Drilling On-Off Valve

Abstract

The present invention proposes a drilling switch valve, which is mainly composed of an outer shell, a ball seat, a pressure ball, a positioning pin, a spring, and a central axis; a radial bypass hole is provided on the upper part of the outer shell, and the positioning pin is arranged on the outer shell. The upper section of the ball seat is in a sealed fit with the bypass hole of the outer shell, and the lower section is in a sealed fit with the pressure ball. The central axis is cylindrical, and the upper section and the positioning pin form a limit fit, and the lower section cooperates with the spring. After the ball seat and the central axis are connected up and down, its exterior and the interior of the outer shell form an axial sliding seal fit. The drilling switch valve of the present invention is installed in a drilling tool assembly. When leakage occurs, there is no need to pull out the drilling tool. It only needs to move the drilling switch valve to the vicinity of the leakage layer, and then put a pressure ball from the wellhead. The plugging operation can be completed by starting and stopping the pump. It has the advantages of simple structure, fast plugging efficiency, high safety and reliability, convenient operation, and low cost.

Description

Technical Field

[0001] The invention relates to downhole drilling tools in the fields of oil and gas drilling, geological exploration, mine drilling and coal bed gas development, in particular to a drilling-while-drilling switch valve. Background Art

[0002] In the fields of oil and gas drilling, geological exploration, and mining drilling, due to the influence of long geological age, complex structure, and lithological heterogeneity, there are cracks of different sizes and shapes inside the strata at different depths. When drilling into these strata, the wellbore is connected to the cracks, and the drilling fluid will enter the cracks, resulting in a large amount of drilling fluid loss, the so-called well leakage or leakage, causing great economic losses. If the cracks are not blocked in time, the amount of drilling fluid leakage in the wellbore is too large, and the liquid column pressure drops rapidly and cannot balance the formation pressure, which will cause well kicks and even blowouts, which are vicious underground accidents, with unimaginable consequences. With the acceleration of the development of deep and ultra-deep shale oil and gas resources in southwest and western my country, the backwardness of the plugging technology while drilling and the lack of supporting special tools have become the key issues restricting the improvement of deep and ultra-deep well drilling efficiency and the reduction of comprehensive drilling costs. Therefore, quickly and accurately plugging the leakage formation is an important link to ensure drilling safety and efficient development of oil and gas resources. In response to the above problems, the method adopted in China is to first pull out the entire drilling tool assembly from the wellbore, then lower the special tool to the vicinity of the leaking layer, and then use the ground drilling pump to transport the plugging material to the leaking layer for plugging construction. This method is very inefficient, and it takes a lot of time to pull up and down the drilling tools alone, which seriously affects the timeliness of the plugging construction. Foreign field experience shows that the shorter the interval between the occurrence of leakage and the completion of plugging, the better the plugging effect and the safer the wellbore, which requires a special plugging device while drilling. At present, there is still a blank in domestic research in this area. Foreign research on this aspect started early and progressed rapidly, and relevant devices have been successfully developed. For example, the PBL device of BICO Company in the United States can realize plugging construction while drilling. Relevant data show that when using the PBL device for plugging while drilling, three pressure balls of different sizes must be put in order to complete a plugging construction. The internal structure of the device is complex, the processing accuracy requirements are high, and the use cost is high, which cannot meet the technical requirements of domestic sites. Summary of the invention

[0003] The purpose of the present invention is to provide a drilling-while-drilling switch valve that can achieve the auxiliary plugging function while drilling and meet the technical requirements and equipment requirements of existing drilling processes, and has a simple structure, safety and reliability, low cost, and easy operation.

[0004] The technical solution adopted by the present invention is:

[0005] A drilling switch valve, mainly composed of an outer shell, a ball seat, a pressure ball, a positioning pin, a spring, and a central axis; wherein: the upper part of the outer shell is provided with a radial bypass hole, and the lower part is provided with an inner convex edge; the positioning pin is arranged on the outer shell above the inner convex edge of the outer shell; the upper section of the ball seat is a cylindrical surface that is tightly matched with the bypass hole of the outer shell, and the lower section of the ball seat is an arc surface that is tightly matched with the pressure ball, and an upper through hole and a lower through hole are respectively arranged above and below the minimum diameter of the arc surface of the ball seat, and the upper through hole is connected to the lower through hole, and the diameter of the ball seat is smaller than the outer diameter of the pressure ball; the central axis is cylindrical, and two sections of slide grooves are axially arranged on the outer wall, the upper section of the slide groove and the positioning pin arranged on the outer shell form a limit fit, the lower section of the slide groove and the inner convex edge of the lower part of the outer shell form an annular spring groove, and the lower part of the central axis is provided with a flow hole; the spring is arranged in the spring groove; after the ball seat is connected to the central axis up and down, its outer part forms an axial sliding seal with the inner part of the outer shell; the central axis slides downward relative to the outer shell to the maximum stroke to meet the ball seat to go down to the bottom of the bypass hole.

[0006] The above solution further includes: the chute is composed of more than two W-shaped units connected in sequence to form a closed loop.

[0007] The W-shaped units of the slide groove are arranged in sequence as a long straight groove, a short straight groove, a short straight groove, and a long straight groove.

[0008] There are more than two positioning pins, and the number of the positioning pins is the same as the number of the W-shaped units of the slide groove.

[0009] There are more than two bypass holes, which are evenly distributed on the outer shell.

[0010] There are more than two flow holes on the central axis, and they are arranged on the wall of the central axis along the axial direction.

[0011] It also includes sealing devices arranged between the ball seat and the outer shell, and between the central shaft and the outer shell.

[0012] The space between the spring and the slideway is filled with lubricating oil.

[0013] Compared with the prior art, the advantages of the present invention are: it can realize the auxiliary plugging function while drilling, and can meet the technical requirements and equipment requirements of the existing drilling process. It can repeatedly put in the pressure ball, plug the leak multiple times, and switch between plugging and normal drilling operations. At the same time, the drilling switch valve also has the characteristics of simple structural design, reliable performance, and easy operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a structural schematic diagram of the drilling-while-drilling switch valve proposed by the present invention.

[0015] Figure 2 It is a schematic diagram of the matching relationship between the positioning pin and the slide groove of the drilling switch valve proposed by the present invention.

[0016] In the figure: 1-outer shell, 2-bypass hole, 3-sealing device, 4-ball seat, 5-upper through hole, 6-lower through hole, 7-sealing device, 8-pressure ball, 9-slide groove, 10-locating pin, 11-sealing device, 12-spring, 13-sealing device, 14-flow hole, 15-center axis. DETAILED DESCRIPTION

[0017] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0018] Embodiment 1:

[0019] See attached Figure 1 A drilling-while-drilling switch valve is mainly composed of an outer shell 1, a ball seat 4, a pressure ball 8, a positioning pin 10, a spring 12, and a central axis 15. Among them: the upper part of the outer shell 1 is provided with a radial bypass hole 2, and the lower part is provided with an inner convex edge; the positioning pin 10 is arranged on the outer shell 1 above the inner convex edge of the outer shell 1; the upper section of the ball seat 4 is a cylindrical surface that is tightly matched with the bypass hole 2 of the outer shell 1, and the lower section of the ball seat 4 is an arc surface that is tightly matched with the pressure ball 8. An upper through hole 5 and a lower through hole 6 are respectively arranged above and below the minimum diameter of the arc surface of the ball seat 4. The upper through hole 5 is connected to the lower through hole 6, and the diameter of the ball seat 4 is smaller than the outer diameter of the pressure ball 8; the central axis 15 is a cylindrical shape, with two sections of slide grooves 9 axially arranged on the outer wall, the upper slide groove 9 and the positioning pin 10 arranged on the outer shell 1 form a limit fit, the lower slide groove and the inner convex edge of the lower part of the outer shell 1 form an annular spring groove, and the lower part of the central axis is provided with a flow hole 14; the spring 12 is arranged in the spring groove; after the ball seat 4 and the central axis 15 are connected up and down, its outer part and the inner part of the outer shell 1 form an axial sliding seal fit; the central axis 15 slides downward relative to the outer shell 1 to the maximum stroke to meet the ball seat 4 to go down to the bottom of the bypass hole 2.

[0020] See attached Figure 2 The chute 9 is composed of two W-shaped units connected in sequence to form a closed loop. The W-shaped units of the chute 9 are arranged in sequence as long straight groove, short straight groove, short straight groove, and long straight groove.

[0021] Embodiment 2:

[0022] On the basis of the above-mentioned embodiment 1, it further includes a sealing device (3, 7, 11, 13) arranged between the ball seat 4 and the outer shell 1, and between the central axis 15 and the outer shell 1.

[0023] There are two positioning pins 10 .

[0024] There are more than two bypass holes 2, which are evenly distributed on the outer shell.

[0025] There are more than two flow holes 14 on the central axis, and they are arranged on the wall of the central axis 15 along the axial direction.

[0026] The space between the spring 12 and the slide groove 9 is filled with lubricating oil.

[0027] Embodiment 3:

[0028] See attached Figure 1 The drilling switch valve mainly consists of an outer shell 1, a bypass hole 2, a sealing device 3, a ball seat 4, an upper through hole 5, a lower through hole 6, a pressure ball 8, a slide groove 9, a positioning pin 10, a spring 12, a flow hole 14, and a center shaft 15. The center shaft 15 penetrates the inner hole of the outer shell 1, and a radial bypass hole 2 is processed on the upper part of the outer shell. The ball seat 4 is located on the upper part of the center shaft 15. Only when the center shaft 15 slides downward to the maximum position relative to the outer shell 1, the bypass hole 2 connects the inside and outside of the outer shell 1 to achieve bypass. The diameter of the ball seat 4 is smaller than the outer diameter of the pressure ball 8, and the ball seat 4 is made of elastic material. The ball seat 4 is provided with an upper through hole 5 and a lower through hole 6 above and below the smallest diameter, respectively, and the upper through hole 5 is connected to the lower through hole 6.

[0029] See attached Figure 2 The outer wall of the central shaft 15 is processed with a slide groove 9, which is in a W shape. The positioning pin 10 is installed on the outer shell 1, and the positioning pin 10 cooperates with the slide groove 9. A spring 12 is installed between the central shaft 15 and the outer shell 1, and a flow hole 14 is processed at the lower part of the central shaft 15. The sealing device 3 and the sealing device 7 are installed between the ball seat 4 and the outer shell 1, and the sealing device 11 and the sealing device 13 are installed between the central shaft 15 and the outer shell 1.

[0030] The drilling switch valve is installed in the drilling tool assembly. If there is no leakage during drilling, there is no need to throw the pressure ball 8. At this time, the drilling fluid enters the central axis 15 of the drilling switch valve, and then flows out from the flow hole 14 to the lower drilling tool assembly. At this time, the positioning pin is located at point P1 of the slide groove on the outer wall of the central axis.

[0031] If a leakage accident occurs underground, the drilling switch valve is first moved to the vicinity of the leakage formation, and then the pressure ball 8 is dropped from the wellhead. The pressure ball 8 reaches the drilling switch valve under the action of the flow of drilling fluid. When the pressure ball 8 reaches the ball seat 4, since the diameter of the ball seat 4 is smaller than the outer diameter of the pressure ball 8, the pressure ball 8 is blocked by the ball seat 4 and cannot move downward, and the pressure ball 8 closes the flow channel in the center of the ball seat 4. The drilling fluid can only pass through the upper through hole 5 and the lower through hole 6 of the ball seat 4 in turn to enter the central axis 15, and reach the lower drilling tool assembly through the flow hole 14 of the central axis 15. Since the flow cross-sections of the upper through hole 5 and the lower through hole 6 are relatively small, the drilling fluid will produce a large pressure drop when it flows and act on the pressure ball 8. As the pressure gradually increases, the pressure ball 8, the ball seat 4, and the central axis 15 move downward at the same time. Since the positioning pin 10 cooperates with the slide groove 9 on the outer wall of the central shaft 15, the central shaft 15 will rotate a certain angle while moving downward. When the positioning pin 10 is located at the P2 point of the slide groove 9, the bypass hole 2 on the outer wall of the drilling switch valve is opened. At this time, the annulus is connected to the inside of the drilling tool, and the drilling fluid carrying the plugging material enters the annulus through the bypass hole 2. Since the drilling switch valve is located near the leaking layer, the plugging material can quickly enter the leaking layer and plug the cracks.

[0032] When the plugging operation is completed, the drilling pump is turned off, the pressure of the liquid column in the drilling tool is reduced, and the pressure ball 8, the ball seat 4, and the central shaft 15 move upward under the action of the spring 12 until the positioning pin is located at the P3 point of the chute. Then the drilling pump is started again, and the pressure of the liquid column in the drilling tool gradually increases. At this time, the pressure ball 8, the ball seat 4, and the central shaft 15 move downward again until the positioning pin 10 is located at the P4 point of the chute 9. Then the pump pressure continues to increase. Since the ball seat 4 is an elastic material, as the pressure of the liquid column increases, the ball seat 4 begins to deform, and the pressure ball 8 begins to move downward under the action of the high-pressure drilling fluid. When the pressure ball 8 passes through the ball seat 4, it falls into the center shaft 15, and the ball seat 4 quickly recovers its deformation. The drilling fluid pressure inside the drilling switch valve drops rapidly, and the drilling fluid also enters the lower drilling tool assembly through the flow hole of the center shaft. At the same time, the center shaft 15 also moves upward under the action of the spring 12 until the positioning pin 10 is located at the P1 point of the chute 9 again, thus completing a drilling plugging layer operation.

[0033] If you want to seal other leaking layers, just put in another pressure ball and repeat the above process to complete the sealing operation.

[0034] The actual application results on site show that the use of the on-off valve while drilling can greatly shorten the construction period of dealing with well leakage, and the plugging construction period is shortened by an average of more than 88.6%. The use effect is very significant, which not only ensures the safety of drilling, but also saves a lot of non-drilling production cycles, greatly reduces the comprehensive cost of drilling, and greatly improves the success rate of plugging. The successful development of the on-off valve while drilling provides strong technical support for improving the drilling technology level and international market competitiveness of my country's deep wells, ultra-deep wells, and complex wells.

Claims

1. A drilling-while-drilling switch valve, mainly composed of an outer shell (1), a ball seat (4), a pressure ball (8), a positioning pin (10), a spring (12), and a center shaft (15); characterized in that: The outer shell (1) is provided with a radial bypass hole (2) at the upper part and an inner convex edge at the lower part; the positioning pin (10) is arranged on the outer shell (1) above the inner convex edge of the outer shell (1); the upper section of the ball seat (4) is a cylindrical surface that is tightly matched with the bypass hole (2) of the outer shell (1), and the lower section of the ball seat (4) is an arc surface that is tightly matched with the pressure ball (8). An upper through hole (5) and a lower through hole (6) are respectively provided above and below the minimum diameter of the arc surface of the ball seat (4), and the upper through hole (5) is connected to the lower through hole (6). The diameter of the ball seat (4) is smaller than the outer diameter of the pressure ball (8); the central axis (15) The outer wall is cylindrical and has two sections of slide grooves (9) axially arranged. The upper section of the slide groove (9) and the positioning pin (10) arranged on the outer shell (1) form a limit fit, and the lower section of the slide groove and the inner convex edge of the lower part of the outer shell (1) form an annular spring groove. The lower part of the central axis is provided with a flow hole (14); the spring (12) is arranged in the spring groove; after the ball seat (4) and the central axis (15) are connected up and down, the outer part thereof forms an axial sliding seal fit with the inner part of the outer shell (1); the central axis (15) slides downward relative to the outer shell (1) to the maximum stroke to meet the ball seat (4) to move downward to the lower part of the bypass hole (2) There are more than two bypass holes (2) evenly distributed on the outer shell; there are more than two flow holes (14) on the central axis, which are axially arranged on the wall of the central axis (15).

2. The drilling-while-drilling switch valve according to claim 1, characterized in that: The chute (9) is composed of two or more W-shaped units connected in sequence to form a closed loop.

3. The drilling-while-drilling switch valve according to claim 2, characterized in that: The W-shaped units of the slide groove (9) are arranged in sequence as a long straight groove, a short straight groove, a short straight groove, and a long straight groove.

4. The drilling-while-drilling switch valve according to claim 3, characterized in that: There are more than two positioning pins (10), and the number is the same as the number of W-shaped units of the slide groove (9).

5. The drilling-while-drilling switch valve according to any one of claims 1 to 4, characterized in that: It also includes sealing devices arranged between the ball seat (4) and the outer shell (1), and between the central axis (15) and the outer shell (1).

6. The drilling-while-drilling switch valve according to any one of claims 1 to 4, characterized in that: The space between the spring (12) and the slide groove (9) is filled with lubricating oil.

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