Check valve for water injection well in oil field

Abstract

The invention provides a check valve for a water injection well of an oil field. The check valve comprises a valve body. A guiding plate, an anti-sand valve core, a movable valve seat and an anti-scale valve core are successively arranged in the valve body. The outer diameter of the anti-sand valve core and the outer diameter of the anti-scale valve core are smaller than the outer diameter of the movable valve seat. A guiding hole is arranged in the middle part of the guiding plate. A water outlet flow pass is arranged on the periphery of the guiding plate. Two water inlet flow passes are respectively arranged in the middle parts of the movable valve seat and of the anti-scale valve core. The left end of the anti-sand valve core is in sliding fit with the guiding hole. The right end of the anti-sand valve core is in sliding fit with the movable valve seat and used for opening or closing a radial through hole in the left end of the movable valve seat. The left end of the anti-scale valve core is fixedly connected with the movable valve core and the right end of the anti-scale vale core can cooperate with the valve body. A spring is arranged between the movable valve seat and the valve body, and sleeves the outer side of the anti-scale valve core. Dual-end guiding is adopted on the anti-sand valve core, so return precision is increased and effects of sand in returning water in stratum can be avoided. The contact pressure of a sealing face of the anti-scale valve core is big, so affects of scale deposit of the sealing face are avoided.

Description

technical field [0001] The invention relates to a check valve, in particular to a check valve for an oilfield water injection well. Background technique [0002] In the process of oil and gas development in an oil field, in order to control the rate of formation energy decline and stabilize crude oil production, high-pressure water injection into the formation is the main way to supplement the formation energy. Since the equipment or supporting devices in the high-pressure water injection system need to be shut down for regular maintenance or troubleshooting, the water injection pressure often fluctuates. In this way, the high-pressure water energy of the water injection formation will flow back to the pipe network under the action of the pressure difference of the pipe network, causing the formation water to leak. out, the pressure returns, and energy is lost. At the same time, a large amount of high-pressure water backflow will drive the sand particles out of the well, wh...

AI Technical Summary

Problems solved by technology

[0004] 1. The reliability of the one-way cut-off is poor: due to the poor return of the valve 3, the working surface is impacted and deformed, resulting in poor sealing between the valve 3 and the valve seat 4, and the spring 2 is easily damaged, and the valve 3 cannot be reset, which often occurs function failure;

[0005] 2. Poor sealing performance: The metal contact seal between the valve seat 3 and the valve seat 4 requires high tolerance precision of the parts, and most of the check valves have leakage during use;

[0006] 3. Large process resistance: spring 2 drives valve 3 to return to valve seat 4. The spring resistance is large. During normal operation of the process, a certain pressure is required to push open valve valve 3. There is a considerable pressure here. Part of the pressure loss;

[0007] 4. Under the influence of sand particles, the one-way cut-off function is lost, and the sealing surface is damaged after cleaning, and the seal is not tight;

[0008] 5. Affected by the fouling of the medium, the movement of the valve parts is blocked, and the sealing function of the sealing surface fails, resulting in the failure of the check valve to work

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