RU177699U1 - CENTRAL CENTER - Google Patents

Abstract

The proposal relates to the field of construction of oil and gas wells, namely to technical equipment for external rigging of the casing string, in particular to devices for centering the casing string. The centerpiece for the casing string includes a casing fixed to the pipe of the casing string in the form of a ring with centering elements made in one piece with the body by casting, spaced at equal distances from each other, while the centering elements are made in a step-like dome-shaped shape, less Shade which is located on the higher level surface with a height not more than one third of the height greater degree and is configured similarly to a greater degree dome shape. Centralizers installed on the casing pipes opposite the problem areas of the well are provided with turbulent wings in the form of plates located between the large steps with an inclination to the right, with a width of no more than two-thirds of the height of the larger stage. The centering elements can be made in the form of stepped spherical segments, or paraboloids, or in the form of a full-bodied truncated cone, the smaller base of which is made with a convex surface. As retaining elements for fixing the centralizer to the pipes A shear bolt or a full-bodied conical wedge, or a one-sided flat wedge with serrated notches on its inclined surface, or a collet fastener, or holes with a thread for a shear bolt, an internal conical bore for a solid conical wedge, respectively, can be used in the casing string , internal grooves communicated with the window under a single-sided flat wedge, and a collet clamped by a nut. The centralizers of the first driving pipe, the columns being lowered into the well, are additionally equipped with a retaining ring mounted above or below the centralizers to prevent them from moving from the installation site from the straining load. 3 s.p. f-ly, 17 ill.

Description

The proposal relates to the field of construction of oil and gas wells, and in particular to technical equipment for external rigging of the casing string, in particular, to devices for centering the casing string.

The well-known casing centralizer (see patent for utility model RF No. 91101, IPC 7 ЕВВ 17/10, published in B.I. No. 3, 01/27/2010 under the name flow turbulator - casing centralizer.) comprising a body in the form of a ring with obliquely located centering elements of a hemispherical shape, made in one piece with the body by casting, and partially protruding at its ends. Holes are made in the housing for driving one-way locking wedges into its internal grooves, with the help of which the centralizer is fixed to the casing pipe.

Its disadvantage is:

- a large gap between the casing and the wellbore, which prevents high-quality centering of the casing;

- the use of locking elements that do not provide reliable fastening of the centralizer to the casing pipes. There were cases of the centralizer sliding off the installation site when lowering the casing string and passing through the problematic sections of the wellbore (ledges, narrowing of the trunk, filter cake in the permeable sections of the wellbore, a large zenith angle of the wellbore, etc.). For example, when the values of the zenith angle of the wellbore are more than 45 °, the force on the centralizer, secured by four retaining wedges (in each of the two windows in the body there are two wedges), can reach 9 tons. In addition, it is metal-intensive.

Known casing centralizer (see RF patent for utility model No. 124300, IPC ЕВВ 17/00, published in B.I. No. 2 on January 20, 2013, under the name a flow turbulator - casing centralizer.), Including a body in the form of a ring with convex centering blades made in one piece with the body by casting and tilting to the left, simultaneously playing, in the opinion of the authors and the patent owner, the role of cement upflow turbulators when fixing the well, and stop elements for fixing it to the outer wall casing pipes s, which are made in the housing constructive elements response thereto.

The specified centralizer in technical essence is closer to the proposed one and can be adopted as a prototype.

Its disadvantage is that, made with a slope to the left, the turbulent ribs can cause, during the descent of the column, unscrewing the extended pipes through the threaded connection, under the radial component and friction forces, which can lead to an emergency. In addition, the design of the mentioned centralizer due to its small size, namely, due to the small width of the body, is often not detected by geophysical instruments when checking the quality of well cementing. A common drawback of both the analogue and the prototype is that the inclined centering elements do not provide turbulence in the cement slurry with sufficient efficiency when attaching the well due to their design features, which makes it necessary to strengthen the turbulizing capabilities of the centralizer, as well as the unreliability of the centralizer to casing pipes.

The technical task of this utility model is to eliminate the disadvantages of the prototype, in particular, to increase the efficiency of centering of the pipes of the column and turbulization of the upward flow of cement, providing increased cross-flow of the centralizer and the column itself along the wellbore.

The stated technical problem is solved by the described casing centralizer, including a housing fixed to the casing pipe by retaining elements in the form of a ring with centering elements made integrally with the housing by casting, spaced from each other at equal distances.

What is new is that the centering elements are made in steps of a dome-shaped shape, the smaller one is made similarly to the larger step of a dome-shaped shape. At the same time, centralizers installed on the casing pipes opposite the problematic sections of the well can be equipped with turbulent wings in the form of plates made in one piece with the body and located in the intervals between large steps with an inclination to the right, with a width of no more than two-thirds of the height of a larger stage.

Also new is the fact that the centering elements can be made in the form of stepped spherical segments, or paraboloids, or in the form of a solid truncated cone, the smaller base of which is made with a convex surface.

Another difference is that as a locking element for fixing the centralizer to the casing pipe, a shear bolt or a solid conical wedge, or a one-sided flat wedge with serrated notches on its inclined surface, or a collet fastening, while in the case, respectively, can be used the centralizer has holes with a thread for a shear bolt, an internal conical bore for a solid conical wedge, internal grooves in communication with the window for a one-sided flat wedge, and a collet clamped with a nut. The centralizers of the first driving pipe, the columns being lowered into the well, can be additionally equipped with a locking ring mounted above or below the centralizers to increase their resistance to the straining load and thereby prevent their displacement from the installation site.

The presented drawings explain the essence of the proposed utility model, where in FIG. 1 shows a three-dimensional view of the proposed centralizer, where stepwise made centering elements in the form of spherical segments are visible on the surface of the housing;

in FIG. 2 is the same as in FIG. 1, where the smaller step is made in the form of a solid truncated cone, in which its smaller base is made with a convex surface, three-dimensional image;

in FIG. 3 is the same as in FIG. 1, where the turbulent wings made in the form of plates, the width of which does not exceed two-thirds of the height of a larger step, are shown in a volumetric image;

in FIG. 4 is the same as in FIG. 1, where a collet is made at one end of the casing, clamped by a lock nut in the form of a ring to fix the centralizer to the outer wall of the casing pipe, where the external thread on the collet segments is also visible, three-dimensional image;

in FIG. 5 is the same as in FIG. 3, where a collet is made at the lower end of the casing, also clamped by a lock nut in the form of a ring when fixing the centralizer to the outer wall of the casing pipe, three-dimensional image;

in FIG. 6 is the same as in FIG. 1, where the centralizer fastening elements are visible to the outer wall of the casing pipe, an internal conical bore for a collet cone is made at one end of the casing, bolt threads are also visible for fastening the collet cone and the centralizer casing to the casing pipe, three-dimensional image;

in FIG. 7 is the same as in FIG. 1, where holes are threaded at one end of the casing for mounting the centralizer with bolts to the outer wall of the casing pipe, volumetric image;

in FIG. 8 is the same as in FIG. 1, where, at one end of the housing, windows for entering locking one-sided wedges are visible, a three-dimensional image;

in FIG. 9 is the same as in FIG. 1, where the elements for securing the centralizer to the outer wall of the casing pipe are visible, windows for introducing one-way retaining wedges are visible at one end of the housing, and holes with threads for the locking bolts are at its other end, and a restrictive retaining ring mounted above the centralizer with holes with threads for locking bolts, three-dimensional image;

in FIG. 10 is the same as in FIG. 1, where restrictive retaining rings are visible mounted on a casing pipe on both sides of a freely installed centralizer;

in FIG. 11 - one-sided locking wedge, side view;

in FIG. 12 is the same as in FIG. 11 is a top view along arrow A on the inclined surface of the wedge, where the fixing gear notches are visible;

in FIG. 13 is a fragment of fixing the centralizer to the outer wall of the casing pipe with one-way retaining wedges;

in FIG. 14 - shear locking bolt with a weakened section, side view;

in FIG. 15 is the same as in FIG. 14, view along arrow B;

in FIG. 16 - one of the stepwise made centering element of the centralizer, front view;

in FIG. 17 - one of the turbulent wings in the form of a centralizer plate.

The centralizer includes a housing 1 (see Fig. 1-10) in the form of a ring with a width of at least 100 mm with a stepwise dome-shaped centering elements and can be made in the form of stepped spherical segments 2 and 3, or paraboloids, or in the form of a solid truncated cone, the smaller step 3 of which is made of the same shape as the large step 2, or of another shape, for example, in the form of a solid truncated cone 4 (see Fig. 2), and its smaller base is made with a convex surface 5. The centering elements are made in one piece with housing of steel by casting and are spaced from each other at equal distances and depending on the diameter of the column, their number can be from 3 to 6. The width of the body of 100 mm is optimal according to the results of experimental and experimental work, and more than 100 mm increases its metal consumption, and with less than 100 mm in most cases, is not detected by geophysical instruments when checking them for possible displacement from the installation site and the quality of cementing.

The implementation of the centering elements of the domed shape, in particular in the form of stepped spherical segments, is dictated by the need to improve the centralizer's cross-flow ability along the wellbore, to reduce the straining loads on the centralizers from the place of their installation, and therefore to the column in its narrowed areas, where the remains of the clay crust are preserved, causing emergency situation. This simplifies the manufacturing technology, reduces metal consumption, increases the efficiency of turbulization of the upward flow of cement mortar due to the strict directivity of the turbulent wings 6 (see Fig. 3 and 5) located between the centering elements, which will significantly reduce the thickness of the clay crust due to the abrasiveness of the cement . Therefore, centralizers with turbulent wings are installed on casing pipes 7 opposite the problem areas of the wellbore, where there are remnants of clay cake.

Turbulent wings are made in the form of plates located in the gaps between large steps with an inclination to the right and with a height of not more than two-thirds of the height of a larger stage. Performing their height of more than two-thirds leads to an increase in metal consumption. They are inclined to the right and at an angle of 18-25 ° relative to the generatrix of the housing 1, while the inclination of 20 ° is optimal, which provides an increase in the effect of turbulization. An effective range of 18-25 ° was established by experimental studies, and their inclination to the right prevents unscrewing of the expanded pipes through the threaded connection during the descent of the column under the force of the radial component of the friction force, as well as from the reaction force of the upward flow twisted by the turbulent wings 6.

Centralizers (see Figs. 1 and 3) can be equipped with locking elements of various designs, depending on the choice of the customer. In FIG. Figures 4-8 show the construction of the locking elements, which can be made, for example, in the form of a collet 8 (see Figs. 4 and 5) with a clamping lock nut 9, a conical collet wedge 10 (see Fig. 6), for which the housing is made conical bore 11, in the form of a one-sided flat retaining wedge 12 (see Fig. 6) with fixing serrated notches 13 located along its inclined surface 14 (see Fig. 11 and 12), while the inner grooves 15 are made in the housing (see Fig. 13), communicated with the window 16 for driving through it the wedges 12 into the grooves, or in the form carved bolts 17 (see. FIGS. 14 and 15) for which the centralizer body openings with threads 18 (see. FIGS. 5, 6, 7, 9 and 10). To increase the resistance of the centralizer to the pulling force from the fixing points in the wells with zenith angles of more than 45 ° and in the productive intervals of the cut, as well as for the centralizer to pass through the problem areas of the trunk, it is necessary to equip the column with a retaining restrictive ring 19 (see Fig. 9 and 10 ), setting it close to the centralizer, fixing it to the column pipe with bolts 17 or wedges 12. At the same time, the centralizer's resistance to the breaking force is significantly increased. For the possibility of axial movement and circular rotation of the centralizer, retainer restrictive rings 20 and 21 are installed above and below it, similar to the retainer ring 19, secured by bolts 17 or retaining wedges 12, which ensures the passage of the centralizers when the column is lowered into an inclined or horizontal well.

The work of the centralizer is as follows.

It is lowered into the well, having previously been put on the casing string 7 (the casing is not shown in FIG.), And fixed with one of the above locking elements (see Figs. 4-6 and 11, 14). So, when using a collet locking element 8 (see Fig. 4 and 5), first the centralizer on the pipe 7 is fixed with bolts 17 (see Fig. 14) with a force sufficient to break its head along the weakened section of the rod, or with one-way locking wedges 12 (see Fig. 14), after which the collet is clamped with a ring 9. The centralizer is fixed on the pipe 7 with a conical locking wedge 10 (see Fig. 6) as follows. As described above, the centralizer on the pipe 7 is fixed with bolts 17 or with one-sided wedges 12, after which the conical retaining wedge 10 is lowered through the pipe against the inner conical bore 11 of the housing 1 and secured with bolts 17 or one-sided wedges 12 and lowered into well. When the column is lowered into the well in the case when the centralizer does not withstand the straining load, it may shift from the installation site in the upward direction. At the same time, he meets a cone wedge 10 with his conical bore and, interacting with it, wedges. The braking effect of the centralizer increases many times if the cone wedge 10 is made in the form of a collet, as shown in Fig. 6, in which not only jamming occurs, but also the petals (segments) of the collet part of the wedge are clamped, thereby increasing its resistance to straining load in jamming process. Therefore, centralizers equipped with the above-described locking element are installed on the pipes of the column run into the wells with an zenith angle of more than 45 ° and in the productive intervals of the section, as well as for passing it through problem areas where large straining loads are predicted.

The centralizer is fixed to the pipe 7 of the column with locking bolts 17 and one-sided locking wedges 12 according to the traditional scheme as follows. Through one of the windows, for example, through the window 16 (see 13) of the housing 1, the sharp end of the first wedge is introduced first, directing its inclined surface 14 with the fixing teeth 13 to the outer surface of the pipe 7. Then, with the hammer blows, the wedge is advanced until it is completely drowned into the groove 15 flush. Moreover, as it moves in the translational direction, bending around the circumference of the groove with its locking teeth, it covers the outer surface of the pipe 7 and fits snugly against its body. Next, in the same window 16, the next wedge 12 is brought in, and in the same way, it is driven into the groove in the opposite direction from the first wedge. So they fix the centralizer to the casing pipe and through other windows, providing a fixed mount, without the possibility of displacement and rotation along the pipe. To increase the resistance of the centralizer to the pulling force from fixing points in wells with zenith angles of more than 45 ° and in productive cut intervals, as well as to pass the centralizer through problem areas of the barrel, it is necessary to additionally equip the column with a retaining restrictive ring 19 (see Figs. 9 and 10) by installing it close to the centralizer, fixing it to the column pipe with bolts 17 or wedges 12. At the same time, the centralizer's resistance to the straining load is significantly increased and can reach, for example, up to 50 kN. To allow axial movement and circular rotation of the centralizer above and below it, it is necessary to install retaining restrictive rings 20 and 21, fastened with bolts 17 or retaining wedges 12, providing increased patency of the centralizers when the column is lowered into an inclined or horizontal well.

In the process of cementing the column, the upward flow of cement passing through the inclined turbulent wings 6 receives a turbulent movement, thereby improving the completeness of displacement from the borehole walls of the mud and replacing it with cement, thereby improving the quality of fastening, the formation of a cement ring around the casing uniform thickness by reducing the eccentricity (displacement of the axes) of the column relative to the axis of the well, and the inclination of the ribs to the right prevents There is an unscrewing of the expanded pipes through a threaded joint under the radial component and friction forces, as well as from the force of the swirling upward flow during the descent of the column. This centralizer design allows you to clearly detect their location in the well by geophysical instruments. The implementation of the centering elements of the dome-shaped shape, in particular in the form of stepped spherical segments, ensures trouble-free centralizer cross-flow along the wellbore, reduction of stress loads on centralizers from the place of their installation, and therefore, columns in its narrowed areas where clay cake remains are preserved, causing emergency situations. In addition, this simplifies the manufacturing technology, reduces metal consumption, increases the efficiency of turbulization of the upward flow of cement mortar due to the strict direction of the turbulent wings 6 (see Fig. 3 and 5) located between the centering elements, which will significantly reduce the thickness of the clay crust with cement mortar having an abrasive property.

Claims (4)

1. Centralizer for the casing string, including a housing fixed to the casing pipe by retaining elements in the form of a ring with centering elements made integrally with the housing by casting, spaced at equal distances from each other, characterized in that the centering elements are made in a stepped dome shape while the smaller stage is similar to the larger stage of the dome-shaped. 2. The centralizer according to claim 1, characterized in that the centering elements can be made in the form of stepped spherical segments, or paraboloids, or in the form of a full-body truncated cone, the smaller base of which is made with a convex surface. 3. The centralizer for PP. 1 and 2, characterized in that the centralizer mounted on the casing pipes opposite the problem areas of the well can be provided with turbulent wings in the form of plates, made in one piece with the body and located in the intervals between large steps with an inclination to the right, with the width of the plates not more than two-thirds of the height of the greater step. 4. The centralizer on PP. 1 and 2, characterized in that as a locking element for fixing the centralizer to the casing pipe, a shear bolt or a solid conical wedge, or a one-sided flat wedge with serrated notches on its inclined surface, or a collet fastening, while in the case, respectively, can be used the centralizer has holes with thread for a shear bolt, an internal conical bore for a solid conical wedge, internal grooves in communication with the window for a one-sided flat wedge, and a collet clamped with a nut, the centralizer of the first driving pipe of the string being lowered into the well can be equipped with an additional retaining ring installed above and below the centralizer to prevent it from moving from the installation site from the straining load.

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