RU2487233C1 - Oil deposit development method - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: at deposit development oil is extracted through production wells in cyclic mode and working agent is pumped through injection wells. The appointed cyclic mode of production wells has duration of 7 days out of which oil withdrawal is done without well shutoff up to 2 weeks and within the remaining time well is shut off. Production efficiency of downwhole pumping equipment is selected by calculation of withdrawal of oil accumulated in the well and during time of oil withdrawal and in injection wells having pressure communication with the above production wells; for the purpose to provide cyclic mode of wells operation withdrawal volumes are limited or injection wells are transferred to periodical mode of operation.

EFFECT: increase in oil recovery and reduction of oil extraction expenses.

1 ex

Description

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

A known method for the development of oil deposits, including the injection of water through injection wells and the selection of oil through production wells [I. Muravyov and others. Development and operation of oil and gas fields. M .: Nedra, 1970, p. 103].

The known method does not allow to develop an oil reservoir with a high oil recovery coefficient due to flooding of produced products.

Closest to the proposed invention in technical essence is a method of developing an oil reservoir, comprising pumping a working agent through injection wells in a cyclic mode and taking oil through production wells. Three groups are distinguished from the stock of production wells, the first includes production wells with an almost complete water cut of oil, the second - production wells with a water cut close to the maximum in economic indicators, and with a fluid flow rate of more than 50 m ³ / day, to the third group - producing wells with a water cut of more than 50% and with a fluid rate of less than 10 m ³ / day. The first group of production wells is operated in a cyclic mode: 2 years, the shutdown of wells, then operation until the water content of the produced products is almost completely water-cut. The second group of wells is divided into zonal subgroups. In the adjacent zonal subgroups in antiphase for 4-6 months, production wells are operated in a cyclic mode: periodic shutdown for the period of decreasing oil-water ratio, then production until the oil-water ratio is increased to the maximum water cut. After that, production wells of all zonal subgroups are stopped for 6-8 months. Zonal subgroups of production wells are formed from the condition of equivalent fluid withdrawal in each zonal subgroup and the presence of production wells of a zonal subgroup in the impact zone of a group of injection wells supplied from a single source of working agent. The third group of producing wells is operated in a cyclic mode: 4-6 months, periodic shutdown for less than a day and production for less than a day, after which shutdown of wells for 6-8 months. When the production wells of the second group are stopped in the zonal subgroups, the injection agent injection volumes are simultaneously reduced to 25% of the average value through the groups of injection wells in the zone of influence of which the zonal subgroup is located. During the operation of production wells, the volume of injection of the working agent is increased to 25% of the average value [RF Patent No. 2047750, cl. E21B 43/20, publ. November 10, 1995 - prototype].

The disadvantage of this method is the low oil recovery deposits and high costs of oil production.

The proposed invention solves the problem of increasing oil recovery and reducing the cost of oil production.

The problem is solved in that in the method of developing an oil reservoir, including the selection of oil through production wells in a cyclic mode and the injection of a working agent through injection wells, according to the invention, the cyclic mode of operation of production wells is prescribed for a duration of 7 days, of which up to 2 days are carried out without oil well shutdowns, and in the remaining time, a well shutdown is performed, while the performance of the downhole pumping equipment is selected based on the selection of oil accumulating in the well and during the time of oil extraction, and in injection wells having a hydrodynamic connection with the indicated production wells, to ensure a cyclic mode of operation of production wells, injection volumes are limited or injection wells are transferred to a periodic operation mode.

SUMMARY OF THE INVENTION

When developing an oil deposit, a significant part of the reserves remains buried in the reservoirs. The cyclic mode of injection of the working agent and oil production contributes to a change in the flow gradients in the reservoir and the involvement of additional oil reserves in the development. However, very long periods of operation of both injection and production wells, in fact, reduce these efforts to zero and do not contribute to reducing the cost of produced oil. The proposed invention solves the problem of increasing oil recovery and reducing the cost of oil production. The problem is solved as follows.

When developing an oil deposit, oil is taken through production wells in a cyclic mode and the working agent is injected through injection wells. The cyclic operating mode of production wells is weekly and amounts to 7 days, of which up to 2 days during Saturday and Sunday they select products without stopping the well. These watches account for cheap electricity tariffs, due to which the low cost of produced oil is formed. From Monday to Friday, during expensive electricity tariffs, production wells are shut down. The productivity of the downhole pumping equipment is selected based on the selection of production of products accumulated in the well during a shutdown time of 120 hours and the duration of oil production up to 48 hours, i.e. up to 2 days. Selection is carried out to a minimum level of bottomhole pressure, but not lower than the pressure of oil degassing. In injection wells having hydrodynamic connection with the indicated production wells, to ensure the declared cyclic mode of operation of production wells, injection volumes are limited if continuously operating wells are in operation, or the operating time of injection wells is limited by putting them into cyclic operation mode.

As practice shows, this mode of operation prevents the formation of watering cones, due to which the water cut of the produced products decreases and the oil recovery of the deposit increases. Oil production costs are reduced due to cheap weekend electricity tariffs.

Concrete example

An oil reservoir is developed with the following characteristics: depth 1600-2100 m, reservoir pressure 13 MPa and higher, reservoir temperature 38-42 ° C, reservoir thickness 2.5 m or more, porosity from 10%, permeability from 250 mD, oil density 0.8 g / cm ³ , reservoir of the reservoir - terrigenous Devonian. The deposit is developed using flooding. The working agent-produced (produced) water is pumped through injection wells, formation products are taken through production wells.

15 production wells with a flow rate of 2 to 150 m ³ / day and a water cut of 70 to 99% are operated in a cyclic mode of 7 days, of which production and 120 hours are taken for 2 days on Saturday and Sunday every day for 24 hours from Monday to Friday stop the well. In injection wells having hydrodynamic connection with the indicated production wells, in order to ensure the declared cyclic mode of operation of production wells, injection volumes are limited to 0 m ³ / day for wells that are constantly in operation, or the operating time of injection wells is limited to 50% for wells.

As a result, the oil recovery of the reservoir increases by 2% and amounts to 35%, while according to the known methods of development, the oil recovery does not exceed 33%. Electricity consumption is reduced by 30%.

The application of the proposed method will improve oil recovery and reduce the cost of oil production.

Claims (1)

A method of developing an oil deposit, including the selection of oil through production wells in a cyclic mode and the injection of a working agent through injection wells, characterized in that the cyclic mode of operation of the producing wells is prescribed for a duration of 7 days, of which up to 2 days, oil is taken without stopping the well, and the remaining time, the well is shut down, while the productivity of the downhole pumping equipment is selected based on the selection of oil accumulating in the well and during the selection time minute, and in injection wells having a hydrodynamic communication with said production wells for cyclic operation of producing wells limit the injection volume or injection wells is converted into periodic operation.