RU2374422C1 - Borehole equipment centraliser - Google Patents

Abstract

FIELD: oil-and-gas production.

SUBSTANCE: invention related to oil-and-gas production, particularly to devices for centralising borehole equipment. Borehole equipment centraliser consists of case with a central a canal, top and bottom connection threads, top and bottom projections between each locate swage which is able to rotate on a external surface of case, sealing at the ends relatively to case, in case walls create end-to-end canals within swage limits and install slips on the its external surface evenly along perimeter. Swage between ends execute in a shape of thin-walled void cylinder with longitudinal cuts between which slips to be fixed, inside the thin-walled cylinder install elastic hose equipped with antiflow opposite to cuts, hermetically fixed to swage ends, at the same time one of the swage ends perform limited ability to move longwise towards another one. Described above borehole equipment centraliser advantages are in its simple in design and reliability.

EFFECT: centraliser provides reliable stabilisation of borehole equipment, especially in sloped and horizontal wells, avoid its fluctuation and vibration during a process, which enables to perform high quality borehole works.

3 dwg

Description

The proposal relates to the oil and gas industry, namely, devices for centering downhole equipment.

The well-known "Centralizer" (US patent No. 4284154, E21B 17/10, prior. 08/18/1981), comprising a housing with connecting threads and a rotating mandrel with longitudinal samples located within the housing, while several supports are located between the housing and the mandrel rotation, wear-resistant dies with cavities located around the perimeter in the longitudinal samples of the mandrel, guides installed with a sliding fit in the cavities of the dies, each die equipped with a radially outward spring washer installed in one of its polos Tei.

The disadvantage of this device is the design complexity and high requirement for manufacturing accuracy, as well as the insufficient reliability of mounting dies in the mandrel, because impacts of the device against the walls of the well during its axial movement can lead to the breakage of the clamps and plates used for this purpose and the subsequent tearing of the dies from the mandrel of the device.

The closest in technical essence and the achieved result is “Centralizer of downhole equipment” (patent PM RU No. 65099, ЕВВ 17/10, publ. Bull. No. 21 dated 07/27/2007), comprising a housing with a central channel, upper and lower connecting threads and upper and lower protrusions, between which a mandrel is placed rotatably on the outer surface of the housing, sealed at the ends relative to the housing, in the walls of which there are through channels within the ends of the mandrel, and on the outer surface of the mandrel uniformly around the perimeter of the die set.

The disadvantage of this device is the design complexity and its lack of reliability, which is manifested in the low centering ability with respect to the longitudinal axis (especially inclined and horizontal) of the well due to the fact that the mechanism of preloading the centering dies allows lateral movements and tilts of the centralizer body. Additional efforts from pressure on the dies are insufficient, since they act on small areas. As a result, the accuracy of the direction of movement of the centered equipment during operation (for example, the expander when milling the column) is reduced, there is no necessary rigidity when working between the column and the centered equipment. As a result, vibration, shock and, as a result, premature failure of the centered equipment occur.

The technical task of the proposed centralizer downhole equipment is to simplify the design and increase the reliability of its work.

The technical problem is solved by the downhole equipment centralizer, comprising a housing with a central channel, upper and lower connecting threads and upper and lower protrusions, between which a mandrel is sealed at the outer surface of the housing, sealed at the ends relative to the housing, in the walls of which there are through channels within the ends of the mandrel, and on the outer surface of the mandrel uniformly installed along the perimeter of the die.

What is new is that the mandrel between the ends is made in the form of a thin-walled hollow cylinder with longitudinal cuts between which the dies are fixed, and inside the thin-walled cylinder there is an elastic sleeve with anti-seals opposite the cuts, hermetically fixed at the ends of the mandrel, while one of the ends of the mandrel is made with the possibility longitudinal limited movement away from the other end.

Figure 1 shows the centralizer of downhole equipment.

Figure 2 is a section bB in figure 1.

Figure 3 - callout And figure 2.

The downhole equipment centralizer (centralizer) comprises a housing 1 (see FIG. 1) with a central channel 2, upper 3 and lower 4 connecting threads, upper 5 and lower 6 protrusions, between which are rotatably mounted on the outer surface 7 and 8 of housing 1 the mandrel 9, sealed at the ends 10 and 11 with seals 12, in the walls of which there are through holes 13 within the ends 10 and 11 of the mandrel 9. The mandrel 9 between the ends 10 and 11 is made in the form of a thin-walled hollow cylinder with longitudinal sections 14, between which are longitudinal and rav the dies 15 are numbered around the perimeter, and inside it there is an elastic sleeve 16 with anti-seals 17 (Fig. 2) opposite the cuts 14, which is tightly fixed at the ends 10 (Fig. 1) and 11, for example, with bushings 18. One of the ends 10 or 11 (not shown in FIG. 1), the mandrel 9 is connected to the housing 1, for example, by means of a hinge lock 19 in the form of a ball bearing placed between the seals 12. The diameter of the surface 7 of the housing 1 is larger than the diameter of the surface 8, as a result of which a stop 20 is formed for the end 11 ( or 10 - not shown in Fig. 1) of the mandrel 9. The lower protrusion 6 form by screwing on the thread of the housing 1 of the adapter 21. Between the ends 10 and 11, the mandrel 9 with the dies 15 (between the longitudinal sections 14) is made in the form of sections 22 from an elastically deformable material, and its maximum outer diameter over the dies 15 is equal, in the working position, to the internal well diameter. The mandrel 9 can be made from a single piece. Anti-leakage 17 is made of thin-sheet elastically deformable (spring) material. Limiters 23 can be made in them to orient them relative to longitudinal sections 14 (Fig. 3). Wear resistant material can be applied to the surface of the dies 15. An elastic sleeve 16 is made of a rubberized material capable of operating in a downhole environment.

The centralizer works as follows.

The centralizer is connected to the downhole equipment 24 (Fig. 1) (expander, flare, and others are not shown) using a connecting thread 4, and with a drill pipe string 25, thread 3. When descending into the well, the centralizer moves with the downhole equipment translationally, centering them relative to the walls of the well (not shown). The greatest departure of the dies 15, in the working position, is limited by the interaction of the end 11 (or 10) of the mandrel 9 with the stop 20 of the housing 1.

Inside the drill string 25, drilling fluid is supplied by a mud pump, and the drill string and downhole equipment begin to rotate. The flushing fluid along the central channel 2 of the housing 1 of the hole 13 enters the mandrel 9 and presses the elastic sleeve 16 with sections 22 of the thin-walled cylinder with dies 15 between the longitudinal sections 14 to the walls of the well. Due to the fact that the mandrel 9 is connected to the movable end 11 (or 10), when it moves towards the other end 10 (or 11) to the stop 20, all the dies 15 together with the mandrel 9 expand synchronously, which is very important when working in horizontal and horizontal-deviated wells, when the downhole equipment lies on one of the walls of the well. Under the action of pressure on the dies 15 of the mandrel 9, the downhole equipment is lifted and centered relative to the axis of the well. The mandrel 9 with dies 15 in this case performs mainly translational motion due to the upper lock 19 and the presence of friction forces of the dies 15 against the borehole walls, and the outer surfaces 7 and 8 of the housing 1 rotate in conjugations of the ends 10 and 11 of the mandrel 9. The effective fluid pressure increases the degree pressing the dies 5 to the walls of the well, which improves the centering of the downhole equipment and reduces the radial runout of a rotating tool, reliably centering it relative to the axis of the well, which is especially important at high loads. The protrusions 5 and 6 protect the mandrel 9 from external influences. Anti-leakage 17 prevent the flow of material of the sleeve 16 into the longitudinal grooves 14 of the mandrel 9.

The advantage of the proposed centralizer downhole equipment is that it is simple in design and reliable in operation. The centralizer provides reliable stabilization of downhole equipment, especially in deviated and horizontal wells, eliminates its vibrations and vibrations during operation, which ensures high quality downhole operations.

Claims (1)

A downhole equipment centralizer comprising a body with a central channel, upper and lower connecting threads and upper and lower protrusions, between which a mandrel is sealed at the outer surface of the body, rotatable at its ends relative to the body, in the walls of which there are through channels within the ends of the mandrel, moreover, on the outer surface of the mandrel, dies are installed uniformly around the perimeter, characterized in that the mandrel between the ends is made in the form of a thin-walled hollow cylinder ra with longitudinal slits between which the fixed dies and is placed within the thin-walled cylinder with an elastic sleeve antizatekatelyami opposite sections, hermetically fixed to the ends of the mandrel, with one end of the mandrel is configured for limited longitudinal movement in the direction from the other end.

Images