Oil field produced liquid desanding device, system adopting same and system using method

Abstract

The invention discloses an oil field produced liquid desanding device which comprises an inertia desander composed of an inlet pipeline, a separation pipeline and a plurality of outlet pipelines, the other end of each outlet pipeline is fixedly connected with a cyclone desander, and the bottom end of the inertia desander and the bottom end of the cyclone desander are fixedly connected with a sand storage chamber. And the top end of the cyclone desander is fixedly connected with a gas-liquid collecting chamber. According to the desanding system, an inlet pipeline is communicated with a feeding pipeline, a flow detector, a feeding valve and a feeding pressure gauge are sequentially connected from the inlet pipeline to an inlet of the feeding pipeline, a gas-liquid collecting chamber is communicated with a discharging pipeline, and a discharging valve and a discharging pressure gauge are sequentially connected from a gas-liquid outlet to an outlet of the discharging pipeline. And the sand storage chamber is respectively connected with a flushing valve and a sand discharging valve. According to the desanding device and system for the oilfield produced liquid, the problems that in the prior art, the desanding performance cannot be adjusted according to the incoming material flow, and a cyclone desander is seriously abraded and short in service life due to large-particle-size fracturing sand are solved.

Description

Technical Field

[0001] This invention belongs to the field of multiphase separation technology of oil and gas gathering and transportation systems, and relates to a sand removal device for oilfield produced fluid, as well as a system for using the device and a method for using the system. Background Technology

[0002] In current oil production, shale oil is extracted using hydraulic fracturing with sand, which disrupts the formation structure and commonly results in sand production. This leads to the production fluid containing a large amount of sand particles, causing problems such as pipeline blockage and accelerated corrosion in the gathering and transportation system and processing equipment, while also reducing transportation efficiency. To ensure the safe and efficient operation of the shale oil extraction surface system, it is necessary to perform desanding operations on the sand-bearing production fluid produced at the wellhead.

[0003] In existing technologies, hydrocyclones combining hydrocyclones and sand storage tanks are commonly used for desanding operations. However, the hydrocyclone's desanding performance is fixed and cannot adapt to the large fluctuations in wellhead production and gas-liquid ratio during shale oil extraction. Replacing the hydrocyclone would lead to prolonged downtime and increased workload. Furthermore, the high pressure and velocity of the hydrocyclone's internal swirling field result in high workload when processing large-diameter fracturing sand in shale oil produced fluid. Large-diameter fracturing sand can severely wear down the inner wall of the hydrocyclone, reducing its service life.

[0004] To achieve efficient desanding throughout the entire shale oil extraction cycle, it is necessary to invent a desanding device that can automatically adjust its desanding performance according to the incoming material flow rate. This device can pre-separate large-diameter sand particles to reduce the workload of the hydrocyclone and has good adaptability to changes in production and gas-liquid ratio during shale oil extraction, thus ensuring the safe and efficient operation of the shale oil extraction process system. Summary of the Invention

[0005] The purpose of this invention is to provide an oilfield produced fluid desander device that solves the problems in the prior art where the desander performance cannot be adjusted according to the incoming flow rate, and where large-diameter fracturing sand causes severe wear on the inner wall of the hydrocyclone desander, reducing its service life.

[0006] The technical solution adopted in this invention includes an inlet pipe, one end of which is fixedly connected to a separation pipe, which is connected to several outlet pipes. The other end of each outlet pipe is connected to a feed pipe, and the other end of the feed pipe is fixedly connected to a desander shell. An overflow pipe is fixedly connected to the top of the desander shell and extends into the desander shell. Several horizontal guide vanes are fixedly connected to the outer wall of the overflow pipe inside the desander shell. Each horizontal guide vane spirally surrounds the outer wall of the overflow pipe and is fixedly connected to the desander shell. A limiting strip is fixedly connected between adjacent horizontal guide vanes along the circumferential direction. One side of the upper end of the limiting strip is close to the outer wall of the overflow pipe and gradually approaches the desander shell downward along the spiral direction of the horizontal guide vane.

[0007] The invention is further characterized by: A first electric valve is installed between the outlet pipe and the inlet pipe.

[0008] The outer shell of the desander includes a cylindrical section connected to the feed pipe, and a cylindrical cone section and an underflow pipe are fixedly connected to the bottom of the cylindrical section in sequence.

[0009] The overflow pipe extends only into the cylindrical section, and each horizontal guide vane is located below the connection point between the feed pipe and the cylindrical section.

[0010] Each underflow pipe and separation pipe is fixedly connected to a sand storage chamber at its bottom end. A sand level detector is fixedly connected to the outer wall of the sand storage chamber. A flushing port is opened on the outer wall of the sand storage chamber, and a sand discharge port is opened at the bottom end of the sand storage chamber. A second electric valve is installed between the underflow pipe and the sand storage chamber.

[0011] Each overflow pipe is connected to a gas-liquid collection chamber at its top, and a third electric valve is installed between the overflow pipe and the gas-liquid collection chamber. A gas-liquid outlet is opened on the outside of the gas-liquid collection chamber.

[0012] Another technical solution adopted in this invention is a desanding system using the aforementioned oilfield produced fluid desanding device. The inlet pipeline is connected to a feed pipeline, and a feed pressure gauge, a feed valve, and a flow detector are sequentially connected from the feed pipeline inlet to the inlet pipeline. The gas-liquid outlet is connected to a discharge pipeline, and a discharge valve and a discharge pressure gauge are sequentially connected from the gas-liquid outlet to the discharge pipeline outlet. A flushing valve is connected to the flushing port, and a sand discharge valve is connected to the sand discharge port.

[0013] The feed valve and feed pressure gauge are connected to the discharge valve and discharge pressure gauge via a pipeline, which is equipped with a short-circuit valve.

[0014] The sand level detector is electrically connected to the feed valve, discharge valve, flushing valve and sand discharge valve, and the flow detector is electrically connected to the first electric valve, the second electric valve and the third electric valve.

[0015] Another technical solution adopted in this invention is that the above-mentioned sand removal system is used in a manner that specifically follows these steps: Step 1: Open the feed valve and discharge valve, keep the short-circuit valve, flushing valve and sand discharge valve closed, and send the sand-containing produced fluid through the feed pipeline into the oilfield produced fluid desanding device for desanding. Step 2: After sand removal is completed, the liquid enters the discharge pipe through the gas-liquid outlet on the gas-liquid collection chamber, and then the liquid is discharged. Step 3: When the sand particles in the sand storage chamber reach the height specified by the sand level detector, the sand level detector controls the feed valve and discharge valve to close and stop the sand removal operation, while opening the flushing valve and sand discharge valve to clean the inside of the sand storage chamber. Step 4: After the sand level detector detects that the sand particles in the sand storage chamber have been discharged, the sand level detector closes the flushing valve and the sand discharge valve, and controls the opening of the feed valve and the discharge valve to carry out the next round of sand removal operation.

[0016] Beneficial effects: 1. The oilfield produced fluid desanding device of the present invention adopts a two-stage separation method of inertial desanding + cyclone desanding. Large-diameter sand particles are removed in the tubular inertial desander, which effectively reduces the working intensity of the cyclone desander and reduces the impact wear of large-diameter sand particles on the inner wall of the cyclone desander, thereby extending the service life of the desanding equipment.

[0017] 2. In the desanding system of the present invention, multiple sets of hydrocyclone desanders are arranged in parallel. The electric valve can be automatically controlled to switch on and off according to the incoming material flow rate, thereby changing the number of hydrocyclone desanders participating in the desanding operation. This ensures that each hydrocyclone desander is in the high-efficiency desanding operation flow range, so as to adapt to the production characteristics of large fluctuations in wellhead production and gas-liquid ratio during shale oil extraction. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the tubular inertial sand separator in this invention; Figure 2 This is a schematic diagram of the cyclone sand separator in this invention; Figure 3 This is a schematic diagram of the overflow pipe, horizontal guide vane, and limiting strip in this invention; Figure 4 This is a schematic diagram of the desanding device for oilfield produced fluid in this invention; Figure 5 This is a schematic diagram of the sand storage chamber in this invention; Figure 6 This is a schematic diagram of the gas-liquid collection chamber in this invention; Figure 7 This is a schematic diagram of the sand removal system in this invention.

[0019] In the diagram: 1. Inlet pipe; 2. Separation pipe; 3. Outlet pipe; 4. First electric valve; 41. Feed pipe; 42. Sand separator shell; 421. Cylindrical section; 422. Conical section; 423. Underflow pipe; 43. Overflow pipe; 44. Horizontal guide vane; 45. Limiting strip; 5. Second electric valve; 6. Sand storage chamber; 61. Sand level detector; 62. Flushing port; 63. Sand discharge port; 7. Gas-liquid collection chamber; 71. Gas-liquid outlet; 8. Incoming material pipe; 9. Flow detector; 10. Feed valve; 11. Feed pressure gauge; 12. Discharge pipe; 13. Discharge valve; 14. Discharge pressure gauge; 15. Short-circuit valve; 16. Flushing valve; 17. Sand discharge valve; 18. Third electric valve. Detailed Implementation

[0020] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0021] Example 1: The oilfield produced fluid desander removal device of the present invention is implemented according to the following structure: like Figure 1 and Figure 2 As shown, it includes an inlet pipe 1, one end of which is fixedly connected to a separation pipe 2, and the separation pipe 2 is connected to several outlet pipes 3. The other end of each outlet pipe 3 is connected to a feed pipe 41.

[0022] The inlet pipe 1, the separation pipe 2, and the outlet pipe 3 form a tubular inertial desander. When the oilfield produced fluid falls in the separation pipe 2, the sand storage chamber 6 connected below the separation pipe 2 is closed. Therefore, under the action of pressure, the liquid and gas in the produced fluid cannot move downward and can only flow towards the outlet pipe 3 where the pressure is low. At the same time, the smaller sand particles in the liquid, due to their small mass and low inertia, follow the liquid flow to the outlet pipe 3 under the action of fluid drag. The larger sand particles, due to their large mass and high inertia, are difficult to change their direction of movement and therefore fall into the sand storage chamber 6, thus completing the separation of large sand particles.

[0023] like Figure 2 and Figure 3 As shown, the other end of the feed pipe 41 is fixedly connected to the desander housing 42. The top of the desander housing 42 is fixedly connected to the overflow pipe 43, which extends into the desander housing 42. Several horizontal guide vanes 44 are fixedly connected to the outer wall of the overflow pipe 43 inside the desander housing 42. Each horizontal guide vane 44 spirally wraps around the outer wall of the overflow pipe 43 and is fixedly connected to the desander housing 42. A limiting strip 45 is fixedly connected between adjacent horizontal guide vanes 44 along the circumferential direction. One side of the upper end of the limiting strip 45 is close to the outer wall of the overflow pipe 43 and gradually approaches the desander housing 42 downward along the spiral direction of the horizontal guide vane 44. Two adjacent horizontal guide vanes 44 form a spiral pipe around the overflow pipe 43. The diameter of the spiral pipe formed by the horizontal guide vanes 44 gradually decreases due to the setting of the limiting strip 45.

[0024] The feed pipe 41, the desander shell 42, the overflow pipe 43, the limiting strip 45, and the horizontal guide vane 44 constitute a cyclone desander. As the produced fluid passes through the spiral pipe formed by the limiting strip 45 and the horizontal guide vane 44, the flow velocity of the produced fluid gradually increases due to the gradually decreasing pipe diameter. The high-speed produced fluid is ejected from the spiral pipe and rotates along the inner wall of the cylindrical section 421, moving downwards under gravity. When the produced fluid reaches the conical section 422 of the cylindrical section, due to the different densities of the solids, liquids, and gases in the produced fluid, under the action of centrifugal force and centripetal force, the order from the inner wall of the conical section 422 towards the center is solid, liquid, and gas, with lower pressure at the center. The denser solids move downwards along the wall under gravity and are eventually discharged through the underflow port. Liquids and gases with lower densities cannot be discharged from the bottom outlet because the bottom outlet pipe 423 is closed. However, because the overflow pipe 43 is in a low-pressure area, the liquids and gases move towards the overflow pipe under the action of pressure difference, exhibiting an upward rotating motion, and are discharged from the overflow pipe 43.

[0025] Example 2: Based on Example 1: like Figure 4 As shown, a first electric valve 4 is installed between the outlet pipe 3 and the feed pipe 41.

[0026] like Figure 2 As shown, the desander housing 42 includes a cylindrical section 421 connected to the feed pipe 41. A cylindrical conical section 422 and an underflow pipe 423 are fixedly connected below the cylindrical section 421 in sequence. The cylindrical conical section 422 is used to accelerate the velocity of the fluid therein, thereby enhancing the centrifugal force and further separating different substances in the mixture. At the same time, it can also stabilize the low-pressure area near the central axis.

[0027] like Figure 2 As shown, the overflow pipe 43 extends only into the cylindrical section 421, and each horizontal guide vane 44 is located below the connection between the feed pipe 41 and the cylindrical section 421, ensuring that the produced fluid can enter multiple spiral pipes for acceleration and increase the rotation speed of the produced fluid.

[0028] like Figure 4 and Figure 5 As shown, each underflow pipe 423 and the bottom end of the separation pipe 2 are fixedly connected to a sand storage chamber 6. A sand level detector 61 is fixedly connected to the outer wall of the sand storage chamber 6. At the same time, a flushing port 62 is opened on the outer wall of the sand storage chamber 6, and a sand discharge port 63 is opened at the bottom end of the sand storage chamber 6. A second electric valve 5 is provided between the underflow pipe 423 and the sand storage chamber 6.

[0029] like Figure 4 and Figure 6As shown, each overflow pipe 43 is connected to a gas-liquid collection chamber 7 at its top end via an electric valve 5, and a third electric valve 18 is provided between the overflow pipe 43 and the gas-liquid collection chamber 7. A gas-liquid outlet 71 is provided on the outside of the gas-liquid collection chamber 7.

[0030] The number of cyclone desanders participating in the desandering operation can be adjusted by regulating the opening and closing of the first electric valve 4, the second electric valve 5, and the third electric valve 18, in order to adapt to the production characteristics of large fluctuations in wellhead production and gas-liquid ratio during shale oil extraction.

[0031] In typical oilfield produced fluid desandering systems, a single hydrocyclone desander is usually used to treat the produced fluid. However, due to the high pressure and velocity of the high-speed rotating liquid within the hydrocyclone, large-diameter sand particles can severely abrade the inner wall of the hydrocyclone, reducing its service life. To address this issue, the oilfield produced fluid desandering system proposed in this application incorporates a two-stage separation system: an inertial desander and a hydrocyclone desander. First, large-diameter sand particles in the produced fluid are pre-separated in the inertial desander. Then, the pre-separated produced fluid is fed into the hydrocyclone desander for secondary desandering, preventing large-diameter sand particles from damaging the hydrocyclone desander. Meanwhile, since the liquid flow rate in the inertial desander should not be too high, otherwise the oilfield produced fluid may fall into the sand storage chamber 6 along with large-diameter sand particles. The cyclone desander requires the initial separated produced fluid to rotate at high speed to achieve the desanding effect. Therefore, this application sets up a spiral pipe with a gradually decreasing diameter to accelerate the initial separation of produced fluid and meet the operating requirements of this device.

[0032] Example 3: The desanding system of the oilfield produced fluid desanding device described in Examples 1 and 2 is implemented according to the following structure: like Figure 4 , Figure 6 and Figure 7 As shown, the inlet pipe 1 is connected to the incoming material pipe 8. From the incoming material pipe 8 to the inlet pipe 1, the inlet pressure gauge 11, the inlet valve 10, and the flow detector 9 are connected in sequence. The gas-liquid outlet 71 is connected to the outlet pipe 12. From the gas-liquid outlet 71 to the outlet of the outlet pipe 12, the outlet valve 13 and the outlet pressure gauge 14 are connected in sequence. The flushing port 62 is connected to the flushing valve 16, and the sand discharge port 63 is connected to the sand discharge valve 17.

[0033] The feed pressure gauge 11 and the discharge pressure gauge 14 are used to measure the pressure of the oilfield produced fluid before and after desanding. The pressure difference between the two can be used to assess the operating status of the system and facilitate timely maintenance.

[0034] Example 4: Based on Example 3: like Figure 7As shown, the feed valve 10 and the feed pressure gauge 11 are connected to the discharge valve 13 and the discharge pressure gauge 14 through a pipeline, and a short-circuit valve 15 is installed on the pipeline.

[0035] By setting up the short-circuit valve 15, the incoming pipeline 8 and the outgoing pipeline 12 can be short-circuited when the oilfield produced fluid desander device malfunctions, so that the oilfield produced fluid desander device does not participate in the desander removal work, which facilitates the maintenance of the device.

[0036] The sand level detector 61 is electrically connected to the feed valve 10, the discharge valve 13, the flushing valve 16 and the sand discharge valve 17, and the flow detector 9 is electrically connected to the first electric valve 4, the second electric valve 5 and the third electric valve 18.

[0037] The flow detector 9 can adjust the number of cyclone desanders participating in the desandering work in real time according to the oilfield produced fluid entering the system, thereby changing the performance of the desandering device, reducing manual operation, and lowering the maintenance cost of the device.

[0038] The sand content in the sand storage chamber 6 is detected by the sand level detector 61, and the sand is discharged by adjusting the opening and closing of the feed valve 10, discharge valve 13, flushing valve 16 and sand discharge valve 17 when the sand is stored to a specified amount. The whole sand discharge process is automated and does not require manual operation, which reduces the operating cost of the system.

[0039] In typical desanding systems, multiple hydrocyclones work with the sand storage chamber 6 to remove sand. However, during shale oil extraction, the wellhead production and gas-liquid ratio of the produced fluid fluctuate greatly. Existing desanding systems cannot adjust the number of hydrocyclones involved in operation based on wellhead production, increasing unnecessary equipment wear and tear and reducing the effectiveness of hydrocyclone desanding. The aforementioned desanding system, through the coordinated operation of the electric valve 5 and the flow detector 9, can automatically adjust the number of hydrocyclones operating according to the incoming material flow rate. Simultaneously, the sand level detector 61 detects the sand content in the sand storage chamber 6, thereby achieving automatic sand discharge. This reduces manual operation throughout the process, improves the service life and desanding efficiency of the hydrocyclones, and lowers the system's operating costs.

[0040] The above-mentioned sand removal system operates according to the following steps: When performing sand removal operations: Step 1: Open the feed valve 10 and the discharge valve 13, and keep the short-circuit valve 15, flushing valve 16 and sand discharge valve 17 closed. Send the sand-laden produced fluid into the oilfield produced fluid desander through the feed pipeline 8. When the sand-laden produced fluid passes through the flow detector 9, the flow detector 9 adjusts the opening and closing of each electric valve 5 according to the feed flow rate, and adjusts the number of cyclone desanders participating in the desander removal. Step 2: The sand-laden produced fluid enters the separation pipeline 2 through the inlet pipeline 1. When the sand-laden produced fluid falls in the separation pipeline 2, the larger sand particles continue to fall into the sand storage chamber 6 due to inertia, while the liquid, gas and smaller sand particles in the sand-laden produced fluid are discharged from the outlet pipeline 3 under pressure and enter the hydrocyclone desander through the feed pipe 41. Step 3: After the initial separation produced fluid enters the hydrocyclone desander, it flows into the spiral pipe composed of the horizontal guide vane 44 and the limiting strip 45 under the action of gravity. The flow rate of the initial separation produced fluid is increased through the spiral pipe with a gradually decreasing diameter. Step 4: After the initial separation produced fluid is discharged from the spiral pipe, it rotates at high speed along the inner wall of the cylindrical section 421 and the conical section 422 of the cylinder, causing the low-density gas and liquid in the initial separation produced fluid to rise and enter the gas-liquid collection chamber 7 through the overflow pipe 43, while the high-density sand particles move downward and enter the sand storage chamber 6 through the sand discharge port 63. Step 5: After the liquid enters the gas-liquid collection chamber 7, it enters the discharge pipe 12 from the gas-liquid outlet 71 and then the liquid is discharged. Step 6: When the sand particles in the sand storage chamber 6 reach the specified height of the sand level detector 61, the sand level detector 61 controls the feed valve 10 and the discharge valve 13 to close, and opens the flushing valve 16 and the sand discharge valve 17. Water flows into the sand storage chamber 6 through the flushing valve 16, causing the sand particles in the sand storage chamber 6 to form sand-containing wastewater which is discharged through the sand discharge port 63. Step 7: After the sand particles in the sand storage chamber 6 have been discharged, the sand level detector 61 controls the feed valve 10 and the discharge valve 13 to open, and closes the flushing valve 16 and the sand discharge valve 17 to carry out the next round of sand removal operation.

[0041] When the desander removal system of the oilfield produced fluid needs maintenance: Open the short-circuit valve 15 to connect the incoming material pipeline 8 and the outgoing material pipeline 12, so that the oilfield produced fluid desander does not participate in the desandering process, and the equipment can be maintained.

Claims

1. A desander removal device for oilfield produced fluid, characterized in that, Includes an inlet pipe (1), one end of which is fixedly connected to a separation pipe (2), the separation pipe (2) being connected to several outlet pipes (3), the other end of each outlet pipe (3) being connected to a feed pipe (41), the other end of which is fixedly connected to a desander housing (42), the top of which is fixedly connected to an overflow pipe (43), and the overflow pipe (43) extending into the desander housing (42). 43) Several horizontal guide vanes (44) are fixedly connected to the outer wall inside the desander housing (42). Each horizontal guide vane (44) is spirally wrapped around the outer wall of the overflow pipe (43) and fixedly connected to the desander housing (42). A limiting strip (45) is fixedly connected between adjacent horizontal guide vanes (44) along the circumferential direction. One side of the upper end of the limiting strip (45) is close to the outer wall of the overflow pipe (43) and gradually approaches the desander housing (42) downward along the spiral direction of the horizontal guide vane (44).

2. The oilfield produced fluid desander device according to claim 1, characterized in that, A first electric valve (4) is provided between the outlet pipe (3) and the feed pipe (41).

3. The oilfield produced fluid desander removal device according to claim 1, characterized in that, The outer shell (42) of the desander includes a cylindrical section (421) that communicates with the feed pipe (41), and a cylindrical cone section (422) and an underflow pipe (423) are fixedly connected below the cylindrical section (421).

4. The oilfield produced fluid desander device according to claim 3, characterized in that, The overflow pipe (43) extends only into the cylindrical section (421), and each horizontal guide vane (44) is located below the connection position between the feed pipe (41) and the cylindrical section (421).

5. The oilfield produced fluid desander device according to claim 3, characterized in that, Each underflow pipe (423) and separation pipe (2) is fixedly connected to a sand storage chamber (6) at its bottom end. A sand level detector (61) is fixedly connected to the outer wall of the sand storage chamber (6). A flushing port (62) is opened on the outer wall of the sand storage chamber (6). A sand discharge port (63) is opened at the bottom end of the sand storage chamber (6). A second electric valve (5) is provided between the underflow pipe (423) and the sand storage chamber (6).

6. The oilfield produced fluid desander removal device according to claim 1, characterized in that, Each overflow pipe (43) is connected to a gas-liquid collection chamber (7) at its top end, and a third electric valve (18) is provided between the overflow pipe (43) and the gas-liquid collection chamber (7). A gas-liquid outlet (71) is provided on the outside of the gas-liquid collection chamber (7).

7. A desandering system using the oilfield produced fluid desandering device according to claims 1-6, characterized in that, The inlet pipe (1) is connected to the feed pipe (8). The feed pipe (8) is connected in sequence from the inlet of the feed pipe (8) to the inlet pipe (1) with a feed pressure gauge (11), a feed valve (10) and a flow detector (9). The gas-liquid outlet (71) is connected to the discharge pipe (12). The discharge pipe (12) is connected in sequence from the gas-liquid outlet (71) to the outlet of the discharge pipe (12) with a discharge valve (13) and a discharge pressure gauge (14). The flushing port (62) is connected to a flushing valve (16). The sand discharge port (63) is connected to a sand discharge valve (17).

8. The sand removal system according to claim 7, characterized in that, The feed valve (10) and the feed pressure gauge (11) are connected to the discharge valve (13) and the discharge pressure gauge (14) through a pipeline, and a short-circuit valve (15) is provided on the pipeline.

9. The sand removal system according to claim 7, characterized in that, The sand level detector (61) is electrically connected to the feed valve (10), discharge valve (13), flushing valve (16) and sand discharge valve (17), and the flow detector (9) is electrically connected to the first electric valve (4), the second electric valve (5) and the third electric valve (18).

10. A sand removal method using the sand removal system according to claims 7-8, characterized in that, The specific steps are as follows: Step 1: Open the feed valve (10) and discharge valve (13), keep the short-circuit valve (15), flushing valve (16) and sand discharge valve (17) closed, and send the sand-containing produced fluid into the oilfield produced fluid desanding device through the feed pipe (8) for desanding. Step 2: After the sand removal is completed, the liquid enters the discharge pipe (12) through the gas-liquid outlet (71) on the gas-liquid collection chamber (7), and then the liquid is discharged, while the sand particles fall into the sand storage chamber (6). Step 3: When the sand particles in the sand storage chamber (6) reach the height specified by the sand level detector (61), the sand level detector (61) controls the feed valve (10) and discharge valve (13) to close and stop the sand removal operation, and at the same time opens the flushing valve (16) and the sand discharge valve (17) to clean the inside of the sand storage chamber (6); Step 4: When the sand level detector (61) detects that the sand particles in the sand storage chamber (6) have been discharged, the sand level detector (61) closes the flushing valve (16) and the sand discharge valve (17), and controls the feed valve (10) and the discharge valve (13) to open, and carry out the next round of sand removal operation.

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