The way to develop low-permeability oil and gas or gascondensate-oil system horizontal and inclined wells

 

The invention relates to the oil and gas industry and may find application in the development of tight oil and gas or gascondensate-oil deposits, in particular, their oil rims. The objective of the invention is to increase the flow rate of oil wells in low-permeability reservoirs. The inventive low-permeability oil and gas or gascondensate-oil reservoir develop a system of horizontal and inclined wells for oil extraction. Thus have the perforation interval of these wells in pure oil zone, and also in the field of oil and gas contact when the distance to the contact 0-5 m 1 PL., 2 Il.

The invention relates to the oil and gas industry and may find application in the development of tight oil and gas or gascondensate-oil deposits, in particular, their oil rims.

There is a method of extracting oil from podgotovki zone oil and gas reservoirs in the system producing horizontal and/or vertical wells, the relationship between the production well carried out on sections of an oil rim with a relatively high filtration seprately he is in low-permeability reservoirs, reduces oil production. Reduced oil production and productivity of wells for oil.

The closest in technical essence of the present invention is a method of developing oil and gas or gascondensate-oil system horizontally-inclined of wells, their location bottom of perforation interval in podgotovki area and selection of oil [2]. The upper perforation interval wells placed below the gas-oil contact (GOC) on 6 or more meters of the Development are in the mode of maintaining the current reservoir pressure by injection of the working agent is water.

The known method can be used in high-permeability reservoirs, and in low-permeability reservoirs, it leads to a lower production rate and productivity of wells for oil.

The invention solves the problem of increasing production of oil wells in low-permeability reservoirs.

The task is solved in that in the known method the development of low-permeability oil and gas or gascondensate-oil system horizontal / directional wells with the location of the bottom of the perforated interval in podgotovki area and the selection of oil, according to the invention the upper perforation interval horizontally-Natacha.

The essential features of the method are:

1. Development of low-permeability oil and gas or gascondensate-oil system horizontal directional wells.

2. The location of the bottom of perforation interval horizontal and inclined wells in podgotovki zone.

3. The selection of oil.

4. Placing the top of the perforated interval horizontal and inclined wells in pure oil zone.

5. Placing the bottom of perforation interval horizontal and inclined wells in the area of gas-oil contacts.

Signs 1-3 are common with the prototype of the essential features and characteristics 4, 5 - distinctive essential features of the invention.

The invention

In the known technical solutions in the development of oil and gas and gascondensate-oil deposits horizontally-inclined wells with the location of the bottom of the perforated interval in podgotovki zone oil zone below the gas cap), in high-permeability reservoirs of gas is far ahead of the oil, gas breakout occurs with a significant decrease in oil production rate. The problem of increasing production wells solve by removing the top of the perforated interval of the wells at a distance of 6 m and the battle deposits to reduce breakthrough gas and thereby increase the flow rate of oil.

During the development of low-permeability oil and gas or gascondensate-oil deposits, this solution is not acceptable. Therefore, the proposed technical solution, using a well-known fact a significant impact on the oil production, gas-liquid factor and utilization wells, placement of the working part (perforation) of the wells with respect to the STC, respectively, the upper perforation interval horizontal and inclined wells placed in pure oil zone, and the lower interval is placed in the STC region. During the development of deposits on the mode of gas repression lower perforation interval support at the level of the STC, for example, by isolating the bottom of the perforated interval of the well exposed above the STC. It is known that the extraction of oil from low-permeability reservoirs reservoir pressure in this well is declining rapidly. When placing the bottom of the perforated interval in the region of the STC gas from the gas cap, when in the well, will be partially dissolved in the oil, increasing its volume, and thereby contribute to raising the pressure. The upper perforation interval feature in pure oil zone (the zone above which is not the gas cap, there is no STC, i.e., in the oil rim).

Accommodation n the wells will be significantly lower than on the former location of the bottom of the perforated interval in the region of the STC, and the top of the perforated interval in pure oil zone.

The development of deposits are to maintain reservoir pressure by injection of working agent (water, gas) or gas mode repression.

As a result, the flow rate is increased by 50% or more.

The invention is illustrated by drawings, where:

in Fig.1 shows a section of oil and gas deposits, developed by maintaining reservoir pressure horizontally-inclined borehole at the location of the top of the perforated interval in pure oil zone and the bottom of the perforated interval in the region of the STC and injection wells;

in Fig.2 - cut the oil and gas deposits under the regime of the gas repression horizontally-inclined well.

The method is as follows.

The development of low-permeability oil and gas or gascondensate-oil deposits carry out a system of horizontal and inclined wells. While their lower perforation interval feature in the field of STC podgotovki zone, and the upper perforation interval in pure oil zone. The development of deposits carried out by maintaining reservoir pressure by secac the/p>

The oil under the effect of reservoir pressure is supplied to the horizontally inclined hole, and the gas flowing through the lower perforation interval of the gas cap, plays the role of the internal gas and contributes to the rise of oil. During the development of deposits on the mode of gas repression varies the position of the STC (reducing the STC during the expansion of the gas cap).

Is the projection of the bottom of perforation interval over STC. In order to maintain the specified spacing of the perforations in the region of the STC, move it around in the STC region, for example, by isolating the bottom of the perforated interval of the well exposed above the STC. The selection of oil passes through horizontally-inclined well.

Examples of specific performance

Example 1

As an example, the data on oil production from the Eastern Block of the Orenburg field

Average depth, m 1800-1950.

Average net gas pay thickness is 25 m

The average saturated thickness is 105 meters

Porosity, D. E. - 0,08-0,12.

The average saturation, D.% - 0,75-0,85.

Permeability, 10-3μm2- 0,005-0,015.

Reservoir temperature, °C - 37.

Reservoir pressure, MPa - 21,4.

Oil viscosity at reservoir conditions, MPa.with - 0,44.

Platnost is their oil, m3/t - 150.

Horizontal wells 5.2 drilled at the site of the Eastern Block of the Orenburg field. Well 5.2 has an upper perforation interval in pure oil zone, and the lower perforation interval is podgotovki zone in the region of the STC. Well 5.2 works with a rate of 44 tonnes.

Example 2

Horizontally-inclined well 4.3 drilled on the same section of the Eastern Block of the Orenburg field. It has an upper perforation interval in pure oil zone, and the lower perforation interval is podgotovki the area below the STC 25 m Bore 4.3 works with a rate of 22 t/day.

Thus, the flow rate 5.2 in example 1 (the proposed solution) is two times higher than wells 4.3 example 2.

As a result, the oil production rate horizontal and inclined wells on the proposed technical solution is increased by 50% or more.

Sources of information

1. Baturin Y. E., Bogdanov, C. L., Degtyaryov E. A., Medvedev N. I., Sarkisyants B. R., George, A. N. The way to develop complex oil with a thin oil rim. RF patent 95116013/03.

2. Analysis of the results of the drilling and operation of horizontal wells shareholdings field. The “Oil industry”, No. 8, 2000nter; margin-top:2mm;">Claims

The way to develop low-permeability oil and gas or gascondensate-oil system horizontal / directional wells for oil extraction, including the location of the perforation interval in pure oil zone, and gas-oil contacts when the distance to gas-oil contacts 0-5 m



 

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