RU2648410C1 - Method of utilizing produced water - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: invention relates to the oil industry, in particular to utilization methods of produced water during operation of water-flooded oil wells at late stage of operating oil field. Utilization methods of produced water includes injection of production of exploitation wells into inactive well that serves as clay pit. Production of a number of producing wells with a total flow rate of 25–65 m³/day are pumped directly into tubular annulus of clay pit to absorb water with reservoir having injectivity of 0.7–4.3 m³/(day⋅atm). Simultaneously with the injection, fountain method is used to separate oil through flow column.

EFFECT: proposed method allows to separate qualitatively oil and water in the clay pit and reduce the energy costs spent on transporting of produced water for long distances.

1 cl, 1 dwg

Description

The invention relates to the oil industry and can be used in the operation of highly watered oil wells at a late stage of operation of an oil field.

A known method of developing an oil field (GS Lutoshkin "The collection and preparation of oil, gas and water" M .: Nedra, 1974, p. 13), which includes collecting production wells and transporting it with pumps of booster pumping stations to the central collection point and the preparation of oil, which produces the discharge of water, its purification and subsequent pumping of cluster pumping stations into the reservoir to maintain reservoir pressure.

The disadvantage of this method is the significant cost of electricity spent on the transportation of produced water along long distances.

There is a method of disposing of associated petroleum gas and produced water, which consists in the fact that the production of flooded wells is directed to receive at least one compressor pump and pumped through a distribution comb into injection wells, while the injection is carried out into inactive flooded wells by lift pipes through nozzles having two branches, inside of which there is a vertical channel and a lattice of guide plates, which form a flat tangential parietal descending at an angle of 45 ° to the cross section of the wellbore, the flow of injected fluid (see RF patent No. 2435944, IPC ЕВВ 43/16, publ. 10.12.2011).

The disadvantage of this method is the significant material costs due to the injection of waterlogged production wells through the pump-compressor and distribution comb.

Another disadvantage of this method is the use of a nozzle with bends, which increases the metal consumption and requires the use of non-standard equipment, in addition, pumping the production of flooded wells into an idle well, acting as a settler, through lift pipes leads to insufficient separation of water and oil due to the high flow rate of liquid from - due to the small passage section of the elevator pipes, which leads to the injection of oil into the reservoir of the well-sump or the flow of water into the collection reservoir.

The specified method is closest to the proposed one and can be taken as a prototype.

An object of the invention is the utilization of associated produced water in the well-sump to reduce the cost of electricity spent on transporting produced water over long distances, with a high-quality separation of oil and water in the well-sump due to the lower flow rate of the liquid in the annulus which is the separation.

The problem is solved by the described method of utilization of produced produced water, including the injection of production of producing wells into an idle producing well that acts as a sump.

New is the fact that the products of adjacent production wells located adjacent to each other with a total fluid flow rate of 25-65 m ³ / day are pumped directly into the annulus of the settling well for water absorption by the formation having an injectivity of 0.7-4.3 m ³ / ( sutatm), while simultaneously separating the separated oil in a fountain way through the tubing string.

The drawing shows a scheme for collecting production of producing wells and injecting produced produced water into an idle well, where 1 is an producing well, 2 is an idle well acting as a sump, 3 is a reservoir of a settling well, 4 is a prefabricated line that ties production wells, 5 - annulus of the well-sump; 6 - production casing of the well-sump; 7 - column tubing.

The method of disposal of produced produced water by the proposed method is carried out by the following sequence of actions.

1. The group (bush) is determined adjacent to each other irrigated production wells 1 with a total fluid rate of 25-65 m ³ / day.

2. The injectivity of the formation 3 of the well-sump 2 is determined, the value of which should be in the range of 0.7-4.3 m ³ / (sutatm).

3. The production wells 1 are strapped and their products are injected through the collection line 4 into the annulus 5 of the idle well, which acts as a settler 2, between production casing 6 and tubing string 7.

4. Injection of production of production wells 1 into the annulus 5 of an inactive well, acting as a settler 2.

5. In the annular space 5 between the production string 6 and the tubing string 7 there is a gravitational separation of oil and water. Due to the fact that the cross-section of the annular space 5 has a larger area than the internal section of the tubing 7, more efficient separation of water and oil is ensured due to the lower fluid flow rate.

6. Absorption of separated water by reservoir 3 with an injectivity of 0.7-4.3 m ³ / (sutatm). The selection of the total production rate of production wells 1 and injectivity of the formation 3 is determined by the fluid flow rate in the annulus 5, at which the fluid flow laminarity is maintained by comparison with the critical Reynolds number, as well as the sedimentation rate (deposition) of phase particles in the medium.

The fluid flow rate in the annulus 5 is determined by the formula

where Q is the fluid flow rate [m ³ / s],

S is the cross-sectional area through which the fluid flows [m ² ].

Reynolds number is determined by the formula

where V is the velocity of the fluid [m / s],

d is the diameter of the annular space through which the fluid flows [m],

ρ is the density of the liquid [kg / m ³ ],

μ is the viscosity of the liquid [Pa⋅s].

The rate of sedimentation (deposition) of particles is determined by the Hadamard-Rybchinsky formula for real emulsions:

Where

μ ₁ , μ ₂ - dynamic viscosities of the dispersed medium and the dispersed phase [Pa⋅s],

r is the particle radius [m],

ρ ₁ , ρ ₂ - the density of the dispersed medium and the dispersed phase [kg / m ³ ],

n is the number of particles.

7. The selection of the separated oil in a fountain way along the tubing string 7 to the surface in a collection manifold.

Thus, the inventive method ensures the utilization of produced produced water in the well-sump, which reduces the energy costs spent on transporting produced water over long distances, with high-quality separation of oil and water in the well-sump due to the lower flow rate annulus in which separation occurs.

Claims (1)

The method of disposal of produced produced water, including the injection of production of production wells into an idle well, which acts as a sump, characterized in that the production of production wells located adjacent to each other with a total flow rate of 25-65 m ³ / day is pumped directly into the annulus of the well - a sump for water absorption by a formation having an injectivity of 0.7-4.3 m ³ / (sut-atm), while simultaneously separating the separated oil in a fountain way through a tubing string.

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