SU1430501A1 - Sleeve for stagewise cementing of casing - Google Patents

Abstract

The invention relates to the mining and oil and gas industry and m. used in drilling wells. The purpose of the invention is to increase the reliability of the coupling. It contains a double-walled case 1 with inlet 2 and outlet 3 holes, hollow destructible fingers 6, with shear bushings, installed in the holes 3. The coupling has filtering element 7 located in the annular cavity (KP) 4. The lower part of the KP 4 is made in screw through channels 5, each of the latter communicates the upper part of the gearbox 4 with one of the holes 2. The wall of the housing 1 is internally made with a side channel 8 with a check valve and fingers 6. Element 7 is located opposite channel 8. The presence of channels 5 contributes to the closing - chiva iju fluid flow mz7fte..Etim uniform filling is achieved KP 4 cement mortar. At the end of the push, the solution rushes into the column space. At the same time, the process of dewatering the filter on the filter with the filter inlet into the column space through the channels 8 begins. The resulting precipitate jumps over the KP 4 opposite the filtrate, then fills it to the level of the holes 3. Due to this, the resistance of the coupling increases. 1 il. (L 4 SB about SP

Description

The invention relates to the mining industry, and more specifically to the oil and gas industry, and can be used in the drilling of wells, cementing casing 1,

The aim of the invention is to improve the reliability of the α-muff.

The drawing shows a clutch for step cementing.

The coupling includes a double-walled case with inlet 2 and outlet 3 openings and an annular cavity 4, the lower part of which is made in the form of helical through channels 5, each of which communicates the upper part of the annular cavity 4 with one of the inlet openings 2 blocked by destructible pins 6 with shear bushings. In the upper part of the annular cavity 4, a filtering element 7 is installed, which is connected to the internal space of the coupling by side channels 8, made in the wall of the double-walled body 1, blocked by breakable fingers 9 with check valves installed in them,

The device works as follows 1m,

The coupling, as an integral part of the casing, is installed in the lower part of the well interval, cemented by the second stage

The first plug cementation plug destroys fingers 6 and 9, however, the penetration of cement mortar into the annular cavity of the coupling was eliminated at this stage due to the presence of shear bushings in the inlet ports 2 and check valves in the side channels 8. After receiving the Stop time, the casing is pressurized , providing cutting or destruction of shear bushings in the inlet holes 2, Then, reducing the pressure in the casing string, push the bushings into the column with liquid flowing into the annular cavity from the annular space a. Opening the inlet ports 2, the second stage is cemented, pushing the cement slurry into the annulus through the sleeve. The presence of the screw channel 5 in the lower part of the annular cavity contributes to the twisting of the fluid flow in the coupling. This achieves a uniform filling of the annular cavity with cement mortar. At the end of pushing, the pressure in the casing is reduced, the cement slurry rushes into the column space under the action of a pressure differential equal to the pressure difference between the columns of the cement slurry and the squeezing fluid. At the same time, the process of intensive dehydration of the cement slurry on the filter with filtrate drainage into the column space through the side channels 8 begins. The cement sediment formed on the filter first overlaps the annular cavity opposite the filter, then fills it to the level of the inlet ports 3,

Due to the presence in the annular cavity of a hardened, partially dehydrated cement mortar, the resistance of the coupling to the hydraulic pressure increases 10-15 times. For a coupling with a housing height of 250 mm, it reaches t5.0-22.5 Mia,

F o rm ula invention

t

Coupling for step cementing of the casing, including. . a double-walled case with inlet and outlet openings, hollow destructible fingers with shear bushings installed in the inlet holes, and an element installed in the annular cavity of the filtering, in order to increase the reliability of the coupling operation a part of the annular cavity is made in the form of helical through channels, each of which communicates the upper part of the annular cavity with one of the inlet openings, while the wall of the double-walled body is made from the inside with a side channel with a check valve and destructible fingers, and the filter element is located opposite the side channel.

Claims (1)

Φ o rm of the invention Coupling for stepwise casing cementing, including a double-walled casing with inlet and outlet openings, hollow destructible fingers with shear sleeves installed in the inlet openings, and a filter element installed in the annular cavity, characterized in that, in order to increase the reliability of the coupling, the lower part of the annular cavity is made in the form of screw through channels, each of which communicates the upper part of the annular cavity with one of the inlets, while the wall of the double-walled casing with The back side is made with a side channel with a check valve and destructible fingers, and the filter element is placed opposite the side channel.