CN203008808U - Casing centralizer with variable diameter and rotational flow function - Google Patents

Abstract

The utility model relates to a variable-diameter casing centralizer with swirl function. Its technical scheme is: it is made up of collar, inner sealing ring, outer sealing ring, piston, spring, back-stop pin, hydraulic chamber, righting spring piece, main body. The design significance is as follows: the structure is simple, the centralizing spring piece is wrapped in the hydraulic chamber before being lowered, and is in a pre-bent state; during the lowering process, its outer diameter can be much smaller than that of conventional rigid centralizers, which can effectively reduce the size of the casing Run-in friction increases run-in safety, especially in small boreholes, and the centralizer has obvious advantages; when it goes down to the design well depth, it pressurizes and straightens the casing, and its centering degree can reach 100%; it has a spiral groove on the outside, During cementing, swirling flow can be generated, thereby improving the displacement efficiency of cement slurry, and finally significantly improving the cementing quality of oil and gas wells.

Description

Variable diameter casing centralizer with swirl function

technical field

The invention relates to a variable-diameter casing centralizer with swirl function in the technical field of oil and gas well cementing and well completion. the

Background technique

At present, because horizontal wells can communicate with more reservoirs or fractures, which can greatly increase the drainage area of oil and gas, horizontal wells are the first choice for production. The casing cementing and completion of horizontal wells can not only effectively reduce the complex conditions at the bottom of the hole due to borehole deformation, wellbore collapse, and sand production in the reservoir; The fracturing effect plays a very positive role, and it is especially widely used in the exploitation of unconventional oil and gas resources. For example, more than 80% of global shale gas exploitation uses casing cementing and completion of horizontal wells. However, the quality of casing cementing and completion of horizontal wells has always been very poor, and the pass rate is very low. Due to factors such as formation pressure, the casing is severely deformed, which damages the oil production pipeline, and restricts the application of stimulation measures such as refracturing. application, greatly reducing oil and gas production. Due to the limitation of the outer diameter of conventional centralizers, the centering improvement of conventional centralizers is limited, especially in small holes such as 6 inches. In order to ensure the smooth running of the casing, the outer diameter of the centralizer is designed to be very small. Moderation is often below 70%. Moreover, usually the wellbore is usually larger than the size of the drill bit due to the vibration of the drill bit and the erosion of the drilling fluid during the drilling process. Therefore, the conventional casing centralizer cannot meet the requirements for improving the centrality of the cementing quality. In short, there are problems in casing cementing and completion of horizontal wells, such as low casing centering and poor cementing quality; the outer diameter of the centralizer is large, which seriously affects the safety of casing running. This situation is particularly prominent in small wells. the

Through the above analysis, it can be seen that the current centralizers seriously restrict the cementing quality of horizontal well casing cementing and the running safety of casing, especially in slim holes, it is necessary and urgent to solve this problem. The present invention has a simple structure, and the centralizing spring piece is wrapped in the hydraulic cavity before being lowered, and is in a pre-bent state, which makes it easier to push out the centralizing spring piece. Compared with its outer diameter, it can be reduced by 20%, and its centering degree can reach 100%, and it can also provide swirling flow to increase the displacement efficiency of cement slurry, and finally improve the cementing quality of horizontal wells. the

Utility model content

The present invention has a simple structure, and the centralizing spring piece is wrapped in the hydraulic chamber before being lowered, and is in a pre-bent state, which makes it easier to prop up the centralizing spring piece; fully avoiding the general shortcomings of the existing casing centralizer, and adopting hydraulic drive The principle of spring leaf deformation makes the centering degree up to 100%, and the outer diameter is reduced by 20%. While improving the centering degree and increasing the safety of casing running, it can also make the cementing slurry generate swirling flow to improve the cement quality. The displacement efficiency of the slurry really improves the quality of casing cementing in horizontal wells to a new stage. the

The utility model is achieved in this way: on the main body (11) by the collar (1), the inner sealing ring (3), the outer sealing ring (4), the piston (5), the spring (6), the back pin (7) ), the hydraulic chamber (8), and the righting spring (10) are assembled, and its features are: the inner sealing ring (3), the outer sealing ring (4), the piston (5), the spring (6), the stop pin ( 7), the righting spring (10) is assembled in the hydraulic chamber (8), the coupling (1) and the main body (11) are screwed to limit the hydraulic chamber (8), the spring (6), the stop pin (7) ) are assembled in the axially symmetrically distributed small holes on the piston (5), and there are four hydraulic holes (2) and back-stop holes (9) axially symmetrically opened on the main body (11). the

Said: the hydraulic chamber (8) has 3 to 6 spiral grooves (12) at an angle of 30° to 60° with the axis. the

Said: There are 3 to 8 support pieces evenly distributed axisymmetrically on the righting spring piece (10), which are wrapped in the hydraulic chamber (8) when the support pieces are not stretched, and are in a radially pre-bent state. the

Working principle: Assemble the centralizer before running in, so that the centralizing spring (10) is in a radially pre-bent state, so that the hydraulic pressure required for straightening the casing is smaller and easier to right; during the casing running, The centralizing spring piece (7) shrinks inside the hydraulic chamber (2), which not only ensures that the centralizing spring piece (10) will not protrude during the lowering process, but also makes the outer surface of the variable-diameter casing centralizer with swirl function The diameter becomes very small, which can greatly reduce the casing friction when running the casing, which can significantly increase the safety of casing running; when the cementing string is run into the specified position, the variable diameter The casing centralizer is pressed, and the hydraulic pressure is transmitted from the hydraulic hole (2) on the main body (11) to the piston (5), and the piston (5) moves to the right, thereby axially squeezing the spring leaf (10) for the centralization, and the centralization The radially pre-bent support piece on the spring piece (10) deforms and displaces in the radial direction, and at the same time the spring (6) and the backstop pin (7) move to the right. 6) cooperates with the stop hole (9) under the elastic force to prevent the spring leaf from moving to the left. At this time, the spring leaf will not be able to shrink radially, and the casing will be straightened; when cementing the wellbore, the cement slurry will A swirling flow is generated on the groove (12), thereby improving the displacement efficiency of the cement slurry, and finally achieving the purpose of improving the cementing quality. the

The advantages and beneficial effects of the present invention are: the structure is simple, the centralizing spring piece is wrapped in the hydraulic cavity before being lowered, and is in a pre-bent state, which can make the centralizing spring piece easier to stretch out; during the lowering process, its outer diameter is larger than that of the conventional The outer diameter of the centralizer can be reduced by about 20%, which can effectively reduce the friction resistance of casing running and increase the safety of running, especially in small holes. , its centering degree can reach 100%, can generate swirling flow, improve the displacement efficiency of cement slurry, can effectively meet the requirements of improving cementing quality, increase wellbore stability, and increase oil and gas production. This casing centralizer can be effectively applied for various well types. the

Description of drawings

Figure 1 is a half-sectional view of a variable-diameter casing centralizer with swirl function;

FIG. 2 is a sectional view of FIG. 1 . the

Detailed ways

As shown in Figure 1, Figure 2, and Figure 3: Assemble the centralizer before running in, so that the centralizing spring (10) is in a radially pre-bent state, so that the hydraulic pressure required for centralizing the casing is smaller and easier Righting: during the running of the casing, the righting spring (7) shrinks inside the hydraulic chamber (2), which not only ensures that the spring will not be stretched out during the running, but also makes the variable diameter sleeve with swirl function The outer diameter of the pipe centralizer becomes very small, which can greatly reduce the casing friction when running the casing, and significantly increase the safety of casing running; The variable-diameter casing centralizer is pressed, and the hydraulic pressure is transmitted from the hydraulic hole (2) on the main body (11) to the piston (5), and the piston (5) moves to the right, thereby axially squeezing the centralizing spring (10 ), the radially pre-bent supporting piece on the righting spring piece (10) is radially deformed and displaced, and at the same time the spring (6) and the stop pin (7) move to the right, and when it moves to the design position, the stop pin (7) Cooperate with the stop hole (9) under the elastic force of the spring (6) to prevent the spring leaf from moving to the left. At this time, the spring leaf will not be able to shrink radially, and the casing is righted. When cementing the wellbore, the cement The slurry generates swirling flow on the spiral groove (12), thereby improving the displacement efficiency of the cement slurry, and finally achieving the purpose of improving the cementing quality. the

Claims (3)

1. radial variable casing tube centralizer with the eddy flow function, upper by box cupling (1) in main body (11), inner seal ring (3), exterior seal ring (4), piston (5), spring (6), retaining pin (7), hydraulic cavities (8), righting spring leaf (10) is assembled, it is characterized in that: inner seal ring (3), exterior seal ring (4), piston (5), spring (6), retaining pin (7), righting spring leaf (10) is assemblied in inside hydraulic cavities (8), box cupling (1) is threaded connection hydraulic cavities (8) spacing with main body (11), spring (6), retaining pin (7) is assemblied in the aperture of the upper axial symmetry distribution of piston (5), the upper axial symmetry of main body (11) has 4 hydraulic pressure holes (2) and retaining hole (9).

2. the radial variable casing tube centralizer with the eddy flow function according to claim 1 is characterized in that: hydraulic cavities (8) outside has 3 to 6 and becomes 30 ° of helicla flutes to 60 ° of angles (12) with axis.

3. the radial variable casing tube centralizer with the eddy flow function according to claim 1, it is characterized in that: the support chip that has 3 to 8 Homogeneous Axisymmetricals to distribute on righting spring leaf (10), be wrapped in when support chip does not strut inside hydraulic cavities (8), and be in radially pre-bending state.

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