Multizone oil reservoir development method

FIELD: oil industry, particularly enhanced recovery methods for obtaining hydrocarbons.

SUBSTANCE: method involves cyclically extracting oil from the reservoir zones through productive wells and injecting working agent into reservoir zones through injection wells. Discharge water and oil-field water of low mineralization having thickness of 1-1.005 kg/m3 is used as the working agent. Discharge water is cyclically injected in upper reservoir zones. Oil-field water of low mineralization is cyclically injected in lower reservoir zone for 7-9 months and discharge water is also cyclically injected in lower reservoir zone for 3-5 months.

EFFECT: increased output.

 

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

There is a method of developing multilayer oil fields, including the allocation of production facilities, drilling of production and injection wells on a dedicated production facilities, the injection of the displacing agent in injection wells and extraction of oil from producing wells. First, determine the total increase in initial amplitude of the flow rate of the oil project wells. The allocation of operational objects produced in accordance with the criteria of rational Association (Patent RF № 2142046, CL E 21 In 43/20, publ. 27.11.1999).

The known method allows you to select the main oil reserves, but production remains low due to the formation in the layers washed channels, through which passes a working agent without affecting the bypassed zone and displacing low ability worker agent.

The closest to the proposed invention the technical essence is a way of developing multilayer oil deposits, including the assessment of the average values of porosity and permeability of the formations, the selection of oil from the reservoir through the production wells, water injection in a cyclic mode with the selection of the cycle time of the injection and the production of layers. PLA is you are divided into groups. The assessment of average values of porosity and permeability are carried out for each group. In the first group include layers with higher permeability. The second group includes less permeable layers. The cycle of water injection is chosen from the condition of ensuring the smallest difference in the averaged velocities of the fronts of the displacement of the layers of the productive section of the first and second groups (RF Patent No. 2132940, CL E 21 In 43/20, publ. 10.07.1999 - prototype).

The known method allows you to select the main reserves of oil and water injection in the cyclic mode, the oil from the stagnant zones. However, production remains low due to low displacing water capacity (operating agent).

In the proposed invention solves the problem of increasing oil deposits. The task is solved in that in the method of developing multilayer oil deposits, including the selection of oil from the reservoir through the production wells, injection working agent layers in a cyclic mode, according to the invention, as the operating agent use waste water and produced water of low salinity in the upper layers of the cyclically pumped waste water in the lower reservoir in cyclic mode download for 7-9 months. produced water of low salinity and within 3-5 months. waste water.

Signs of izaberete the Oia are:

1. the selection of oil from the reservoir through the production well;

2. download working agent layers in a cyclic mode;

3. use as a working agent of waste water;

4. use as a working agent produced water of low salinity;

5. injection in the upper layers in cyclic mode wastewater;

6. injection into the lower reservoir in a circular mode for 7-9 months. produced water of low salinity and within 3-5 months. waste water.

Signs 1, 2 are shared with the prototype, signs 3-6 are the salient features of the invention.

The invention

In the development of oil deposits of part of the reserves remains in the reservoir. Existing methods allow to take deposits from the main inventory. However, oil recovery reservoir remains low.

In the proposed method solves the problem of increasing oil deposits.

The problem is solved as follows.

When designing multilayer oil deposits are a selection of oil from the reservoir through the production wells and the injection of the working agent in the reservoir in cyclic mode. As a working agent use of waste water produced after separation of oil-water emulsions produced from deposits, and produced water of low salinity, specially extracted from the water-saturated layer. In the upper layers in aliceson mode pump waste water, in the lower reservoir in cyclic mode download for 7-9 months. produced water of low salinity and within 3-5 months. waste water. Cyclic injection regime working agent involves the injection within a certain time and stop pumping for a certain period of time. For example, pumping in 10-20 days. and stop pumping within 10-20 days. For each stratum, or even part of the reservoir to define its mode.

As the reservoir water of low mineralization use produced water with a density of from 1 to 1,005 kg/m3. Produced water is extracted through a specially drilled wells from strata above the producing formations of oil deposits. Produced water is injected through injection wells in the reservoir oil deposits immediately and without any training. When this water is not cooled and is not saturated with oxygen.

Specific example

Develop an oil field with the following characteristics. Deposit multilayer. In development there are three productive formation: Tula layer, bobrikovskian Tournaisian reservoir and the reservoir.

Tula layer has the characteristics: depth 1161-1171 m, terrigenous reservoir pore, the average saturated thickness of 2 m, the porosity 19-23%, the saturation 0,72, the permeability of 1.26-1, μm 2the initial reservoir temperature of 25°C, initial reservoir pressure of 11.8 MPa, the viscosity of the oil at reservoir conditions to 40.6 MPa·C, the density of the oil at reservoir conditions 868 kg/m3the pressure of the oil saturation gas to 3.2 MPa, the gas oil 11.4 m3/t, the viscosity of water at reservoir conditions of 1.65 MPa·C, the density of water at reservoir conditions 1160 kg/m3

Bobrikovskian layer has the characteristics: depth 1173 m, terrigenous reservoir pore, the average saturated thickness of 2.7 m, a porosity of 23%, the saturation 0,72, permeability 1,072 μm2the initial reservoir temperature of 25°C, initial reservoir pressure 12 MPa, the viscosity of the oil at reservoir conditions to 36.8 MPa·C, the density of the oil at reservoir conditions 885 kg/m3the pressure of the oil saturation gas to 3.4 MPa, the gas oil 13,9 m3/t, the viscosity of water at reservoir conditions of 1.65 MPa·C, the density of water at reservoir conditions 1160 kg/m3.

Tournaisian reservoir has the characteristics: depth 1181-1204 m, collector carbonate porous fractured, the average saturated thickness of 9.0-11.5 m, porosity 10-12%, the saturation of 0.74-0.74 and the permeability of 0.005-of 0.23 μm2the initial reservoir temperature of 25°C, initial reservoir pressure of 12.1 MPa, the viscosity of the oil at reservoir conditions 35 MPa·C, the density of the oil at reservoir conditions 854 kg/m3pressure is their oil saturation gas to 4.1 MPa, the gas oil 27.5 m3/t, the viscosity of water at reservoir conditions of 1.66 MPa·C, the density of water at reservoir conditions 1160 kg/m3.

All producing wells are working in continuous mode. Injection wells operate in periodic mode: 15 days. upload a working agent 15 days. stop.

Through producing wells selected oil from Tula layer. Through producing wells selected oil from Bobrikovsky layer. Through producing wells take away oil from the Tournaisian reservoir.

In Tula the reservoir through injection wells inject the working agent of waste water in cyclic mode 15 days. upload a working agent 15 days. stop.

In Bobrikovsky the reservoir through injection wells inject the working agent of waste water in cyclic mode 15 days. upload a working agent 15 days. stop.

In the Tournaisian reservoir through injection wells within 8 months. inject produced water of low salinity in cyclic mode 15 days. upload a working agent 15 days. stop in for 4 months. waste water in cyclic mode 15 days. upload a working agent 15 days. stop.

Waste water has the following characteristics: density of 1160 kg/m3pH is 6.2, the oil content 14,67 mg/l, EHF 20,67 mg/L.

As the reservoir water of low salinity used in isout produced water Sakmarian stage, located at a depth of 300-500 m the composition of the water next, g/l: CL of 0.8, SO41,5 HCO30,24, CA* 0,13, Mg* 0,23, Na+K 0,79, the amount 3,68. The density of water 1,003 kg/m3.

The average rate of production wells for oil is 4,13 t/d., liquid - 5,81 m3/day. The average capacity of wells is 80 m3/day.

Estimates of recoverable oil deposits show that the use as a working agent of waste water and produced water of low salinity, pumping regimes wastewater and produced water of low salinity can increase the recovery factor with the design 0,289 to 0.30.

The application of the proposed method will allow to increase the recovery rate of oil deposits.

The method of developing multilayer oil deposits, including the selection of oil from the reservoir through the production wells and the injection of the working agent in the reservoir in a cyclic mode, characterized in that as a working agent use waste water and produced water of low salinity density 1 - 1,005 kg/m3in the upper layers of the cyclically pumped waste water in the lower reservoir in cyclic mode download for 7-9 months produced water of low salinity and within 3-5 months of waste water.



 

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