RU2443853C1 - Development method of oil deposit with oil-water zones - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: method involves construction at least of one well with horizontal section, fluid injection and extraction of the bed product. Section of deposit in the form of oil-bearing lens and level of oil-water contact - OWC - is determined. Well is built with horizontal section arranged below OWC level and with ascending working face located above OWC level. After that, drilling of the bed of two well sections arranged above OWC level and horizontal section, and insulation of horizontal section from the drilling section located above OWC level on the side of the well mouth is performed. After that, the product is extracted from the drilled section of the bed, which is located above OWC level on the mouth side, and fluid is injected from horizontal section to the drilling section located above OWC level, on the side of working face due to negative pressure created with the bed product extraction above OWC level.

EFFECT: improving the development degree of oil resources, reducing the costs for construction of additional wells and achieving complete output of productive bed.

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Description

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

A known method of development (patent RU No. 2196885, IPC ЕВВ 43/22, published on January 20, 2003) of an oil field in fractured carbonate reservoirs, including drilling a field with a system of wells with vertical and horizontal shafts. An injection well is drilled with a vertical wellbore and the lower bottom part of the formation is opened, and a production well with a horizontal well is located in the roofing part of the productive formation. The plugging solution is pumped into the injection well, and the production well is stopped for the time of injection, and the plugging solution is injected at a pressure exceeding the pressure of the opening of vertical cracks.

The disadvantages of this method are the low efficiency in the operation of watered deposits, cone formation, contributing to the rapid watering of the produced products.

A known method of development (patent RU No. 2387812, IPC ЕВВ 43/16, published on 04/27/2010) of an oil reservoir with oil-water zones, comprising drilling at least one horizontal production and injection wells, placing the horizontal production well parallel to the oil-water contact at a distance that allows putting the well into operation with an anhydrous period, an injection vertical or horizontal well is placed above the producing well in the roof of the productive formation and the displacing agent is injected a specific gravity lower than the specific weight of the produced water.

The disadvantages of this method are the high costs of the construction of production and injection wells, low efficiency in the development of oil deposits with oil-water zones due to the low coverage of the reservoir injection agent.

The technical objectives of the proposed method are to increase the degree of development of oil reserves, save money on the construction of additional wells, achieve full production of the reservoir.

The technical problem is solved by the method of developing an oil reservoir with oil-water zones, including the construction of a single well with a horizontal section, pumping fluid and selecting reservoir products.

New is that they determine the area of the reservoir in the form of an oil-bearing lens and the level of water-oil contact (VOC), build a well with a horizontal section located below the level of the VOC, and an ascending bottom located above the level of the VOC, after which the formation of the two sections of the well located above the level of the oil well, and the horizontal section, isolation of the horizontal section from the opening section located above the level of the oil hole, from the side of the wellhead, after which the production of the formation is taken from the opened section, located above the decomposition BHK, from the mouth, and forcing fluid from the horizontal portion in the opening portion located above the OWC, with the bottom side due to the vacuum created by the selection of product formation BHK higher level.

The drawing shows a diagram of the implementation of the method.

The drawing shows: horizontal well 1; oil lens 2; packer or cement bridge 3; rarefaction zone 4; oil-water contact (WOC) 5;

wellhead 6; bottom hole 7; 8 and 8 '- the intervals of opening of the formation 2 above the level of the BHC 5, 8' '- the interval of opening of the horizontal section 9; horizontal section 9 of the well 1.

The implementation of this method, we consider the example of deposits, presented in the form of an oil-bearing lens in Bashkir sediments with a water-oil zone. Oil-saturated thickness is 10 m, water-saturated - 5 m, oil-water contact on the deposits opened at minus 600 m.

The area of the reservoir is determined in the form of an oil lens 2 at minus 570 m and the level of water-oil contact (VOC) 5 at minus 600 m. Then, well 1 is drilled with a horizontal section located below the level of VNK 5 and an upstream bottom 7 located above the level of VNK 5. Then open 8 and 8 'of the oil-bearing lens 2 of two sections of the well 1 located above the level of HOC 5, and open 8 "of the horizontal section 9. Next, isolate the horizontal section 9 of the well 1 from the opening section 8 and 8' using packer 3 located above VNK level 5, from the side of the wellhead.

Then carry out the selection of the production of oil-bearing lenses from the exposed sections 8 and 8 'located above the level of the BHK 5, from the side of the mouth 6, and the injection of fluid from the horizontal section 9 to the opening section 8', located above the level of the BHK 5, from the bottom 7 account of the rarefaction zone 4 created by the selection of oil-bearing lens products above the level of WOC 5.

The proposed method allows to extend the anhydrous period of the well’s operation, to increase the coverage coefficient by the development of oil reserves and, as a result, the final oil recovery. The application of the method allows to expand the technological capabilities of the development of deposits, presented in the form of an oil-bearing lens, to include in the work of the oil-water zone of the reservoir, previously not involved in oil production.

Claims (1)

A method of developing an oil reservoir with oil-water zones, including the construction of at least one well with a horizontal section, injection of fluid and selection of formation products, characterized in that they determine the section of the reservoir in the form of an oil lens and the level of the oil-water contact - VOC, the well is built with horizontal a site located below the level of the oil-water supply, and an ascending bottom, located above the level of the oil-water supply, after which an opening is made of the formation of two sections of the well located above the level of the oil-water supply, and a horizontal section , isolation of the horizontal section from the opening section located above the level of the oil-water supply, from the side of the wellhead, after which the production of the formation is taken from the exposed section located above the level of the oil-hole cutting, from the side of the well, and fluid injection from the horizontal section into the opening section located above the level VNK, from the side of the bottom due to the vacuum created by the selection of formation products above the level of VNK.

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