Well completion and workover flow-back fluid treatment system based on oil-based mud

Abstract

The utility model discloses a well workover flow-back fluid treatment system based on oil-based mud. The well workover flow-back fluid treatment system comprises a first heating reaction kettle and a second heating reaction kettle, the vibrating screen is communicated with one end of the first heating reaction kettle; one end of the second heating reaction kettle is communicated with the vibrating screen; one end of the horizontal screw centrifuge is communicated with the other end of the second heating reaction kettle; the three-phase disc type centrifugal machine is communicated with the other end of the horizontal screw centrifugal machine; the oil-water separation filter is communicated with the three-phase disc type centrifugal machine; the rock debris collecting box is communicated with the vibrating screen, the horizontal screw centrifuge and the three-phase disc type centrifuge at the same time; and the white oil tank is simultaneously connected with the oil-water separation filter and the three-phase disc type centrifugal machine. And the oil-based mud well completion flow-back fluid can be directly and continuously operated on site, so that the wastewater reaches the standard and is discharged, and the wellhead operation efficiency of a drilling platform is improved.

Description

Technical Field

[0001] The utility model relates to a well completion flowback fluid processing system based on oil-based mud, which is applied to the on-site processing of the waste fluid returned from the well completion flowback operation of the oil and gas field on the drilling platform, and the processing of the waste fluid from the wellhead operation of the land oil and gas field. Background Art

[0002] In the process of oil and gas field development and oil and gas extraction, drilling and completion, production completion, well washing and well repair are essential steps in the process of oil field development and production increase. The completion and repair process will produce a certain amount of return waste liquid, and this oil-water mixed waste liquid needs to be harmlessly treated or recycled. Due to the small space of the drilling platform, the on-site drilling and completion operations are limited by the site, and it is impossible to store and centrally treat the return waste liquid from drilling and completion for a long time. The conventional land oil field mud pool storage and sedimentation followed by centralized treatment mode cannot be applied on the platform.

[0003] During the field operation, the return waste liquid from different wellheads has the characteristics of large differences in liquid volume, intermittent return, and complex components. Due to the addition of a large number of chemical additives in the drilling and completion process, the chemical composition of the return waste liquid is very complex, and oil-water separation is difficult. At present, the field process mostly uses oil-water separators for treatment. The treated sewage does not meet the discharge standards and needs to be shipped to land for centralized treatment, resulting in low overall operation efficiency and high treatment costs.

[0004] The current treatment technology for the waste fluid from well completion on drilling platforms is not very applicable to the water quality of the waste fluid from various wellheads, and the treated waste fluid cannot meet the requirements of environmentally friendly discharge. The waste fluid needs to be stored in an environmental tank and then transported to land for treatment, which has low treatment efficiency and high cost. Utility Model Content

[0005] The utility model designs and develops a well completion flowback fluid treatment system based on oil-based mud, which can directly perform on-site continuous operation on the oil-based mud well completion flowback fluid, so that the wastewater meets the discharge standards and improves the operation efficiency of the wellhead of the drilling platform.

[0006] The technical solution provided by the utility model is:

[0007] A well completion flowback fluid processing system based on oil-based mud, comprising:

[0008] A first heating reactor;

[0009] A vibrating screen connected to one end of the first heating reactor;

[0010] A second heating reaction kettle, one end of which is connected to the vibrating screen;

[0011] a horizontal screw centrifuge, one end of which is connected to the other end of the second heating reactor;

[0012] A three-phase disc centrifuge, which is connected to the other end of the horizontal screw centrifuge;

[0013] An oil-water separation filter, which is connected to the three-phase disc centrifuge;

[0014] A cuttings collection box, which is simultaneously connected to the vibrating screen, the horizontal screw centrifuge, and the three-phase disc centrifuge;

[0015] The white oil tank is connected to the oil-water separation filter and the three-phase disc centrifuge at the same time.

[0016] Preferably, the oil-water separation filter comprises two interconnected first filters and second filters;

[0017] Wherein, a water inlet is arranged on one side of the first filter, and a water outlet is arranged on one side of the second filter.

[0018] Preferably, the first filter and the second filter are both provided with a sewage outlet at the bottom, an oil collector at the top, and a filter element inside.

[0019] Preferably, it also includes:

[0020] A first lifting pump, which is connected and arranged between the first heating reaction kettle and the vibrating screen;

[0021] a second lifting pump, which is connected and arranged between the horizontal screw centrifuge and the second heating reactor;

[0022] A third lifting pump is connected and arranged between the three-phase disc centrifuge and the oil-water separation filter.

[0023] Preferably, the filter element is made of super hydrophilic and super oleophobic material, and the filter pore size is 0.02-10 μm.

[0024] Preferably, the applicable temperature of the filter element is 0-95°C and the pH value is 2-12.

[0025] Beneficial effects of the utility model:

[0026] The utility model has a high degree of integration and modularization, adopts a skid-mounted design, meets the load requirements of the drilling platform while controlling the floor space to the minimum size, and can meet the requirements of platform site restrictions; the functions of each unit in the process technology route are complete, and it has compatibility and strong impact resistance for the water quality and water volume of the waste liquid, and is more suitable for the treatment of oil-water mixed waste liquid returned from the wellhead; by adding a special demulsifier, the separation of emulsified oil in the waste liquid is effectively solved; the two-stage centrifugal separation technology has strong applicability to solid particles and oil and water of different particle sizes and concentrations, and the separated oil can be recycled; the preferred iron-based coagulant agent, which can improve the processing efficiency of the three-phase disc centrifuge; the oil-water separation filter adopts a super-hydrophilic and super-oleophobic material filter element to achieve the separation of water and oil, and the effluent meets the environmental protection standards and can be discharged directly; the oil-water separation filter element has a large optional pore size, and the filtration accuracy can be adjusted according to the water quality; all oil-water interfaces adopt a union connection method, which can be quickly installed and put into use; the utility model is also suitable for the return treatment of wellhead waste liquid in onshore oil fields. It adopts a standard skid-mounted method, which can better adapt to the wellhead sewage treatment in various geographical environments and road conditions, and mobile transportation and on-site installation are flexible and convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The utility model is a schematic structural diagram of a well completion flowback fluid processing system based on oil-based mud.

[0028] Figure 2 This is a schematic diagram of the structure of the oil-water separation filter described in this practical information. DETAILED DESCRIPTION

[0029] The present invention will be further described in detail below in conjunction with the accompanying drawings so that those skilled in the art can implement the invention with reference to the description.

[0030] like Figure 1-2 As shown, the utility model provides a well completion flowback fluid processing system based on oil-based mud, comprising: a first heating reactor 1, a first lifting pump 2, a vibrating screen 3, a second heating reactor 4, a second lifting pump 5, a horizontal screw centrifuge 6, a three-phase disc centrifuge 7, a cuttings collection box 8, a lifting pump 9, a white oil tank 10, an oil-water separation filter 11, a second oil collector 1101, a first oil collector 1102, a first filter 1103, a first treatment chamber 1104, a first filter element 1105, a water inlet 1106, a first sewage outlet 1107, a second sewage outlet 1108, a water outlet 1109, and a second filter 1110.

[0031] The first heating reactor 1 is provided with oil-based mud backflow waste liquid, one end of the first heating reactor 1 is connected to the vibrating screen 3 through the first lifting pump 2, one end of the second heating reactor 4 is connected to the vibrating screen 3, and the other end is connected to one end of the horizontal screw centrifuge 6 through the second lifting pump 5, and the other end of the horizontal screw centrifuge 6 is connected to the three-phase disc centrifuge 7; the oil-water separation filter 11 is connected to the three-phase disc centrifuge 7, and the cuttings collection box 8 is simultaneously connected to the vibrating screen 3, the horizontal screw centrifuge 6 and the three-phase disc centrifuge 7; the white oil tank 10 is simultaneously connected to the oil-water separator 11 and the three-phase disc centrifuge 7.

[0032] The oil-water separation filter includes a first filter 1103 and a second filter 1110 which are interconnected. The first filter 1103 is a primary filter. A water inlet 1106 is arranged on one side of the first filter 1103, a first oil collector 1102 is arranged on the top, a first sewage outlet 1107 is arranged on the bottom, and a treatment chamber 1104 is arranged on the upper part. A first filter element 1105 is arranged inside the first filter 1103, and a water outlet 1109 is arranged on one side of the second filter 1110, a second oil collector 1101 is arranged on the top, a second sewage outlet 1108 is arranged on the bottom, and a second filter element is arranged inside.

[0033] In the present utility model, as a preferred embodiment, the first filter element and the second filter element are both made of super hydrophilic and super oleophobic materials, suitable for wastewater with different oil contents and suspended matter, applicable temperature of 0-95°C, pH value of 2-12, the filtration process is fully automatically controlled, and no agents are added during the process.

[0034] In the utility model, as a preference, the filtration pore sizes of the first filter element and the second filter element are 0.02-10 μm, and the filtration accuracy can be adjusted according to the water quality. Under the conditions that the inlet water contains 1000-5000 mg / L of oil and 500-1000 mg / L of suspended solids, the outlet water can stably maintain an oil content of less than 5 mg / L and a suspended solid content of less than 5 mg / L.

[0035] This system consists of reactor demulsification treatment, vibrating screen cuttings separation, decanter centrifuge and plate centrifuge oil-sludge-water separation, and oil-water separation and filtration system process units. It adopts skid-mounted modular design and is divided into four skid-mounted modules, which can be combined and connected on site. The four skid-mounted modules are: vibrating screen and dosing skid-mounted module, two-phase decanter separation skid-mounted module, three-phase disc separation skid-mounted module, and oil-water separation and filtration skid-mounted module. The single skid size range of modular equipment is L≤6000mm, W≤2500mm, and H≤3000mm.

[0036] The main processing units of the system include: a first heating reactor 1, a second heating reactor 4, a vibrating screen 3, a horizontal screw centrifuge 6, a three-phase disc centrifuge 7, and an oil-water separation filter 11.

[0037] The treatment process includes: after the waste liquid is demulsified in the first heating reactor 1, the waste liquid enters the vibrating screen 3 to separate the rock chips into the rock chip collection box 8, the separated waste liquid flows by gravity into the heating reactor 2 for temperature adjustment, and then is pumped into the horizontal screw centrifuge 6 for mud-liquid separation, the separated sludge is sent to the rock chip collection box 8, the liquid phase is firstly pre-treated by adding coagulant and flocculant, and then centrifuged by the three-phase disc centrifuge 7, the sludge is returned to the rock chip collection box 8, and the oil is pumped to the white oil tank 10, the waste water enters the oil-water separation filter 11 for treatment through the third lifting pump 9, and the effluent meets the discharge standards.

[0038] The oil-based mud return waste liquid is in the first heating reactor 1, the temperature is controlled at 30-70°C, and the agent 1 is added and stirred and mixed. The agent 1 is demulsifier 1 and demulsifier 2; wherein, demulsifier 1 and demulsifier 2 are special agents, demulsifier 1 is characterized by yellow liquid and non-irritating, and demulsifier 2 is characterized by white solid powder and non-irritating; the dosing concentration of demulsifier 1 is 10-100 mg / L, and the dosing concentration of demulsifier 2 is 20-150 mg / L.

[0039] The waste liquid separated by the vibrating screen flows into the second heating reactor 2, and the temperature is controlled at 30-70°C. When the waste liquid enters the horizontal screw centrifuge 6, a flocculant is added to enhance the separation effect. The coagulant used in the horizontal screw centrifuge 6 and the three-phase disc centrifuge 7 is a preferred iron-based coagulant, which improves the compactness and sedimentation rate of the waste liquid floc particles; the waste liquid treatment capacity of this process technology equipment is 2-10m 3 / h, and the processing volume meets the processing requirements of wellhead drainage on drilling platforms.

[0040] In the present utility model, as a preferred embodiment, the lifting pump and the mixer adopt the EXDIIBT4 explosion-proof grade, and the control cabinet adopts the IP65 and above protection grade, which meets the explosion-proof and open-air operation requirements of oil field operations. The water inlet, sewage outlet, water outlet, and waste oil recovery port of the equipment are all connected by a union.

[0041] Although the implementation scheme of the utility model has been disclosed as above, it is not limited to the applications listed in the specification and implementation modes. It can be fully applied to various fields suitable for the utility model. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the utility model is not limited to the specific details and the illustrations shown and described herein.

Claims

1. A well completion flowback fluid processing system based on oil-based mud, characterized in that: include: A first heating reactor; A vibrating screen connected to one end of the first heating reactor; A second heating reaction kettle, one end of which is connected to the vibrating screen; a horizontal screw centrifuge, one end of which is connected to the other end of the second heating reactor; A three-phase disc centrifuge, which is connected to the other end of the horizontal screw centrifuge; An oil-water separation filter, which is connected to the three-phase disc centrifuge; A cuttings collection box, which is simultaneously connected to the vibrating screen, the horizontal screw centrifuge, and the three-phase disc centrifuge; The white oil tank is connected to the oil-water separation filter and the three-phase disc centrifuge at the same time.

2. The oil-based mud based well completion flowback fluid processing system according to claim 1, characterized in that: The oil-water separation filter comprises two interconnected first filters and a second filter; Wherein, a water inlet is arranged on one side of the first filter, and a water outlet is arranged on one side of the second filter.

3. The oil-based mud based well completion flowback fluid processing system according to claim 2, characterized in that: The first filter and the second filter are both provided with a sewage outlet at the bottom, an oil collector at the top, and a filter element inside.

4. The oil-based mud based well completion flowback fluid processing system according to claim 3, characterized in that: Also includes: A first lifting pump, which is connected and arranged between the first heating reaction kettle and the vibrating screen; a second lifting pump, which is connected and arranged between the horizontal screw centrifuge and the second heating reactor; A third lifting pump is connected and arranged between the three-phase disc centrifuge and the oil-water separation filter.

5. The oil-based mud based well completion flowback fluid processing system according to claim 3 or 4, characterized in that: The filter element is made of super hydrophilic and super oleophobic material, and the filter pore size is 0.02-10 μm.

6. The oil-based mud based well completion flowback fluid processing system according to claim 5, characterized in that: The applicable temperature of the filter element is 0-95°C and the pH value is 2-12.

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