Efficient while-drilling multi-stage treatment system and method for ocean water-based drilling cuttings

Abstract

The invention belongs to the technical field of petroleum drilling environmental protection, and discloses an efficient while-drilling multi-stage treatment system and method for ocean water-based drilling cuttings. The efficient while-drilling multi-stage treatment system and method can improve the treatment efficiency of the ocean water-based drilling cuttings. The system comprises a solid control vibrating screen, a spiral conveyor, a first-stage drilling cutting drying device, a first liquid phase temporary storage tank, a transfer pump, a second-stage solid phase removing device, a second liquid phase temporary storage tank, a second feeding pump, a third-stage liquid phase purifying device, a third-stage settling tank and an efflux pump which are sequentially connected in series. The first solid-phase transfer device, the second solid-phase transfer device and the third solid-phase transfer device are respectively connected with solid-phase outlets of the first-stage drilling cutting drying equipment, the second-stage solid-phase removing equipment and the third-stage liquid-phase purifying equipment, and the dispensing tank is respectively connected with a first dosing pump and a second dosing pump. The first dosing pump is connected with the second-stage solid-phase removing device after being connected with an outlet of the transfer pump in parallel, the second dosing pump is connected with the third-stage liquid-phase purifying device after being connected with an outlet of the second feeding pump in parallel, and filtrate of the third-stage settling tank flows back to the dispensing tank through an efflux pump.

Description

Technical Field

[0001] The present invention relates to the technical field of environmental protection for oil drilling, and in particular to a system and method for efficiently processing marine water-based drill cuttings while drilling. Background Art

[0002] Compared to onshore oilfield cuttings, water-based drill cuttings from offshore oilfields have higher density, higher solids content, and a wider range of solid particle size distribution. As marine environmental regulations become increasingly stringent, offshore drilling platforms are required to achieve "zero discharge" of drill cuttings.

[0003] However, the existing marine water-based drill cuttings processing systems and processes have the following significant defects: First, the processing efficiency is insufficient: the processing capacity of traditional systems is generally less than 10m 3 / h, which cannot match the speed of drill cuttings generated while drilling; second, it takes up a lot of space: the split equipment requires additional valves and instruments, the layout is loose, and it occupies a large area; third, process interruption: reliance on offline flocculation tank pretreatment leads to discontinuous operation; fourth, the classification is not fine: the removal rate of solid particles (75-300μm) is insufficient, and the residual solid phase in the liquid phase makes reuse difficult. Summary of the Invention

[0004] In order to improve the processing efficiency of marine water-based drill cuttings, the present invention proposes a high-efficiency multi-stage processing system and method for marine water-based drill cuttings while drilling.

[0005] According to the present invention, the high-efficiency multi-stage processing system for marine water-based drill cuttings while drilling includes: a solid control vibrating screen, a screw conveyor, a first-level drill cuttings drying equipment, a No. 1 liquid phase temporary storage tank, a transfer pump, a second-level solid phase removal equipment, a No. 2 liquid phase temporary storage tank, a No. 2 feed pump, a third-level liquid phase purification equipment, a third-level sedimentation tank and an external transfer pump connected in series; a No. 1 solid phase transfer device connected to the solid phase outlet of the first-level drill cuttings drying equipment, a No. 2 solid phase transfer device connected to the solid phase outlet of the second-level solid phase removal equipment, a No. 3 solid phase transfer device connected to the solid phase outlet of the third-level liquid phase purification equipment, and a drug dispensing tank respectively connected to the No. 1 dosing pump and the No. 2 dosing pump, wherein the No. 1 dosing pump is connected in parallel with the outlet of the transfer pump and then connected to the second solid phase removal equipment, the No. 2 dosing pump is connected in parallel with the outlet of the No. 2 feed pump and then connected to the third-level liquid phase purification equipment, and the filtrate of the third-level sedimentation tank is refluxed to the drug dispensing tank through the external transfer pump.

[0006] Furthermore, the various devices of the marine water-based drill cuttings efficient while-drilling multi-stage processing system are directly connected through pipelines without intermediate valves and instruments.

[0007] Furthermore, the first-level drill cuttings drying equipment is a water-based dryer. The hopper slope of the water-based dryer ranges from 70 to 80 degrees, and the screen mesh ribs include 0.4mm and 0.45mm screen types. The processing capacity is 15 to 25m 3 / h (preferably 20m3 / h), can process solid phase with particle size greater than 250μm, and has a maximum floor area of ​​19.5m 2 .

[0008] Furthermore, the secondary solid phase removal equipment is a flocculation centrifuge, the effective diameter of the drum is 600-700 mm (preferably 650 mm), the effective length of the drum is 1900-2100 mm (preferably 2000 mm), and the maximum floor area is 16.8 m 2 , the processing capacity is 20~30m 3 / h (preferably 25m 3 / h), processing solid phase with particle size of 100 to 300 μm.

[0009] Furthermore, the three-stage liquid phase purification equipment (11) is an explosion-proof belt filter press with a maximum floor area of ​​14.9m 2 , the processing capacity is 15~20m 3 / h (preferably 18m 3 / h), processing solid phase with particle size <100μm.

[0010] Furthermore, the density of the filtrate from the tertiary sedimentation tank is ≤1.050 g / cm 3 , directly returned to the dispensing tank or drilling system.

[0011] According to the method for efficiently processing marine water-based drill cuttings while drilling, the method uses the above-mentioned system for efficiently processing marine water-based drill cuttings while drilling, including the following steps: Step 1: After the drill cuttings are pre-processed by a solid control vibrating screen, they are fed into a first-level drill cutting drying device through a screw conveyor to separate a first-level solid phase and a first-level liquid phase. The first-level solid phase is packaged by a No. 1 solid phase transfer device, and the first-level liquid phase enters a No. 1 liquid phase temporary storage tank; Step 2: The first-level liquid phase entering the No. 1 liquid phase temporary storage tank is transported to the second-level solid phase removal device via a transfer pump, and the No. 1 dosing pump injects flocculants. The coagulant is mixed in the pipeline; Step 3: The secondary solid phase removal equipment separates the secondary solid phase and the secondary liquid phase, the secondary solid phase is packaged by the No. 2 solid phase transfer device, and the secondary liquid phase enters the No. 2 liquid phase temporary storage tank; Step 4: The secondary liquid phase entering the No. 2 liquid phase temporary storage tank is transported to the tertiary liquid phase purification equipment by the No. 2 feed pump, and the No. 2 dosing pump injects flocculant on the way. The liquid phase purified by the tertiary liquid phase purification equipment enters the tertiary sedimentation tank, and the solid phase is packaged by the No. 3 solid phase transfer device; Step 5: The filtrate of the tertiary sedimentation tank is recycled to the dispensing tank via the external transfer pump.

[0012] Furthermore, in step 1, the water content of the primary solid phase is <30%, in step 3, the water content of the secondary solid phase is <45%, and in step 4, the water content of the tertiary separated solid phase is <60%.

[0013] Furthermore, in step 5, the density of the filtrate recycled to the dispensing tank is ≤1.050 g / cm3 , the total solid phase clearance rate was 100%.

[0014] Furthermore, the flow ratio of the No. 1 dosing pump to the transfer pump ranges from 1:200 to 1:50, and the flow ratio of the No. 2 dosing pump to the No. 2 feed pump ranges from 1:500 to 1:100.

[0015] Compared with the prior art, the marine water-based drill cuttings high-efficiency multi-stage processing system of the present invention has the following advantages:

[0016] Beneficial effects:

[0017] 1) In view of the wide distribution of solid particle size and large differences in solid density in water-based drill cuttings, centrifugal sedimentation, high-pressure belt dehydration and filtration processes are coupled to achieve efficient multi-stage while-drilling water-based drill cuttings reduction treatment. This can operate continuously while meeting the requirements of while-drilling treatment efficiency and floor space.

[0018] 2) The multi-stage, high-efficiency, while-drilling water-based drill cuttings reduction method efficiently integrates "gravity filtration separation + flocculation centrifugal deep desolidification + high-pressure crawler deep dewatering process" to create a highly efficient water-based drill cuttings reduction technology that can be used to increase the while-drilling processing speed of water-based drill cuttings on offshore platforms.

[0019] 3) The total area of ​​the system is 51.2m 2 , with the advantages of small footprint, graded processing, and continuous process, laying the foundation for upgrading the process of automated processing of water-based drill cuttings;

[0020] 4) After multi-stage treatment, the liquid phase of water-based drilling fluid waste is clear and the density can reach 1.050g / cm 3 , reaching the reuse standard, the moisture content of the treated solid phase is low, meeting the bagging requirements, and the final solid phase removal rate reaches 100%. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Schematic diagram of the structure of a high-efficiency multi-stage processing system for marine water-based drill cuttings while drilling according to an embodiment of the present invention. DETAILED DESCRIPTION

[0022] In order to better understand the purpose, structure and function of the present invention, the present invention is further described in detail below with reference to the accompanying drawings.

[0023] Figure 1 FIG. 1 shows the structure of a multi-stage system 100 for efficiently processing marine water-based drill cuttings while drilling according to an embodiment of the present invention. Figure 1As shown, the marine water-based drill cuttings efficient multi-stage processing system 100 may include: a solid control vibrating screen 1, a screw conveyor 2, a primary drill cuttings drying device 3, a No. 1 liquid phase temporary storage tank 5, a transfer pump 6, a secondary solid phase removal device 7, a No. 2 liquid phase temporary storage tank 9, a No. 2 feed pump 10, a tertiary liquid phase purification device 11, a tertiary sedimentation tank 13 and an external transfer pump 14 connected in series; a No. 1 solid phase transfer device 4 connected to the solid phase outlet of the primary drill cuttings drying device 3, a No. 1 solid phase transfer device 4 connected to the solid phase outlet of the secondary solid phase removal device 7, and a No. 1 solid phase transfer device 4 connected to the solid phase outlet of the secondary solid phase removal device 7. The No. 2 solid phase transfer device 8 is connected to the outlet, the No. 3 solid phase transfer device 12 is connected to the solid phase outlet of the tertiary liquid phase purification equipment 11, and the dispensing tank 15 is respectively connected to the No. 1 dosing pump 16 and the No. 2 dosing pump 17, wherein the No. 1 dosing pump 16 is connected in parallel with the outlet of the transfer pump 6 and then connected to the secondary solid phase removal equipment 7, the No. 2 dosing pump 17 is connected in parallel with the outlet of the No. 2 feed pump 10 and then connected to the tertiary liquid phase purification equipment 11, and the filtrate of the tertiary sedimentation tank 13 is refluxed to the dispensing tank 15 through the external transfer pump 14.

[0024] When the marine water-based drill cuttings efficient drilling multi-stage processing system 100 of the embodiment of the present invention is in operation, drill cuttings pretreatment and primary separation are first performed: the water-based drill cuttings are first preliminarily screened by the solid control vibrating screen 1 to remove larger particles of solid impurities, and the screened drill cuttings are transported to the primary drill cuttings drying equipment 3 by the screw conveyor 2. In the water-based spin dryer, the drill cuttings are dried by the action of centrifugal force to achieve preliminary separation of solid and liquid. The separated solid phase drill cuttings are transported out of the system through the No. 1 solid phase transfer device 4 and packaged in ton bags, and the liquid phase flows into the No. 1 liquid phase temporary storage tank 5 for temporary storage. Online flocculation and secondary separation are then performed: in the dispensing tank 15, the filtrate produced by the tertiary liquid phase purification equipment 11 is precipitated in the tertiary sedimentation tank 13 and then a flocculant is prepared. The No. 1 dosing pump 16 pumps the prepared flocculant into the inlet pipeline of the secondary solid phase removal equipment 7, where it mixes with the liquid phase in the No. 1 liquid phase temporary storage tank 5 during transportation, achieving online flocculation. This eliminates the need for a separate flocculation tank and increases floor space. The flocculated liquid phase enters the secondary solid phase removal equipment 7, where it undergoes further solid-liquid separation under centrifugal force. The separated solid phase is transported out of the system via the No. 2 solid phase transfer device 8 and packaged in ton bags. The liquid phase then flows into the No. 2 liquid phase temporary storage tank 9. Finally, deep purification and tertiary separation are performed: the No. 2 feed pump 10 transfers the liquid phase in the No. 2 liquid phase temporary storage tank 9 to the tertiary liquid phase purification equipment 11. Simultaneously, the No. 2 dosing pump 17 pumps the prepared flocculant into the delivery pipeline, where it mixes with the liquid phase for flocculation treatment. This also eliminates the need for a separate flocculation tank and increases floor space. In the tertiary liquid phase purification equipment 11, the liquid phase is deeply purified, and the solid phase is transported out of the system through the No. 3 solid phase transfer device 12 and packed in ton bags. The purified liquid phase flows into the tertiary sedimentation tank 13, and the external transfer pump 14 transports the filtrate to the dispensing tank for the preparation of flocculants, or is directly reused in the drilling system, realizing the recycling of the liquid phase, reducing the demand for fresh water resources for drilling operations, and reducing waste emissions.

[0025] Through the above working process, the efficient multi-stage treatment system 100 for marine water-based drill cuttings while drilling of the embodiment of the present invention realizes efficient multi-stage treatment of water-based drill cuttings while drilling, ensuring the uninterrupted progress of drilling operations. The efficient multi-stage treatment system 100 for marine water-based drill cuttings while drilling of the embodiment of the present invention, with its advantages such as compact layout, continuous treatment process, efficient graded separation technology, online flocculation function and filtrate recycling, significantly improves the treatment efficiency and environmental performance of water-based drill cuttings on offshore platforms, and effectively solves the problems of small treatment capacity, large floor space and inability to operate continuously in the existing technology. By optimizing the parameters and functions of each device, efficient reduction and resource utilization of water-based drill cuttings can be achieved, thereby reducing the impact of offshore drilling operations on the environment, while improving economic benefits and safety, and providing a more advanced and reliable technical solution for the environmentally friendly disposal of marine oil drilling waste.

[0026] According to the present invention, Figure 1 As shown, the various devices of the marine water-based drill cuttings efficient drilling multi-stage processing system 100 are directly connected by pipelines without intermediate valves and instruments. This configuration not only makes the overall layout of the marine water-based drill cuttings efficient drilling multi-stage processing system 100 more compact, but also reduces the total floor space to only 51.2m 2 , effectively saving valuable space on offshore platforms; it can also eliminate the risk of valve and instrument leakage and reduce maintenance costs.

[0027] According to the present invention, in the multi-stage high-efficiency drilling-while-drilling processing system 100 of an embodiment of the present invention, different devices process solid phases with different particle size ranges during the graded processing process. The first-stage drill cuttings drying device 3 can process solid phases with a particle size >250 μm, the second-stage solid phase removal device 7 can process solid phases with a particle size of 100 to 300 μm, and the third-stage liquid phase purification device 11 can process solid phases with a particle size <100 μm, thereby achieving graded processing, improving solid-liquid separation efficiency, and reducing subsequent processing pressure.

[0028] In a preferred embodiment, the primary cuttings drying device 3 can be a water-based dryer, the hopper slope of the water-based dryer ranges from 70 to 80 degrees, the screen mesh ribs include 0.4 mm and 0.45 mm screen types, and the processing capacity is 15 to 25 m 3 / h (preferably 20m 3 / h), can process solid phase with particle size greater than 250μm, and has a maximum floor area of ​​19.5m 2In this embodiment, the hopper slope of the water-based spin dryer is set at 70-80 degrees to reduce the accumulation of drill cuttings, facilitate the discharge of drill cuttings, and reduce the cleaning frequency. By increasing the screen types of 0.4mm and 0.45mm, the separation efficiency can be increased while ensuring the processing capacity. The separation efficiency can be increased by about 15%, thereby reducing the processing pressure of subsequent equipment. When the discharge port height of the water-based spin dryer meets the requirements of bagging or boxing, the length of the solid phase discharge device can be reduced from 3.82m to 1.84m, and the equipment's operating space is reduced by 10.68m. 2 .

[0029] Furthermore, the water-based dryer adopts a split upper cover and is designed with an annular groove flushing pipeline to make the flow channel clean more thoroughly and reduce the accumulation of drill cuttings.

[0030] In a preferred embodiment, the secondary solid phase removal device 7 can be a flocculation centrifuge with an effective drum diameter of 600-700 mm (preferably 650 mm), a larger processing capacity, and a processing capacity that is twice that of an existing centrifuge with a drum diameter of 550 mm. The effective length of the drum is 1900-2100 mm (preferably 2000 mm), the length of the processing section is increased, the residence time of the material in the drum is increased, the drying time is longer, and the solid phase moisture content is lower; the maximum floor area is 16.8 m 2 , the processing capacity is 20~30m 3 / h (preferably 25m 3 / h), processing solid phase with particle size of 100 to 300 μm.

[0031] In a preferred embodiment, the three-stage liquid phase purification equipment 11 can be an explosion-proof belt filter press with a maximum floor area of ​​14.9 m 2 , the processing capacity is 15~20m 3 / h (preferably 18m 3 / h), processing solids with particle sizes <100μm. The explosion-proof belt filter press deeply purifies the liquid phase through the filtration and compression action of the filter belt. The separated solids have a moisture content of less than 60%, meeting the safety requirements of offshore platforms and preventing accidents caused by equipment failure.

[0032] According to the present invention, Figure 1 As shown, the density of the filtrate in the third-stage sedimentation tank 13 is ≤1.050g / cm 3 , meeting the reuse standards, and can be directly reused in the dispensing tank 15 or the drilling system through the external transfer pump 14, realizing the recycling of the liquid phase, reducing the dependence of drilling operations on fresh water resources, reducing wastewater discharge, saving costs, and avoiding secondary pollution to the environment, thereby improving the resource utilization efficiency and environmental benefits of the entire system.

[0033] The present invention also proposes a method for efficiently processing marine water-based drill cuttings while drilling, and the application of the above-mentioned marine water-based drill cuttings efficient multi-stage processing system 100 while drilling can include the following steps: Step 1: After the drill cuttings are pre-treated by the solid control vibrating screen 1, they enter the first-level drill cutting drying equipment 3 through the screw conveyor 2 to separate the first-level solid phase and the first-level liquid phase. The first-level solid phase is packaged by the first solid phase transport device 4, and the first-level liquid phase enters the first liquid phase temporary storage tank 5; Step 2: The first-level liquid phase entering the first liquid phase temporary storage tank 5 is transported to the second-level solid phase removal equipment 7 by the transport pump 6, and the first-level dosing pump 16 is used to inject flocculant for real-time processing. The pipeline is now mixed; Step 3: The secondary solid phase removal equipment 7 separates the secondary solid phase and the secondary liquid phase, the secondary solid phase is packaged by the No. 2 solid phase transfer device 8, and the secondary liquid phase enters the No. 2 liquid phase temporary storage tank 9; Step 4: The secondary liquid phase entering the No. 2 liquid phase temporary storage tank 9 is transported to the tertiary liquid phase purification equipment 11 by the No. 2 feed pump 10, and the No. 2 dosing pump 17 injects flocculant on the way. The liquid phase purified by the tertiary liquid phase purification equipment 11 enters the tertiary sedimentation tank 13, and the solid phase is packaged by the No. 3 solid phase transfer device 12; Step 5: The filtrate of the tertiary sedimentation tank 13 is recycled to the dispensing tank 15 via the external transfer pump 14.

[0034] This treatment method enables efficient, multi-stage, while-drilling treatment of water-based drill cuttings. From pretreatment of the cuttings, solid-liquid separation, online flocculation, to final liquid phase purification and reuse, the entire process is continuous and efficient, ensuring that the moisture content of the solid phase after each stage of treatment meets bagging requirements, the liquid phase ultimately meets reuse standards, and the total solid phase removal rate reaches 100%, fully meeting the environmentally friendly treatment needs of water-based drill cuttings from offshore platforms, effectively protecting the marine ecological environment, and at the same time improving the economic benefits and sustainability of drilling operations.

[0035] According to the present invention, in step 1, the moisture content of the primary solid phase is less than 30%, in step 3, the moisture content of the secondary solid phase is less than 45%, and in step 4, the moisture content of the tertiary separated solid phase is less than 60%. This arrangement ensures that the solid phase can achieve good dehydration effects at different processing stages, facilitating subsequent packaging, transportation, and disposal, meeting environmental protection and practical engineering requirements, and also helps improve the performance evaluation and quality control of the entire processing system, ensuring stable and efficient system operation.

[0036] According to the present invention, in step 5, the density of the filtrate recycled to the dispensing tank 15 is ≤1.050 g / cm 3 , with a total solids removal rate of 100%. This setup achieves resourceful utilization of the liquid phase, reducing drilling costs and alleviating environmental impact. At the same time, the entire system achieves a 100% total solids removal rate for water-based drill cuttings, effectively reducing drill cuttings and thoroughly resolving the environmentally friendly disposal of water-based drill cuttings. This complies with strict marine environmental regulations and provides strong support for the sustainable development of offshore oil drilling operations.

[0037] In a preferred embodiment, the flow ratio between dosing pump 16 and transfer pump 6 ranges from 1:200 to 1:50, and the flow ratio between dosing pump 17 and feed pump 10 ranges from 1:500 to 1:100. By setting the flow ratios between dosing pump 16 and transfer pump 6, and between dosing pump 17 and feed pump 10, precise control of flocculant addition is achieved, ensuring optimal flocculation results at various treatment stages and under varying liquid flow rates. Precise dosing ensures effective flocculation while avoiding agent waste, reducing treatment costs and improving system operational stability and efficiency.

[0038] It should be noted that, unless otherwise specified, the technical or scientific terms used in this application should have the common meanings understood by those skilled in the art to which the present invention belongs.

[0039] In the description of this application, it should be understood that the terms "first", "second", etc. are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features.

[0040] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and description of the present invention. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. An efficient multi-stage processing system for marine water-based drill cuttings while drilling, characterized in that: include: A solid control vibrating screen (1), a screw conveyor (2), a first-stage drill cuttings drying device (3), a No. 1 liquid phase temporary storage tank (5), a transfer pump (6), a second-stage solid phase removal device (7), a No. 2 liquid phase temporary storage tank (9), a No. 2 feed pump (10), a third-stage liquid phase purification device (11), a third-stage sedimentation tank (13) and an external transfer pump (14) are sequentially connected in series; a No. 1 solid phase transfer device (4) connected to the solid phase outlet of the first-stage drill cuttings drying device (3), a No. 2 solid phase transfer device (8) connected to the solid phase outlet of the second-stage solid phase removal device (7), a No. 3 solid phase transfer device (9) connected to the solid phase outlet of the third-stage liquid phase purification device (11), a No. 3 solid phase transfer device (1 ... A third solid phase transport device (12) is connected to the solid phase outlet of the phase purification equipment (11), and a dispensing tank (15) is connected to the first dosing pump (16) and the second dosing pump (17) respectively, wherein the first dosing pump (16) is connected in parallel with the outlet of the transport pump (6) and then connected to the secondary solid phase removal equipment (7), the second dosing pump (17) is connected in parallel with the outlet of the second feed pump (10) and then connected to the third liquid phase purification equipment (11), and the filtrate of the third sedimentation tank (13) is refluxed to the dispensing tank (15) through the external transfer pump (14).

2. The high-efficiency multi-stage processing system for marine water-based drill cuttings while drilling according to claim 1 is characterized in that: The various devices of the marine water-based drill cuttings efficient multi-stage processing system while drilling are directly connected through pipelines without intermediate valves and instruments.

3. The high-efficiency multi-stage processing system for marine water-based drill cuttings while drilling according to claim 1 or 2, characterized in that: The first-level drill cuttings drying equipment (3) is a water-based drying machine. The hopper slope of the water-based drying machine ranges from 70 to 80 degrees. The shape of the sieve ribs includes 0.4mm and 0.45mm sieve types. The processing capacity is 15 to 25m 3 / h, can process solid phase with particle size greater than 250μm, and has a maximum floor area of ​​19.5m 2 .

4. The high-efficiency multi-stage processing system for marine water-based drill cuttings while drilling according to claim 1 or 2, characterized in that: The secondary solid phase removal device (7) is a flocculation centrifuge, the effective diameter of the drum is 600-700 mm, the effective length of the drum is 1900-2100 mm, and the maximum floor area is 16.8 m 2 , the processing capacity is 20~30m 3 / h, processing solid phase with particle size of 100 to 300 μm.

5. The high-efficiency multi-stage processing system for marine water-based drill cuttings while drilling according to claim 1 or 2, characterized in that: The three-stage liquid phase purification equipment (11) is an explosion-proof belt filter press with a maximum floor area of ​​14.9m 2 , the processing capacity is 15~20m 3 / h, processing solid phase with particle size <100μm.

6. The high-efficiency multi-stage processing system for marine water-based drill cuttings while drilling according to claim 1 or 2, characterized in that: The filtrate density of the three-stage sedimentation tank (13) is ≤1.050 g / cm 3 , directly returned to the dispensing tank (15) or drilling system.

7. A method for efficiently processing marine water-based drill cuttings while drilling, using the system for efficiently processing marine water-based drill cuttings while drilling according to any one of claims 1 to 6, characterized in that: The following steps are involved: Step 1: After being pre-treated by the solid control vibrating screen (1), the drill cuttings enter the first-level drill cutting drying device (3) through the screw conveyor (2) to separate the first-level solid phase and the first-level liquid phase. The first-level solid phase is packaged by the first solid phase transport device (4), and the first-level liquid phase enters the first liquid phase temporary storage tank (5); Step 2: The first-stage liquid phase entering the first liquid phase temporary storage tank (5) is transported to the second-stage solid phase removal device (7) via the transfer pump (6), and the first dosing pump (16) injects flocculant to achieve pipeline mixing; Step 3: The secondary solid phase removal device (7) separates the secondary solid phase and the secondary liquid phase, the secondary solid phase is packaged by the second solid phase transfer device (8), and the secondary liquid phase enters the second liquid phase temporary storage tank (9); Step 4: The secondary liquid phase entering the No. 2 liquid phase temporary storage tank (9) is transported to the No. 3 liquid phase purification device (11) via the No. 2 feed pump (10), and the No. 2 dosing pump (17) injects flocculant on the way. The liquid phase purified by the No. 3 liquid phase purification device (11) enters the No. 3 sedimentation tank (13), and the solid phase is packaged by the No. 3 solid phase transport device (12); Step 5: The filtrate from the tertiary sedimentation tank (13) is recycled to the drug dispensing tank (15) via the external transfer pump (14).

8. The method for efficiently processing marine water-based drill cuttings while drilling according to claim 7, characterized in that: In the step 1, the water content of the primary solid phase is less than 30%, in the step 3, the water content of the secondary solid phase is less than 45%, and in the step 4, the water content of the tertiary separated solid phase is less than 60%.

9. The method for efficiently processing marine water-based drill cuttings while drilling according to claim 7, characterized in that: In the step 5, the density of the filtrate recycled to the dispensing tank (15) is ≤1.050 g / cm 3 , the total solid phase clearance rate was 100%.

10. The method for efficiently processing marine water-based drill cuttings while drilling according to claim 7, characterized in that: The flow ratio of the No. 1 dosing pump (16) to the transfer pump (6) ranges from 1:200 to 1:50, and the flow ratio of the No. 2 dosing pump (17) to the No. 2 feed pump (10) ranges from 1:500 to 1:100.

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