HU194968B - Method for exploiting the cap gas of pool - Google Patents

Abstract

Nitrogen or nitrogen/oxygen mixt. contg. 5% oxygen by vol is injected into the gas contg. dome, pref. at the top. Gas is extracted from a lower point, pref. at the same rate as that of the inert gas injection.(0/0)

Description

The present invention relates to a process for the extraction of oil gas from a petroleum plant, in particular in the presence of several hydrocarbons with a large gas cap.

There are well-known oil plants over which a relatively large, so-called. Caps contain natural gas which can only be extracted after the completion of petroleum production, otherwise the final yield of petroleum production would be very low due to the significant reduction in the layer energy.

It is generally not advisable to tap the gas caps, thus maintaining petroleum production under decreasing bed pressures, since such large gas cap oil plants are generally located in a reservoir with unlimited water supply. In the event of a significant fall in bed pressure, the amount of water inflow would require costly investment and technical measures to maintain oil production and prevent oil-gas cap and reduction in output.

A significant reduction in the layer pressure would in itself lead to a reduction in the final yield.

It is an object of the present invention to provide a solution that can produce a significant amount of the cap gas from oil plants with a large gas cap while maintaining oil production.

SUMMARY OF THE INVENTION It is an object of the present invention to provide that the extraction of gas cap gases is not accompanied by a reduction in bed pressure.

According to the present invention, the above problem is solved by the process of injecting into the gas cap of the oil cap with gas cap, preferably at the maximum of the geological structure, a nitrogen gas mixture containing up to 5% by volume of oxygen and the gas cap gas at the injection point. points lower than points, or. points, preferably in the same volume as the gas volume of the injected gas.

In a preferred embodiment of the process according to the invention, the injection is first performed in the gas caps of the deepest structural position (s).

In a further preferred embodiment of the process according to the invention, injection and extraction are carried out simultaneously on several sites.

In a further preferred embodiment of the process according to the invention, injection is carried out via at least one injection well and extraction is carried out through at least one production well.

In a further preferred embodiment of the process according to the invention, the production of gas cap gases is carried out through production wells for oil extraction. 2

The process of the invention will be described in more detail with reference to the accompanying drawings.

In the drawing, Figure 1 is a sectional view of a geological structure for which the method of the present invention is applicable.

The geological structure of Figure 1 comprises an upper barrier layer 1, a gas layer 2, petroleum 3, water 4 and a lower barrier layer 5.

The upper barrier layer 1 and the lower barrier layer 5 separate the oil plant under investigation from the environment.

In order to carry out the process, at least one injection well 6 and at least one production well 7 are introduced into the structure. In practice, of course, in general, both the injection well 6 and the production well 7 are more individual. Through the 6 injection wells the nitrogen or injection of a mixture of oxygen and nitrogen gas containing up to 5% by volume of oxygen. The injected nitrogen or the gas mixture fills the highest area of the gas cap, while the cap gases are best extracted above the level of 3 crude oil. Preferably the injected and extracted gases have the same bed volume, so that the bed pressure is approximately constant. This ensures that oil production remains unchanged, but the cap-gas produced can be used without jeopardizing oil production, since it is replaced by energy-free nitrogen.

In the process, the condensate in the pore space saturated with condensate evaporates behind the displacement point, so that a significant portion becomes usable.

Optionally, low-oil production wells 7 may be used to produce cap gas.

When the extracted capillary gas is significantly enriched in nitrogen (20-50%), the rate of injection and extraction is reduced.

After the complete extraction of a battery, the upper barrier layer l is sealed and the injection or insertion layer is closed. extraction is continued through wells already established in a site with a higher structural position. Of course, injection and extraction can be carried out in several sites at the same time and, where appropriate, dual-trained wells may be used.

An advantage of the process according to the invention is that it enables the extraction of cap gases from oil plants with gas caps without jeopardizing petroleum production. A further advantage is that a significant portion of the hydrocarbons condensed as condensates in the gas storage layer can also be utilized.

Claims (4)

PATENT CLAIMS 1.) Process for extracting capillary gas from an oil plant, characterized in that the gas cap of the oil plant having a gas cap is preferably a geological structure. -2194968 at maximum - a nitrogen / nitrogen gas mixture containing 5% by volume of nitrogen and 5% by volume of gas is pressed, and the gas cap gases are pressed at the point of injection and / or. points lower than points, or. points, preferably in the same volume as the gas volume of the injected gas. Process according to claim 1, characterized in that the injection and the extraction are carried out simultaneously on several sites. Method according to claim 2, characterized in that the injection is first carried out in the gas caps of the deepest structural position (s). 4). 1-3. A process according to any one of claims 1 to 3, characterized in that the gas cap gas is extracted through production wells for oil extraction.