A method of operating a multi-layer oil fields

 

(57) Abstract:

The invention can be used in the extraction of oil and gas in multilayer oil and gas fields. Provides improved reliability of the method and the optimal selection of fluids. The method involves separation of the barrel of the production well into zones of separate fluid reservoir, adjustable bypass them in the column tubing and joint ascent to the surface. Fluids from zones separate selection perepuskat in the column tubing in critical flow conditions, the relevant specified for each layer of the flow of fluid and the amount of depression on the formation. The pressure in the tubing pipe support at the level not exceeding the smallest of the critical pressure propuskayuschih fluid fittings. 1 Il.

The invention relates to the oil and gas industry and can be used in the extraction of oil and gas from multiple zone oil and gas fields.

The known method the joint exploitation of the layers of the multilayer deposits of similar filtration properties. In this method of operation the layers are combined into one object, productivity is ornago pipes (tubing) (1).

The disadvantage of this method is the impossibility to control the pace of product selection from each stratum separately, which often leads to uneven development of the reservoir, and when the difference of the filtration characteristics of the layers to the lack of inflow to the reservoir with poorer reservoir properties.

The known method of operation of multilayer deposits together with separate operation of reservoirs, including the separation of the well packer in the area of sampling fluid from a separate reservoir, the fluid in the separated zone, bypass them in the drill pipe and joint lifting of fluids on the surface of one column (2).

The disadvantages of the method are associated with low reliability required for it equipment, the need to change the fitting as changes in the properties of the extracted Neftegazovaya mixture, as well as the inability of the joint operation of more than two layers, as the regulation is only one layer.

The technical task of the invention is to improve the reliability of the method and ensuring optimal selection of fluids in reservoirs and co-operation of more than two layers with different collection soudani, including when together-separate sampling of reservoir fluids, providing for the separation of the barrel of the production well into zones of separate fluid reservoir, adjustable bypass them in the drill pipe and joint ascent to the surface, the fluids from zones separate selection perepuskat into the tubing string at critical flow conditions, the relevant specified for each layer of the flow of fluid and the amount of depression of the reservoir, the pressure in the tubing string is supported at a level not exceeding the smallest of the critical pressure propuskayuschih fluid fittings.

The proposed method of mining involving together-separate operation of several layers one well, is illustrated by a drawing.

Field drilled according to the scheme of development of injection wells and producer, arranged in the following way. In the well 1 down tubing (tubing) 2 packers 3, which share the productive formations, and placed under the packers in the area of productive layers fittings 4 critical flow (3) designed for individual consumption of fluid and the amount of depression for each stratum. Tubing 2 with packers 3 and the critical value is set tubing 2 install the lifting column 6, which is a standard fontanne equipment or standard equipment for the mechanized method of lifting fluid.

Field development in productive strata support the pressure being pumped into them through injection wells displacing agent (water), and wireline fluid to rise up to the surface through production wells. The work of producing wells 1 with the joint operation of reservoirs proposed method is as follows. During the development of wells in the fountain mode or by mechanical means on the fittings 4 are the differential pressure between the bottom of the respective reservoir and the cavity of the tubing 2. As well in mode, the differential pressure on the fittings increases and reaches its critical value. The velocity of flow at the outlet of the nozzle reaches a critical speed, and the consumption of its maximum value, for each individual nozzle. Further reduction of pressure in the stationary tubing does not change the costs and established the calculated values of depression on each layer, as in the nozzle critical flow velocity cannot exceed the critical (thermal) velocity of the molecules.

The proposed method for joint operation of reservoirs stacked field has the following advantages: a layer of low gas content, which in a separate operation, the oil must be raised by mechanical means, in the presence of a layer with high gas content can be operated fountain way; uneven watering reservoirs watering reservoir may be designed fountain way up to 90% water cut and above by the energy of the other layers; can be connected together for separate operation of one well several (more than three) of productive horizons; as a result of joint operation of reservoirs will significantly increase the total well flow rate, and consequently, will increase the flow rate and temperature sistemafinleasing tubes.

An example of the calculation.

East-Yangtinskoe field, the well 19, the joint operation of reservoirs BS11-12and th1presented in the table.

The reservoir permeability differ considerably. The joint operation of reservoirs one object impossible.

Calculation of the critical nozzles (nozzles) for each object operation.

The reservoir BS11-12.

The calculated critical pressure fitting

Pc= 0,5 PC.

The calculated critical speed

vc= 103[Pc/a (1-a) W]1/2= 103[10,5/0,3560,644794]1/2= 240 m/s,

where a = 0,356 is the volume fraction of gas at the critical pressure;

W= 794 - density liquid phase.

The estimated cross-sectional area of the nozzle (nozzle)

S = QWb/vc= 2401,82/240243600 = 2,110-5m2,

where b = 1,82 - volume ratio.

The estimated diameter of the fitting

d = [4S/ ]1/2= [42,110-5/3,14]1/2= 5,210-3m

The estimated length of the critical fitting

L = 510-3(vc2c/PC-Pc) = 510-324020,510-3/10,5 =0,0137 m,

wherec= 0,510-3kg/m3the density of the mixture.

The reservoir Yu1 The calculated critical speed

vc= 103[Pc/a(1-a)W]1/2= 103[13,5/0,3140,686864]1/2=269 m/s,

where a = 0,314 is the volume fraction of gas at the critical pressure;

W= 864 - density liquid phase.

The estimated cross-sectional area of the nozzle (nozzle)

S = QWb/vc= 631,61/269243600=4,3610-6m2,

where b = 1,61 - volume ratio.

The estimated diameter of the fitting

d = [4S/ ]1/2= [44,3610-6/3,14]1/2=2,36 10-3m

The estimated length of the critical fitting

L = 510-3(Vcc/PC- Pwith) = 510-326920,6 10-3/13,5 = 0,016 m,

wherec= 0,6 10-3kg/m3the density of the mixture.

The optimal mode of operation of the reservoir Yu1provided critical fitting diameter of 2.36 mm and a length of 16 mm at a critical pressure of 13.5 MPa.

To ensure optimum performance of both layers in the pipe 2 (see drawing) it is necessary to maintain the pressure above the 10.5 MPa.

When the pressure at the wellhead is not higher than 3 MPa is provided gushing mode of operation of the well.

Sources of information

1. Gimatdinov W. K. Reference book on oil production. M., "Nedra", 3. Great Soviet encyclopedia (see "nozzle").

A method of operating a multi-layer oil fields together with separate sampling of reservoir fluids, providing for the separation of the barrel of the production well into zones of separate fluid reservoir, adjustable bypass them in the column tubing and joint ascent to the surface, characterized in that the fluids from zones separate selection perepuskat in the column tubing in critical flow conditions, the relevant specified for each layer of the flow of fluid and the amount of depression of the reservoir, the pressure in the tubing pipe support at the level not exceeding the smallest of the critical pressure propuskayuschih fluid fittings.

 

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