Differential pressure type oil well oil drainage device

Abstract

The utility model discloses a differential pressure type oil well oil drainage device for oil field workover treatment. A differential pressure type oil well oil drainage device comprises an upper connector, a hole opening pipe, a shear pin and a sealing sliding sleeve, the sealing sliding sleeve and the hole opening pipe are sealed through an upper section sealing ring, a middle section sealing ring and a lower section sealing ring, and the sealing diameter of the upper section sealing ring is equal to that of the middle section sealing ring. When an oil well is put into production, the differential pressure type oil well oil drainage device is connected to the lower end of an oil pipe column. When an oil well is subjected to well repair operation, the high-pressure pump truck is used for applying pressure to liquid in the oil pipe column, and the oil drainage device is started. The interior of the oil pipe column is communicated with the annular sleeve space of the sleeve, and the purpose of oil drainage is achieved. The shear pins with corresponding diameters are selected according to different pump hanging depths, so that the pump pressure for starting the oil drainage device can be controlled within a certain range, the performance requirements of a high-pressure pump truck are met, and the safety of an oil pipe can be ensured.

Description

Technical Field

[0001] The utility model relates to an oilfield downhole tool, in particular to a differential pressure type oil well drain valve for oilfield workover operations. Background Art

[0002] Before the present utility model, when each oilfield conducts workover operations on oil wells, sometimes various drain valves are used to open holes at the lower end inside the tubing string, so that when pulling out the tubing string, the liquid inside the tubing string can be drained into the well to reduce the environmental impact on the ground. Due to the influence and limitation of many factors such as corrosion, scaling, wax deposition, eccentric wear, annulus space, annulus fluid level height, tubing internal space, and operation mode conditions in the well, there has not been a satisfactory and widely applicable hole-opening measure and method so far. Content of the Utility Model

[0003] The purpose of the present utility model is to provide a hole-opening device for the tubing string of a pumping oil well - a differential pressure type oil well drain valve for oilfield workover operations. This device is pre-installed at the lower end of the tubing string during the production of the oil well. When conducting workover operations on the oil well, a high-pressure pump truck is used to apply pressure to the liquid inside the tubing string. Under the action of high pressure, the sealing sliding sleeve sealed at the hole-opening position on the hole-opening pipe is pushed open, and the hole on the hole-opening pipe is opened, so that the inside of the tubing string communicates with the annulus space. Through this hole, when pulling out the tubing string, the liquid inside the tubing string can be drained into the oil well annulus.

[0004] The purpose of the present utility model is achieved through the following measures: The differential pressure type oil well drain valve includes an upper joint, a hole-opening pipe, shear pins, and a sealing sliding sleeve. Its characteristics are: The sealing sliding sleeve and the hole-opening pipe are sealed by an upper section sealing ring, a middle section sealing ring, and a lower section sealing ring, and the sealing diameters of the upper section sealing ring and the middle section sealing ring are equal.

[0005] This drain valve has the following characteristics:

[0006] 1. It does not change the outer diameter of the tubing string, and there is no phenomenon of getting stuck in the well when pulling out or running in the tubing string due to the installation of this drain valve.

[0007] 2. It does not affect the installation of various accessories such as centralizers inside the tubing string.

[0008] 3. It will not be damaged due to corrosion, scaling, wax deposition, eccentric wear, etc. in the well.

[0009] 4. This drain valve has no impact on the production of the oil well.

[0010] 5. During the normal production process of the oil well, the function of this drain valve is not damaged.

[0011] 6. The applied opening pump pressure is not affected by the fluid level height and pump setting depth in the annulus space.

[0012] 7. The cross-sectional area of the oil drain hole is large, and the oil drains quickly. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic structural diagram of a differential pressure type oil well drainer. SPECIFIC EMBODIMENTS

[0014] The differential pressure type oil well drainer is composed of an upper joint 1, an open-hole pipe 2, shear pins 4, and a sealing sliding sleeve 6. An upper section sealing ring 3, a middle section sealing ring 5, and a lower section sealing ring 7 are provided between the sealing sliding sleeve 6 and the open-hole pipe 2, and the sealing diameters of the upper section sealing ring 3 and the middle section sealing ring 5 are equal. A through hole K is opened on the open-hole pipe 2. The sealing sliding sleeve 6 seals the K hole, and the end face areas F1 at both ends of the sealing sliding sleeve 6 are greater than F2.

[0015] The upper joint 1 is connected to the open-hole pipe 2 by threads.

[0016] The working principle and usage method of the differential pressure type oil well drainer are as follows:

[0017] When the oil well is put into production, the differential pressure type oil well drainer is connected to the lower end of the tubing string.

[0018] When workover operations are carried out on the oil well, a high-pressure pump truck is used to apply pressure to the liquid in the tubing string. Since the pressure-bearing area F1 at both ends of the sealing sliding sleeve 6 is greater than F2, under the same pressure on both end faces (the length of the sealing sliding sleeve 6 is very different from the pump setting depth, and the pressure difference at both ends is negligible), the axial force borne by the F1 end face is greater than the axial force borne by the F2 end face, thus forcing the sealing sliding sleeve 5 to slide in the direction of the F2 end face. As the pump pressure increases, the difference between the two forces gradually increases. When the difference between the two forces is sufficient to cut off the shear pins 4, the shear pins 4 are cut off and the drainer is opened. As the sealing sliding sleeve 6 continues to slide, the K hole is opened, and the space between the tubing string and the casing annulus is communicated to achieve the purpose of oil drainage.

[0019] Since the sealing diameters of the upper section sealing ring 3 and the middle section sealing ring 5 are equal, the height of the dynamic liquid level in the oil well has no effect on the up and down movement of the sealing sliding sleeve 6, that is, whether the shear pins 4 are cut off or not only depends on the pressure in the tubing and is not affected by the height of the dynamic liquid level.

[0020] According to the different pump setting depths, shear pins 4 with corresponding diameters are selected, so that the pump pressure for opening the drainer can be controlled within a certain range, which not only meets the performance requirements of the high-pressure pump truck but also ensures the safety of the tubing.

Claims

1. Differential pressure type oil well drainer, comprising an upper joint, an open hole pipe, shear pins, and a sealing sliding sleeve, characterized in that: The sealing sliding sleeve and the perforated pipe are sealed by an upper sealing ring, a middle sealing ring, and a lower sealing ring, and the sealing diameters of the upper sealing ring and the middle sealing ring are equal.

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