SU868053A1 - Device for closing-off drilling mud absorption zones - Google Patents

Description

The invention relates to the drilling of wells, in particular, to devices for blocking wells when eliminating the absorption of washing fluid. A device for blocking the absorption zones of the washing liquid is known, comprising a housing and an elastic shell t1 fixed on its outer surface. The drawback of the device is its low operational reliability due to the possibility of the shell breaking during its descent into the well. The closest to the invention is a device for blocking the zones of absorption of drilling fluid in a well, including a perforated body, an elastic shell G fixed to its outer surface by a limiter moving its upper part and a protective casing 2. A disadvantage of this device is that its elastic shell laid around the perforated case 1} with transverse folds, when leaving the protective casing in the process of filling it with a tg1mponiruyuschim solution with filler it cannot be completely l configuration overlapping interval due to premature sliding of the shell down the body. In addition, the use of elastic shells made in BH.ije of nodal grids with a cell size of 6.5 x 6.5 mm in this device makes it necessary to assemble two identical grids worn over one another in one device. As a result, the assembly technology of the device becomes complicated and the total strength of the elastic shell decreases due to the unevenness of the blocking of its cells with plugging mixture with filling material separately in each shell. All this leads to a decrease in the quality of the insulation work carried out in the well, while eliminating the absorption of the washing liquid. The purpose of the invention is to increase the reliability of the overlap of the absorption zones by increasing the strength and mobility of the elastic shell. This goal is achieved by the fact that the elastic shell is made of a knitted fabric, having a cellular loop that stretches in the longitudinal and transverse directions, the structure, and the limiter for moving the upper part of the shell is made in the form of an elastic friction clutch. In addition, the elastic shell in the upper part is made of a material with greater elasticity than the elasticity of the rest. To prevent rupture of the casing from loads in the process of filling with a tamponing mixture, it is made of loops with long stretches that automatically open and close the gaps in the loops. The shell may have different transverse dimensions at different parts of its length, depending on the profile of the overlapping areas. FIG. 1 shows the proposed device in the transport position; in fig. 2 - the same, after filling the casing with a tampon mixture; in fig. 3 shows the structure of the knitted sheath in various states; in fig. 4 shows a variant of the embodiment of the shell. I. The device for blocking the absorption zones of the drilling fluid in the well consists of a sub 1, which serves to connect with drill pipes, a central pipe 2 connected to a sub and serving to supply a plugging mixture, a connecting pipe 3, a centralizer 4, a friction coupling 5, made in in the form of an elastic ring, a safety valve 6 for the passage of excess quantities of the plugging mixture. It prevents overstretching of the sheath during its filling and is made in the form of an elastic ring (or ring), covering the upper neck of the sheath, or in the form of a section of increased elasticity knitted material, which is part of the neck itself. The perforated body 7 consists of a pipe (or pipes), which in its lower part has two groups of holes. An elastic sheath 9 made of knitted fabric is placed in the protective casing 8, which, after leaving the protective casing 8 and injecting the plugging mixture, contacts the well walls and blocks the absorption channels. The rings 10 are used for temporary fixation of the casing 7 on the device and its inlet well and. broken in the process of filling the shell. Clamp 11 serves to fasten the lower end of the shell on the housing 7 (perforated pipe). When mounting a multi-section overlapping device, a grip 12 is used. To support the device on an artificially created bottom hole (cement block, cement bridge), a support shoe 13 is used, provided with grippers (dogs), preventing its upward rise when lifting the casing 8. The casing 8 is connected to the shoe 13 for the period of transporting the device to the installation site with a shear pin 14 after the device has reached the specified operating interval The ball valve 15 is deposited. It closes the flushing openings of the shoe, poppy 13, and causes an increase in the hydraulic pressure inside the pipes, by which the connection between the shoe 13 and the casing 8 is broken. Figure 3 shows the structure of the knitted sheath in various states: 16 - ORIGINAL or two-dimensional stretched; 17- stretched longitudinally; 18- stretched in the transverse direction. The casing (Fig. 4) consists of a cylindrical part 19 with conical transitions 20 and 21, a lower neck 22 rigidly mounted on a frame (perforated tube), an upper movable neck 23, which can be made of a material of increased elasticity to ensure a tight fit pipe and valve effect, nipple valve 6 in the form of an elastic ring (or several rings), friction clutch 5, which slides along the frame, creating sufficient frictional force to prevent premature creep of the casing downwards. The overlap of the absorption zones of the drilling fluid in the well is carried out as follows. The assembled device (Fig. 1) is lowered on the drill pipe to the required depth (slightly below the bottom of the absorbing horizon) where the packer tube or cement bridge is pre-installed. The descent of the device to the artificial bottom is performed with washing, preferably with water. After that, a ball valve 15 is thrown into the pipes, then the instrument is installed at a height of 0.50, 6 m from the artificial bottom. When the valve achieves a conical seat in the shoe 13 when pumping the pumping oil inside the drill and central pipes, the pressure rises and reaches such a magnitude when the pins 14 are cut off under its action. After that, the bearing bag 13 with the body 7, the sheath 9 and the central part. rum 4 goes down. The pawl pads are released to prevent this part of the device from moving upwards. The fluid passes freely through the lower holes in the housing. For the complete exit of the casing 9 from the casing 8, upward lifting of the bore pipes to the length of the assembled casing is carried out. After euogo in the casing 8 remains upper - (and perforated).

a part of the housing 7 with a centralizer 4 with a length of up to 3-5 m, which is necessary for the tool to be pivoting when pumping and forcing the plugging mixture.

The filling of the shell 9 with the cement slurry with the filler is carried out as follows.

First, a small amount of cement slurry (for example, cement) without filler is pumped into the drill pipes. At the end of the injection of this amount, a small portion of coarse filler (cord fiber, crushed rubber, etc.) is added to the solution, the particles of which are blocked in the lower holes of small diameter in the housing 7. After this, the downloads are. Estimated amount of cement slurry with a smaller filler (for example, cement mortar, wood sawdust or other filler).

This tamponage mixture fills the casing and presses it against the walls of the well and against the absorption channel. As the shell is filled with the cement mixture, its diameter increases, at which the rings 10 are broken, the shell is pressed against the walls of the squivus and the absorption channels, taking the shape corresponding to the configuration of the well.

When the sheath is made, the first knitting structure of the knitted fabric occurs; shell cells change their slit-like shape and turn into open holes. At this point, the most are created (there are no favorable conditions for the passage through the cells of the required amount of the mixing mixture with a small filling into the wellbore and the absorption channels necessary to fill the absorption channels and make solid, monolithic connection of the shell with the walls wells.

Further transverse stretching of the shell is accompanied by stretching: the cells in the transverse direction and turning them into gaps, which gradually overlap with loops. This feature of the casing material allows the flow of the casing of the tamping mixture and some (smaller) part of the filler to be controlled over a wide range. In this case, the slits, which are blocked by protrusions, are peculiar Safety Valves, which prevent overvoltage and rupture of the shell during its filling:

After the calculated amount of the tampon swab is injected into the mixture to overlap the absorption zone, it is pumped out with a washing solution. A portion of the warming mix penetrates through the shell cells into the absorption channels, and its excess is forced through the safety valve 6 into the barrel.

wells above the frame. The volume of the slug must be such that the total hydrostatic pressure of the cement column left in the drill pipe and the squeezing fluid column equilibrates or is slightly greater than the reservoir pressure in the absorption zone (at the time of the end of the slug). After that, the drill pipes and removable parts of the device (1, 2, 3, and 8) are lifted to the surface.

0

The state of the well and the position of the parts of the device left in it are shown in FIG. 2

After the tamponing mixture has hardened, the rest of the Squigina

5 part of the device is being drilled.

Positive from the use of the overlapping device is achieved mainly due to its shell, made of knitted

0 canvas with a cellular structure and provides the following positive properties of the shell:

high elongation in the longitudinal and transverse directions, due to the use of a special lateral structure with diane broaches;

the variability of the shape and size of the flow area of the cells in the process of filling with a tampon mixture, which

0 ensures the passage of the technologically necessary amount of the mixture and a certain amount of filler of a certain fractional composition beyond the shell; .

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preservation of filtration capacity at cells that are blocked and closed by stretching, due to the mobility of the looped structure, in which the cells that are repeatedly interrupted by the stretches are multiple pressure limiting valves. Prevent overvoltage and rupture of the shell during its filling;

the ability to manufacture shells

5 of any length, without longitudinal and transverse seams, with a smooth change in the diameter of modern thermo- and chemically resistant high-strength materials on essential knitwear

0 cars;

casing with the size of cells is based on the requirements of the technological process, which will simplify the filling technology

5 and improve its quality and reliability by applying the necessary TEIM-. understandable mixture and filler of optimal size and F11 stock composition.

ABOUT

The formula of the invention 1. A device for blocking the zones of absorption of drilling fluid in a well, including a perforated body, attached to its outer surface 5

an elastic shell with a limiting movement of its upper part and a protective casing, characterized in that, in order to increase the reliability of overlapping the absorption zones by increasing the strength and mobility of the elastic shell, the latter is made of a knitted fabric having x stretchable in the longitudinal and transverse directions the hinge structure, and the limiter of movement of the upper part of the shell is made in the form of an elastic friction clutch.

2. The device according to claim 1, characterized in that the elastic shell in the upper part is made of a material with greater elasticity, than the elasticity of the rest of the shell.

Sources of information taken into account in the examination

1. USSR author's certificate number 126829, cl. E 21 V 33/14, 1959.

2. Mishchevich V.I. Hydrodynamic studies of absorbing formations and methods for their isolation. M., Nedra, 1974, p. 132 (prototype).

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Claims (2)

The claims, 1. A device for blocking the zones of absorption of flushing fluid in the well, including a perforated body, mounted on its outer 8680 53 of the surface, an elastic shell with a limiter for moving its upper part and a protective casing, in order to increase the reliability of overlapping absorption zones by increasing the strength and mobility of the elastic shell, the latter is made of knitted fabric having a honeycomb loop structure stretchable in the longitudinal and transverse directions, and the limiter for moving the upper part of the shell is made in the form of an elastic friction clutch. 2. The device according to claim 1, characterized in that the elastic shell in the upper part is made of a material with greater elasticity than the elasticity of the rest of the shell.