Reverse lifting leather cup assembly and method for controlling oil and gas wellhead pressure through leather cup assembly

Abstract

The invention discloses a reverse lifting leather cup assembly which comprises a fixing seat, a female buckle connector is arranged at the head of the fixing seat, a male buckle connector is arranged at the tail of the fixing seat, and a leather cup is arranged between the fixing seat and the male buckle connector. According to the reverse lifting leather cup assembly, the reverse lifting leather cup is adopted, emergency wellhead pressure control can be easily achieved in the middle-shallow layer drilling process or under the condition that a blowout preventer fails, performance is stable, a wellhead device is effectively simplified, the well control risk is reduced, the drilling period is shortened, and drilling efficiency is improved.

Description

Technical Field

[0001] The invention relates to a pressure control device for an oil and gas well, and more specifically to a reverse lifting cup assembly. Background Art

[0002] During shallow drilling, since there is no well control equipment installed at the wellhead, well control failures are prone to occur when encountering unexpected abnormal pressure or oil, gas and water layers. The existing method can only try to close the blowout preventer as much as possible, and then release the pressure and blowout through the choke manifold, while simultaneously using weight slurry to pressurize the well. Before the weight slurry enters the well and pressurizes it, the wellhead is basically in an out-of-control / semi-out-of-control state. Summary of the Invention

[0003] Based on this, it is necessary to provide a reverse lifting leather cup assembly to address the above technical problems.

[0004] In order to solve the above technical problems, the present invention adopts the following technical solutions: A reverse lifting leather cup assembly is characterized in that the reverse lifting leather cup assembly includes a fixing seat, a female buckle connector is provided at the head of the fixing seat, a male buckle connector is provided at the tail of the fixing seat, and a leather cup is provided between the fixing seat and the male buckle connector.

[0005] As a preferred embodiment of the present invention, the leather cup is an O-ring, and the leather cup includes a V-shaped surface, and the V-shaped surface faces the bottom of the oil and gas well.

[0006] As a preferred embodiment of the present invention, the leather cup is made of rubber, and the sealing pressure of the leather cup is generally 15MPa to 70MPa.

[0007] A method for controlling oil and gas wellhead pressure using the aforementioned reverse lifting cup assembly comprises the following steps: Step S1, connecting a reverse lifting cup assembly to a drill pipe, wherein the reverse lifting cup assembly is located above the drill bit and close to the wellhead of an oil and gas well; Step S2: When the oil and gas well overflows or encounters shallow gas, the reverse lifting cup assembly bears the downhole pressure from below, and after heavy slurry is used to kill the well, the drill is pulled out and the casing is lowered to install the wellhead casing head and the blowout preventer; Step S3: When downhole overflow occurs in the oil and gas well and the blowout preventer fails, the bottom hole pressure of the oil and gas well reaches the wellhead, and the reverse lifting leather cup assembly is pulled upward to move the reverse lifting leather cup assembly above the blowout preventer and the guide pipe, and the well is re-slurried to pressure the well. When the bottom hole pressure of the oil and gas well is controlled, the drill pipe is pulled upward, a new blowout preventer is replaced or casing is lowered to isolate the abnormal pressure layer, and normal drilling is resumed.

[0008] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides a reverse lifting leather cup assembly, which adopts a reverse lifting leather cup and can easily realize emergency wellhead pressure control during medium and shallow drilling or when the blowout preventer fails. It has stable performance, effectively simplifies the wellhead device, reduces well control risks, shortens the drilling cycle, and improves drilling efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] In order to more clearly illustrate the solutions in the present invention, a brief introduction will be given below to the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0010] Figure 1 This is a schematic structural diagram of the reverse lifting cup assembly of the present invention; Figure 2 for Figure 1 Schematic diagram of the reverse lifting cup assembly in use, when an oil and gas well overflow occurs; Figure 3 for Figure 1 Schematic diagram of the reverse lifting cup assembly in use, when the oil and gas well overflows and the blowout preventer fails. DETAILED DESCRIPTION

[0011] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0012] like Figure 1 As shown, the reverse lifting leather cup assembly 10 includes a fixing seat 1, a female buckle connector 2 is provided at the head of the fixing seat 1, a male buckle connector 3 is provided at the tail of the fixing seat 1, and a leather cup 4 is provided between the fixing seat 1 and the male buckle connector 3.

[0013] It should be noted that in Figure 1 In the figure, the threads of the female connector 2 and the male connector 3 are not shown.

[0014] In addition, the leather cup 4 is an O-ring, and includes a V-shaped surface 41, which faces the bottom of the oil and gas well. The leather cup 4 is made of rubber, and the sealing pressure of the leather cup 4 is generally 15MPa to 70MPa.

[0015] The following describes a method for controlling oil and gas wellhead pressure using a reverse lifting cup assembly, including the following steps: Step S1: Connect the reverse lifting cup assembly 10 to the drill pipe 20. The reverse lifting cup assembly 10 is located above the drill bit 30 and close to the wellhead of the oil and gas well. Step S2: Figure 2 As shown, when an oil and gas well overflows or encounters shallow gas, the reverse lifting cup assembly 10 bears the downhole pressure from below. After the well is killed by heavy slurry, the drill is pulled out and the casing 40 is lowered to install the wellhead casing head and the blowout preventer (not shown in the figure); Step S3: Figure 3 As shown, when an oil and gas well overflows and the blowout preventer 50 fails, the bottom hole pressure of the oil and gas well reaches the wellhead, and the reverse lifting leather cup assembly 10 is pulled upward, so that the reverse lifting leather cup assembly 10 moves to above the blowout preventer and the guide pipe 60, and the well is re-slurried to pressure the well. When the bottom hole pressure of the oil and gas well is controlled, the drill pipe 20 is pulled upward, a new blowout preventer is replaced or casing is lowered to isolate the abnormal pressure layer, and normal drilling is resumed.

[0016] It should be noted that in step S2, the outer wall of the leather cup 4 of the reverse lifting leather cup assembly 10 contacts the inner wall of the casing 40 and achieves sealing. Since the V-shaped surface of the leather cup 4 faces the bottom of the oil and gas well, under the action of a certain internal pressure, the V-shaped surface 41 expands outward, thereby increasing the mutual contact stress, making the fit tighter and the sealing performance better.

[0017] The reverse lifting cup assembly 10 adopts a reverse lifting cup, which can easily achieve emergency wellhead pressure control during shallow and medium drilling or when the blowout preventer fails. It has stable performance, effectively simplifies the wellhead equipment, reduces well control risks, shortens the drilling cycle, and improves drilling efficiency.

[0018] Obviously, the embodiments described above are only part of the embodiments of the present application, rather than all the embodiments. The drawings provide preferred embodiments of the present application, but do not limit the patent scope of the present application.

Claims

1. A reverse lifting cup assembly, characterized in that: The reverse lifting leather cup assembly (10) includes a fixing seat (1), a female buckle connector (2) is provided at the head of the fixing seat (1), a male buckle connector (3) is provided at the tail of the fixing seat (1), and a leather cup (4) is provided between the fixing seat (1) and the male buckle connector (3).

2. The reverse lifting cup assembly according to claim 1, characterized in that: The leather cup (4) is an O-shaped sealing ring, and the leather cup (4) includes a V-shaped surface (41), and the V-shaped surface faces the bottom of the oil and gas well.

3. The reverse lifting cup assembly according to claim 1, characterized in that: The leather cup (4) is made of rubber, and the sealing pressure of the leather cup (4) generally reaches 15MPa to 70MPa.

4. A method for controlling oil and gas wellhead pressure using the reverse lifting cup assembly as claimed in claim 1 or 3, comprising the steps of: Step S1, connecting the reverse lifting cup assembly (10) to the drill pipe, wherein the reverse lifting cup assembly (10) is located above the drill bit and close to the wellhead of the oil and gas well; Step S2: When the oil and gas well overflows or encounters shallow gas, the reverse lifting cup assembly (10) bears the downhole pressure from below, and after heavy slurry pressure is applied to the well, the drill is pulled out and the casing is lowered, and the wellhead casing head and blowout preventer are installed; Step S3: When the oil and gas well overflows and the blowout preventer fails, the bottom hole pressure of the oil and gas well reaches the wellhead, and the reverse lifting cup assembly (10) is pulled upward, so that the reverse lifting cup assembly (10) moves to the top of the blowout preventer and the guide pipe, and the well is re-slurried to pressure the well. When the bottom hole pressure of the oil and gas well is controlled, the drill pipe is pulled upward, a new blowout preventer is replaced or casing is lowered to isolate the abnormal pressure layer, and normal drilling is resumed.

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