RU2463433C1 - Method of drilling extra bore from well production string - Google Patents

Abstract

FIELD: oil-and-gas production.

SUBSTANCE: proposed method comprises smaller-diameter side tracking with tailing in using standoff wedge. Additional casing is carried out in two steps. First, reaming tubes are lowered down to pay roof after side tracking. Then, after injection of isolation material, reaming tube are lowered to rest on roof, reamed and expanded by using composition with longer polymerisation which allows expanding auxiliary borehole over its entire length.

EFFECT: reduced costs, higher well performance, easier repair and maintenance.

2 dwg

Description

The invention relates to the oil and gas industry, in particular to a technology for drilling an additional wellbore from a production casing of a well.

A known method of drilling an additional barrel from the production casing of a well (RF patent No. 2172384 C2, EV 7/06, publ. Bull. No. 23 from 08.20.2001), including drilling an additional barrel of a smaller diameter compared to the main one using a deflector wedge drilling an additional wellbore and securing it with expansible profile pipes, the additional well being drilled to the top of the reservoir, after which insulating material is pumped into the well and the exposed part of the additional well is expanded emymi profiled pipes, and then autopsied reservoir while maintaining the downhole pressure in equilibrium with the depression in situ or in relation to it.

The disadvantages of this method are:

- a long period of time between the injection of insulating material into the exposed part of the additional wellbore and the mounting of the barrel by expansible profiled pipes, spent on the descent and installation of profiled pipes, which can lead to incomplete installation or inability to install due to premature setting of the insulating material and will make it impossible to continue drilling;

- the implementation of this method requires repeated lowering and lifting of downhole equipment, which also leads to an increase in the cost of this method;

- reducing the diameter of the section of the additional trunk, revealing the reservoir, which leads to a decrease in the filtration area of the product from the reservoir, i.e. reduces the production capacity of the well.

The closest technical solution is the method of drilling an additional wellbore from the production casing of the well (RF patent No. 2365728 C1, E21B 7/06, publ. Bull. No. 24 dated 08.28.2009), including drilling an additional well of smaller diameter compared to the main one using a wedge-deflector to the roof of the reservoir, descent of the expanded profile pipes for its fastening, injection of insulating material through profile pipes in a suspended state and having channels in the lower part through which they produce filling the additional barrel with insulating material from the bottom up, after which the profile pipes are lowered with support on the bottom, and the channels are closed, followed by the expansion of the profile pipes and their upper part being expanded and the productive formation is opened while maintaining the pressure at the bottom, which is equilibrium with the in-situ or depressive towards it .

The disadvantages of this method are:

- the implementation of this method requires repeated lowering and lifting of downhole equipment, which leads to significant material costs when using it;

- reducing the diameter of the section of the additional trunk, revealing the reservoir, which leads to a decrease in the filtration area of the product from the reservoir, i.e. reduces the production capacity of the well;

- the possibility of underreduction of profile pipes, as after the injection of insulating material and straightening of the profile pipes, only the upper part located in the main barrel is flared, which can lead to non-passage of maintenance and repair equipment;

- the possibility of a breakthrough of the liquid along the walls of the profile pipes, because without expansion of the expanded pipes, only due to their straightening, the insulating material is not significantly “crushed” into the permeable sections of the barrel.

The technical objectives of the invention are to reduce material costs by reducing the number of tripping operations during the construction of an additional wellbore, increasing the production capacity of the well by maintaining the diameter of the section of the additional well opening the producing formation, creating the possibility of guaranteed passage of production and repair equipment to the additional well due to the fact that the composition with increased the polymerization period, which allows to expand the additional trunk to the entire length, as well as the maximum reduction in the risk of annular flows along the walls of the profile pipes due to a more complete "crushing" of the insulating material into the permeable sections of the additional barrel.

The solution to this problem is achieved by a method that includes drilling with the opening of a productive layer of an additional trunk of a smaller diameter compared to the main one using a deflector wedge, securing it with expandable pipes supported by the bottom, with the injection of insulating material through channels located in the lower part of the profile pipes.

What is new is that the additional shaft is fastened in two stages: first, the expansion pipes are lowered to the roof of the exposed reservoir after drilling the additional shaft, and then, after the insulating material is injected, the expanded pipes are lowered to the bottom for stop, followed by their expansion and expansion.

Figure 1 shows the descent into the additional trunk of the column of profile pipes to the top of the reservoir and the injection of viscoelastic waterproofing material into the additional wellbore.

Figure 2 shows the descent of the column of profile pipes to the bottom, the closure of the channels of the shoe-valve and the expansion of the column of profile pipes until it is pressed against the walls of the additional wellbore.

The method is carried out in the following sequence.

In a given interval of production casing 1 (Fig. 1) of the well being bore 2 to be eliminated by means of a deflector wedge 3, orienting it in the desired azimuth direction, an additional smaller bore 4 is drilled in comparison with the main shaft 2, which allows the drilling tool to pass through production casing 1 before the project face 5 with the opening of the reservoir 6.

After drilling an additional shaft 4 wells on a drill pipe string (not shown), a string of expandable pipes 8 is lowered to the roof 7 of the producing formation 6, having a shoe valve 9 with channels 10 at the lower end. The shoe 9 is installed with the possibility of moving up. Then, through the drill pipe string and the expanded pipe string 8 connected through it through the channels 10 of the valve shoe 9, the viscoelastic insulation material 11 is pumped from the roof 7 of the productive formation 6 to the mouth along the entire length of the additional barrel 4. In this case, the liquid 12 located below the shoe valve 9 in the interval of the productive formation 6, does not allow the viscoelastic insulating composition 11 to get into the productive formation 6. After pumping the required volume of the viscoelastic insulating composition 11 into the additional barrel 4, the expander column washable pipes 8 are lowered to the bottom 5 (figure 2), the shoe-valve 9 enters the lower pipe of the column of expanded pipes 8, hermetically blocking the channels 10.

Next, the column of expandable pipes 8 is expanded by hydraulic pressure until their walls are pressed against the walls of the production string 1 and additional barrel 4, after which the drill pipe string with the landing tool (not shown) is disconnected from the column of profile pipes 8 and flared to its entire length (for example, by roller flarers, mandrel, etc.), while the viscoelastic insulating composition 11 having an increased polymerization time is distributed along the entire length of the additional barrel and is crushed into the permeable sections of the additional casing 4. In this case, packers 13 installed on the column of expandable pipes 8 further eliminate the possibility of liquid breakthrough along the column of expandable pipes 8. Then, the column of expandable pipes 8 is perforated in a predetermined interval of the productive formation 6 and the well is drilled.

Thus, the proposed method allows to reduce material costs by reducing the number of tripping operations during the construction of an additional wellbore, to increase the production capacity of the well by maintaining the diameter of the section of the additional well opening the producing formation, to create the possibility of guaranteed passage of production and repair equipment to the additional wellbore due to the fact that as an insulating material a composition with an increased polymer life is used ation, allowing additional razvaltsevat the entire length of the barrel, as well as to minimize the risk of casing flows along the walls ekspandiruemyh pipes by distributing the entire length of the barrel additional and more complete "zadavlivaniya" permeable insulating material in additional barrel sections.

Claims (1)

A method of drilling an additional wellbore from a production casing of a well, including drilling with opening a productive formation of an additional wellbore of a smaller diameter compared to the main one using a deflector wedge, securing it with expandable pipes supported by the bottom, with the injection of insulating material through channels located in the bottom of the profile pipes, characterized in that the additional barrel is mounted in two stages: first, the expansion pipes are lowered to the roof of the opened productive fin after drilling an additional barrel, and then after the injection of the insulating material ekspandiruemyh descent pipes until it stops on the slaughter followed by their expansion and flare.

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