RU2491404C1 - Method to extend casing string in well without diameter reduction - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: method to extend a casing string in a well without diameter reduction, including well deepening to the foot of the string extension zone, expansion of the extension zone with a reamer, lowering of the additional string from profile pipes into the well into the expanded interval, fixation of its upper end in the lower previously expanded part of the casing string, and expansion of profile pipes by development of hydraulic pressure in them with their further expanding as even. Prior to expansion of the well shaft with the reamer, the lower part of the casing string is expanded by the expanding method to form a socket with an expander, the diameter of which is selected such that the inner diameter of the socket during connection of the casing and additional strings provides for their reliable and tight connection between each other without reduction of well diameter.

EFFECT: method makes it possible to extend a casing string without diameter reduction in wells, which have not been previously planned for expansion, for instance, when a string has not been lowered to the bottom during cementing, in case of a complication when drilling from under a string, as a result, to reduce material costs and to speed up the process of well construction.

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Description

The invention relates to the oil and gas industry, and in particular to a technology for lengthening a casing string in a well by increasing it from below.

A known method of lengthening the casing strings in the well, including a device for lengthening the casing strings, comprising a docking nozzle installed at the lower end of the string, equipped with an internal process sampling from the bottom, cementing the string with a nozzle, lowering an additional string of profile and cylindrical pipes into the well, securing it the upper end in the connecting pipe and the expansion of the profile pipes by creating hydraulic pressure in them, followed by calibration of the profile and flaring of the cylinder pipes (Sh.F. Takhautdinov et al. “Elongation of casing strings and profile overlaps without reducing the diameter of the well and cementing it.” Article in the journal Oil Industry No. 7, 2002, p. 87).

The disadvantages of the device are:

- limited conditions of use, since the device is used in cases where they plan to build the casing;

- non-standard layout of the bottom of the casing string, including the connecting pipe with the shoe, limits the passage along the borehole during the descent, and also complicates the cementing process;

- after cementing the column and drilling the cement plug on the inner walls of the nozzle, a layer of hardened cement mortar remains, which is cleaned by milling before installing an additional column, which is associated with additional time and material costs.

The closest in technical essence and the number of essential features coinciding with the claimed is the "Method of lengthening the casing strings in the well" (patent RU No. 2259458, IPC ЕВВ 7/20, 33/14 publ. Bull. No. 24 dated 08/27/2005), including a device for extending the casing strings in the well, comprising a docking nozzle mounted at the lower end of the string and an easily drilled shoe at the end, the docking nozzle equipped with an internal process sampling from below and a cylindrical glass of easily drilled material with gray scrap under the cement plug at the top, while the space between the technological selection of the pipe and the cylindrical cup is filled with grease.

The disadvantages of the device are:

- limited conditions of use, since the device is used in cases where they plan to build the casing;

- non-standard layout of the bottom of the casing string, including the connecting pipe with the shoe, limits the passage along the borehole during the descent, and also complicates the cementing process;

- the complexity of manufacturing the device, namely for the manufacture of a cylindrical glass, it is necessary to manufacture a complex mold for pouring, which is associated with additional material costs.

The technical tasks are to simplify the method of building up the casing without reducing its diameter with the possibility of using it on any wells, including those not previously planned for building, as well as reducing material costs and accelerating the well construction process.

The technical problem is solved by the method of lengthening the casing string in the well without reducing the diameter, including deepening the well with expanding to the bottom of the zone of extension of the string, lowering the additional string from the profile pipes into the extended interval, securing its upper end in the lower pre-expanded part of the casing and expanding the profile pipes by creating hydraulic pressure in them with their subsequent flaring flush.

What is new is that before lowering the additional string from the profile pipes, the lower part of the casing is expanded by flaring to form a flare with a flare, the diameter of which is chosen so that the inner diameter of the flange when connecting the casing and additional casing ensures reliable and tight connection between them without reducing borehole diameter.

Figure 1 shows the deepening of the well to the bottom of the extension zone; figure 2 - the expansion of the lower part of the casing flare, figure 3 - the expansion of the wellbore expander, figure 4 - the connection of the casing and additional columns between them.

The method is carried out in the following sequence.

The well 1 is deepened (see Fig. 1) to the sole 2 of the elongation zone 3 of the column 4, for example, to isolate the formation 5, incompatible with drillability with the upper layer overlapped by the column 4, or to isolate the zone of complication 5 that arose during the deepening of the well 1 below columns 4. Then expand the lower part of the casing 4 (see figure 2) by flaring with the formation of a bell 6 flare 7. Expander 8 (see figure 3) expand the extension zone 3. Next, run down into the well of an additional column 9 (see figure 4) from profile tr UB 10 in the extended interval of the extension zone 3. After which, by creating hydraulic pressure in the additional column 9, the profile pipes 10 are expanded, as a result, their upper end 11 is fixed in the socket 6 of the casing 4, followed by flaring of the profile pipes in a flush. The diameter of the flare 7 is chosen so that the inner diameter of the socket 6 provides a reliable and tight connection of the casing 4 and the upper end 11 of the expanded profile pipes 10 of the additional column 9 without reducing the internal diameter of the well 1.

The proposed method allows to increase the casing without reducing the diameter in any wells, including previously not planned to be extended, for example, when the column is not run during cementing, with the complication that arose when drilling from under the string, as a result, reduce material costs and accelerate the well construction process .

Claims (1)

A method of extending a casing string in a well without reducing the diameter, including deepening the well to the bottom of the casing elongation zone, expanding the extension zone with an expander, lowering an additional casing from the profile pipes into the extended interval, securing its upper end in the lower pre-expanded part of the casing and expanding the profile pipes by creating hydraulic pressure in them, followed by flaring them in a flush, characterized in that before expanding the wellbore with an expander odyat extension of the lower part of the casing by razvaltsovyvaniya razvaltsevatelem to form a funnel, whose diameter is selected such that the inner diameter of the socket when connecting the casing and the additional columns provide a reliable and tight connection between them without reducing a diameter of the borehole.

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