence of structural elements in the claimed technical solution, as well as in connection with their implementation and relative position, the claimed device and method for processing gas-oil emulsions ensure the achievement of a new technical result:

- compared with traditional methods, the method of deep separation of oil from gas and produced water in a settling tank according to the invention requires significantly lower costs (see table);

- separation of gas-oil emulsion into components (oil, gas, water) without the use of reagents and / or additional heating;

- an increase in the rate of natural complete separation of the gas-oil emulsion into ingredients, which allows, if necessary, to increase the power of the system;

- the claimed technical solution in the conditions of oil fields is reliable in operation and easy to maintain;

- allows you to get commercial oil of higher quality, in particular, to reduce the residual content of water, salts and gas in commercial oil;

- there is no need for frequent stops and preventive maintenance, which will be carried out only during the overhaul of tanks;

- improves the general environmental situation at oil treatment facilities, eliminating harmful emissions into the atmosphere.

Thus, the above information shows that when using the claimed invention, the following set of conditions:

- a tool embodying the claimed method and device in its implementation, is intended for use in industry, namely in oil production and refining;

- for the claimed invention in the form as described in the paragraphs of the claims, the possibility of its implementation using the means described in the application is confirmed.

Therefore, the claimed invention meets the condition of “industrial applicability”.

Sources of information:

1. Baykov N.M., Pozdnyshev G.N., Mansurov R.I. Collection and field preparation of oil, gas and water. - M .: Nedra, 1981, p. 71-81.

2. RF patent No. 2142093, F 17 D 3/14 “Scheme of field oil treatment”.

Claims (2)

1. A system for the comprehensive preparation of well products, consisting of pipelines, heat exchangers, an oil heater, a settling tank and a commodity tank, characterized in that the settling tank is equipped with an internal individual separation unit integrated in the upper zone and connected through a vertical drain pipe to a mother liquor distributor, which provides complete gas separation and production of marketable oil and clean produced water in the same sump tank. 2. A method of comprehensive preparation of well products, including the separation of gas and produced water from oil, characterized in that the gas-oil emulsion is introduced into the separation unit tangentially in order to obtain the effect of a hydrocyclone and uniform distribution of the separated liquid through the drain pipe through the mother liquor-distributor located under the layer water.

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