Multi-stage solid control treatment system and treatment method for non-weighted slurry

Abstract

According to the multi-stage solid control treatment system and method for the non-weighted slurry, negative pressure vibration screening and drying vibration screening are carried out on the non-weighted slurry, and it is guaranteed that drilling cuttings in the slurry conveyed to a multi-stage centrifugal separation part are reduced to 100 micrometers or below; therefore, the adverse effect of the large-particle drilling cuttings on the centrifugal separation efficiency is reduced; meanwhile, the liquid-phase slurry is subjected to multi-stage centrifugal separation treatment, so that the particle size of the drilling cuttings in the finally recycled liquid-phase slurry is reduced to 0.01-0.1 mu m, it is guaranteed that the proportion of the drilling cuttings in the recycled liquid-phase slurry is smaller than or equal to 1%, and the performance quality of the recycled liquid-phase slurry is greatly improved.

Description

Technical Field

[0001] The invention belongs to the technical field of drilling mud treatment, and relates to a multi-stage solid control treatment system and a treatment method for non-weighted mud. Background Art

[0002] For the non-weighted mud that does not contain barite produced during the drilling process, in order to avoid the pollution of the non-weighted mud to the external environment and to recover the liquid phase in the non-weighted mud, it is necessary to perform solid-liquid separation on the non-weighted mud. In the prior art, the non-weighted mud is usually swirl-dried in advance by setting a cyclone with different nominal diameters and cyclone screen hole sizes, and the solid phase and liquid phase in the non-weighted mud are initially separated by swirl, and then the liquid phase is further centrifuged by a centrifuge, and finally the drill cuttings in the non-weighted mud are separated. However, the screening particle size of the existing cyclone is usually 65-120μm, which results in the non-weighted mud after the cyclone screening still containing a large amount of drill cuttings with larger particle size. Therefore, when the centrifuge is used to centrifuge the liquid phase for subsequent centrifugal separation, it will be affected by a large amount of drill cuttings with larger particle size, which will cause the centrifugal separation efficiency of the centrifuge to decrease, and the proportion of drill cuttings contained in the mud obtained by the final centrifugal separation is still above 5%, affecting the performance of the recovered liquid phase mud.

[0003] Therefore, in view of the above technical problems existing in the process of treating non-weighted mud in the prior art, the present invention discloses a multi-stage solid control treatment system and a treatment method for non-weighted mud. Summary of the invention

[0004] The object of the present invention is to provide a multi-stage solid control treatment system and treatment method for non-weighted mud, which can perform multi-stage vibration screening and multi-stage centrifugal separation on non-weighted mud, effectively reduce the content of drill cuttings in the recovered liquid phase mud, and improve the efficiency of the centrifugal treatment process.

[0005] The present invention is achieved through the following technical solutions: A multi-stage solid control processing system for non-weighted mud includes a multi-stage vibrating screening section, a multi-stage centrifugal separation section, and a tail phase processing section. The multi-stage vibrating screening section is used to separate the non-weighted mud to obtain a vibrating screened solid phase and a vibrating screened liquid phase. The multi-stage centrifugal separation section is used to perform multi-stage centrifugal separation on the vibrating screened liquid phase to obtain a centrifugal solid phase and a centrifugal liquid phase. The tail phase processing section is used to dry and centrifuge the vibrating screened solid phase to obtain drill cuttings and a tail liquid phase. The multi-stage centrifugal separation section transports the centrifugal solid phase to the multi-stage vibrating screening section, and the multi-stage vibrating screening section transports the vibrating screened liquid phase to the multi-stage centrifugal separation section to form a cycle.

[0006] The non-weighted mud that does not contain barite is subjected to negative pressure vibration screening and dry screening in sequence through the multi-stage vibration screening section. The solid phase obtained by the negative pressure vibration screening continues to be subjected to dry vibration screening, and the solid phase obtained by the dry vibration screening is transported to the tail phase treatment section for further drying and harmless treatment. The liquid phase obtained by the negative pressure vibration screening and the dry vibration screening is uniformly transported to the multi-stage centrifugal separation section for multi-stage centrifugation. Centrifugal separation with decreasing particle size is performed in sequence through multi-stage centrifugation to grade and separate the solid phases such as silt and gravel in the non-weighted mud. The solid phase after multi-stage centrifugal separation is transported to the multi-stage vibration screening section for dry vibration screening, and the liquid phase obtained by multi-stage centrifugal separation is returned to the circulation tank for storing non-weighted mud.

[0007] In order to better realize the present invention, further, the multi-stage centrifugal separation part includes a first-stage centrifuge, a second-stage centrifuge, and a third-stage centrifuge connected in sequence, the first-stage centrifuge is used for centrifugally screening materials with a particle size of 10-100 μm as a vibrating screening solid phase, and centrifugally screening materials with a particle size of 1-10 μm as a vibrating screening liquid phase; the second-stage centrifuge is used for centrifugally screening materials with a particle size of 1-10 μm as a vibrating screening solid phase, and centrifugally screening materials with a particle size of 0.1-1 μm as a vibrating screening liquid phase; the third-stage centrifuge is used for centrifugally screening materials with a particle size of 0.1-1 μm as a vibrating screening solid phase, and centrifugally screening materials with a particle size less than or equal to 0.1 μm as a vibrating screening liquid phase.

[0008] In order to better realize the present invention, further, the multi-stage vibration screening section includes a negative pressure vibration screen and a drying vibration screen, the vibration screening liquid phase ends of the negative pressure vibration screen and the drying vibration screen are connected to the first-stage centrifuge, the vibration screening solid phase end of the negative pressure vibration screen is connected to the drying vibration screen, and the vibration screening solid phase end of the drying vibration screen is connected to the tail phase processing section; the centrifugal separation solid phase ends of the first-stage centrifuge, the second-stage centrifuge, and the third-stage centrifuge are all connected to the drying vibration screen.

[0009] In order to better realize the present invention, further, the tail phase processing part includes a dryer and a tail phase centrifuge, the inlet end of the dryer is connected to the vibrating screening solid phase end of the drying vibration screen, and the liquid phase end of the dryer is connected to the tail phase centrifuge.

[0010] In order to better implement the present invention, further, the vibrating screening liquid phase end of the negative pressure vibrating screen is connected to the primary centrifuge through a vacuum degasser.

[0011] In order to better implement the present invention, further, the liquid phase end of the tail phase centrifuge and the centrifugal separation liquid phase end of the tertiary centrifuge are both connected to the circulation tank.

[0012] A multi-stage solids control treatment method for non-weighted mud is implemented based on a multi-stage solids control treatment system, comprising the following steps: Step 1, negative pressure vibration screening is performed on the drilling fluid through a multi-stage vibration screening part to obtain a negative pressure vibration screening solid phase with a particle size greater than or equal to 100 μm and a negative pressure vibration screening liquid phase with a particle size less than 100 μm; Step 2: Dry and vibrate the negative pressure vibration screening solid phase obtained in step 1 through a multi-stage vibration screening section to obtain a dry vibration screening solid phase with a particle size of 10-100 μm and a dry vibration screening liquid phase with a particle size of less than 10 μm, and transport the secondary vibration screening solid phase to the tail phase processing section; Step 3, sequentially performing primary centrifugal separation, secondary centrifugal separation, and tertiary centrifugal separation on the negative pressure vibration screening solid phase and the dry vibration screening solid phase through a multi-stage centrifugal separation section, obtaining a primary centrifugal separation solid phase with a particle size of 10-100 μm and a primary centrifugal separation liquid phase with a particle size of less than or equal to 10 μm through the primary centrifugal separation, performing secondary centrifugal separation on the primary centrifugal separation liquid phase, and performing dry vibration screening on the primary centrifugal separation solid phase; obtaining a secondary centrifugal separation solid phase with a particle size of 1-10 μm and a secondary centrifugal separation liquid phase with a particle size of less than or equal to 1 μm through the secondary centrifugal separation, performing tertiary centrifugal separation on the secondary centrifugal separation liquid phase, and performing dry vibration screening on the secondary centrifugal separation solid phase; obtaining a tertiary centrifugal separation solid phase with a particle size of 0.1-1 μm and a tertiary centrifugal separation liquid phase with a particle size of less than or equal to 0.1 μm through the tertiary centrifugal separation, and performing dry vibration screening on the tertiary centrifugal separation solid phase; Step 4: returning the dry vibration screening liquid phase obtained by dry vibration screening to the multi-stage centrifugal separation part to participate in the first-stage centrifugal separation.

[0013] In order to better realize the present invention, further, after the dry vibration screening solid phase is transported to the tail phase processing part, the dry vibration screening solid phase is dried and separated by the tail phase processing part to obtain a dried separated solid phase and a dried separated liquid phase, and then the dried separated liquid phase is subjected to tail phase centrifugation by the tail phase processing part, and the tail phase centrifuged liquid phase obtained by tail phase centrifugation is mixed with the tertiary centrifuged liquid phase and returned to the circulation tank.

[0014] In order to better realize the present invention, further, before the negative pressure vibration screening liquid phase is subjected to primary centrifugal separation, the negative pressure vibration screening liquid phase is preliminarily subjected to vacuum degassing treatment.

[0015] Compared with the prior art, the present invention has the following advantages and beneficial effects: The present invention ensures that the drill cuttings particles in the mud transported to the multi-stage centrifugal separation part are reduced to below 100μm by performing negative pressure vibration screening and dry vibration screening on the non-weighted mud, thereby reducing the adverse effects of large-particle drill cuttings on the centrifugal separation efficiency; at the same time, by performing multi-stage centrifugal separation on the liquid phase mud, the drill cuttings particle size in the finally recovered liquid phase mud is reduced to 0.01-0.1μm, ensuring that the proportion of drill cuttings in the recovered liquid phase mud is less than or equal to 1%, thereby greatly improving the performance quality of the recovered liquid phase mud. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of a multi-stage solid control treatment system. DETAILED DESCRIPTION

[0017] The following detailed descriptions are all illustrative and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0018] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the present invention explicitly states otherwise, singular forms are also intended to include plural forms. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0019] For the convenience of description, if the words "up", "down", "left" and "right" appear in the present invention, they only indicate that they are consistent with the up, down, left and right directions of the drawings themselves, and do not limit the structure. They are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the present invention.

[0020] Terminology explanation section: The terms "install", "connect", "connect", "fixed" and the like in the present invention should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be an internal connection between two elements, or an interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0021] Embodiment 1: A multi-stage solids control treatment system for non-weighted mud in this embodiment, such as Figure 1As shown, it includes a multi-stage vibrating screening section, a multi-stage centrifugal separation section, and a tail phase processing section. The multi-stage vibrating screening section is used to separate non-weighted mud to obtain a vibrating screening solid phase and a vibrating screening liquid phase. The multi-stage centrifugal separation section is used to perform multi-stage centrifugal separation on the vibrating screening liquid phase to obtain a centrifugal separation solid phase and a centrifugal separation liquid phase. The tail phase processing section is used to dry and centrifuge the vibrating screening solid phase to obtain drill cuttings and a tail liquid phase. The multi-stage centrifugal separation section transports the centrifugal separation solid phase to the multi-stage vibrating screening section, and the multi-stage vibrating screening section transports the vibrating screening liquid phase to the multi-stage centrifugal separation section to form a cycle.

[0022] The multi-stage centrifugal separation part includes a first-stage centrifuge, a second-stage centrifuge, and a third-stage centrifuge connected in sequence. The first-stage centrifuge is used for centrifugally screening materials with a particle size of 10-100 μm as a vibrating screening solid phase, and centrifugally screening materials with a particle size of 1-10 μm as a vibrating screening liquid phase; the second-stage centrifuge is used for centrifugally screening materials with a particle size of 1-10 μm as a vibrating screening solid phase, and centrifugally screening materials with a particle size of 0.1-1 μm as a vibrating screening liquid phase; the third-stage centrifuge is used for centrifugally screening materials with a particle size of 0.1-1 μm as a vibrating screening solid phase, and centrifugally screening materials with a particle size less than or equal to 0.1 μm as a vibrating screening liquid phase.

[0023] The multi-stage vibration screening section includes a negative pressure vibration screen and a drying vibration screen. The vibration screening liquid phase ends of the negative pressure vibration screen and the drying vibration screen are connected to the first-stage centrifuge, the vibration screening solid phase end of the negative pressure vibration screen is connected to the drying vibration screen, and the vibration screening solid phase end of the drying vibration screen is connected to the tail phase processing section; the centrifugal separation solid phase ends of the first-stage centrifuge, the second-stage centrifuge, and the third-stage centrifuge are all connected to the drying vibration screen.

[0024] The tail phase processing part includes a drier and a tail phase centrifuge. The inlet end of the drier is connected to the vibrating screening solid phase end of the drying vibration screen, and the liquid phase end of the drier is connected to the tail phase centrifuge.

[0025] The non-weighted mud is pre-screened by negative pressure vibration through a negative pressure vibrating screen, that is, negative pressure is also applied to the non-weighted mud during the process of applying vibration to the non-weighted mud for screening, so that the non-weighted mud passes through the vibrating screen quickly to improve the efficiency of solid and liquid phase screening. The solid phase obtained by the negative pressure vibrating screen for negative pressure screening of the non-weighted mud is transported to the dry vibrating screen for further screening, and the liquid phases obtained by the negative pressure vibrating screen and the dry vibrating screen are uniformly transported to the first-stage centrifuge for first-stage centrifugal treatment. The solid phase obtained by the dry vibrating screen screening is transported to the tail phase processing section for further drying and centrifugal treatment to effectively separate the drill cuttings from the non-weighted mud, so that the drill cuttings content in the treated non-weighted mud is less than or equal to 1%.

[0026] The liquid phase obtained by screening enters the first-stage centrifuge, the second-stage centrifuge and the third-stage centrifuge in sequence. The rotation speeds of the first-stage centrifuge, the second-stage centrifuge and the third-stage centrifuge are increased in sequence. The non-weighted mud is centrifugally separated by the first-stage centrifuge, the second-stage centrifuge and the third-stage centrifuge, so that the solid drill cuttings in the non-weighted mud are separated step by step, so that the solid particle size in the non-weighted mud is finally between 0.01-0.1μm.

[0027] Furthermore, the vibrating screening liquid phase end of the negative pressure vibrating screen is connected to the primary centrifuge via a vacuum degasser.

[0028] Furthermore, the liquid phase end of the tail phase centrifuge and the centrifugal separation liquid phase end of the tertiary centrifuge are both connected to the circulation tank.

[0029] Embodiment 2: A multi-stage solids control treatment method for non-weighted mud is implemented based on the multi-stage solids control treatment system described in Example 1, comprising the following steps: Step 1, negative pressure vibration screening is performed on the drilling fluid through a multi-stage vibration screening part to obtain a negative pressure vibration screening solid phase with a particle size greater than or equal to 100 μm and a negative pressure vibration screening liquid phase with a particle size less than 100 μm; Step 2: Dry and vibrate the negative pressure vibration screening solid phase obtained in step 1 through a multi-stage vibration screening section to obtain a dry vibration screening solid phase with a particle size of 10-100 μm and a dry vibration screening liquid phase with a particle size of less than 10 μm, and transport the secondary vibration screening solid phase to the tail phase processing section; Step 3, sequentially performing primary centrifugal separation, secondary centrifugal separation, and tertiary centrifugal separation on the negative pressure vibration screening solid phase and the dry vibration screening solid phase through a multi-stage centrifugal separation section, obtaining a primary centrifugal separation solid phase with a particle size of 10-100 μm and a primary centrifugal separation liquid phase with a particle size of less than or equal to 10 μm through the primary centrifugal separation, performing secondary centrifugal separation on the primary centrifugal separation liquid phase, and performing dry vibration screening on the primary centrifugal separation solid phase; obtaining a secondary centrifugal separation solid phase with a particle size of 1-10 μm and a secondary centrifugal separation liquid phase with a particle size of less than or equal to 1 μm through the secondary centrifugal separation, performing tertiary centrifugal separation on the secondary centrifugal separation liquid phase, and performing dry vibration screening on the secondary centrifugal separation solid phase; obtaining a tertiary centrifugal separation solid phase with a particle size of 0.1-1 μm and a tertiary centrifugal separation liquid phase with a particle size of less than or equal to 0.1 μm through the tertiary centrifugal separation, and performing dry vibration screening on the tertiary centrifugal separation solid phase; Step 4: returning the dry vibration screening liquid phase obtained by dry vibration screening to the multi-stage centrifugal separation part to participate in the first-stage centrifugal separation.

[0030] Furthermore, after the dry vibration screened solid phase is transported to the tail phase processing section, the dry vibration screened solid phase is dried and separated by the tail phase processing section to obtain a dried separated solid phase and a dried separated liquid phase, and then the dried separated liquid phase is subjected to tail phase centrifugation by the tail phase processing section. The tail phase centrifuged liquid phase obtained by the tail phase centrifugation is mixed with the tertiary centrifuged liquid phase and returned to the circulation tank.

[0031] Furthermore, before the negative pressure vibration screening liquid phase is subjected to primary centrifugal separation, the negative pressure vibration screening liquid phase is subjected to vacuum degassing treatment in advance.

[0032] The other parts of this embodiment are the same as those of Embodiment 1, and thus will not be described in detail.

[0033] The above are only preferred embodiments of the present invention and are not intended to limit the present invention in any form. Any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present invention fall within the protection scope of the present invention.

Claims

1. A multi-stage solids control treatment system for non-weighted mud, characterized in that: It includes a multi-stage vibrating screening section, a multi-stage centrifugal separation section, and a tail phase processing section. The multi-stage vibrating screening section is used to separate non-weighted mud to obtain a vibrating screening solid phase and a vibrating screening liquid phase. The multi-stage centrifugal separation section is used to perform multi-stage centrifugal separation on the vibrating screening liquid phase to obtain a centrifugal solid phase and a centrifugal liquid phase. The tail phase processing section is used to dry and centrifuge the vibrating screening solid phase to obtain drill cuttings and a tail liquid phase. The multi-stage centrifugal separation section transports the centrifugal solid phase to the multi-stage vibrating screening section, and the multi-stage vibrating screening section transports the vibrating screening liquid phase to the multi-stage centrifugal separation section to form a cycle.

2. A multi-stage solids control treatment system for non-weighted mud according to claim 1, characterized in that: The multi-stage centrifugal separation part includes a first-stage centrifuge, a second-stage centrifuge, and a third-stage centrifuge connected in sequence. The first-stage centrifuge is used for centrifugally screening materials with a particle size of 10-100 μm as a vibrating screening solid phase, and centrifugally screening materials with a particle size of 1-10 μm as a vibrating screening liquid phase; the second-stage centrifuge is used for centrifugally screening materials with a particle size of 1-10 μm as a vibrating screening solid phase, and centrifugally screening materials with a particle size of 0.1-1 μm as a vibrating screening liquid phase; the third-stage centrifuge is used for centrifugally screening materials with a particle size of 0.1-1 μm as a vibrating screening solid phase, and centrifugally screening materials with a particle size less than or equal to 0.1 μm as a vibrating screening liquid phase.

3. A multi-stage solids control treatment system for non-weighted mud according to claim 2, characterized in that: The multi-stage vibration screening section includes a negative pressure vibration screen and a drying vibration screen. The vibration screening liquid phase ends of the negative pressure vibration screen and the drying vibration screen are connected to the first-stage centrifuge, the vibration screening solid phase end of the negative pressure vibration screen is connected to the drying vibration screen, and the vibration screening solid phase end of the drying vibration screen is connected to the tail phase processing section; the centrifugal separation solid phase ends of the first-stage centrifuge, the second-stage centrifuge, and the third-stage centrifuge are all connected to the drying vibration screen.

4. A multi-stage solids control treatment system for non-weighted mud according to claim 3, characterized in that: The tail phase processing part includes a drier and a tail phase centrifuge. The inlet end of the drier is connected to the vibrating screening solid phase end of the drying vibration screen, and the liquid phase end of the drier is connected to the tail phase centrifuge.

5. A multi-stage solids control treatment system for non-weighted mud according to claim 4, characterized in that: The vibrating screening liquid phase end of the negative pressure vibrating screen is connected to the primary centrifuge via a vacuum degasser.

6. A multi-stage solids control treatment system for non-weighted mud according to claim 5, characterized in that: The liquid phase end of the tail phase centrifuge and the centrifugal separation liquid phase end of the tertiary centrifuge are both connected to the circulation tank.

7. A multi-stage solids control treatment method for non-weighted mud, implemented based on the multi-stage solids control treatment system according to any one of claims 1 to 6, characterized in that: The following steps are involved: Step 1, negative pressure vibration screening is performed on the drilling fluid through a multi-stage vibration screening part to obtain a negative pressure vibration screening solid phase with a particle size greater than or equal to 100 μm and a negative pressure vibration screening liquid phase with a particle size less than 100 μm; Step 2: Dry and vibrate the negative pressure vibration screening solid phase obtained in step 1 through a multi-stage vibration screening section to obtain a dry vibration screening solid phase with a particle size of 10-100 μm and a dry vibration screening liquid phase with a particle size of less than 10 μm, and transport the secondary vibration screening solid phase to the tail phase processing section; Step 3, sequentially performing primary centrifugal separation, secondary centrifugal separation, and tertiary centrifugal separation on the negative pressure vibration screening solid phase and the dry vibration screening solid phase through a multi-stage centrifugal separation section, obtaining a primary centrifugal separation solid phase with a particle size of 10-100 μm and a primary centrifugal separation liquid phase with a particle size of less than or equal to 10 μm through the primary centrifugal separation, performing secondary centrifugal separation on the primary centrifugal separation liquid phase, and performing dry vibration screening on the primary centrifugal separation solid phase; The secondary centrifugal separation solid phase with a particle size of 1-10 μm and the secondary centrifugal separation liquid phase with a particle size of less than or equal to 1 μm are obtained by secondary centrifugal separation, the secondary centrifugal separation liquid phase is subjected to tertiary centrifugal separation, and the secondary centrifugal separation solid phase is subjected to drying and vibration screening; A third-stage centrifugal separation solid phase with a particle size of 0.1-1 μm and a third-stage centrifugal separation liquid phase with a particle size of less than or equal to 0.1 μm are obtained by three-stage centrifugal separation, and the third-stage centrifugal separation solid phase is dried and vibrated and sieved; Step 4: returning the dry vibration screening liquid phase obtained by dry vibration screening to the multi-stage centrifugal separation part to participate in the first-stage centrifugal separation.

8. A multi-stage solids control treatment method for non-weighted mud according to claim 7, characterized in that: After the dry vibration screening solid phase is transported to the tail phase processing section, the dry vibration screening solid phase is dried and separated by the tail phase processing section to obtain a dried separated solid phase and a dried separated liquid phase, and then the dried separated liquid phase is subjected to tail phase centrifugation by the tail phase processing section. The tail phase centrifuged liquid phase obtained by the tail phase centrifugation is mixed with the tertiary centrifuged liquid phase and returned to the circulation tank.

9. A multi-stage solids control treatment method for non-weighted mud according to claim 8, characterized in that: Before the negative pressure vibration screening liquid phase is subjected to primary centrifugal separation, the negative pressure vibration screening liquid phase is subjected to vacuum degassing treatment in advance.

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