RU2828942C1 - Downhole flow diverter - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: invention relates to oil and gas industry and can be used in cementing casing strings during well construction. Downhole flow diverter includes a housing fixed on a casing pipe. At that, the diverter body is made in the form of a cylinder with a conical projection in the lower part with four axes uniformly fixed in the upper part of the projection, on which there are blades, which follow the shape of the casing pipe body and are made in the form of slides with outward directed skids with skewed upper and lower ends, and inner projections are made on the inner side of the blades. On the axes there are additionally installed torsion springs with the possibility of pressing the blades to the deflector housing. Diverter body is equipped with a movable rod with a conical end. On conical end there are external projections, mirror to inner projections of blades, and in the upper part the housing is equipped with a cage of water-swelling rubber with the possibility of acting on the movable rod and its movement downwards until the internal projections of the blades and external projections of the conical end of the movable rod are fixed. On the outer side of the cage in the upper part of the housing there is an external cylinder having through holes along the entire diameter.

EFFECT: providing displacement of drilling mud residues and complete replacement of drilling mud with cement mortar during well casing and improving the quality of casing.

1 cl, 4 dwg

Description

The invention relates to the oil and gas industry and can be used in cementing casing columns during well construction.

A flow turbulator centralizer for a casing string is known, used for well casing (RU patent No. 2159839, IPC E 21 B 17/10, 11/27/2000, bulletin No. 33), containing a hollow body in the form of 2 rings, spiral centering ribs rigidly fixed with their ends to the body and bars placed between the centralizers with scrapers fixed to them.

The well-known centralizer allows to deflect the flow of cement slurry during well casing and partially turbulize it, but it is not capable of fully washing out the drilling slurry from the caverns.

The closest is a centralizer for a casing string (patent RU No. 49090, IPC E 21 B 17/10, published 10.11.2005), which includes a hollow body, which is made in the form of a branch pipe with inclined windows in the form of a slot at an angle of α = 25-45 to the generators of its outer surface, limited on the lower side by a ring, while the centering elements placed between the slots are made hemispherical in cross-section and are rigidly fixed to the body using electric welding.

The disadvantage of the known centralizer is that it can provide a small turbulence, but does not provide flow deflection into the cavity.

The technical task is to ensure the displacement of drilling mud residues and the complete replacement of drilling mud with cement mortar when casing a well by redirecting the flow of process fluids deep into the caverns, improving the quality of casing.

The technical problem is solved by a well flow diverter, which includes a housing that is fixed to the casing pipe.

What is new is that the diverter body is made in the form of a cylinder with a conical protrusion in the lower part with four axes uniformly fixed in the upper part of the protrusion, on which blades are mounted, the shape of which repeats the body of the casing pipe and is made in the form of skids with outwardly directed runners with beveled upper and lower ends, and on the inner side of the blades there are internal ledges, while torsion springs are additionally installed on the axes with the possibility of pressing the blades to the diverter body, the diverter body is equipped with a movable rod with a conical end, on the conical end there are external ledges mirroring the internal ledges of the blades, and in the upper part the body is equipped with a collar made of water-swelling rubber, with the possibility of acting on the movable rod and moving it downwards until the internal ledges of the blades and the external ledges of the conical end of the movable rod are fixed and engaged, while on the outer side of the collar in the upper part of the body there is an external cylinder, having through holes across the entire diameter.

Fig. 1 shows a general view of the well flow diverter in the transport position.

Fig. 2 shows a top view of a well flow diverter in the transport position.

Fig. 3 shows view A of a well flow diverter.

Fig. 4 shows a general view of the well flow diverter in the working position when lowered into the cavern.

The well flow diverter (hereinafter referred to as the diverter) is a body 1 (Fig. 1) rigidly secured to the casing pipe 2 by locking elements 3, for example, by wedges, bolts or in another way (the authors do not claim to have specified the method of fastening), wherein the body 1 of the diverter is made in the form of a cylinder with a conical projection 4 in the lower part with four axes 5 uniformly secured in the upper part of the conical projection 4. Blades 6 (Figs. 1, 2, 4) are mounted on the four axes 5, repeating the shape of the body of the casing pipe 2 (Fig. 1), made in the form of skids with outwardly directed runners 7 (Figs. 1, 2), wherein the upper and lower ends of the runners 7 are beveled, for example, at an angle of 45°, which ensures unimpeded movement of the casing string (not shown in Figs. 1-4) from the casing pipes 2 (Fig. 1) with installed deflectors during descent into the well. On the inner side of the blades 6, internal ledges 8 are made (Fig. 1, 4). Torsion springs (not shown in Fig. 1-4) are additionally installed on the axes 5 (Fig. 1) with the possibility of pressing the blades 6 (Fig. 2) to the body 1 (Fig. 1) of the deflector.

The body 1 of the deflector is equipped with a movable rod 9 with a conical end; on the conical end, on the outside, external steps 10 are made, mirroring the internal steps 8 of the blades 6 (Fig. 4). In the upper part, the body 1 (Fig. 1) of the deflector is equipped with a collar 11 (Fig. 3, 4) made of water-swelling rubber, with the possibility of acting on the movable rod 9 (Fig. 1) after its swelling and moving the movable rod 9 under the action of pressure from the swollen collar 11 (Fig. 4) downwards until the internal ledges 8 of the blades 6 are fixed and engaged with the external ledges 10 of the conical end of the movable rod 9. In this case, on the outer side of the collar 11 in the upper part of the body 1 (Fig. 1) by means of a thread 12 (Fig. 3), an outer cylinder 13 (Fig. 1) is installed, under which the upper edge of the movable rod 9 goes, and the outer cylinder 13 has through holes 14 (Fig. 1, 3) over its entire diameter. For reliable fastening, the outer cylinder 13 (Fig. 1) is secured to the casing pipe 2 using locking elements 3.

The well flow diverter operates as follows.

In the well interval with deep caverns 15 (Fig. 4), where it is necessary to ensure high quality cementing, a deflector is lowered, having previously installed it on the casing pipe 2 (Fig. 1) of the casing string. As a rule, the number of deflectors is selected depending on the number of caverns 15 (Fig. 4) in the well. On the casing pipes 2 (Fig. 1), the deflector is secured with locking elements 3 (Fig. 1). During the lowering of the flow deflector, the blades 6 (Fig. 1) in the form of skids with runners 7 are pressed against the body 1 due to the operation of the torsion springs, passing nominal sections, without interfering with the passage of the ascending flow of drilling mud, simultaneously centering the casing pipes 2 of the casing string relative to the wellbore. After the casing pipe 2 reaches the bottom, the deflector is positioned opposite the caverns 15 (Fig. 4) present in the wellbore.

During the cleaning flushing of the well before the start of cementing, drilling mud gets into the collar 11 made of water-swelling rubber through the through holes 14 (Fig. 1), whereby the collar 11 (Fig. 4) begins to increase, acting on the movable rod 9 with a conical end, which moves downwards under pressure until the internal ledges 8 of the blades 6 and the external ledges 10 of the conical end of the movable rod 9 get into the catch, as a result of which the blades 6 are deflected towards the caverns 15.

During the cementing process, the ascending flows of first the spacer fluid and then the cement slurry, when passing through the blades 6 of the diverter, are redirected deep into the caverns 15 (Fig. 4) due to the outwardly directed runners 7 (Fig. 2), thereby displacing the remainder of the drilling fluid from there, and replacing it with the cement slurry. Due to the proposed design of the flow diverter, the completeness of the displacement of the drilling fluid from the well, including from the caverns, and its replacement with the cement slurry is improved, the quality of the fastening is improved by forming a solid cement stone around the casing string even in the caverns.

The proposed design of the flow diverter improves the permeability of the casing string and the downhole equipment lowered with it in the wellbore, and improves the conditions for flushing during the lowering and cementing of the well. At the same time, the quality of the well mount is ensured by giving the ascending flow of cement mortar the necessary direction in the caverns, and, consequently, by separating the layers.

An example of practical application.

A well was drilled with a bit of 143 mm in diameter to a depth of 1800 m. Geophysical surveys of the wellbore (GIS) were conducted with a caliper and 2 intervals with deep caverns, up to 350 mm, were identified. Before starting to lower a casing string of 114x7.0 mm in diameter, two well flow diverters (hereinafter referred to as the diverter) were delivered to the well with through holes in the outer cylinder of the diverter, with a collar made of water-swelling rubber pre-installed inside the outer cylinder, while each diverter is equipped with four blades in the form of skids with runners directed outward, the ends of which are beveled at an angle of 45 °, installed on the axes of the diverters, a torsion spring is pre-installed on each axis, pressing the blades to the body.

Before lowering into the wellbore, the deflectors were rigidly installed on the casing pipes of the casing column in such a way that the conical projections of the deflector body were at the bottom, taking into account their placement opposite the caverns identified using GIS.

The casing string was lowered from the casing pipes to the design bottomhole and the well was flushed with drilling mud in the amount of 1.5 well volumes. Then the casing string was cemented using the generally accepted technology with successively pumping the spacer fluid, then the cement slurry, squeezing the latter with the squeezing fluid until the STOP signal was received. After cementing, the casing string was left to wait for cement hardening (WCH) for 48 hours. After the WCH time of 48 hours, a geophysical device - an acoustic cement meter (ACM) - was lowered into the well and studies were carried out along the entire wellbore. The results of the studies carried out using the ACM showed full adhesion of the cement in the cavern intervals both with the casing pipe and with the rock. As a result of the well development, anhydrous oil was obtained.

In this way, it was possible to maximally displace the drilling fluid from the wellbore during cementing, including from cavernous areas, and obtain a full-fledged support.

Claims (1)

A well flow diverter comprising a housing secured to a casing pipe, characterized in that the diverter housing is made in the form of a cylinder with a conical protrusion in the lower part with four axes uniformly secured in the upper part of the protrusion, on which blades are mounted, the shape of which repeats the body of the casing pipe and is made in the form of skids with outwardly directed runners with beveled upper and lower ends, and on the inner side of the blades internal ledges are made, while on the axes additionally torsion springs are installed with the possibility of pressing the blades to the diverter housing, the diverter housing is equipped with a movable rod with a conical end, on the conical end external ledges are made, mirroring the internal ledges of the blades, and in the upper part the housing is equipped with a collar made of water-swelling rubber with the possibility of acting on the movable rod and moving it downwards until the internal ledges of the blades and the external ledges of the conical end of the movable rod are fixed and engaged, while with On the outer side of the clip, in the upper part of the body, an outer cylinder is installed, which has through holes along the entire diameter.