RU1798484C - Composite cementing plug - Google Patents

Abstract

Use: for cementing casing run by sections and flush casing. SUMMARY OF THE INVENTION: A composite cement plug includes upper and lower cement plugs. The upper cementing plug has a conical surface in the head part, in which a conical recess defined by an edge is made outside the central axis, and there is a central axial channel, the bottom of which is located in the head of the plug between the lower cuff and the conical recess. The lower plug is made with a flowing central axial channel, which in the aft part of the plug has a conical surface corresponding to the conical surface of the head of the upper plug. Through apertures of the lower plug are made through holes in which fingers are inserted. The inner ends of the fingers are interconnected by a rod, and movement limits are provided at the outer ends of the fingers. Composite cementing plug The cork is made of rubber-rubber. This embodiment of the composite cement plug allows to increase its operational reliability. 1 s, item f-l, 2 ill.

Description

...; The invention relates to well cementing,

An object of the invention is to increase the reliability of a composite cement plug.

: The installation of fingers in the upper part of the elastic cuff of the lower plug with the possibility of longitudinal displacement allows using this opportunity in order to reliably remove the fingers inside the plug; rather than cutting them off with pressure. The realization of this possibility is provided by connecting the ends of the fingers, for example.

the rod, which creates the condition of mechanical interaction with the head part of the upper tube when it fits into the lower tube. Bending and retraction of the rod by the upper plug into the central axial channel of the lower plug entails drawing the fingers into the plug and freeing it from hanging on the fingers in the casing. Installing a travel limiter on the outer ends of the fingers prevents fingers from falling out of the plug and also prevents the upper plug from being pushed through the flowing central axial channel in the lower

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traffic jam. A conical recess in the rubber head of the upper plug, made outside the central axis of the plug, ensures the fixation of the head of the upper plug, since the edge of such a hole expands when it fits onto the rod, which is pressed slightly into the rubber edge and is wrapped around it, thereby preventing the plug from passing through past the rod.

The implementation of the upper and lower plugs of solid rubber increases the reliability of passage of the plug in the casing strings, increases the manufacturability and ergonomics of the plug construction / The presence of a blind axial channel with a bottom between the lower cuff and the conical recess in the top of the plug determines the transfer of the driving force of the pressure drop to the head of the plug, This, on the one hand, ensures stable cork management in the casing. On the other hand, the alignment of the upper plug and the coaxial entry of its head into the lower plug are achieved, and after landing on the rod, the longitudinal misalignment of the plug is eliminated, the rod is bent steadily deep into the central channel and the fingers are reliably drawn into the plug body.

In this way, an increase in the reliability of the composite cement plug is achieved.

. FIG. 1 shows a composite cement plug; in FIG. 2.- section AA in FIG. 1,

The cork includes upper and lower cementing plugs. The upper plug 1 has a conical surface in the head part 2, in which a conical recess 3 defined by the edge 4 is formed on the outside along the central axis, and there is a central axial channel 5, the bottom of which is located in the head of the plug between the lower cuff and the conical recess. The lower plug 6 is made with a flowing central axial channel 7, which in the aft of the plug has a conical surface 8 corresponding to the conical surface of the head of the upper plug. Through holes 9 are made in the upper part of the lower plug, into which the fingers are inserted 10. The inner ends of the fingers are interconnected by a bond (rod, wire) 11. and on the outer ends of the fingers there are travel stops 12. The number of fingers can be two or more.

Composite cement plug works as follows.

The lower plug 6 is installed on the fingers 10 at the mouth of the casing string (liner), which is lowered into the well using a drill string. Upload to

column cement mortar, which pushes into annular space using squeezing fluid. Between the cement mortar and squeezing fluid, an upper plug 1 is installed

to separate the solution and fluid in the drill string. In this case, the driving force of the differential pressure, being applied to the bottom of the channel 5 in the head of the plug, provides a stable, without distortion, movement of the upper plug 1 in the drill string 1 and its coaxial entry by the head part 2 into the aft part 8 of the flow channel 7 of the lower plug 6, having a mating surface. After landing on the rod 11.

0 of the upper tube with the edge 4 of the conical hole 3, there is some expansion of the edge 4 with the pressing of the rod 11, which as a result engages with the upper tube 1. The further movement of the tube 1

5 leads to the deflection of the rod 11 and its retraction into the depth of the channel 7.

At the same time, fingers 10 are pulled into the body of the plug 6 through the holes 9 and the plug is freed from hanging at the mouth

0 casing string. In this case, the movement stops 12 hold the fingers 10 and the rod 11 from falling out, and also prevents the possibility of forcing the upper plug 1 through the flow channel 7.

5 of the bottom plug 6. After retracting fingers 10 and releasing the bottom plug b, the upper 1 and bottom 6 plugs move together in the casing with reliable separation of the cement mortar and squeezing fluid.

In this way, reliable plug operation is ensured, leading to an improvement in cementing quality of the wells. For m u l a and z.o b re te ni

5 1. Composite cementing plug, including the upper plug with the conical surface of the head part and the lower plug with the counter surface of the flowing central axial channel and axially symmetrically mounted fingers for fixing the bottom plug in the casing, as well as that, in order to increase the reliability of operation, the fingers for fixing the lower plug in the casing 5 are not mounted in the upper part of the elastic cuff of the lower plug with the possibility of longitudinal displacement, are interconnected by inner ends and have m at the outer ends stops moving, while the head of the upper stopper

outside, a conical recess is made along the central axis.

2. The cork according to claim 1, with the fact that it is made of solid rubber.

while in the upper plug is made a blind axial channel with a bottom between the lower cuff and the conical recess.