Method development of a zone-inhomogeneous oil field

 

The invention relates to the oil industry, in particular to the development of oil fields, and can be used in the development of heterogeneous oil reservoirs. Provides a more effective way by increasing the tempo selection from low permeability zones of the reservoir. The inventive method involves drilling project net production and injection wells, the input of additional injection wells in low permeability reservoir, the change of the direction of filtration flows in the reservoir by changing the mode of production and injection wells that discover low permeability layers. After drilling, field grid reveal kolmat plots in the low permeability zone of the formation, the production wells that discover low permeability layers, and injection wells, uncapped with high permeability. Then in areas with low permeability reservoirs introduce additional injection well with a horizontal shaft. Trunks is directed towards kolmat plot. Pressure in the permeable formation zone support more pressure in the high-permeability zone. Horizontal stvol Il.

The invention relates to the oil industry, in particular to the development of oil fields, and can be used in the development of heterogeneous oil reservoirs.

There is a method of developing a heterogeneous oil reservoir ( see patent RU No. 2055164 from 08.09.93,, publ. BI No. 6 from 27.02.96, including the allocation of the Deposit of highly productive and low productive areas, followed by placement of injection wells in low productive area and production wells in a highly productive zone, the injection of working agent through the injection wells to the regulation of injection and extraction of oil through production wells, thus shall record the distribution of the mobility of the formation fluid at a late stage of development of deposits and highly productive zone are areas with a monotonic variation of mobility, the development of which are sequential injection of the working agent in the direction of increasing the mobility of the formation fluid, while controlling formation pressure and water cut wells, adjacent to the injection well and included in the area of its impact, the regulation of the injection of the working agent is carried out by reducing the rate of injection with increasing ¾ zones produced between the rows of wells in pairs from different sides of the productive zone at a distance from its edges, defined mathematical expression.

The method allows to increase oil production while reducing the production of fluid.

The disadvantage of this method is the complexity of implementation and the limited use, because for successful implementation it is necessary to ensure certain conditions of operation and the placement of injection wells.

In addition, under conditions of heterogeneous petroleum reservoirs injected fluids are filtered primarily through high permeability zones of the reservoir, and low-permeability remain uninvolved in the development, the current value remains low.

There is also known a method of developing a heterogeneous oil field (see the book "Geology and development of the largest and unique oil and gas fields of Russia", t 1, M, VNIIEM, 1996, S. 65), including the drilling of an inhomogeneous field mesh production and injection wells, the input of additional injection wells in low permeability zones of the reservoir, the change of the direction of filtration flows in the reservoir by changing the mode of production and injection wells.

The disadvantage of this method is the low current value, because the pickup squag the mi, resulting from the crushing of the grains of the reservoir rock, as a result of these zones remain unreached by the impact of preemptive or injected reagent.

The closest in technical essence and the achieved result to the present invention is the method of development of a zone-inhomogeneous oil field (see U.S. Pat. RU # 2118448 from 15.12.96,, publ. BI No. 24 27.08.98, including the drilling grid production and injection wells, the input of additional injection wells, change of the direction of filtration flows in the reservoir by changing the mode of production and injection wells, additional injection wells injected at sites in low permeability reservoir with permeability higher than the average low permeability reservoir, the injection pressure in these wells is maintained at the pressure level of the crack, while in a loop injection of the displacing agent under these pressures producing wells located in low permeability reservoirs, stop.

The method allows to increase the oil recovery by increasing the coverage of the influence of low permeability zones of the formation.

However, the rate of oil extraction from samokonservatsii deposition the solid particles is comparable with the pore size of the low permeability of the reservoir.

The technical object of the present invention is the increased efficiency of the development of a zone-inhomogeneous oil fields by increasing the rate of selection involved in the development of reserves of low permeability zones of the formation.

The problem is solved is described by way of the development of a zone-inhomogeneous oil fields, including drilling project net production and injection wells, the input of additional injection wells in low permeability reservoirs, the change of the direction of filtration flows in the reservoir by changing the mode of production and injection wells that discover low permeability layers.

What's new is that after drilling field grid, identify kolmat plots in the low permeability zone of the formation, the production wells that discover low permeability layers, and injection wells, uncapped with high permeability, then in areas with low permeability reservoirs introduce additional injection well with a horizontal shaft, and the trunks are directed towards kolmat plot, and the pressure in the deposition zone of the reservoir supported above the pressure in udkast during well operation on the spout.

New is also that as a displacing agent for injection into the injection well with a horizontal wellbore using reagents based on the properties of low permeability formations, such as clay - saline produced water or compositions based on anionic and nonionic surfactants.

The proposed method differs from the prototype sequence of technological operations and the availability of new features that improve the development efficiency of a zone-inhomogeneous oil fields by increasing the rate of selection involved in the development of reserves of low permeability zones of the formation.

From the patent and scientific literature is unknown to us declare the set of distinctive features, therefore, the claimed method meets the criterion of "significant differences".

In Fig. 1 schematically shows the design stage of a zone-inhomogeneous field before applying the proposed method. In Fig. 2 - introduction injection well with a horizontal shaft. In Fig. 3 schematically shows the development status of a zone-inhomogeneous oil fields after the application of the proposed method.

According to the plans the location of the drilled vertical wells and built lithological maps reveal producing wells that discover low permeability layers, and injection wells, uncapped with high permeability, as well as areas with low permeability reservoirs. Then on this site of injection wells (3) are drilling horizontal sidetrack, directing it in the direction of maximum spread of low permeability zones of the reservoir (Fig. 2). Depending on the design of the wells (diameter of the production string and others), the thickness of the deposition layer, its strength and other horizontal wellbore may obzivatsya column or operated by the open trunk. In the lateral horizontal trunk of the zone with the lowest permeability values reveal a deep perforation. Possible hydraulic fracturing. Well equipped with equipment and tools, which allows the injection of the displacing agent with pressure on allopregnanolone injection into a horizontal shaft supported above the pressure in the injection wells, uncapped with high permeability. Organization of injection of the displacing agent in the deposition area of the reservoir with high pressure allows the change of filtration flows in the reservoir and to clean up the clogged part of the reservoir. Solid particles are entrained in the high part of the reservoir and carried away through the borehole to the surface. The lower filtration resistance of the reservoir system due to its purification, increased filtration area horizontal wellbore injection wells in low permeability of the reservoir, increased downhole pressure help to provide a stable injection wells and accordingly the selection of fluids from producing wells.

To improve development efficiency, low permeability formations and prevent clogging of the reservoir system using saline produced water. It is known that the use is compatible with the reservoir environment of highly mineralized formation water displacement factor above, is less clogging of the porous medium, than other waters.

For improved responsiveness low permeability formations are of interest composition of nonionic and anionic poverino. The last combined in one product the best properties of nonionic (good compatibility with saline fishing waters) and anionic (high surface activity of the surfactant. Such compositions provide the reduction of interfacial tension on the border "oil-water" up to 10-2-10-3mn/m

When the attenuation pickup unproductive reservoir need to be able to let the well to clean up by putting it on the mechanized extraction of product from the reservoir. Therefore, the horizontal wellbore to be drilled below the estimated dynamic level.

The set of distinctive features can improve oil recovery by increasing coverage of low permeability zones of the reservoir (Fig. 3).

A specific example of the way

Zone-inhomogeneous plot deposits of oil (Fig. 1) drilled five wells, one injection and four operators. The distance between the wells 400 feet,

Wells opened the oil-saturated reservoir with an average permeability, respectively, of highly - 0,750 μm2permeable - 0,200 μm2. In highly permeable reservoir well No. 2 permeability is 0,500 μm2. Permeability low permeability No. 5 - 0,300 μm2.

These data indicate that the Deposit is of a zone-inhomogeneous. Balance reserves deposits amounts to 800 thousand tons, including low permeability zone of the reservoir 160 thousand tons After drilling zone of the well came into production with an average rate of deposition on the layer 5 tons/day (Fig. 1).

After selecting 1.6 thousand tons of oil flow rates of producing wells 1, 4, 5 decreased to 0.5 t/day. The injection capacity of the well # 3 decreased from 150 mC/day in the initial stage of operation of the site to 135 mC/day.

On the basis of the conducted research in low permeability zone of the formation from the injection well # 3 was drilled horizontal sidetrack, oriented in the direction of maximum spread of low permeability zones of the reservoir (Fig. 2).

The injection of water into the injection well No. 3 in the amount of 100% of the fluid extraction in situ was carried out within 4 months. Increased extraction of fluid from the well No. 2 reservoir injection pressure in the high permeability of the reservoir is maintained at 1.5 MPa lower than in low permeability.

Further operation of the site showed that the commissioning of the injection wells with lateral shaft # 3 was allowed to reach near the productive area of the reservoir up to 10 t/day. The recovery factor low permeability zones of the reservoir amounted to 41% (Fig. 3).

Technical and economic efficiency of the proposed method of development of a zone-inhomogeneous field of the sum due to involvement in the development of low permeability zones of the reservoir and increasing the rate of selection of them, which increases the current value of the field as a whole.

Claims

1. Method development of a zone-inhomogeneous oil fields, including drilling project net production and injection wells, the input of additional injection wells in low permeability reservoir, the change of the direction of filtration flows in the reservoir by changing the mode of production and injection wells that discover low permeability layers, characterized in that after drilling field grid reveal kolmat plots in the low permeability zone of the formation, the production wells that discover low permeability reservoirs and injection wells, uncapped with high permeability, then in areas with low permeability reservoirs introduce additional injection well with a horizontal shaft, and toderive above the pressure in the high-permeability zone, the horizontal barrel spending below the estimated dynamic liquid level during operation of the wells on the spout.

2. The method according to p. 1, characterized in that the displacing agent for injection into the injection well with a horizontal wellbore using reagents based on the properties of low permeability formations, such as clay - saline produced water or compositions based on anionic and nonionic surfactants.

 

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