RU2103486C1 - Method for development of oil deposit - Google Patents

Abstract

FIELD: oil production industry. SUBSTANCE: method is aimed at accelerated reformation of watered oil deposit and involving low-permeable interlayers in development. According to method, productive bed is initially subjected to vibro-seismic treatment by means of source of elastic vibrations installed in one of central wells of deposit. This treatment is carried out until watering of recovered product in whole across deposit is reduced by 3-5%. After that, injection of displacing agent into bed is periodically stopped and renewed. In watered oil bed, vibro-seismic treatment substantially (by 2-3 orders) accelerates process of gravitational separation of oil and water. Cyclic injection induces involvement in development of oil reserve concentrated in low-permeable interlayers. EFFECT: high efficiency.

Description

 The invention relates to the oil industry, in particular, to methods for developing oil fields.

 A known method for the development of oil deposits, which consisted in the application of the cyclic injection method, carried out with periodic changes in pressure (flow) of the injected and injected liquid [1].

 The disadvantage of this method is its low efficiency when used in a heterogeneous formation.

 The closest in technical essence and the achieved effect is a method of developing an oil reservoir using vibroseismic effects on the reservoir using borehole sources of elastic vibrations [2].

 The disadvantage of this method is a slight increase in oil recovery when used in flooded deposits.

 The purpose of the invention is a reformed waterlogged oil reservoir and the inclusion in the development of low permeability layers.

 The goal is achieved by the fact that in the known method of developing an oil reservoir, which includes injecting the displaced agent into injection wells, taking fluid from production wells, conducting vibroseismic action on the reservoir by elastic vibrations, first produce a vibroseismic effect on the reservoir using a source of elastic vibrations installed in one of the wells located in the central part of the reservoir until the water cut of the produced product as a whole in the reservoir decreases by 3 - 5%, after which it periodically stops and resumes the agent in the reservoir.

 The method is carried out in the following way.

 To effectively use the energy of elastic vibrations in the formation, a vibration source is installed in one of the wells located in the central part of the reservoir, then a vibroseismic effect is produced on the reservoir until the water cut of the whole product in the reservoir decreases by 3 - 5%. After that, the vibration source is turned off.

 The well-known formula [3] determines the duration of the half-cycle of injection of the displacing agent.

,
где t - время полуцикла закачки, с;
l - расстояние между нагнетательной и эксплуатационной галереями;
x - средняя пьезопроводность незаводненного объема пласта, м²/с.

,
where t is the injection half-cycle time, s;
l is the distance between the discharge and production galleries;
x is the average piezoconductivity of the unfilled reservoir volume, m ² / s.

 Then periodically stop and start up all injection wells.

 Carrying out vibroseismic effects on the watered reservoir will lead to acceleration of the gravitational separation of oil and water, the reformation of the reservoir.

 Cyclic injection will contribute to the involvement of low permeability layers in the development.

This development method was tested on reservoir with the following geological and physical parameters:
Depth of occurrence of a deposit - 2400 m
Oil saturated thickness - 9.8 m
Porosity - 12%
Permeability - 0.124 μm ²
Oil viscosity in reservoir conditions - 3.1 MPa • s
Reservoir pressure
Initial - 27.5 MPa
Current - 25.8 MPa
Well stock
Mining - 16 units.

 Injection - 7 units.

 Initially, a vibroseismic effect on the reservoir was carried out using a source of elastic vibrations installed in well A, located in the central part of the reservoir. The impact continued until the time when the water cut of the extracted product as a whole in the reservoir decreased by 4% (from 76 to 72%).

Next, we determined the duration of the injection half-cycle by the formula (1)
at l = 500 m, x = 0.05 m ² / s.

,
Время полуцикла закачки оказалось равным 29 сут.

,
The injection half-cycle turned out to be 29 days.

 In the first half-cycle, equal to 29 days, all the injection wells were stopped. In the second half-cycle (within 29 days), water was pumped into all injection wells.

 The technological efficiency of the proposed development method amounted to 19.2% of the total annual oil production of the reservoir.

Claims (1)

 A method of developing an oil reservoir, including pumping a displacing agent into injection wells, taking fluid from production wells, conducting vibroseismic action on the reservoir by elastic vibrations, characterized in that it first produces a vibroseismic effect on the reservoir using an elastic oscillation source installed in one of the wells located in the central part of the reservoir until the water cut of the produced fluid in the reservoir as a whole decreases by 3 5% after which They periodically stop and resume the injection of the displacing agent into the formation.