RU2381353C1 - Oil field development method - Google Patents

Abstract

FIELD: oil-and-gas industry.

SUBSTANCE: invention related to oil-and-gas industry and can be used in oil fields development. Execute working agent pumping through injection wells and oil withdrawal though production wells. Execute working agent with solid suspended particles dispersion. Grain working agent solid suspended particles with help of dispersion, until dispersion in a range 1-5 mcm, keeping pressure in a range 2-10 MPa during dispersion and working agent injection, and the working agent rate in a range 180-360 m³/day.

EFFECT: injection wells overhaul life increase due to decrease of the bottom hole zone packing with solid suspended particles.

1 ex, 1 dwg

Description

The invention relates to the oil industry and may find application in the development of oil deposits.

A known method of developing an oil field, including the selection of fluid through production wells and injection into the injection wells of the gas mixture. This mixture is obtained at the wellhead by gas ejection in a jet pump. In this case, the water-gas mixture is dispersed and homogenized. For this, the gas-water mixture is supplied by a jet pump to a hydrodynamic cavitation unit and then to a jet disperser to convert the energy of the jets into the energy of acoustic waves and the formation of pulsating cavitation. The device includes a jet pump with a conical nozzle on the central pipe for supplying water, a side pipe for supplying gas and a central outlet of the gas-liquid mixture. According to the invention, the device is equipped with a hydrodynamic cavitation unit and a jet disperser, arranged in series behind the jet pump in a single housing. The hydrodynamic cavitation unit is made in the form of a chamber, on the end wall of which there is a glass having a central cavity and a tangential inlet for a gas-liquid mixture. The inkjet dispersant is made in the form of a chamber with a glass fixed to its end wall with a central cavity, radial inlets and a recess in the bottom of the glass. The cavities of the glasses of the cavitation unit and the jet dispersant are interconnected by means of a central channel. The outlet for the dispersed gas-liquid mixture is made in the form of a centrally located nozzle fixed to the second end wall of the jet disperser chamber (RF patent No. 2266396, publ. 2005.12.20).

The known method provides enhanced oil recovery, however, when using formation water as a working agent, frequent shutdowns of injection wells occur to clean the bottom-hole zones from deposits of mechanical particles, which leads to a decrease in reservoir pressure and a loss in the rate of field development.

Closest to the proposed invention in technical essence is a method of developing an oil reservoir, comprising pumping a suspension of chemically modified silica into an organic solvent and selling the suspension with a squeezing liquid. Use a suspension containing, wt.%: 0.08-0.15 hydrophobic silica with hydrophobicity 98.0-99.5%; 0.02-0.10 diphilic silica with a hydrophobicity of 40-60% and an additional 0.1-0.3 cationic surfactant CPAS. The resulting suspension is pumped through the dispersant into the bottomhole zone of the PPP formation. Water is used as a squeezing liquid. After selling the suspension in the bottomhole formation zone, the well is added to the reservoir pressure maintenance system without any additional time delay. Moreover, quaternary ammonium or phosphonium bases, tertiary sulfonium bases are used as a surfactant, aerosil, white soot, filter perlite, talc and other amorphous silicas with discrete particles of 0.005-0.1 μm are used as silica, and a wide organic solvent fraction of light hydrocarbons, nefras, unstable gasoline, diesel fuel (RF patent No. 2191257, publ. 2002.10.20 - prototype).

The method provides an increase in the injectivity of injection wells at the same or lower injection pressure and an increase in the duration of the treatment effect. However, the increase in injectivity during the injection of formation water as a working agent is short-term due to clogging with solid suspended particles of the bottom-hole zone of the injection well. As a result, frequent shutdowns of injection wells occur to repair and clean bottom-hole zones from deposits of mechanical particles, which leads to a decrease in reservoir pressure and a loss in the rate of field development.

The proposed method solves the problem of increasing the overhaul period of injection wells by reducing the mudding of the bottom-hole zone by solid suspended particles.

The problem is solved in that in a method for developing an oil deposit, comprising dispersing and pumping a working agent through injection wells and taking oil through production wells, according to the invention, a working agent with solid suspended particles is dispersed, and solid suspended particles contained in the working agent are crushed by dispersion to a dispersion in the range of 1-5 microns, while the pressure during dispersion and injection of the working agent is maintained within 2-10 MPa, and the flow rate of the working agent is maintained they are in the range of 180-360 m ³ / day.

The features of the invention are:

1) dispersion;

2) injection of a working agent through injection wells;

3) oil extraction through production wells;

4) dispersion of the working agent with solid suspended particles;

5) due to dispersion, grinding of solid suspended particles in the working agent;

6) the same to a dispersion in the range of 1-5 microns;

7) pressure during dispersion and injection of the working agent within 2-10 MPa;

8) the consumption of the working agent in the range of 180-360 m ³ / day.

Signs 1-3 are common with the prototype, signs 4-8 are the salient features of the invention.

SUMMARY OF THE INVENTION

When using produced (associated, produced, wastewater) water separated from oil produced and pumped through injection wells into productive formations as a working agent, the injectivity of injection wells decreases due to deposits of solid suspended particles, dirt, and pipeline corrosion products in the bottomhole zone etc. At the moment, there are no easy-to-use and efficient effective wellhead filters operating under high pressure and fluid flow conditions that can clean the working agent. Refining in oil treatment workshops does not ensure the absence of suspended solids, because even by existing standards, water to maintain reservoir pressure contains a certain amount of suspended solids. When such water is injected, the reservoir properties of many wells may deteriorate, which will lead to the need for expensive repairs to restore the injectivity of injection wells.

The proposed method solves the problem of increasing the overhaul period of injection wells by reducing the mudding of the bottom-hole zone by solid suspended particles. The problem is solved as follows.

When developing an oil deposit, the working agent is pumped through injection wells and oil is taken through production wells. At the mouth of the injection well on the injection line, the flow of the working agent (water) from the pipeline is divided into two streams and directed towards each other with acceleration. The flow rate and solid suspended particles increases. In the collision of flows, solid suspended particles hit each other and break into small particles. Dispersion occurs with the grinding of solid suspended particles in the working agent. The required dispersion of solid suspended particles is determined by the dispersion regimes. The required dispersion of solid suspended particles within 1-5 microns, i.e. less than the pore size of the reservoir, is achieved at a pressure at the mouth of the injection well during dispersion and injection of the working agent in the range of 2-10 MPa and consumption of the working agent in the range of 180-360 m ³ / day. After dispersion, the streams are reconnected into a single stream and sent to the injection well.

For dispersion, a dispersant is placed at the mouth of the injection well, capable of grinding solid suspended particles in the working agent to sizes smaller than the pore sizes of the reservoir of the reservoir. In this case, suspended solids are able to penetrate into the formation without mudding or with significantly less mudding of the bottom-hole zone of the injection well.

The drawing shows a dispersant for placement on an injection well.

The dispersant has two input channels 1, starting with holes 2, and one output channel 3, ending with a hole 4. Channels 1 and 3 are connected by choking channels 5 having a smaller diameter than channels 1 and 3. The dispersant is made of a single metal volume, therefore, to form (drilling) chucking channels 5 provides a technological hole 6, which after the manufacture of the dispersant is suppressed.

Dispersant works as follows.

The flow of the working agent (water) from the pipeline is divided into two streams and sent through the openings 2 to the channels 1. Then these two streams through the connecting channels 5 are directed towards each other, connected again into one stream in the outlet channel 3 and sent through the hole 4 to the discharge well. By reducing the flow area when passing through the nozzle channel 5, the flow rate and solid suspended particles increases. In the collision of flows, solid suspended particles hit each other and break into small particles. The diameters and lengths of channels 1 and 5 are selected empirically to achieve a dispersion of solid suspended particles of 1-5 microns. Specifically, the dispersant may have channels 1 of a length of 20 to 26 mm and a diameter of 8 to 18 mm and channels 5 of a length of 6 to 11 mm and a diameter of 4 to 8 mm.

The dispersant uses as the energy necessary for grinding particles, the pressure already existing at the wellhead, created by the work of a cluster pumping station, which pumps the working agent into several (from 3 to 50) wells. The dispersant operates without the use of electricity, is simple in design and manufacture (consists of one housing).

Concrete example

An oil reservoir is being developed with the following characteristics: a reservoir depth of 1147.5 m, a water-oil contact depth of 1000 m, reservoir pressure of 12.5 MPa, reservoir temperature of 28 ° C, porosity of 16%, permeability of 0.171 μm ² , oil saturation of 0.8, oil viscosity in reservoir conditions 1.8 MPa · s, oil density under surface conditions 0.916 g / cm ³ , saturation pressure 5 MPa, gas factor 3.557 m ³ / t, reservoir - pore. The permeability of the formations ranges from 0.176 to 0.083 μm ² . The balance reserves vary from 17,000 to 100,000 thousand tons in formations.

A working agent is injected - produced water through 180 injection wells, production (oil) is taken through 600 producing wells.

To carry out dispersion at the mouth of each injection well, a dispersant made according to the drawing is placed. The dispersant has channels 1 with a length of 25 mm and a diameter of 16 mm and channels 5 with a length of 10 mm and a diameter of 5 mm. The pressure during dispersion and injection of the working agent is maintained within 7 MPa, and the flow rate of the working agent is maintained within 300 m ³ / day.

As a result, it is possible to bring the dispersion of solid suspended particles to sizes of 1-5 microns and to eliminate the decrease in injectivity of injection wells for 1 year, while without dispersion after 4-6 months. injectivity of injection wells decreased by 50-80%.

The use of a dispersant and injection modes will allow maintaining a sufficient injectivity of the injection well for a long time, which will lead to a decrease in the number of repair work due to a decrease in injectivity, to an increase in oil recovery due to the maintenance of a sufficient injection volume and coverage of the reservoir by water flooding.

Application of the proposed method will allow to solve the problem of increasing the overhaul period of injection wells by reducing the mudding of the bottom-hole zone by solid suspended particles.

Claims (1)

A method of developing an oil deposit, including dispersing, injecting a working agent through injection wells and extracting oil through producing wells, dispersing a working agent with suspended solids, dispersing crushed solid suspended particles in the working agent to dispersion in the range of 1-5 μm, while the pressure during dispersion and injection of the working agent is maintained within 2-10 MPa, and the flow rate of the working agent is maintained within 180-360 m ³ / day.

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