RU2542070C1 - Double-hole well operation method - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: according to the method a removable whipstock is installed. Then a window is cut in boring case. An offshoot is drilled from the main borehole. Offshoot drilling is made with running in of the boring case, its continuous cementing, perforation and provision of required reliability of attachment in the area of offshoot tracking. At that behind-the-casing flows of gas and liquid mixture are excluded. To this end upon window cutting a cement ring is cut in the boring casing and adjoining soil is cut as well in direction of offshoot drilling forming a cavern with diameter exceeding diameter of the offshoot. The cavern is poured with solid sealing compound and offshoot is drilled through the cavern. Downhole pumping equipment is placed in the main borehole and oil is extracted from the main borehole and offshoot.

EFFECT: increased oil extraction from offshoot at operated main borehole.

3 cl, 2 dwg

Description

The invention relates to the field of oil production from sediments represented by sandstones, namely the construction of oil and gas wells having more than one bottom.

There is a method of oil production, including drilling from an earth’s surface of an inclined directional well with a horizontal section of the wellbore, lowering a deep pump to slaughter an additional wellbore, the cut-off point of which is located below the statistical fluid level in the well (RF Patent No. 2046930, E21B 43/00, 1995 )

However, due to the placement of pumping equipment in the sidetrack, the likelihood of jamming of the nodes of the above-mentioned equipment in the trunk during tripping operations increases, and there is also a limitation on the magnitude of the zenith angle of the sidetrack.

There is a method of constructing multilateral wells, including opening a window in the casing of the primary wellbore, for which the bottom of the casing of the primary wellbore is equipped with slots and landing on the slots of the extracted landing site, filling the installation interval of the extracted landing site with a non-hardening viscoplastic fluid with a static shear stress determined by by mathematical dependence. Drilling a new additional trunk to the design depth using a wedge diverter. After drilling a new additional wellbore, the whipstock is removed from the well. The mouth of the new additional wellbore is sealed, for which a knot for sealing the mouth is lowered there, including a packer-cutter with a medium separator, containing a wedge having holes for the passage of the grouting mixture, and an auxiliary pipe with cuffs in the upper part, the grouting mixture is injected into the shank and flushing the well, after which the auxiliary pipe with cuffs in the upper part is drilled with a chisel. After the completion of the development of a new additional barrel, the landing unit is removed (RF Patent No. 2279522, E21B 7/08, 2004).

Despite the presence of a sealing unit for the mouth of the new additional wellbore, it performs its protection functions against sludge and mechanical particles only during the drilling of the sidetrack; subsequently, its tightness is violated, which leads to annular overflows from the additional wellbore during well operation.

Closest to the proposed invention by its technical nature (prototype) is a method of operating a water-cut oil well, which includes analyzing the condition of the well: preliminary determination of the liquid level in the well, installing a cement bridge below the cut-off point of the sidetrack, installing a recoverable deflector wedge, cutting a window in the casing, sidetracking from a core below the dynamic fluid level in the well, cementing the flooded face and placement of downhole pumping equipment Niya to the trunk, followed by selection of oil (RF patent №2190086, E21B 43/00, 2002).

When implementing this method, the sealing annular space in the field of sidetracking is insufficient, because there are no technologies for continuous cementing of the sidetrack along its entire length, including the place of its kickoff, and, as a result, there is an annular overflow of the gas-liquid mixture from the sidetrack. The application of the method is limited to waterlogged wells, because the bottom of the main trunk is cemented.

The solved problem of the invention is to increase the selection of oil from the side trunk, with the main trunk operating.

The problem is solved in that the method of operating a double-well borehole, including installing a recoverable deflector wedge, milling a window in a casing string, drilling a sidetrack from the main one and placing downhole pumping equipment in the main shaft with subsequent oil extraction, differs in that after window milling a cement ring and adjacent rock are cut out in the casing in the direction of drilling the lateral shaft with the formation of a cavity with a diameter exceeding the diameter of the lateral shaft, fill the cavity with a sealing hardening compound, a sidetrack is drilled through a cavity, oil is taken from the bottom of the main and sidetracks. Moreover, the cement ring and the adjacent rock are cut to a depth of 4-5 m. In addition, a resin reinforced with a composite material is used as a sealing hardening composition.

Creating a cavity by milling to a depth of 4-5 m in the direction of drilling the sidetrack and pouring it with a sealing hardening compound, for example, resin reinforced with composite material, make it possible to achieve the effect of exceptional sealing of the sidetracking area, unattainable during continuous or local cementing, due to the lack of technology cementing the sidetracking area. Therefore, when drilling a sidetrack, including composite material that filled the cavity, it is possible to lower the pumping equipment into the main trunk to operate the well from the bottom of the main and sidetracks, which increases the efficiency of the well and allows us to conclude that the proposed method meets the criterion " inventive step ".

An example implementation of the method is shown in figures 1 and 2, which shows the following operations and the listed items:

a) installation of the wedge of the diverter:

1. The main trunk

2. Slaughter

3. Wedge deflector

b) cutting the window in the casing and milling to a depth of 4-5 m:

4. The window

5. Casing of the main trunk

6. Milling cutter

7. Drill pipes screwed into the drill string

8. Cavern

c) pouring with a sealing hardening composition, for example, resin with a composite material, a cavity formed during opening the window and milling:

9. Sealing hardening composition

d) sidetracking:

10. Side trunk

e) descent of the casing string of the sidetrack:

11. Casing of the lateral shaft

f) perforation of the lateral shaft during continuous cementing:

12. Sidetracking

g) descent of downhole pumping equipment:

13. Deep-well pumping equipment in working position.

A method of operating a double-well well is as follows.

A wedge-deflector 3 is installed in the main wellbore 1 of the well that has been selected according to the technical condition, with an uncemented face 2, a window 4 is milled in the casing 5 of the main wellbore 1, and the cement ring and the rock adjacent to the well are cut to a depth of 3-8 meters in depending on the type, hardness, rock properties, optimally to a depth of 4-5 m in the direction of subsequent drilling of the side trunk 10 with the formation of a cavity 8 with a diameter larger than the diameter of the side trunk 10, which is then poured with a sealing hardening composition 9 (for example, resin reinforced with a composite material, plasticized with aluminum asbestos powder, chopped fiberglass, etc.), which provides reliable fastening of sand deposits in the area of the sidetrack 10 and eliminates annular flow of the gas-liquid mixture. Drilling of the lateral bore 10 with the descent of the casing 11 of the lateral bore and its continuous cementing is carried out (cement is pumped into the annular space formed by the drilled lateral bore and the outer wall of the casing). Perforation 12 of the side barrel 10 is carried out, the deflecting wedge 3 is removed. The downhole pumping equipment 13 is placed in the main barrel 1, followed by oil extraction from the side barrel 10 and the bottom hole 2 of the main barrel 1.

Thus, the method of operating a double-hole well, which includes reliable sealing of the sidetracking area, creating a cavity with its subsequent filling with a sealing hardening compound (for example, resin reinforced with composite material) during continuous cementing of the sidetrack, completely eliminates annular flow of the gas-liquid mixture, which allows increase oil recovery from the sidetrack. In addition, the absence of cementing of the bottom of the main trunk allows the selection of oil from the main and lateral shafts at the same time, which does not limit the use of this method by watered and low-yield wells.

Claims (3)

1. A method of operating a double-well borehole, including installing an extractable deflector wedge, milling a window in a casing string, drilling a sidetrack from the main well and placing downhole pumping equipment in the main wellbore followed by oil extraction, characterized in that the sidetracking is carried out with a casing run columns, its continuous cementing, perforation and ensuring the necessary reliability of fastening in the field of sidetracking and elimination of annular flows of gas-liquid mixture whereupon after milling the window, a cement ring and adjacent rock are cut out in the casing in the direction of drilling the sidetrack with the formation of a cavity with a diameter exceeding the diameter of the sidetrack, the cavity is filled with a sealing hardening composition and the sidetrack is drilled through the cavity, and oil is selected from the bottom of the main and sidetracks . 2. The method according to claim 1, characterized in that the cement ring and the adjacent rock are cut to a depth of 4-5 m 3. The method according to claim 1, characterized in that the resin reinforced with a composite material is used as a sealing hardening composition.

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