SU1747679A1 - Apparatus for stepped cementation of wells - Google Patents

Abstract

The invention relates to the mining industry and is used in the construction of wells. The goal is to increase the reliability of the device. The device includes a housing 1 with lateral openings 2, inside of which, on shear pins 3 and 4, are fixed, respectively, the upper 5 and lower 6 locking bushings. The cement mortar of the first stage is pushed by the sales separating plug 9, and the cement mortar of the second stage by the upper plug. A plug 9 is made in the form of a hollow cylinder 12 with a spherical element 13 and an elastic diaphragm 14 connected to the plug 9 with shear pins. An additional sleeve 16 is installed inside the hollow cylinder. The ratio between the masses of the additional sleeve 16 and the ball locking element 13 and the ratio between the outer diameter of the additional sleeve and the diameter of its mounting seat is related by the dependence D / d V | Vl / m −f 1. where D and c are respectively the outer diameter of the additional bushing and the diameter of the mounting saddle of the additional bushing; M and m are the masses of the additional sleeve and the ball valve, respectively. 4 il.

Description

The invention relates to the mining industry, namely to oil and gas production, and can be used in the construction of wells for step cementing.

The purpose of the invention is to increase the reliability of the device.

Figure 1 presents a quarter section of the device at the time of fixation of the valve on the lower locking lane; figure 2 - the same, when the movement of the closing of the stopper of the first stage below the device; FIG. 3 shows the position of parts of the device during the washing and cementing of the second stage; Fig. 4 shows the position of parts of the device after the end of cementing a well.

The device includes a housing 1 with lateral circulation openings 2. Inside the housing, shear pins 3 and 4 are fixed to the upper 5 and lower 6 locking sleeves, respectively. The space between the top 5 and bottom 6 closure sleeves is sealed with seals 7 and 8, respectively. The cement mortar of the first stage is pressed through the squeeze separating plug 9, and the cement mortar of the second stage is shut off by a separating stopper 10. With the longitudinal separating plug 9 shear

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pins 11. a valve in the form of a hollow cylinder 12 with a spherical closure element 13 and an elastic diaphragm 14 in the middle part of the hollow cylinder 12 is mounted. An additional sleeve 16 is mounted for axial movement. The hollow cylinder 12 against the additional sleeve 16 is made with radial channels 17, and in the lower part - with a mounting seat 18 for an additional sleeve 16. On the outer surface a hollow cylinder 12 against the radial channels placed an additional check valve, made in the form of an elastic ring 19, the upper end connected to the surface of the hollow cylinder. The additional sleeve 16 is made with a seating saddle 20 under the ball stop member 13. The ratio between the masses of the additional sleeve 16 and the ball shut-off element 13 and the ratio between the outer diameter of the additional sleeve and its landing seat diameter are related

Ј | y1ETT7

where D and d are respectively external

the diameter of the additional sleeve and the diameter of the seat of the additional sleeve,

Mit is the mass of the additional sleeve and the ball closure element corresponds to. „,

This dependence ensures reliable sealing of the internal space of the device below the valve during the second stage cementing due to the effect of fluid pressure.

The device works as follows.

At the first cementing stage, after pumping the calculated volume of the cement slurry, a squeeze separation plug 9 with a valve fixed on it with a shear pin 11 is put into the cemented column. The separation plug 9 passes freely through the upper 5 and lower 6 locking sleeves and is fixed on the lower locking sleeve 6 with locking pin 15. After that, shear pins 11 are destroyed by pressure and the slug tube 9 is moved from the sludge column below the device. When separating from the hollow cylinder 12, an additional sleeve 16 is displaced before seating it on the landing seat 18.

together with the ball locking element 13, the radial channels 17 are opened and the liquid under the device is pressed through them by an elastic ring 19. There is a complete displacement of the cement slurry into the annulus,

After planting the squeezing separator plug 9 onto the stop ring, the circulation stops, the pressure in the system increases sharply, compressing the column of squeezing fluid in the column and giving a signal that the squeeze has ended. By this signal, the pumps stop and open the valves on the cementing head, thereby removing the overpressure at the wellhead and allowing the liquid column to expand to an equilibrium state corresponding to its hydrostatic pressure. Expanding the mouth, the liquid column forms an upward flow, flowing through the valves and displacing the ball valve 13 in front of them. First, the additional sleeve 16 and the ball valve rise together to the initial position of the sleeve, and then the ball valve 13 pushes above the elastic diaphragm 14, occupying a working position (see, fig.Z).

Then, when the valve is closed with overpressure, the side cementing openings 2 are opened, moving the lower closure sleeve 6 down, after having destroyed the shear pins 4 by overpressure. Then the well is rinsed in the annular space above the device and cemented the second stage in the usual order. Following the cement slurry of the second stage, a shut-off separating plug 10 is allowed. When the upper shut-off bush 5 is reached, the shut-off separator stopper 10 interacts with it, causing shear pins 3 to collapse and displaces it down to block the side cementing openings 2. The bush is fixed in this position, for example spring ring, and the cementing process ends.

Reliable operation of the device is ensured by the fact that the valve ball valve 13 is protected from wear and is forcibly charged to the operating position with a minimum flow of upward fluid through the valve.

Claims (1)

Invention Formula A device for step cementing of wells, including a housing with lateral circulation openings, upper and lower locking sleeves located inside the housing, a squeeze and locking separation plugs, a valve, associated with a sales separating plug and made in the form of a hollow cylinder with a ball locking element and an elastic diaphragm in the middle part of the hollow cylinder, and a locking device for the lower locking sleeve, characterized in that it is equipped with an additional sleeve installed inside a hollow cylinder under the elastic diaphragm with the possibility of axial movement, and an additional non-return valve, wherein the hollow cylinder is made with radial channels against the additional sleeve and sediment at the bottom of the seat under the extra sleeve, the additional sleeve - with a mounting seat for the ball valve element, and the additional non-return valve - as 0 five elastic ring mounted on the outer surface of the hollow cylinder against the radial channels and connected with the upper end to the surface of the latter, the ratio between the masses of the additional bushing and the ball valve and the ratio between the outer diameter of the additional bushing and the diameter of its mounting seat are related as% D where d and d - respectively, the outer diameter of the additional sleeve and the diameter of the seat of the additional sleeve; Mit-mass, respectively, of an additional sleeve and ball valve element. FIG. i phage. 2 fie.Z And / 4 fi.4