RU2268982C1 - Multilateral well building method - Google Patents

Abstract

FIELD: oil and gas production industry, particularly multilateral well construction.

SUBSTANCE: method involves lowering pipe string provided with diverter at end thereof; cutting casing pipe within predetermined interval; lowering flexible pipe with nozzle until flexible pipe enters into opened casing pipe zone under the action of the diverter in alternation with supplying pressurized liquid via flexible pipe provided with nozzle; performing translational flexible pipe movement to create additional well bores having necessary lengths along with removing the flexible pipe to create predetermined number of additional bores. Before casing pipe lowering in the well the casing pipe is provided with acid-soluble insert arranged opposite to formation to be opened. Casing pipe cutting is performed around the full perimeter thereof for necessary length within predetermined opening interval by solving the acid-soluble insert during acid supplying through pipe string into above predetermined interval. After that the diverter having several diverting channel is installed in the interval. After each additional well bore forming flexible string with nozzle is removed only from the pipe string and diverter to create predetermined number of additional bores. After that the flexible pipe with nozzle is finally removed from the casing pipe.

EFFECT: reduced number of trips.

2 dwg

Description

The invention relates to the oil and gas industry, namely the construction of bushes of oil and gas wells.

The well-known "Method of construction of a multilateral well" (AS No. 1798466, MKI E 21 B 7/06, publ. BI No. 8, 02.28.93), including drilling a vertical main shaft, installation and fastening in the main barrel of the drum with guiding columns located in its plane and a deflecting unit in the lower part, alternately drilling, drilling and securing additional trunks, while drilling the lower section of the main trunk, increase its diameter, the drum is installed directly above the lower section of the main shaft, and borehole borehole is carried out through the wall of the latter.

The disadvantages of this method are:

firstly, the need to drill the main trunk of large diameter, which requires a lot of time, especially with deep wells, and, as a result, to high material costs;

secondly, the presence of guide columns also leads to an increase in the cost of building a multilateral well;

thirdly, such a layout of the well is complicated both during construction and during operation.

The closest in technical essence and the achieved result is the "Method and device for horizontal drilling of wells" (US patent No. 5413184, IPC E 21 B 7/08, publ. 05/09/1995), including the descent into the casing to a predetermined depth of the string pipes, at the end of which a diverter is located, the descent into the string of pipes of a flexible shaft with a mill at the end before interacting with the diverter, rotation with the translational movement of the flexible shaft with a mill, which, as a result of interaction with the diverter, cuts a window in the casing and enters the formation a predetermined distance to obtain a technological channel, removing a flexible shaft with a mill from a well, lowering a flexible pipe with a nozzle into the pipe string before entering the casing string under the action of a diverter, supplying liquid under pressure through a flexible pipe with a nozzle with simultaneous translational movement to increase the technological channel to the required length.

The disadvantages of this method are the need for constructing a multi-hole well to perform sequential operations: turning the pipe string to the required angle, lowering the flexible shaft with a cutter, cutting the channel, deepening the channel using flexible pipes with a nozzle under the influence of fluid pressure, and so for each horizontal additional well, which leads to large losses of time and, as a result, to material costs (see RadTech International Inc.’s construction instructions for wells (US No. 5413184), including multi-barrel ones).

The technical objective of the invention is to reduce material costs and financial costs by reducing the number of trips and equipment and avoiding the rotation of the pipe string during the construction of a multilateral well using flexible pipes with a nozzle under the influence of fluid pressure, due to the opening of the casing along the entire diameter.

The technical problem is solved by the method of constructing a multilateral well, including the descent into the casing of the pipe string, at the end of which the diverter is located, the opening of the casing in the required interval, the alternation of the descent of the flexible pipe with the nozzle into the casing before entering under the action of the diverter into the opening zone of the casing, liquid under pressure through a flexible pipe with a nozzle with its simultaneous translational movement to form additional shafts to the required length with the flexible pipe being removed to the floor cheniya necessary number of additional boreholes, after which the flexible tube with a nozzle completely removed from the casing.

New is that the casing string is preliminarily equipped with an acid-soluble insert, which is located opposite the reservoir being opened, and the casing is opened along its entire diameter and the required length in the required opening interval by eliminating the acid-soluble casing string when acid is supplied through the pipe string in the opening interval, after which the deflector, which is made with several deflecting channels, is installed in the opening interval, and a flexible column with a nozzle follows the formation of each additional trunk is removed only from the pipe string and the whipstock to obtain the necessary number of additional trunks.

Figure 1 shows a diagram of the elimination of acid-soluble insert.

Figure 2 shows a diagram of the formation of an additional barrel.

Concrete example

The method of constructing a multilateral well is as follows. The casing 1 (see Figure 1), equipped with an acid-soluble insert 2, is lowered into the well, while it is placed in the opening interval 3 opposite the reservoir 4. Next, the casing 1 is cemented using any of the existing technologies (not shown). After waiting for the cement to solidify into the casing 1, the pipe string 5 is lowered with a diverter 6 and a sleeve 7 rigidly connected to it at the end. Moreover, in the transport position, the sleeve 7 is fixed with a collet stop 8 by means of a shear element 9. The width of the fixing part - From the color stop 8 is greater than the width of the joints (not shown) of the casing 1. The diverter 6 has inside bending channels 10, the number of which is determined by the number necessary additional trunks in the reservoir 4.

As an example, consider a deflector 6 having two bending channels 10 'and 10' '.

After the descent into the well, a string of pipes 5 with a diverter 6 is placed above the roof of the producing formation 4. Then, through a string of pipes 5 through bending channels 10 'and 10' 'of the diverter 6, acid 11 (for example, technical hydrochloric acid) is pumped into the casing 1 in the interval opening 3 and leave for a thermochemical reaction for a time sufficient for the complete destruction of the acid-soluble insert 2.

After a certain time allotted for the thermochemical reaction, the result of which is the destruction of the insert 2 in the casing 1 in the opening interval 3 opposite the reservoir 4, the pipe string 5 is lowered until the collet stop 8 is fixed relative to the opening zone 3 at the lower end 12 casing string 1. Next, unload the string of pipes 5 (Figure 2), while the shear element 9 is destroyed, and the deflector 6 is lowered and sits on the collet stop 8, squeeze it to the lower end 12 of the casing 1. this bending channels 10 'and 10' 'of the diverter 6 are located in the opening interval 3 opposite the reservoir 4. Then, the flexible pipes 13 are lowered into the pipe string 5 with the nozzle 14 before entering under the action of the diverter 6 through its bending channel 10' in the opening interval 3 of the casing columns 1, which is fixed on the wellhead by a weight indicator (not shown), and then a mark (not shown) is applied to the wellhead on the flexible pipe 13 — the formation of the additional barrel 15 begins. Next, liquid under pressure is supplied through the flexible pipe 13 with the nozzle 14 simultaneously arrive By proper movement, as a result, in the opening interval 3, an additional barrel 15 is formed, which increases to the required length L. Then the flexible pipe 13 with the nozzle 14 is removed from the additional barrel 15 of the casing string 1 and the diverter 6 of the pipe string 5 to the above mark plus the length of the bending channel 10'. Then the flexible pipe 13 with the nozzle 14 is led into the second bending channel 10 ″ of the deflector 6 - this is determined by the reduction in the weight of the flexible pipe 13 (according to the weight indicator) when it is lowered to the mark on the mouth. Then form a new additional barrel 15 '. Then, again under the action of the pressure of the liquid supplied through the flexible pipes 13 with the nozzle 14, a second additional barrel 15 'of the required length L is formed in a predetermined interval.

In cases where the mark of the flexible pipe 13 drops to the mouth significantly lower without changing the weight, the flexible pipe 13 is removed to the mark plus the length of the bending channel 10 ', after which the flexible pipe 13 is rotated by a small angle so that its natural residual curvature changes its orientation, and again try again until the flexible pipe 13 stops at the mark, which is fixed at the wellhead according to the weight indicator. Practically getting into the next bending channel 10 ″ by a flexible pipe is ensured in 1-3 attempts in the presence of four bending channels 10 in the deflector 6.

In the above example, the option of building a multilateral well with two additional shafts 15 is considered, similar work is carried out for the required number of additional shafts 15, but for this it is necessary to use a diverter 6 with the number of bending channels 10 equal to the number of additional shafts 15.

Using the proposed method due to the opening of the casing along the entire diameter reduces the number of trips, and the presence of a deflector with several bending channels eliminates the operation of turning the pipe string, which together reduces the material and financial costs of constructing a multilateral well using for sinking a flexible pipe with a nozzle under the influence of fluid pressure.

Claims (1)

A method of constructing a multilateral well, including the descent into the casing string of the pipe string, at the end of which the diverter is located, opening the casing string in the required interval, alternating the descent of the flexible pipe with the nozzle into the casing string before entering the diver into the opening area of the casing string, supplying liquid under pressure through a flexible pipe with a nozzle with its simultaneous translational movement for the formation of additional trunks to the required length with the removal of the flexible pipe to obtain the required number of additional shafts, after which the flexible pipe with the nozzle is finally removed from the casing string, characterized in that the casing string is preliminarily equipped with an acid-soluble insert, which is located opposite the formation being opened, and the casing string is opened along its entire diameter and to the required length in the required interval opening by eliminating the acid-soluble casing insert when supplying acid through the pipe string to the opening interval, after which the diverter, which is made with ring deflecting channels are installed in the opening zone, and a flexible column with a nozzle after the formation of each additional barrel is removed only from the pipe string and diverter to obtain the required number of additional shafts.

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