A multi-stage circulating filtration and purification system for well killing fluid

Abstract

This invention discloses a multi-stage circulating filtration and purification system for well control fluid, relating to the field of water treatment technology. It aims to solve the technical problem of insufficient effectiveness of single-method filtration in reusing well control fluids collected under different conditions. The system includes a control pump located at the output end of an initial filtration treatment tank; a primary filtration mechanism is installed at the output end of the control pump; and a secondary filtration mechanism is connected to one of the output ends of the primary filtration mechanism via a control valve. Based on the primary and secondary filtration mechanisms, this invention creates a graded filtration system for well control fluid, achieving targeted operation by performing primary filtration, secondary fine filtration, and tertiary ultrafiltration on well control fluids used in different oil wells. This results in well control fluids filtered by the multi-stage circulating filtration and purification system having adaptability characteristics, meeting the operational needs of different oil wells.

Description

Technical Field

[0001] This invention relates to the field of water treatment technology, and more specifically, to a multi-stage circulating filtration and purification system for well control fluid. Background Technology

[0002] Kill fluid, a major component of oilfield wastewater, is a crucial fluid used to maintain wellbore pressure balance during oil drilling. It is primarily composed of water-based or oil-based liquids, clay, weighting agents, and chemical additives. After drilling operations are completed, the kill fluid becomes highly polluting wastewater due to the mixing of mud, sand, oil, heavy metals, and chemicals.

[0003] Currently, the frequency of well workover operations is increasing in the mid-to-late stages of oilfield development, leading to a significant rise in the consumption of kill fluid. The average cost per well for high-density kill fluid (above 1.20 g / cm³) reaches 91,100 yuan, with total annual costs exceeding 4.55 million yuan. Traditional kill fluid usage suffers from problems such as significant waste from single-use applications, improper recycling and disposal, and difficulty in precise mixing due to mixed storage.

[0004] Existing multi-stage circulating filtration and purification systems for well control fluids mostly rely on single-stage filtration. However, different oil wells have different impurity contents in their well control fluids. Conventional filtration often results in either insufficient or excessive filtration, increasing costs. Therefore, it is particularly important to develop a multi-stage filtration and purification system. In view of this, we propose a multi-stage circulating filtration and purification system for well control fluids. Summary of the Invention

[0005] The purpose of this invention is to provide a multi-stage circulating filtration and purification system for well control fluid, in order to solve the technical problem that a single filtration method is insufficient for the reuse of well control fluid collected under different conditions when treating oilfield wastewater.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a multi-stage circulating filtration and purification system for well control fluid, comprising a control pump arranged at the output end of the initial filtration treatment tank; a primary filtration treatment mechanism is provided at the output end of the control pump; a secondary filtration treatment mechanism is provided at one output end of the primary filtration treatment mechanism via a control valve; a filtered liquid phase storage mechanism is provided on one side of the secondary filtration treatment mechanism; the filtered liquid phase storage mechanism includes a graded storage tank; the interior of the graded storage tank is provided with a primary temporary storage chamber, an insufficient filtration temporary storage chamber, and a classified storage chamber arranged sequentially from top to bottom; wherein, at least two primary temporary storage chambers and classified storage chambers are provided; wherein a safety mechanism is provided at the top of the primary temporary storage chamber; and a manifold pipe connected to the insufficient filtration temporary storage chamber is provided at the top of each primary temporary storage chamber; and a siphon pipe is provided on the side of the primary temporary storage chamber; the siphon pipe is connected to the classified storage chamber; wherein both the primary and secondary filtration treatment mechanisms have normal pressure and abnormal pressure states.

[0007] This invention, based on a primary and secondary filtration system, creates a multi-stage circulating filtration and purification system for well fluid, employing a graded filtration approach. By performing primary filtration, first-stage filtration, second-stage fine filtration, and third-stage ultrafiltration on the kill fluid used in different oil wells, targeted operations are achieved. This results in a kill fluid with adaptability that meets the operational needs of different oil wells.

[0008] Preferably, the primary filtration mechanism includes a primary filtration tank; the primary filtration tank is equipped with a plurality of bag filters; wherein the output end of the control pump is connected to the input end of the bag filters.

[0009] Preferably, the secondary filtration mechanism includes a secondary filtration tank arranged on one side of the primary filtration tank; the secondary filtration tank is provided with a plurality of fine filters.

[0010] Preferably, the top of the graded storage tank is provided with a threaded seat relative to the primary temporary storage cavity; a guide sleeve is provided on the side of the threaded seat; wherein, the top of the graded storage tank is also provided with an adaptive one-way engagement mechanism; the adaptive one-way engagement mechanism and the safety mechanism are in a movable engagement connection.

[0011] Preferably, the input end of the safety mechanism is connected to the bottom output ends of the primary and secondary treatment filter tanks via a control valve and a connecting pipe A; the safety mechanism includes a pressure-boosting movable bushing passing through the threaded seat; wherein, a one-way meshing ratchet is provided on one side of the pressure-boosting movable bushing; the pressure-boosting movable bushing is movably connected to the output end of the connecting pipe A; and, at least one diversion hole is provided at the bottom of the pressure-boosting movable bushing; wherein, a driven sleeve is provided at the bottom of the pressure-boosting movable bushing; and, the driven sleeve is movably connected to the siphon pipe; a support seat is screwed onto the threaded seat; the support seat is elastically connected to the pressure-boosting movable bushing via a pressure-holding spring.

[0012] Preferably, the adaptive one-way meshing mechanism includes a connecting shaft fixed to the top of the graded storage tank; connecting arms are sequentially arranged on the connecting shaft from top to bottom via hinged bushings; wherein only the hinged bushing at the top is movably connected to the connecting shaft; meshing racks are respectively arranged on both sides of the connecting shaft; the meshing racks are hinged to the connecting arms; a threaded adjusting shaft is arranged at the top of the connecting shaft; the threaded adjusting shaft is elastically connected to the hinged bushing at the top via a tension spring; wherein the meshing racks and the one-way meshing ratchets are shape-matched, and the convex angle between the meshing racks and the one-way meshing ratchets is less than 90°.

[0013] Preferably, under normal pressure conditions, the pressure-boosting movable bushing is positioned by the support of the pressure-holding spring, causing the primary temporary storage chamber to be connected to the classified storage chamber through a siphon pipe to form an independent diversion storage structure.

[0014] Preferably, under abnormal pressurization conditions of the primary and secondary filtration mechanisms, the pressurization movable sleeve moves downward due to the increase in pressure, causing the driven sleeve to descend synchronously, thereby closing the siphon pipe inlet and forming a circulating confluence structure.

[0015] Compared with the prior art, the beneficial effects of the present invention are:

[0016] 1. The present invention is based on a primary filtration mechanism and a secondary filtration mechanism, which enables the well fluid multi-stage circulation filtration and purification system to form a graded filtration mode. By performing primary filtration, primary filtration, secondary fine filtration and tertiary ultrafiltration on the kill fluid used in different oil wells, targeted operation is achieved. As a result, the kill fluid filtered by the multi-stage circulation filtration and purification system has adaptability characteristics and meets the needs of different oil well operations.

[0017] 2. This invention is based on the treatment of the connecting pipe A and the movable sleeve of the pressure boosting device. Under the elastic force of the pressure holding spring, the movable sleeve of the pressure boosting device remains stationary during the normal well kill fluid transportation process. In abnormal conditions, such as the filter material being damaged due to improper use, causing the pressure in the filtration system to increase, the movable sleeve of the pressure boosting device will descend. This setting is used to store the normally filtered well kill fluid in a general manner and to perform isolation and reflux filtration of the insufficiently filtered well kill fluid.

[0018] 3. This invention utilizes the elastic force of a tension spring to cause the upper hinged bushing to slide downwards. This, combined with the parallel structure of the meshing rack and connecting shaft, causes the meshing rack to unfold, allowing it to contact a one-way ratchet. The angle between the meshing rack and the one-way ratchet is less than 90°, and the inclined surface, combined with the compressibility of the tension spring, allows the one-way ratchet and the pressurized movable bushing to slide downwards without naturally returning to their original position, forming a linear one-way ratchet structure. This method enables the switching between storing conventionally filtered or insufficiently filtered kill fluid in different filtration and delivery states, reducing contamination of previously filtered kill fluid. Furthermore, based on the primary temporary storage chamber, insufficiently filtered kill fluid caused by time differences during the switching process of the multi-stage circulating filtration and purification system flows in for temporary storage. Delayed confluence storage prevents insufficiently filtered kill fluid from flowing into the classified storage chamber. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall three-dimensional structure of the present invention;

[0020] Figure 2 This is a cross-sectional three-dimensional structural diagram of the primary filtration mechanism and the secondary filtration mechanism of the present invention.

[0021] Figure 3 This is a three-dimensional cross-sectional structural diagram of the graded storage tank of the present invention;

[0022] Figure 4 This is a three-dimensional structural diagram of the graded storage tank of the present invention;

[0023] Figure 5 This is a three-dimensional structural diagram of the adaptive unidirectional meshing mechanism of the present invention;

[0024] Figure 6 This is a three-dimensional structural diagram of the insurance institution of the present invention;

[0025] Figure 7 For the present invention Figure 6 A magnified schematic diagram of the structure at point A in the middle.

[0026] Explanation of the labels in the diagram:

[0027] 1. Control pump; 2. Primary filtration system; 3. Secondary filtration system; 4. Filter liquid storage system; 5. Staged storage tank; 6. Safety mechanism; 7. Manifold; 8. Siphon system; 10. Adaptive one-way engagement mechanism;

[0028] 201. Primary treatment filter tank; 202. Bag filter; 301. Secondary treatment filter tank; 302. Fine filter;

[0029] 501, Primary storage chamber; 502, Insufficient filtration storage chamber; 503, Classification storage chamber; 505, Threaded seat; 5051, Guide sleeve;

[0030] 601, Pressure-boosting movable bushing; 6011, Diverter hole; 6012, Driven sleeve; 6013, One-way meshing ratchet; 602, Support seat; 603, Pressure-holding spring;

[0031] 1001, Connecting shaft; 1002, Connecting arm; 1003, Meshing rack; 1004, Threaded adjusting shaft; 1006, Tensioning spring. Detailed Implementation

[0032] like Figures 1 to 7 As shown, the present invention relates to a multi-stage circulating filtration and purification system for well control fluid, comprising a control pump 1 arranged at the output end of the initial filtration treatment tank; a primary filtration treatment mechanism 2 is provided at the output end of the control pump 1; a secondary filtration treatment mechanism 3 is provided at one output end of the primary filtration treatment mechanism 2 via a control valve; a filtered liquid phase storage mechanism 4 is provided on one side of the secondary filtration treatment mechanism 3; the filtered liquid phase storage mechanism 4 includes a graded storage tank 5; the graded storage tank 5 is provided with a primary temporary storage chamber 501, an insufficient filtration temporary storage chamber 501, and an incomplete filtration temporary storage chamber 502, arranged sequentially from top to bottom inside the primary storage tank 501. The system includes a storage chamber 502 and a classification storage chamber 503; at least two primary temporary storage chambers 501 and classification storage chambers 503 are provided; a safety mechanism 6 is provided at the top of the primary temporary storage chamber 501; and a manifold pipe 7 connected to the insufficiently filtered temporary storage chamber 502 is provided at the top of each primary temporary storage chamber 501; a siphon pipe 8 is provided on the side of the primary temporary storage chamber 501; the siphon pipe 8 is connected to the classification storage chamber 503; both the primary filtration mechanism 2 and the secondary filtration mechanism 3 have normal pressure and abnormal pressure states. This invention, based on the primary filtration mechanism 2 and the secondary filtration mechanism 3, enables the multi-stage circulating filtration and purification system of well fluid to form a graded filtration mode. By performing primary filtration, primary filtration, secondary fine filtration, and tertiary ultrafiltration on the kill fluid used in different oil wells, targeted operations are achieved, resulting in a kill fluid with adaptability characteristics that meets the operational needs of different oil wells.

[0033] In an embodiment of the present invention, the primary filtration treatment mechanism 2 includes a primary filtration tank 201; a plurality of bag filters 202 are disposed inside the primary filtration tank 201; wherein, the output end of the control pump 1 is connected to the input end of the bag filter 202.

[0034] In an embodiment of the present invention, the secondary filtration mechanism 3 includes a secondary filtration tank 301 arranged on one side of the primary filtration tank 201; the secondary filtration tank 301 is provided with a plurality of fine filters 302.

[0035] In an embodiment of the present invention, a threaded seat 505 is provided on the top of the graded storage tank 5 at a position relative to the primary temporary storage cavity 501; a guide sleeve 5051 is provided on the side of the threaded seat 505; wherein, an adaptive one-way engagement mechanism 10 is also provided on the top of the graded storage tank 5; the adaptive one-way engagement mechanism 10 and the safety mechanism 6 are in a movable engagement connection.

[0036] In an embodiment of the present invention, the input end of the safety mechanism 6 is connected to the bottom output ends of the primary treatment filter tank 201 and the secondary treatment filter tank 301 via a control valve and a connecting pipe A; the safety mechanism 6 includes a pressure-boosting movable bushing 601 passing through a threaded seat 505; wherein, a one-way meshing ratchet 6013 is provided on one side of the pressure-boosting movable bushing 601; the pressure-boosting movable bushing 601 is movably connected to the output end of the connecting pipe A; and, at least one diversion hole 6011 is provided at the bottom of the pressure-boosting movable bushing 601; wherein, a driven sleeve 6012 is provided at the bottom of the pressure-boosting movable bushing 601; wherein, a Tesla valve chamber is provided inside the pressure-boosting movable bushing 601, and the driven sleeve 6012 is movably connected to the siphon pipe 8; a support seat 602 is screwed onto the threaded seat 505; the support seat 602 is elastically connected to the pressure-boosting movable bushing 601 via a pressure-holding spring 603. This invention is based on the process of connecting pipe A and the movable sleeve 601 for pressure boosting. Under the elastic force of the pressure-holding spring 603, the movable sleeve 601 remains stationary during the normal well-killing fluid transportation process. In abnormal conditions, such as when the filter material is damaged due to improper use, resulting in increased pressure in the filtration system, or when the filter material breaks, resulting in increased liquid flow per unit time, the movable sleeve 601 descends under the action of the internally set Tesla valve chamber. This setting allows for the general storage of conventionally filtered well-killing fluid and the isolation and recirculation filtration of insufficiently filtered well-killing fluid.

[0037] In an embodiment of the present invention, the adaptive one-way meshing mechanism 10 includes a connecting shaft 1001 fixed to the top of the graded storage tank 5; connecting arms 1002 are sequentially arranged on the connecting shaft 1001 from top to bottom via hinged bushings; wherein only the hinged bushing at the top is movably connected to the connecting shaft 1001; meshing racks 1003 are respectively arranged on both sides of the connecting shaft 1001; the meshing racks 1003 are hinged to the connecting arms 1002; a threaded adjusting shaft 1004 is arranged at the top of the connecting shaft 1001; the threaded adjusting shaft 1004 is elastically connected to the hinged bushing at the top via a tension spring 1006; wherein the meshing racks 1003 and the one-way meshing ratchet 6013 are adapted in shape, and the angle between the meshing racks 1003 and the one-way meshing ratchet 6013 is less than 90°. This invention utilizes the elastic force of the tension spring 1006 to cause the upper hinged bushing to slide downwards. This, combined with the parallel structure of the meshing rack 1003 and the connecting shaft 1001, causes the meshing rack 1003 to unfold, bringing it into contact with the one-way meshing ratchet 6013. The angle between the meshing rack 1003 and the one-way meshing ratchet 6013 is less than 90°, and the inclined surfaces, combined with the compressibility of the tension spring 1006, cause the one-way meshing ratchet 6013 and... The pressurized movable bushing 601 can slide downwards and cannot be naturally reset, forming a linear one-way ratchet structure. This method enables the switching of storing conventionally filtered or insufficiently filtered kill fluid in different filtration and delivery states, thereby reducing the possibility of contamination of previously filtered kill fluid. At the same time, based on the primary temporary storage chamber 501, the insufficiently filtered kill fluid caused by the time difference during the switching process of the multi-stage circulating filtration and purification system flows in for temporary storage. The delayed confluence storage avoids the insufficiently filtered kill fluid from flowing into the classification storage chamber 503.

[0038] In an embodiment of the present invention, under normal pressure conditions of the primary filtration treatment mechanism 2 and the secondary filtration treatment mechanism 3, the pressure boosting movable bushing 601 is positioned under the support of the pressure holding spring 603, causing the primary temporary storage chamber 501 to be connected to the classification storage chamber 503 through the siphon pipe 8 to form an independent diversion storage structure.

[0039] In an embodiment of the present invention, under abnormal pressurization of the primary filtration mechanism 2 and the secondary filtration mechanism 3, the pressurization movable sleeve 601 moves downward due to the increase in pressure, causing the pressurization movable sleeve 601 to simultaneously drive the driven sleeve 6012 to descend, thereby closing the input end of the siphon pipe 8 to form a circulating confluence structure.

[0040] Working principle: This embodiment provides a multi-stage circulating filtration and purification system for well control fluid. Usage steps:

[0041] S100, Pretreatment: The kill fluid impurities are initially treated and precipitated through an oil-liquid separation and storage tank; then, it enters the oil-liquid separation and storage tank through a pipeline for preliminary separation, and the floating kill fluid is connected to the control pump 1;

[0042] S200, Filtration: The kill fluid is pumped to the upper layer of the primary treatment filter tank 201 by controlling the operation of the pump 1, and flows into the bag filter 202 for primary filtration; if secondary filtration is required, the control valve at the bottom of the primary treatment filter tank 201 is closed, and the control valve connecting the primary treatment filter tank 201 and the secondary treatment filter tank 301 is opened, causing the kill fluid filtered in the primary treatment to flow into the secondary treatment filter tank 301, and then flow through the fine filter 302 to the bottom of the secondary treatment filter tank 301;

[0043] S300, off-line storage processing:

[0044] Conventional diversion and storage processing: Open the control valve at the bottom of the primary processing filter tank 201 or the secondary processing filter tank 301 to allow the filtered kill fluid to flow into the primary temporary storage chamber 501 in the connecting pipe A for temporary storage. As the kill fluid level continues to increase, the kill fluid forms a siphon effect with the siphon pipe 8, thereby delivering the corresponding kill fluid to the corresponding classified storage chamber 503.

[0045] Abnormal diversion storage handling: Open the control valve at the bottom of the primary treatment filter tank 201 or the secondary treatment filter tank 301 to allow the filtered kill fluid to flow into the connecting pipe A. If the filter material is damaged, the pressure in the multi-stage circulating filtration and purification system of the kill fluid will increase. The increased pressure will cause the pressure boosting movable sleeve 601 to descend. The driven sleeve 6012 will descend synchronously and fit against the inside of the staged storage tank 5 to block the siphon pipe 8. As the kill fluid level continues to rise, the kill fluid will flow through the manifold pipe 7 into the insufficiently filtered temporary storage chamber 502, and then through the pipe to the other output end of the control pump 1. A one-way valve is installed in the other output end of the control pump 1 to prevent abnormal diversion during the normal filtration process.

[0046] The embodiments disclosed in this invention are preferred embodiments, but are not limited thereto. Those skilled in the art can easily understand the spirit of this invention based on the above embodiments and make different extensions and variations, but as long as they do not depart from the spirit of this invention, they are all within the protection scope of this invention.

Claims

1. A multi-stage circulating filtration and purification system for well control fluid, characterized in that, It includes a control pump (1) located at the output end of the initial filtration treatment tank; a primary filtration treatment mechanism (2) is provided at the output end of the control pump (1); a secondary filtration treatment mechanism (3) is provided at one of the output ends of the primary filtration treatment mechanism (2) via a control valve; and a filtrate storage mechanism (4) is provided on one side of the secondary filtration treatment mechanism (3). The primary filtration unit (2) includes a primary filtration tank (201). The secondary filtration mechanism (3) includes a secondary filtration tank (301) arranged on one side of the primary filtration tank (201). The filtered liquid phase storage mechanism (4) includes a graded storage tank (5); the graded storage tank (5) is provided with a primary temporary storage chamber (501), an insufficient filtration temporary storage chamber (502) and a classified storage chamber (503) arranged from top to bottom inside. The primary temporary storage cavity (501) and the classification storage cavity (503) are provided in at least two forms; The primary temporary storage cavity (501) is provided with a safety mechanism (6) at its top. Furthermore, each of the primary storage chambers (501) is provided with a manifold (7) at the top, which is connected to the insufficiently filtered storage chamber (502); and a siphon pipe (8) is provided on the side of each primary storage chamber (501). The siphon pipe (8) is connected to the sorting and storage cavity (503); The input end of the manifold (7) is higher than the input end of the siphon pipe (8); The primary filtration unit (2) and the secondary filtration unit (3) both have normal pressure and abnormal pressure states. The top of the graded storage tank (5) is provided with a threaded seat (505) positioned relative to the primary temporary storage chamber (501); a guide bushing (5051) is provided on the side of the threaded seat (505). The top of the graded storage tank (5) is also provided with an adaptive one-way engagement mechanism (10); the adaptive one-way engagement mechanism (10) and the insurance mechanism (6) are connected by a movable engagement. The input end of the insurance mechanism (6) is connected to the bottom output end of the primary treatment filter tank (201) and the secondary treatment filter tank (301) through a control valve and a connecting pipe A; The safety mechanism (6) includes a pressure-boosting movable bushing (601) passing through the threaded seat (505); wherein, a one-way meshing ratchet (6013) is provided on one side of the pressure-boosting movable bushing (601). The pressurizing movable bushing (601) is movably connected to the output end of the connecting pipe A; and the pressurizing movable bushing (601) has at least one diversion hole (6011) at its bottom; wherein, the pressurizing movable bushing (601) has a driven sleeve (6012) at its bottom; and the driven sleeve (6012) is movably connected to the siphon pipe (8); A support seat (602) is screwed onto the threaded seat (505); the support seat (602) is elastically connected to the pressure-boosting movable bushing (601) through a pressure-holding spring (603).

2. The multi-stage circulating filtration and purification system for well control fluid according to claim 1, characterized in that, The primary treatment filtration tank (201) is equipped with several bag filters (202); wherein the output end of the control pump (1) is connected to the input end of the bag filter (202).

3. The multi-stage circulating filtration and purification system for well control fluid according to claim 2, characterized in that, The secondary treatment filtration tank (301) is equipped with several fine filters (302).

4. The multi-stage circulating filtration and purification system for well control fluid according to claim 1, characterized in that, The adaptive one-way meshing mechanism (10) includes a connecting shaft (1001) fixed to the top of the graded storage tank (5); connecting arms (1002) are arranged on the connecting shaft (1001) from top to bottom through hinged bushings; wherein only the hinged bushing at the top is movably connected to the connecting shaft (1001); The connecting shaft (1001) is provided with meshing racks (1003) on both sides; the meshing racks (1003) are hinged to the connecting arm (1002); The top of the connecting shaft (1001) is provided with a threaded adjusting shaft (1004); the threaded adjusting shaft (1004) is elastically connected to the hinged bushing located at the top through a tension spring (1006); The meshing rack (1003) and the one-way meshing ratchet (6013) are adapted in shape, and the angle between the meshing rack (1003) and the one-way meshing ratchet (6013) is less than 90°.

5. The multi-stage circulating filtration and purification system for well control fluid according to claim 4, characterized in that, Under normal pressure conditions, the pressure-boosting movable bushing (601) is positioned under the support of the pressure-holding spring (603) of the primary filtration treatment mechanism (2) and the secondary filtration treatment mechanism (3), so that the primary temporary storage chamber (501) is connected to the classification storage chamber (503) through the siphon pipe (8) to form an independent diversion storage structure.

6. The multi-stage circulating filtration and purification system for well control fluid according to claim 4, characterized in that, Under abnormal pressurization conditions of the primary filtration mechanism (2) and the secondary filtration mechanism (3), the pressurization movable sleeve (601) moves downward due to the increase in pressure, causing the pressurization movable sleeve (601) to drive the driven sleeve (6012) to descend synchronously, thereby closing the input end of the siphon pipe (8) to form a circulating confluence structure.

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