CN111072210B - A multi-station combined treatment system and method for oil field reinjection water - Google Patents

Abstract

The invention provides a multi-station combined treatment system and method for oilfield reinjection water. The oil field reinjection water multi-station combined treatment system and the method comprise the following steps: the system comprises a reinjection water heating device, a reinjection water heating bypass device, a reinjection water return conveying device of a water injection station, a reinjection water return conveying bypass device, a reinjection water injection stratum device, a combined station and a water injection station; and one side of the reinjection water heating device is connected with the combined station. The oil field reinjection water multi-station combined treatment system and the method thereof inhibit new separation and coalescence growth of suspended solids by improving the conveying temperature and flow rate of the reinjection water from the combined station to the water injection station, thereby realizing the aim that the content and the median of the suspended solids at the wellhead of the water injection well meet the reinjection requirements; the regulation of the output flow rate and the temperature of the reinjection water is further realized, the problem that the water quality of the wellhead of the reinjection water in the oil field does not reach the standard is solved, and the method has the characteristics of flexible regulation of working conditions, simple process flow and stable water physical property.

Description

A multi-station combined treatment system and method for oil field reinjection water

technical field

The invention relates to the field of oilfield reinjection water treatment, in particular to a multi-station joint treatment system and method for oilfield reinjection water.

Background technique

Water flooding is an oilfield development scheme often used in oilfields. According to OPEC statistics, the current daily oil consumption in the world is about 89.4×10 ⁶ barrels per day, while the water content of oil fields generally exceeds 75%, and some old oil fields even exceed 95%; According to the statistics of academicians, China's crude oil production has exceeded 1.9 × 10 ⁸ tons per year, of which the reserves and production of water injection oilfields account for more than 80% of the country's total. The average water content of oil fields has exceeded 86.0%, and the water content of some old oil fields has exceeded 90% . Therefore, in the process of oilfield development, there will be a lot of problems in the treatment of produced water.

In order to maintain the formation pressure balance and avoid the impact of the produced water on the local environment, the oilfield usually reinjects the produced water into the formation after qualified treatment (that is, reinjection water). According to "Recommended Indicators and Analysis Methods for Water Injection Quality of Clastic Reservoirs" (SY/T5329-2012), it is necessary to control the oil content, suspended solids content and median particle size in the reinjection water to meet the requirements of different geological types of reservoirs. repayment requirements. If the reinjection water contains a large amount of suspended solids with large particle size, the formation pores will be blocked, the oilfield recovery factor will be reduced, and the economic benefits of the oilfield will be reduced. Therefore, the oilfield treats the produced water through the combined station or sewage treatment station so that its oil content, suspended solids content, and median particle size meet the reinjection requirements.

However, during the transportation of the reinjection water from the joint station to the water injection well, the temperature drop of the reinjection water along the way will lead to the decrease of the solubility of solid suspended matter and the continuous precipitation and growth; the turbulent effect of the water flow will also cause the continuous collision and aggregation of solid particles. , forming a solid suspension with large particle size. Therefore, under the above effects, when the reinjection water is transported to the wellhead of the water injection well, the content of suspended solids and the median particle size will not meet the reinjection requirements.

In this regard, oilfields often adopt methods to improve the water quality at the outlet of the combined station, such as switching to agents with better coagulation and coagulation-assisting effects, using ultrafiltration membranes, nanofiltration membranes and other deep membrane filtration technologies or increasing the number of filtration stages to remove Large-sized particles in the reinjection water to improve the quality of the reinjection water. However, these methods do not consider the technical idea of adjusting the temperature and flow rate of the reinjection water.

Therefore, it is necessary to provide a multi-station combined treatment system and method for oil field re-injection water to solve the above technical problems.

SUMMARY OF THE INVENTION

The invention provides a multi-station combined treatment system and method for oil field re-injection water, which solves the problem that the content of suspended solids and the median particle size do not meet the re-injection requirements.

In order to solve the above-mentioned technical problems, the oilfield reinjection water multi-station joint treatment system provided by the present invention includes:

Back-injection water heating device, back-injection water heating bypass device, water-injection station back-injection water return device, back-injection water return-transport bypass device, back-injection water injection into formation device, combined station and water injection station;

One side of the re-injection water heating device is connected to the combined station, the other side of the re-injection water heating device is connected with a re-injection water external pipeline (PL1), and the other end of the re-injection water external pipeline (PL1) connected with the water injection station, and the re-injection water heating bypass device is connected with the re-injection water heating device;

The water injection station is respectively connected with the water injection station back-injection water return device, the back-injection water return-transport bypass device, and the back-injection water injection into the formation device, and the back-injection water return-transport bypass device returns to the water injection station. The water injection return device is connected, the water injection station back injection water return device is connected with a back injection water return pipeline (PL2), and the other end of the back injection water return pipeline (PL2) is connected with the combined station.

Preferably, the re-injection water heating device includes two groups of gate valves (GV), heating furnaces (HF), thermometers (TM), gate valves (GV), check valves (CV) and flow meters (FW).

Preferably, the re-injection water heating bypass device includes a gate valve (GV) and a check valve (CV), and the gate valve (GV) and the check valve (CV) are connected in sequence.

Preferably, the reinjection water return device includes two groups of gate valves (GV), low pressure return pumps (LRP), pressure gauges (PG), gate valves (GV), check valves (CV) and flow meters (FW).

Preferably, the re-injection water return-transport bypass device includes a gate valve (GV) and a check valve (CV), and the gate valve (GV) and the check valve (CV) are connected in sequence.

Preferably, the injection water injection device includes a gate valve (GV), a high pressure injection pump (HPP), a pressure gauge (PG), a gate valve (GV), a check valve (CV) and a flow meter (FM).

Preferably, two groups of gate valve (GV), heating furnace (HF), thermometer (TM), gate valve (GV), check valve (CV) and flow meter (FW) in the re-injection water heating device are connected in sequence.

Preferably, two groups of gate valves (GV), low pressure return pumps (LRP), pressure gauges (PG), gate valves (GV), check valves (CV) and flow meters (FW) in the re-injection water return device are arranged in sequence connect.

Preferably, a gate valve (GV), a high pressure injection pump (HPP), a pressure gauge (PG), a gate valve (GV), a check valve (CV) and a flow meter (FM) are connected in sequence in the injection water injection into the formation device.

A method for an oilfield reinjection water multi-station combined treatment system, comprising the following steps:

S1. Open the gate valve (GV), the screw valve (SV), close the ball valve (BV), and open the heating furnace (HF) in the refilling water heating device, so that the two sets of heating devices are in an independent working state, and then close the refilling water heating Bypass the gate valve (GV) of the device to keep it in a shutdown state;

S2. The reinjection water exiting the joint station flows to the heating furnace (HF) through the gate valve (GV), after heating, the temperature is detected by the thermometer (TM) and the temperature data is recorded, and the flow rate is detected and recorded by the flow meter (FM), and the flow rate data is recorded. The heated re-injection water is transported to the water injection station through the re-injection water export pipeline (PL1);

S3. Open the gate valve (GV), the screw valve (SV), close the ball valve (BV), and turn on the low-pressure return pump (LRP) in the back-injection water return device, so that the two sets of return devices are in their independent working states. Close the gate valve (GV) of the return injection water bypass device to make it in a shutdown state;

S4. Part of the back-injection water of the water injection station flows to the low-pressure return pump (LRP) through the gate valve (GV), after pressurization, the pressure is detected by the pressure gauge (PG) and the pressure data is recorded, and the flow rate is detected and recorded by the flow meter (FM). Flow rate data, the pressurized back-injection water is returned to the union station through the back-injection water return pipeline (PL2);

S5. Open the gate valve (GV) and turn on the high pressure injection pump (HPP) in the reinjection water injection formation device, so that the high pressure reinjection is in a working state. The reinjection water that is not returned in the water injection station flows to the high pressure injection pump through the gate valve (GV). (HPP), after pressurization, the pressure is detected by the pressure gauge (PG) and the pressure data is recorded. The flow rate is detected by the flow meter (FM) and the flow rate data is recorded. After the pressurized water is injected back into the water injection well and finally injected back. to the ground.

Compared with the related art, the oilfield reinjection water multi-station combined treatment system and method provided by the present invention has the following beneficial effects:

The invention provides a multi-station combined treatment system and method for oil field reinjection water. By building a new reinjection water heating process device at the exit of the combined station, the reinjection water temperature is increased through a heating furnace, and the solubility of suspended solids in the reinjection water is increased, so that the It is not easy to separate out; between the union station and the water injection station, a new back-injection water return pipeline is built; at the water injection station, a back-injection water return process device is built, and part of the back-injection water is returned to the union station through the return pump to meet the requirements of the lifting and returning process. The vacancy of the required amount of re-injection water during the water injection flow rate can increase the external flow rate of the re-injection water, make the re-injection water enter the flow area of strong turbulence, enhance the shearing effect of the flow field, inhibit the agglomeration of suspended solids and promote the suspension of large particles of solids. Therefore, the treatment of increasing the water temperature and increasing the flow rate of the reinjection water can inhibit the new precipitation and agglomeration of suspended solids in the reinjection water, so that the content and median particle size of the suspended solids at the wellhead of the water injection well meet the reinjection requirements; It further realizes the adjustment of the flow rate and temperature of the reinjection water, and solves the problem of substandard water quality at the wellhead of the reinjection water in the oil field. It has the characteristics of flexible adjustment of working conditions, simple process flow and stable water quality.

Description of drawings

1 is a schematic structural diagram of a preferred embodiment of a multi-station combined treatment system for oil field re-injection water provided by the present invention;

Fig. 2 is the structural representation of the heating furnace provided by the present invention;

FIG. 3 is a structural cross-sectional view of the heating structure shown in FIG. 2 .

Labels in the figure: 1. Re-injection water heating device, 2. Re-injection water heating bypass device, 3. Re-injection water return device, 4. Re-injection water return and transportation bypass device, 5. Re-injection water injection into formation device, 6. Combined station , 7, water injection station, 8, shell, 9, V-plate, 10, heating structure, 101, heat conduction sleeve, 102, heat conduction rod, 103, heating wire, 11, heat exchange tube, 12, hot oil tank, 13, Hot oil pump, 14, heat pipe.

Detailed ways

The present invention will be further described below with reference to the accompanying drawings and embodiments.

Please refer to FIG. 1, FIG. 2 and FIG. 3 in combination, wherein, FIG. 1 is a schematic structural diagram of a preferred embodiment of a multi-station combined treatment system for oil field reinjection water provided by the present invention; FIG. 2 is a heating furnace provided by the present invention. Schematic diagram of the structure; FIG. 3 is a structural cross-sectional view of the heating structure shown in FIG. 2 . The oilfield reinjection water multi-station combined treatment system and method include:

Back-injection water heating device 1, back-injection water heating bypass device 2, water-injection station back-injection water return device 3, back-injection water return-transport bypass device 4, back-injection water injection into formation device 5, combined station 6 and water injection station 7;

One side of the re-injection water heating device 1 is connected to the combined station 6, and the other side of the re-injection water heating device 1 is connected with a re-injection water external pipeline (PL1), and the re-injection water external pipeline (PL1) The other end is connected with the water injection station 7;

The re-injection water heating bypass device 2 is connected to the re-injection water heating device 1, and the water-injection station 7 is respectively connected to the water-injection station re-injection water return device 3, the re-injection water return-transport bypass device 4 and the The back-injection water injection formation device 5 is connected, and the back-injection water return-transportation bypass device 4 is connected with the water-injection station back-injection water-return device 3, and the water-injection station back-injection water return device 3 is connected with a back-injection water return pipeline (PL2 ), the other end of the back injection water return pipeline (PL2) is connected to the combined station 6 .

The re-injection water heating device 1 includes two groups of gate valves (GV), a heating furnace (HF), a thermometer (TM), a gate valve (GV), a check valve (CV) and a flow meter (FW).

The re-injection water heating bypass device 2 includes a gate valve (GV) and a check valve (CV), and the gate valve (GV) and the check valve (CV) are connected in sequence.

The reinjection water return device 3 includes two groups of gate valves (GV), low pressure return pumps (LRP), pressure gauges (PG), gate valves (GV), check valves (CV) and flow meters (FW).

The reinjection water return bypass device 4 includes a gate valve (GV) and a check valve (CV), and the gate valve (GV) and the check valve (CV) are connected in sequence.

The reinjection water injection device 5 includes a gate valve (GV), a high pressure injection pump (HPP), a pressure gauge (PG), a gate valve (GV), a check valve (CV) and a flow meter (FM).

The two groups of gate valve (GV), heating furnace (HF), thermometer (TM), gate valve (GV), check valve (CV) and flow meter (FW) in the refill water heating device 1 are connected in sequence.

Two groups of gate valves (GV), low pressure return pumps (LRP), pressure gauges (PG), gate valves (GV), check valves (CV) and flow meters (FW) in the reinjection water return device 3 are connected in sequence.

The gate valve (GV), high pressure injection pump (HPP), pressure gauge (PG), gate valve (GV), check valve (CV) and flow meter (FM) in the reinjection water injection formation device 5 are connected in sequence.

A method for an oilfield reinjection water multi-station combined treatment system, comprising the following steps:

S1. Open the gate valve (GV), the screw valve (SV), close the ball valve (BV), and open the heating furnace (HF) in the refilling water heating device 1, so that the two sets of heating devices are in an independent working state, and then close the refilling water. Heat the gate valve (GV) of the bypass device 2 to make it in a shutdown state;

S2. The reinjection water exiting the station 6 flows to the heating furnace (HF) through the gate valve (GV), and after heating, the temperature is detected by the thermometer (TM) and the temperature data is recorded, and the flow rate is detected and recorded by the flow meter (FM). , the heated re-injection water is transported to the water injection station 7 through the re-injection water export pipeline (PL1) by using the residual pressure of the combined station;

S3. Open the gate valve (GV), the screw valve (SV), close the ball valve (BV), and turn on the low-pressure return pump (LRP) in the return injection device 3, so that the two sets of return devices are in independent working states. , close the gate valve (GV) of the return injection water return bypass device 4, so that it is in a shutdown working state;

S4. Part of the back-injection water in the water injection station 7 flows to the low-pressure return pump (LRP) through the gate valve (GV), and after being pressurized, the pressure is detected by the pressure gauge (PG) and the pressure data is recorded, and the flow rate is detected by the flow meter (FM). The flow rate data is recorded, and the pressurized back-injection water is returned to the Union Station 6 through the back-injection water return pipeline (PL2);

S5. Open the gate valve (GV) and turn on the high pressure injection pump (HPP) in the reinjection water injection formation device 5, so that the high pressure reinjection is in a working state, and the reinjection water that is not returned in the water injection station 7 flows to the high pressure through the gate valve (GV). The injection pump (HPP) is pressurized and then the pressure gauge (PG) is used to detect the pressure and record the pressure data, and the flow meter (FM) is used to detect the flow rate and record the flow rate data;

S6. The re-injection water after pressurization flows to the water injection well and is finally re-injected into the formation.

The present invention also provides a heating furnace, comprising a casing 8, a V-shaped plate 9 is fixedly connected between two sides of the inner wall of the casing 8, and a heating structure 10 is fixedly connected to the bottom of the inner wall of the casing 8 , the heating structure 10 includes a heat-conducting sleeve 101, a heat-conducting rod 102 is arranged between the top and bottom of the inner wall of the heat-conducting sleeve 101, and the heat-conducting rod 102 is located between the top and bottom of the inner wall of the heat-conducting sleeve 101 A heating wire 103 is arranged on the outer surface of the V-shaped plate 9, and a heat exchange tube 11 is connected to the top of the V-shaped plate 9. One end of the heat exchange tube 11 penetrates the shell 8 and extends to the outside of the shell 8, so The outer surface of the heat exchange tube 11 is wound around the outer surface of the thermally conductive sleeve 101 .

One side of the inner wall of the housing 8 is fixedly connected with a hot oil tank 12, a hot oil pump 13 is arranged on the top of the hot oil tank 12, and the suction port of the hot oil pump 13 is communicated with the interior of the hot oil tank 12 through an absorption pipe, The outlet of the thermal oil pump 13 is communicated with a heat transfer pipe 14, one end of the heat transfer pipe 14 is communicated with the bottom of the hot oil tank 12, and the outer surface of the heat transfer pipe 14 is wound and connected to the outer surface of the heat transfer sleeve 101;

The inside of the hot oil tank 12 is provided with hot oil, the hot oil is heated by the heating device inside the hot oil tank 12, and then absorbed by the hot oil pump 13, and then discharged to the inside of the heat transfer pipe 14, the top of the shell 8 A water inlet pipe is provided, which is connected to the external reinjection water source, and the reinjection water is sucked into the inside of the shell 8 through the water inlet pipe and enters the inside of the heat exchange pipe 11;

Through the re-injection water into the interior of the heat exchange tube 11, and through the hot oil into the interior of the heat-conducting tube 14, then the temperature inside the heat-conducting tube 14 will exchange heat with the re-injection water inside the heat exchange tube 11, thereby completing the return The heating of the water injection is simple to operate, the heating effect is good, and the re-injection water can be heated quickly.

The working principle of the oilfield reinjection water multi-station combined treatment system and method provided by the present invention is as follows:

Through the reinjection water heating device 1, different operation processes can be selected according to the different temperature requirements of the reinjection water; When it is low, only one set of heating processes can be started; when the reinjection water does not need to be heated, the reinjection water can directly enter the reinjection water external pipeline PL1 through the reinjection water heating bypass device 2;

Through the reinjection water heating device 1, the maintenance of the heating furnace (HF) and the calibration of the flow meter (FM) can be realized according to the different switch settings of the gate valve (GV) and the ball valve (BV); by closing the inlet and outlet of the heating furnace (HF) If the gate valve (GV) is installed, the heating furnace (HF) clamped by the two gate valves (GV) can be overhauled; by closing the gate valve (GV) at the inlet of the flow meter (FM) and opening the ball valve (BV), the heating furnace (HF) can be repaired. The flow meter (FM) is calibrated without affecting the normal operation of the heating process;

Through the back-injection water return device 3, the corresponding operation process can be selected according to the different requirements for the return of the back-injection water; when a large amount of back-injection water is required to be returned, two sets of return-injection processes can be started at the same time; When it is low, only one set of return transportation process can be opened; when the residual pressure of the return injection water of the water injection station meets the return transportation requirements, the return injection water can directly enter the return injection water return pipeline (PL2) through the return injection water return transportation bypass device 4;

Through the back injection water return device 3, the maintenance of the low pressure return pump (LRP) and the calibration of the flow meter (FM) can be realized according to the different switch settings of the gate valve (GV) and the ball valve (BV); by closing the low pressure return pump ( LRP) inlet and outlet gate valve (GV), the low pressure return pump (LRP) between the two gate valves (GV) can be overhauled; by closing the gate valve (GV) at the inlet of the flow meter (FM) and opening the ball valve ( BV), the flow meter (FM) can be calibrated without affecting the normal operation of the return process.

Compared with the related art, the oilfield reinjection water multi-station combined treatment system and method provided by the present invention has the following beneficial effects:

By building a new re-injection water heating process device at the exit 6 of the Union Station, the temperature of the re-injection water is increased through the heating furnace, and the solubility of the suspended solids in the re-injection water is increased, making it difficult to precipitate; Water injection return pipeline; a new return water injection process device is built in the water injection station 7, and part of the return injection water is returned to the joint station 6 through the return pump to meet the vacancy of the return water injection volume required to increase the return water injection flow rate, so as to improve the The flow rate of the reinjection water is transferred to the outside, so that the reinjection water enters the flow area of strong turbulence, enhances the shearing effect of the flow field, inhibits the agglomeration of suspended solids and promotes the fragmentation of large suspended solids. Treatment can inhibit the new precipitation and aggregation growth of suspended solids in the reinjection water, so that the content and median particle size of suspended solids at the wellhead of the water injection well meet the reinjection requirements; It solves the problem that the water quality of the oilfield reinjection wellhead does not meet the standard, and has the characteristics of flexible adjustment of working conditions, simple process flow, and stable water quality and physical properties.

The above descriptions are only the embodiments of the present invention, and are not intended to limit the scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the description and drawings of the present invention, or directly or indirectly applied to other related technologies Fields are similarly included in the scope of patent protection of the present invention.

Claims (1)

1. a working method of oil field re-injection water multi-station joint processing system, is characterized in that, Oilfield reinjection water multi-station combined treatment system includes: Back-injection water heating device, back-injection water heating bypass device, water-injection station back-injection water return device, back-injection water return-transport bypass device, back-injection water injection into formation device, combined station and water injection station; One side of the reinjection water heating device is connected to the combined station, the other side of the reinjection water heating device is connected with a reinjection water external pipeline (PL1), and the other end of the reinjection water external pipeline (PL1) connected to said water injection station; The re-injection water heating bypass device is connected to the re-injection water heating device, and the water injection station is respectively connected to the water-injection station re-injection water return device, the re-injection water return-transport bypass device and the re-injection water injection stratum device The back-injection water return-transport bypass device is connected to the back-injection water-return device of the water-injection station, and the back-injection water-return device of the water-injection station is connected with a back-injection water return pipeline (PL2), and the back-injection water return pipeline (PL2) the other end is connected to the combined station; The reinjection water heating device includes two groups of gate valves (GV), a heating furnace (HF), a thermometer (TM), a gate valve (GV), a check valve (CV) and a flow meter (FW). Two groups of gate valve (GV), heating furnace (HF), thermometer (TM), gate valve (GV), check valve (CV) and flowmeter (FW) are connected in sequence; The reinjection water return device includes two groups of gate valves (GV), low pressure return pumps (LRP), pressure gauges (PG), gate valves (GV), check valves (CV) and flow meters (FW). The two groups of gate valve (GV), low pressure return pump (LRP), pressure gauge (PG), gate valve (GV), check valve (CV) and flow meter (FW) in the water injection return device are connected in sequence; The re-injection water heating bypass device includes a gate valve (GV) and a check valve (CV), and the gate valve (GV) and the check valve (CV) are connected in sequence; The re-injection water return-transport bypass device includes a gate valve (GV) and a check valve (CV), and the gate valve (GV) and the check valve (CV) are connected in sequence; The re-injection water injection device includes a gate valve (GV), a high pressure injection pump (HPP), a pressure gauge (PG), a gate valve (GV), a check valve (CV) and a flow meter (FM); The gate valve (GV), the high pressure injection pump (HPP), the pressure gauge (PG), the gate valve (GV), the check valve (CV) and the flow meter (FM) are connected in sequence in the injection water injection formation device; The working method of the oilfield reinjection water multi-station joint treatment system includes the following steps: S1. Open the gate valve (GV), the screw valve (SV), close the ball valve (BV), and open the heating furnace (HF) in the refilling water heating device, so that the two sets of heating devices are in an independent working state, and then close the refilling water heating The gate valve (GV) of the bypass device keeps the water injection heating bypass device in a shutdown state; S2. The reinjection water exiting the Union Station flows to the heating furnace (HF) through the gate valve (GV), after heating, the temperature is detected by the thermometer (TM) and the temperature data is recorded, and the flow rate is detected and recorded by the flow meter (FM), and the flow rate data is recorded. The heated re-injection water is transported to the water injection station through the re-injection water external pipeline (PL1) using the residual pressure of the combined station; S3. Open the gate valve (GV), the screw valve (SV), close the ball valve (BV), and open the low-pressure return pump (LRP) in the return injection device, so that the two sets of return devices are in their independent working states. Close the gate valve (GV) of the water injection return bypass device, so that the return injection water return bypass device is in a shutdown state; S4. Part of the back-injection water in the water injection station flows to the low-pressure return pump (LRP) through the gate valve (GV), after pressurization, the pressure is detected by the pressure gauge (PG) and the pressure data is recorded, and the flow rate is detected and recorded by the flow meter (FM). Flow rate data, the pressurized back-injection water is returned to the Union Station through the back-injection water return pipeline (PL2); S5. Open the gate valve (GV) and turn on the high pressure injection pump (HPP) in the reinjection water injection formation device, so that the high pressure reinjection is in a working state, and the reinjection water that is not returned in the water injection station flows to the high pressure injection pump through the gate valve (GV). (HPP), after pressurization, the pressure is detected by the pressure gauge (PG) and the pressure data is recorded, and the flow rate is detected by the flow meter (FM) and the flow rate data is recorded; S6. The re-injection water after pressurization flows to the water injection well and is finally re-injected into the formation.

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