Method for extraction of oil deposit

FIELD: oil industry.

SUBSTANCE: method includes drilling vertical product and force wells, extracting oil from product wells, forcing working agent through force wells, making side horizontal shafts in force wells, forcing working agent through side horizontal shafts of force wells. Additionally, side horizontal shafts are made in extraction wells. Oil is taken through side horizontal shafts of extractive wells. With pressure in the well, decreased for 5-10% from hydrostatic pressure, all side horizontal shafts are made by washing away rock under pressure of fluid of around 15-20 mPa. Direction of all side horizontal shafts is set to be parallel to rows of wells.

EFFECT: higher oil yield.

1 ex, 1 dwg

The invention relates to the oil industry and can find application in the development of oil fields.

The known method of selective flooding of oil fields, including drilling of production and injection wells for geometrically regular grid of their placement, identification of zones of low reservoir pressure and drilling there injection (injection) wells to maintain reservoir pressure (see Fazliev GT Areal flooding. - M.: Nedra, 1979).

The disadvantages of the known technical solutions are accelerated dynamics of water cut in crude production, significant amounts of produced water, the low value end of the oil recovery factor, significant capital and operating costs of the development of the field.

Closest to the invention to the technical essence is the way of the oil field development with heterogeneous reservoirs and hard-to-recover oil reserves, including the drilling of vertical wells on sparse grids for examining heterogeneity of reservoir properties of the formation and extraction of oil from drilled wells in terms of elastic filtering mode. According to the invention according to geologic analysis and results of wells reveal riscoprono aimie areas with hard-to-recover oil reserves. Form a system of flooding by water injection into low permeability zones and wipe out the oil in the high-permeability zone. To do this, most of the trunks of injection wells for water injection feature in low-permeability zones by drilling horizontal injection wells while drilling the lateral horizontal stems mainly from marginal vertical producing wells. The ratio of the number of producing wells number of injection wells take less than one. The water injection will compensate for the production of oil, gas and water. Support reservoir pressure at a given level (RF Patent No. 2215128, KP. E 21 In 43/16, publ. 2003.10.27 - prototype).

The known method provides a reduction in the volume of associated water, increasing the oil recovery factor due to the increased impact on poorly drained and hard-to-recover oil reserves in low-permeability reservoirs.

The disadvantage of this method is the relatively low response horizontal boreholes drilled in low permeability zones, and consequently, relatively low production of low-permeable zones of the oil deposits.

The invention solves the problem of increasing oil deposits.

The task is solved in that in the method of developing oil fields, including drilling Vert is unique in producing and injection wells, the selection of oil through the production wells, injection working agent through the injection wells, the drilling of lateral horizontal wells in the injection wells, injection working agent through lateral trunks injection wells, according to the invention, additional lateral trunks are drilling in producing wells, selected oil through the lateral trunks of producing wells, with drilling all lateral horizontal wells produce at reduced pressure in the well by the erosion of rocks under high pressure fluid with the formation of long and thin channels, and the direction of drilling of all lateral horizontal wells installed parallel to the rows of well placement.

Features of the invention are:

1) vertical drilling production and injection wells;

2) selection of oil through the production wells;

3) download a working agent through the injection well;

4) drilling lateral horizontal wells in the injection wells;

5) upload the working agent through lateral trunks injection wells;

6) drilling lateral horizontal wells in the producing wells;

7) selection of oil through the lateral trunks of producing wells;

8) perform all lateral horizontal stole is under reduced pressure in a borehole;

9) the same erosion of rocks under high pressure fluid with the formation of long and thin channels;

10) the direction of drilling of all lateral horizontal wells parallel to the rows of well placement.

Signs 1-5 are common with the prototype, signs 6-10 are the salient features of the invention.

The invention

In the development of oil deposits, especially heterogeneous, part of the reserves of the deposits not covered by the impact. Covered by development, mainly high-permeability zones. For these reasons, the rate of heterogeneous oil reservoir is 10-20 points lower than normal deposits. In the proposed invention solves the problem of increasing oil deposits due to more complete sweep impact, involvement in the development hasn't worked bypassed zones. The problem is solved by the following set of operations.

In the development of oil deposits, drilling of vertical production and injection wells and develop the reservoir, draining the oil through production wells and carrying out the injection of the working agent through the injection wells. During development identify low-permeability zones of the deposits not covered by the impact. Existing injection wells, production wells are drilling lateral trunks. Batavierenrace trunks perform under reduced pressure in the well. For drilling lateral horizontal wells from wells in the first place Buryats from wells with a minimum flow rate or supply wells. The direction of drilling of all lateral horizontal wells appoint parallel to the rows of well placement.

Low pressure in the well to create different ways. One of the most common is air in the tubing pipes and pass through the starting clutch in the annulus, where a water-gas mixture with a density less than the density of the downhole fluid.

Another possible method is repeated swabbing of the column tubing with the selection of the fluid at the wellhead and the establishment of well-down of the liquid column. Based on the fact that the static liquid level is restored in time and gradually, at the time of the operations in the well will be low pressure, accompanied by a flow of formation fluids through the formed lateral trunks.

To create a reduced pressure in the well may connect the annulus of the well to the vacuum cavity of the jet pump at the wellhead. We do not exclude the use of other methods. The optimal is to reduce the pressure in SLE is gene 5-10% of the hydrostatic pressure.

Lateral trunks perform under reduced pressure in the well by the erosion of rocks under high pressure to lose fluid. As scour fluid may be used water or water mixed with a surface-active agent or mixture of surface-active substances.

For the formation of a lateral wellbore in an existing well casing at the depth of the productive formation cut out the side window and contemplate the future of the horizontal trunk. In carved window inserts a thin flexible tube with a nozzle device on the end. Under high pressure of the order of 15-20 MPa serves on the flexible tube to lose fluid and simultaneously promote it in the layer formed on the thin side horizontal bore. Thus for 20-30 minutes could walk 100 meters with a diameter of several mm, the Flow rate of scour fluid is 1-2 l/C.

The effects of scour fluid is at low pressure in the borehole and, therefore, with the active flow of formation fluids through the formed horizontal wellbore in the well. Consequently, there is no clogging of the horizontal walls of the barrel and the bottom zone clogging substances formed the trunk open (uncased) fully ready to receive preemptive working agent. Application Nizkor the initial drilling technology, lateral trunk allows the entire process under reduced pressure in the well. During the excavation of the lateral trunk volume pumped to lose fluid does not have time to fill the well and to equalize the pressure in the well.

After the formation of lateral horizontal wells are pumping working agent through lateral trunks injection wells and extraction of oil through the lateral trunks of producing wells.

The direction of drilling of all lateral horizontal wells in injection and production wells, installed parallel to the rows of well placement.

The drawing shows a diagram of the row for the location of wells according to the proposed method. Producing wells 1 in the ranks of the wells 2 are lateral trunks 3 in both directions from the well. Injection wells 4 in the ranks of the injection wells 5 are lateral trunks 6 also in both directions from the well. All lateral trunks 3 and 6 are parallel to the rows of the location of wells 2 and 5. In this arrangement lateral horizontal wells reached the most complete coverage of the productive formation by impact and maximum oil recovery reservoir.

Specific example

Develop oil reservoir Romashkinskoye field with the following characteristics: porosity - 18,4%, average Pronichev the ü - 0,646 μm²the saturation - 61,1%, absolute mark oil-water contact - 1530 m, the average saturated thickness is 4 m, the initial reservoir pressure of 16 MPa, reservoir temperature - 29°parameters reservoir oil: density of 930 kg/m³the viscosity of 46 MPa·C, the saturation pressure of 1.8 MPa, gas content - 15.2 m³/t sulphur content is of 3.64%. After drilling deposits rows of injection and production wells are oil withdrawal after 2 number of wells 12 wells in each row and download a working agent through 1 the number of injection wells 12 wells in a row. The distance between the wells is 300 meters

Perform horizontal trunks in wells. In the stopped hole in the productive interval of the formation down the pipe with a starting clutch at a depth of 500 m and a knee-pipe on the end. The pipe is passed a flexible shaft with a ball mill. At the depth of the productive formation through the rotating flexible shaft and ball cutter cut out a hole in the casing of the well and form the beginning of a horizontal shaft sinking on the last few meters. The flexible shaft and the ball mill is removed from the pipe. In the lower pipe flexible pipe with nozzle device on the end and enter to allow the apparatus to form a horizontal shaft. In the tube pump the air before his breakthrough in the starting th is Tu and filling the annulus of the well. Well pressure is reduced from 16 to 13 MPa. In a flexible pipe pump to lose fluid, which represents a 0.2 percent aqueous solution of the sulfonic acid. Scour the fluid pumped under a pressure of 20 MPa with a flow rate of 1 l/C. Flexible pipe is gradually fed into the drilled shaft, while a blur fluid erodes the rock of the reservoir. As a result, over 20 min formed a horizontal sidetrack with a diameter of about 50 mm and a length of 100 m in this way form a horizontal sidetrack in the same borehole in the direction deployed to 180°.

According to this technology runs on two lateral horizontal shaft in each injection and production well.

Through the drilled lateral trunks injection wells inject the working agent (produced water). Through the drilled lateral trunks wells selected oil. In the oil recovery deposits increased by 3.5%.

Application of the proposed method will increase the recovery of oil deposits.

The way of the development of oil deposits, including vertical drilling production and injection wells, oil extraction through production wells, injection working agent through the injection wells, performing lateral horizontal wells in injection SC is aging, download working agent through lateral trunks injection wells, characterized in that it further lateral trunks perform in producing wells, selected oil through lateral trunks wells, if the well pressure is reduced by 5-10 % from hydrostatic, all lateral trunks perform the erosion of rocks under the fluid pressure of the order of 15-20 MPa, and the direction of all lateral horizontal wells installed parallel to the rows of well placement.