Energy-saving oilfield wastewater comprehensive treatment system for water injection

Abstract

The utility model discloses an energy-saving oil field wastewater comprehensive treatment system for water injection. The energy-saving oil field wastewater comprehensive treatment system comprises a sewage receiving pool, an oil removal tank, a first buffer tank, an oil-water separator, a PE sintering pipe filter and a water injection tank which are sequentially connected through pipelines, the first buffer tank is further connected with an air floatation tank through a pipeline, the air floatation tank is further sequentially connected with a second buffer tank, a double-layer filter material filter tank, a three-layer filter material filter tank, an ultrafiltration tank and a third buffer tank through pipelines, and the third buffer tank is further connected with a water injection tank through a pipeline; the double-layer filter material filter tank is also connected with a rainwater collection and storage tank through a pipeline, and is also connected with the PE sintered pipe filter through a pipeline. According to the utility model, the produced water with different pollution degrees in the oilfield production process is subjected to targeted treatment, and wastewater treated by different treatment routes can meet the requirements of oilfield injection water recycling, so that the treatment efficiency and the energy-saving effect are greatly improved.

Description

TECHNICAL FIELD

[0001] The utility model belongs to oil production engineering device technical field relates to the energy -conserving type oilfield wastewater comprehensive treatment system for water injection. BACKGROUND

[0002] At present, several main development oil reservoirs in China belong to extra-low permeability oilfield, after decades of rapid development, has formed the crude oil production scale of more than 10 million tons per year, is currently changing from secondary recovery to tertiary recovery. "Injection good water, inject enough water" is an important means for the sustained and stable production of extra-low permeability oilfield. In recent years, with the increasing workload of water injection, sewage treatment and reinjection often face the problems of low comprehensive compliance rate of water injection water quality, unstable water quality and other problems, aiming at the following deficiencies and problems existing in the reuse of oilfield production wastewater:

[0003] (1) the sewage treatment process has defects, leading to unstable water quality before filtration, water quality overload phenomenon, at the same time, the oilfield production wastewater is of multiple types, and the treatment process has poor adaptability;

[0004] (2) the sewage treatment equipment has many problems in operation quality due to selection, corrosion, operation and other reasons, the treatment effect is poor, the self-control configuration level is low, and the filtration effect and service life of filter material are affected.

[0005] (3) the sewage treatment water quality is unstable, mainly manifested in that the suspended solids, oil content, total iron, bacterial content and corrosion rate are reduced after treatment in the station, but the suspended solids and particle size median increase greatly before the water injection pump and the water injection wellhead.

[0006] In view of the above problems, in order to improve the comprehensive production quality of water injection and gas injection in old oilfield injection station, it is necessary to improve and optimize the water injection system at present. INVENTION CONTENTS

[0007] The utility model aims at providing energy -conserving type oilfield wastewater comprehensive treatment system for water injection, the produced water with different pollution degrees in the oilfield production process is treated, the wastewater treated by different treatment routes can meet the requirements of oilfield water injection reuse, and the treatment efficiency and energy saving effect are greatly improved.

[0008] The utility model adopts the technical scheme, energy -conserving type oilfield wastewater comprehensive treatment system for water injection, including sewage receiving pool, oil removal tank, first buffer tank, oil-water separator, PE sintered tube filterer and water injection tank that are connected in sequence through pipeline;

[0009] The first buffer tank is further connected with the air flotation tank through the pipeline, the air flotation tank is further connected with the second buffer tank, double-layer filter material filter tank, three-layer filter material filter tank, ultrafiltration tank and third buffer tank in sequence through the pipeline, and the third buffer tank is further connected with the water injection tank through the pipeline.

[0010] The double-layer filter material filter tank is also connected with a rainwater storage tank through a pipeline.

[0011] The utility model discloses further have characteristics that:

[0012] The pipeline between the sewage receiving tank and the oil removal tank is equipped with a first lifting pump, the pipeline between the second buffer tank and the double-layer filter material filter tank is equipped with a second lifting pump, the pipeline between the rainwater storage tank and the double-layer filter material filter tank is equipped with a third lifting pump, the pipeline between the double-layer filter material filter tank and the PE sintered tube filter is equipped with a fourth lifting pump, and the pipeline between the third buffer tank and the water injection tank is equipped with a fifth lifting pump.

[0013] The double-layer filter material filter tank is internally equipped with a partition plate, which divides the double-layer filter material filter tank into a first chamber and a second chamber, the first chamber is connected with the second buffer tank through a pipeline, the second chamber is connected with the rainwater storage tank through a pipeline, the lower end of the first chamber is connected with a three-layer filter material filter tank through a pipeline, and the lower end of the second chamber is connected with a PE sintered tube filter through a pipeline.

[0014] Two layers of filter materials are arranged in the first chamber and the second chamber and are respectively 1-2mm particle size anthracite in the upper layer of the first chamber and the second chamber and 0.3-0.6mm particle size magnetite in the lower layer of the first chamber and the second chamber.

[0015] The lower layer magnetite in the first chamber is connected with the three-layer filter material filter tank through a pipeline on the corresponding side wall, the lower layer magnetite in the second chamber is connected with the PE sintered tube filter through a pipeline on the corresponding side wall, and the second buffer tank and the rainwater storage tank are connected on the corresponding side wall of the upper layer anthracite in the first chamber and the second chamber through pipelines respectively.

[0016] Three layers of filter materials are arranged in the three-layer filter material filter tank from top to bottom and are respectively 0.5-1.5mm particle size anthracite in the upper layer, 0.4-0.8mm particle size quartz sand in the middle layer and 0.25-0.5mm particle size ceramsite in the lower layer.

[0017] The corresponding side wall of the lower layer magnetite in the first chamber is connected with the corresponding side wall of the uppermost layer anthracite in the three-layer filter material filter tank through a pipeline.

[0018] The sewage receiving tank is equipped with a water quality detector.

[0019] The utility model discloses further have characteristics that:

[0020] (1) The utility model discloses a wastewater treatment route of different function is set, can be aimed at the produced water of different pollution degree in the oilfield production process and carries out pertinence treatment, and the wastewater after being treated to different treatment route can reach the requirement of oilfield water injection reuse, greatly improves the processing efficiency and energy -saving effect, and plays good economic benefit simultaneously, and it is convenient for the popularization and use of extra -low permeability oilfield.

[0021] (2) The utility model discloses increased the treatment relevant route of the accumulated rainwater, because the water quality demand of oilfield injection is not high, therefore rainwater is the available resource, and rainwater collection tank can also excavate synchronous utilization groundwater and rainwater, and rainwater treatment route and original wastewater treatment route do not interfere with each other, realize the cost reduction and efficiency increase. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 It is the whole structure schematic diagram of the energy -conservation type oilfield wastewater comprehensive treatment system of water injection of the utility model,

[0023] Figure 2 It is the inside structure schematic diagram of double -layer filter material filter tank and three -layer filter material filter tank of the energy -conservation type oilfield wastewater comprehensive treatment system of water injection of the utility model,

[0024] Figure 3 It is the inside structure schematic diagram of double -layer filter material filter tank of the energy -conservation type oilfield wastewater comprehensive treatment system of water injection of the utility model.

[0025] In the drawing: 1 - sewage receiving pool, 11 - first lift pump, 12 - water quality detector, 2 - oil removal tank, 3 - first buffer tank, 31 - air floatation tank, 32 - second buffer tank, 33 - double -layer filter material filter tank, 331 - partition, 332 - first chamber, 333 - second chamber, 34 - three -layer filter material filter tank, 35 - ultrafiltration tank, 36 - third buffer tank, 37 - second lift pump, 38 - fourth lift pump, 39 - fifth lift pump, 4 - oil -water separator, 5 - PE sintered tube filter, 6 - water injection tank, 7 - rainwater collection tank. DETAILED DESCRIPTION

[0026] The utility model will be explained in detail below combining with the drawing and specific embodiment.

[0027] Example 1

[0028] The energy -conservation type oilfield wastewater comprehensive treatment system of water injection of the utility model, its structure as Figure 1 Shown, including through pipeline connection in proper order sewage receiving pool 1, oil removal tank 2, first buffer tank 3, oil -water separator 4, PE sintered tube filter 5 and water injection tank 6,

[0029] The first buffer tank 3 is also connected with an air flotation tank 31 through a pipeline, and the air flotation tank 31 is also connected with a second buffer tank 32, a double-layer filter material filter tank 33, a three-layer filter material filter tank 34, an ultrafiltration tank 35 and a third buffer tank 36 in sequence through pipelines.

[0030] The double-layer filter material filter tank 33 is also connected with a rainwater storage tank 7 through a pipeline, and the double-layer filter material filter tank 33 is also connected with the PE sintered tube filter 5 through a pipeline.

[0031] A first lifting pump 11 is arranged on the pipeline between the sewage receiving tank 1 and the oil removal tank 2, a second lifting pump 37 is arranged on the pipeline between the second buffer tank 32 and the double-layer filter material filter tank 33, a third lifting pump 71 is arranged on the pipeline between the rainwater storage tank 7 and the double-layer filter material filter tank 33, a fourth lifting pump 38 is arranged on the pipeline between the double-layer filter material filter tank 33 and the PE sintered tube filter 5, and a fifth lifting pump 39 is arranged on the pipeline between the third buffer tank 36 and the water injection tank 6.

[0032] As shown in Figure 2 and 3 , a partition plate 331 is arranged in the middle of the double-layer filter material filter tank 33, and the double-layer filter material filter tank 33 is divided into a first chamber 332 and a second chamber 333 by the partition plate 331. The first chamber 332 is connected with the second buffer tank 32 through a pipeline, the second chamber 333 is connected with the rainwater storage tank 7 through a pipeline, the lower end of the first chamber 332 is connected with the three-layer filter material filter tank 34 through a pipeline, and the lower end of the second chamber 333 is connected with the PE sintered tube filter 5 through a pipeline.

[0033] As shown in Figure 2 and 3 , two layers of filter materials are arranged in the first chamber 332 and the second chamber 333, respectively, which are upper layer anthracite with a particle size of 1-2 mm and lower layer magnetite with a particle size of 0.3-0.6 mm in the first chamber 332 and the second chamber 333.

[0034] As shown in Figure 2 and 3 , the lower layer magnetite in the first chamber 332 is connected with the three-layer filter material filter tank 34 through a pipeline on the corresponding side wall, the lower layer magnetite in the second chamber 333 is connected with the PE sintered tube filter 5 through a pipeline on the corresponding side wall, and the second buffer tank 32 and the rainwater storage tank 7 are connected with the upper layer anthracite in the first chamber 332 and the second chamber 333 through pipelines on the corresponding side walls.

[0035] As shown in Figure 2 , three layers of filter materials are arranged in the three-layer filter material filter tank 34 from top to bottom.

[0036] A water quality detector 12 is arranged in the sewage receiving tank 1.

[0037] The working principle of the embodiment is as follows:

[0038] In use, first, the source of the wastewater needs to be determined by the water quality detector 12 or manually, if the oil content in the wastewater is greater than 1000 mg / L, or the source of the wastewater is water flooding + carbon dioxide flooding produced water, water flooding + polymer flooding produced water, and the polymer contained therein needs to be strictly treated, then the wastewater of the utility model is uniformly put into the first treatment line;

[0039] If the oil content in the wastewater is greater than 1000 mg / L, and the source of the wastewater is not water flooding + carbon dioxide flooding produced water, water flooding + polymer flooding produced water, but only normal water flooding produced water, then the types of pollutants in the wastewater are less, and the utility model enters the second treatment line;

[0040] When the accumulated rainwater is reused, the utility model enters the third treatment line;

[0041] The treatment process of the first treatment line is as follows:

[0042] The wastewater is pumped into the oil removal tank 2 from the sewage receiving pool 1 by the first lifting pump 11, and after oil removal, it is pumped into the first buffer tank 3, then into the air floatation tank 31 for air floatation treatment, and after the end, it is pumped into the first chamber 332 inside the double-layer filter material filter tank 33 from the second buffer tank 32 by the second lifting pump 37, and after filtration, it is pumped into the three-layer filter material filter tank 34 for further filtration treatment, and then it is pumped into the ultrafiltration tank 35 for deep ultrafiltration, and after the third buffer tank 36 and the fifth lifting pump 39, it is pumped into the water injection tank 6 to complete the wastewater treatment and be used as an oilfield water injection source.

[0043] The treatment process of the second treatment line is as follows:

[0044] The wastewater is pumped into the oil removal tank 2 from the sewage receiving pool 1 by the first lifting pump 11, and after oil removal, it is pumped into the first buffer tank 3, then into the oil-water separator 4 for deep oil removal, and after filtration by the PE sintered tube filter 5, it is pumped into the water injection tank 6 to complete the wastewater treatment and be used as an oilfield water injection source;

[0045] The treatment process of the third treatment line is as follows:

[0046] The accumulated rainwater is pumped into the second chamber 333 in the double-layer filter material filter tank 33 by the third lifting pump 71, and filtration is performed, and at the same time, due to the existence of the partition plate 331, the rainwater will not be mixed with the produced oil-containing wastewater, and after filtration, the rainwater is pumped into the PE sintered tube filter 5 by the fourth lifting pump 38, and then it is pumped into the water injection tank 6 to complete the wastewater treatment and be used as an oilfield water injection source.

[0047] Embodiment 2

[0048] On the basis of embodiment 1, the three layers of filter material in the three layers of filter material filter tank 34 are: the anthracite with a particle size of 0.5-1.5mm is located in the upper layer, the quartz sand with a particle size of 0.4-0.8mm is located in the middle layer, and the ceramsite with a particle size of 0.25-0.5mm is located in the lower layer; the lower layer magnetite in the first chamber 332 is connected to the uppermost layer anthracite in the three layers of filter material filter tank 34 through a pipeline.

[0049] Embodiment 3

[0050] On the basis of embodiment 2, the energy-saving oilfield wastewater comprehensive treatment system for water injection of the utility model is applied to an oilfield, and on the basis of the original (only an oil removal tank, a flotation tank and a PE filter tank), improvement is made to become the energy-saving oilfield wastewater comprehensive treatment system for water injection of the utility model.

[0051] Through comparison, it is found that the daily treatment capacity of the improved system is 1200m 3 / d, which is greater than the original scale of 800m 3 / d, wherein the first treatment line processes 65%, the second treatment line processes 30%, and the third treatment line processes 5%; through scientific and reasonable division of different wastewater treatment routes, resource saving, cost reduction and benefit increase are realized; the routes that are not currently running can be maintained at the same time, the failure rate is reduced, and long-term stable operation of the system is ensured.

Claims

1. An energy-saving oilfield wastewater integrated treatment system for water injection, characterized in that, The sewage receiving tank (1), the oil removal tank (2), the first buffer tank (3), the oil-water separator (4), the PE sintered pipe filter (5) and the water injection tank (6) are sequentially connected by pipelines. The first buffer tank (3) is further connected with the air flotation tank (31) by a pipeline, and the air flotation tank (31) is sequentially connected with the second buffer tank (32), the double-layer filter material filter tank (33), the three-layer filter material filter tank (34), the ultrafiltration tank (35) and the third buffer tank (36) by pipelines. The double-layer filter material filter tank (33) is further connected with the rainwater collection tank (7) by a pipeline, and the double-layer filter material filter tank (33) is further connected with the PE sintered pipe filter (5) by a pipeline.

2. The energy-saving oilfield wastewater comprehensive treatment system for water injection according to claim 1, characterized in that, A first lifting pump (11) is arranged on the pipeline between the sewage receiving tank (1) and the oil removal tank (2), a second lifting pump (37) is arranged on the pipeline between the second buffer tank (32) and the double-layer filter material filter tank (33), a third lifting pump (71) is arranged on the pipeline between the rainwater collection tank (7) and the double-layer filter material filter tank (33), a fourth lifting pump (38) is arranged on the pipeline between the double-layer filter material filter tank (33) and the PE sintered pipe filter (5), and a fifth lifting pump (39) is arranged on the pipeline between the third buffer tank (36) and the water injection tank (6).

3. The energy-saving oilfield wastewater integrated treatment system for water injection according to claim 1, characterized in that, A partition plate (331) is arranged in the middle of the double-layer filter material filter tank (33), and the double-layer filter material filter tank (33) is divided into a first chamber (332) and a second chamber (333) by the partition plate (331), the first chamber (332) is connected with the second buffer tank (32) by a pipeline, the second chamber (333) is connected with the rainwater collection tank (7) by a pipeline, the lower end of the first chamber (332) is connected with the three-layer filter material filter tank (34) by a pipeline, and the lower end of the second chamber (333) is connected with the PE sintered pipe filter (5) by a pipeline.

4. The energy-saving oilfield wastewater comprehensive treatment system for water injection according to claim 3, characterized in that, Two layers of filter materials are arranged in the first chamber (332) and the second chamber (333), which are upper-layer anthracite with a particle size of 1-2mm and lower-layer magnetite with a particle size of 0.3-0.6mm in the first chamber (332) and the second chamber (333).

5. The energy-saving oilfield wastewater comprehensive treatment system for water injection according to claim 4, characterized in that, The lower-layer magnetite in the first chamber (332) is connected with the three-layer filter material filter tank (34) on the corresponding side wall by a pipeline, the lower-layer magnetite in the second chamber (333) is connected with the PE sintered pipe filter (5) on the corresponding side wall by a pipeline, and the second buffer tank (32) and the rainwater collection tank (7) are connected on the corresponding side wall of the upper-layer anthracite in the first chamber (332) and the second chamber (333) by pipelines.

6. The energy-saving oilfield wastewater comprehensive treatment system for water injection according to claim 5, characterized in that, Three layers of filter materials are arranged in the three-layer filter material filter tank (34) from top to bottom, which are upper-layer anthracite with a particle size of 0.5-1.5mm, middle-layer quartz sand with a particle size of 0.4-0.8mm and lower-layer ceramsite with a particle size of 0.25-0.5mm.

7. The energy-saving oilfield wastewater comprehensive treatment system for water injection according to claim 6, characterized in that, The lower magnetite in the first chamber (332) corresponds to the side wall connected by pipeline on the uppermost layer of anthracite corresponding side wall of the three-layer filter material filter (34).

8. The energy-saving oilfield wastewater integrated treatment system for water injection according to claim 1, characterized in that, The sewage receiving tank (1) is provided with a water quality detector (12).

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