RU2137916C1 - Method for development of oil deposit - Google Patents

Abstract

FIELD: oil production industry. SUBSTANCE: method can be used for development of oil deposit with high flooding of recovered product. According to method, working agent is injected through injection wells and oil is recovered through producing wells. Injection wells are operated in cyclic mode that is "injection-stopping". In one of half-cycle "stopping", seismo-acoustic emitter is installed in injection well in upper part of productive interval. Seismo-acoustic treatment is carried out during 20-40 min. Seismo-acoustic emitter is displaced along productive interval with stoppages after every 250-500 m for period of 20-40 min for performing seismo-acoustic treatment. Operations are repeated after 6-50 months. Application of aforesaid method ensures reduction of flooding of recovered product together with increasing oil recovery from deposit. EFFECT: higher efficiency.

Description

 The invention relates to the oil industry and may find application in the development of oil deposits with high water cut of produced products.

 A known method of influencing the oil reservoir by exciting elastic vibrations in the reservoir in the phase of earth tides (1).

 The known method has very little effect on reducing the water content of the extracted products.

 Closest to the invention in technical essence is a method of developing an oil reservoir, including pumping a working agent through injection wells, taking oil through production wells, placing a seismic acoustic emitter in the injection well in the interval of the producing formation and conducting seismic acoustic stimulation of the formation (2).

 The known method allows to increase the flow rates of producing wells, however, it does not lead to a decrease in the water content of the produced products.

 The invention solves the problem of reducing the water content of the produced products and thereby increasing the oil recovery of the reservoir.

 The problem is solved in that in the method of developing an oil reservoir, which includes injecting a working agent through injection wells, taking oil through production wells, placing a seismic acoustic emitter in the injection well in the interval of the producing formation and conducting seismic acoustic stimulation of the formation according to the invention, the injection wells are operated in a cyclic “injection - stop” mode, in one of the “stop” half-cycles in the injection well I place in the upper part of the productive interval seismo-acoustic transducer, carried seismoacoustic effects within 20-40 minutes, seismo-acoustic transducer is moved along the production interval with stops through 250-500 mm 20-40 min, during which exposure is performed seismoacoustic repeated operation over 6-50 months.

The features of the invention are:
1. injection of the working agent through injection wells:
2. the selection of oil through production wells;
3. placement in the injection well in the interval of the reservoir of the seismic acoustic emitter;
4. conducting seismic acoustic stimulation;
5. operation of injection wells in a cyclic mode of "injection - stop";
6. placement in one of the half-cycles "stop" in the injection well of a seismic acoustic emitter in the upper part of the production interval;
7. conducting seismic-acoustic impact for 20-40 minutes;
8. the movement of the seismic acoustic emitter along the production interval with stops after 250-500 mm for 20-40 minutes;
9. conducting seismic-acoustic impact at stops;
10. repetition of operations after 6-50 months.

 Signs 1-4 are common with the prototype, signs 5-10 are the salient features of the invention.

SUMMARY OF THE INVENTION
When developing an oil deposit, a gradual flooding of the produced products occurs. The invention solves the problem of reducing the water content of the produced products. The problem is solved by applying the following actions.

 In the deposits, the working agent is injected through injection wells and oil is taken through production wells. Injection wells are operated in a cyclic "injection - shutdown" mode. In one of the “stop” half-cycles, a seismic acoustic emitter is placed in the injection well at the top of the productive interval and a seismic acoustic effect is performed for 20-40 minutes. The seismic acoustic emitter is moved along the production interval with stops after 250-500 mm for 20-40 minutes, during which the seismic acoustic effect is carried out. Repeat the operation after 6-50 months.

 When injection wells are stopped, formation pressure decreases first in high-permeability zones, where oil flows from low-permeability oil-saturated zones. The application of seismoacoustic effects during this period contributes to the enhancement of this effect. As a result, the water cut of oil is reduced.

 The established parameters for the movement of the seismic acoustic emitter and the duration of the seismic acoustic impact allow the greatest reduction in the water content of the produced products. The repetition of operations after 6-50 months is due to the duration of the effect of reducing the water content of the extracted products.

 The most favorable cyclic "injection - stop" mode involves pumping a working agent through an injection well for 10-15 days and stopping it for 10-15 days. Other cyclic operating modes of injection wells are possible.

 As a seismic acoustic emitter, as in the prototype, use a device including a downhole probe and a ground panel. The downhole probe comprises an energy storage device, a power unit, a trigger pulse generation circuit and a synchronization pulse generation circuit, a controllable spark gap switch and a discharge container with an electro-acoustic transducer.

 The ground panel contains circuits that provide power to the borehole probe, devices for monitoring the voltage in the network, voltage and current supply of the probe, switches that regulate the charge current of the probe and the duration of the charge, as well as a block of equipment protection circuits in case of emergency.

The downhole probe has the following characteristics: the length of the downhole probe is 3.5 m, the diameter of the downhole probe is 100 mm, the weight of the downhole probe is 90 kg, the pulse pressure developed in the water at a distance of 1 m-3 • 10 ⁵ Pa, the emitter performance is 12 imp / min, the supply voltage is 220 V, 50 Hz, the power consumed from the network is 1 kW, the working temperature is 100 ^o C, the working pressure is 40 MPa.

Concrete example
An oil reservoir of the Romashkinskoye field is being developed with the following characteristics: porosity - 11.9%, permeability - 0.029 μm ² , oil saturation - 61.1%, absolute oil-water contact mark -870 m, average oil-saturated thickness - 4 m, initial reservoir pressure - 11 MPa , reservoir temperature - 25 ^o C, reservoir oil parameters: density - 930 kg / m ³ , viscosity - 46 MPa • s, saturation pressure - 1.8 MPa, gas content - 15.2 m ³ / t, sulfur content - 3, 64%

 A working agent is pumped - associated formation water through 40 injection wells, oil is taken through 90 production wells. Injection wells are operated in a cyclic mode: 15 days — injection of a working agent, 15 days — shutdown.

 When one injection well is stopped, a seismic acoustic emitter is placed in the upper part of the productive interval and a seismic acoustic effect is carried out for 30 minutes. The seismic acoustic emitter is moved along the production interval with stops after 300 mm for 25 minutes, during which the seismic acoustic effect is carried out. After completing the entire productive interval, the seismic acoustic emitter is again placed in the upper part of the productive interval and all operations are repeated. In this way, a seismic acoustic effect is carried out during the entire 15 days of shutdown of the injection well. After that, a working agent is pumped through this injection well for 15 days. At the next shutdown of the injection well, seismic-acoustic impact is not carried out. Again, seismic-acoustic impact is performed on this well after 12 months.

 As a result, the water cut of extracted products decreased from 70 to 50%.

 The movement of the seismic acoustic emitter along the production interval with stops ranging from 250 to 500 mm for a period of 20 to 40 minutes, during which the seismic acoustic effect is carried out, leads to a similar result.

 The application of the proposed method will reduce the water content of the extracted products and thereby increase the oil recovery of the reservoir.

Sources of information:
1. RF patent N 2046936, cl. E 21 B 43/25, published. 1995 year

 2. R.Kh. Muslimov and others. Geology, development and operation of the Romashkinskoye oil field. Volume 2-M. ; VNIIOENG, 1995, p. 174, 175, 183 - 185 prototype.

Claims (1)

 A method of developing an oil reservoir, including injecting a working agent through injection wells, extracting oil through production wells, placing a seismic acoustic emitter in the injection well in the interval of the producing formation, and performing seismic acoustic stimulation on the formation, wherein the injection wells are operated in a cyclic "pump-stop ", in one of the half-cycles" stop "in the injection well in the upper part of the productive interval place a seismic acoustic radiation tel, conduct seismic acoustic impact for 20–40 min, move the seismic acoustic emitter of the productive interval with stops after 250–500 mm for 20–40 min, during which they conduct seismic acoustic impact, repeat the operations after 6–50 months.