阅读说明：本技术 一种无负压地热回灌系统及回灌方法 (Negative-pressure-free geothermal recharging system and recharging method ) 是由 刘瑞军 汪浩 卢星辰 李笑天 王洪亮 王荣康 秦玉净 于 2020-11-25 设计创作，主要内容包括：本发明公开了一种无负压地热回灌系统及回灌方法,其中回灌系统包括稳流罐和氮气补偿装置,所述稳流罐的上部设置有稳流罐压力表,所述稳流罐的进口连接地热尾水进口,所述地热尾水进口和稳流罐的进口之间设置有第一流量计,所述稳流罐的出口连接地热回灌井,所述地热回灌井的井口处设置有密封回灌井口装置和井口压力表,所述稳流罐的出口和地热回灌井之间的依次设置有第一电控阀和第二流量计,所述氮气补偿装置通过氮气补偿管线分别连接至稳流罐内和地热回灌井内,本发明通过设置稳流罐将地热尾水进口处不稳定的压力转化为稳流罐内可控的压力,通过氮气补偿装置调节稳流罐与地热回灌井内的压力平衡,从而保证回灌系统稳态运行。(The invention discloses a negative-pressure-free geothermal recharging system and a recharging method, wherein the recharging system comprises a steady flow tank and a nitrogen compensating device, the upper part of the steady flow tank is provided with a steady flow tank pressure gauge, the inlet of the steady flow tank is connected with a geothermal tail water inlet, a first flowmeter is arranged between the geothermal tail water inlet and the inlet of the steady flow tank, the outlet of the steady flow tank is connected with a geothermal recharging well, the well head of the geothermal recharging well is provided with a sealed recharging well head device and a well head pressure gauge, a first electric control valve and a second flowmeter are sequentially arranged between the outlet of the steady flow tank and the geothermal recharging well, the nitrogen compensating device is respectively connected into the steady flow tank and the geothermal recharging well through a nitrogen compensating pipeline, the unstable pressure at the geothermal tail water inlet is converted into controllable pressure in the steady flow tank through the steady flow tank, the pressure balance between the steady flow tank and the geothermal recharging well is adjusted through the nitrogen compensating device, thereby ensuring the steady-state operation of the recharging system.)

1. The utility model provides a no negative pressure geothermal recharging system which characterized in that: including setting up in subaerial stationary flow jar (1) and nitrogen gas compensation arrangement (2), the upper portion of stationary flow jar (1) is provided with stationary flow jar manometer (3), the import of stationary flow jar (1) is through recharging pipeline (4) connection geothermol power tail water import (5), be provided with first flowmeter (6) on recharging pipeline (4) between the import of geothermol power tail water import (5) and stationary flow jar (1), the export of stationary flow jar (1) is connected through recharging pipeline (4) and is set up in geothermal recharging well (7) underground, the well head department of geothermal recharging well (7) is provided with sealed recharging well head device (8) and well head manometer (9), be provided with the installing port of well head manometer (9) and the installing port of recharging pipeline (4) on recharging well head device (8), set gradually first automatically controlled valve (10) and second flow on recharging pipeline (4) between the export of jar (1) and geothermal recharging well (7) The device comprises a flow meter (11), wherein the nitrogen compensation device (2) is connected into a steady flow tank (1) and a geothermal recharging well (7) through a nitrogen compensation pipeline (12), a second electric control valve (13) is arranged on the nitrogen compensation pipeline (12) between the nitrogen compensation device (2) and the steady flow tank (1), a third electric control valve (14) is arranged on the nitrogen compensation pipeline (12) between the nitrogen compensation device (2) and the geothermal recharging well (7), and the nitrogen compensation device (2), the steady flow tank pressure meter (3), a first flow meter (6), a wellhead pressure meter (9), the first electric control valve (10), a second flow meter (11), the second electric control valve (13) and the third electric control valve (14) are electrically connected with a PLC central controller (15) respectively.

2. A non-negative pressure geothermal recharging system as defined in claim 1 wherein: the sealed recharging wellhead device (8) is connected with the wellhead of the geothermal recharging well (7) through a flange, and the joint is sealed.

3. The geothermal recharging method without negative pressure is characterized in that: the method comprises the following steps:

s1: terrestrial heat tail water enters the flow stabilizing tank (1) through an inlet of the flow stabilizing tank (1) after entering through a terrestrial heat tail water inlet (5), and the inlet flow of the flow stabilizing tank (1) is measured to be Q through a first flow meter (6)₁；

S2: the geothermal tail water is gathered at the lower part of the steady flow tank (1) and sequentially passes through the outlet of the steady flow tank (1), the first electric control valve (10) and the second flowThe flow meter (11) is recharged into the geothermal recharging well (7), and the outlet flow of the steady flow tank (1) is measured to be Q by the second flow meter (11)₂；

S3; judgment of Q₁And Q₂The size of (d); when Q is₁≠Q₂In the time, the PLC central controller (15) controls Q by adjusting the opening of the first electric control valve (10)₁＝Q₂；

S4: the pressure in the steady flow tank (1) measured by the steady flow tank pressure gauge (3) is marked as P₁The pressure value in the geothermal recharging well (7) measured by the wellhead pressure gauge (9) is P₂Setting the rated pressure value of the system to be P₀；

S5: judgment of P₁And P₂Are respectively connected with P₀If P is the size of₁<P₀When the nitrogen-supplementing device is started, the PLC central controller (15) controls the nitrogen-compensating device (2) and the second electric valve (13) to be opened, meanwhile, the third electric valve (14) is closed, and nitrogen is supplemented into the flow-stabilizing tank (1) until P₁＝P₀(ii) a When P is present₂<P₀When the system is used, the PLC central controller (15) controls the nitrogen compensation device (2) and the third electric valve (14) to be opened, meanwhile, the second electric valve (13) is closed, and nitrogen is supplemented into the geothermal recharging well (7) until P₂＝P₀。

4. A method of geothermal recharging without negative pressure as in claim 3 wherein: the calculation formula of the opening degree of the first electronic control valve (10) in the step S3 is as follows:

let Q₁＝Q₂，

Then

Wherein phi is the opening degree of the first electric control valve (10), and Qmax is the maximum rated flow of the first electric control valve (10).

Technical Field

The invention relates to the field of geothermal development, in particular to a negative-pressure-free geothermal recharging system and a recharging method.

Background

Geothermal tail water recharging refers to a technology for re-injecting geothermal fluid with reduced temperature into a heat reservoir through a recharging well. The geothermal tail water recharge has very important significance for prolonging the service life of the hot field, reducing the discharge of the heat supply tail water, polluting the environment and preventing the ground from settling caused by mining.

According to different pressure modes of injecting fluid into a reservoir, geothermal tail water recharging modes can be divided into pressurization recharging and negative pressure recharging. When the permeability of the aquifer of the recharge well is poor and the water absorption capacity of the stratum cannot meet the actual recharge requirement, pressure is increased in the recharge system under the action of external force, so that the natural water absorption capacity of the stratum is compensated, and the recharge requirement is met.

When the permeability of the aquifer of the recharge well is strong, such as a karst fracture type geothermal recharge well, the water absorption capacity of the geothermal reservoir of the type is often far greater than the actual recharge requirement, and a negative pressure recharge mode is adopted at the moment. When the negative pressure is used for recharging, the water absorption capacity of the stratum is larger than the tail water flow of the system, so that a vacuum column is formed in the heating system frequently, the heating effect is influenced on one hand, and difficulty is brought to geothermy dynamic monitoring on the other hand, for example, recharging flow monitoring errors are large. Because the conventional negative pressure suppressor can cause air to enter the recharging system, the quality of the recharging tail water is changed, and a recharging channel is blocked, a device is urgently needed to ensure the pressure balance in the recharging system.

Disclosure of Invention

The invention provides a negative-pressure-free geothermal recharge system and a recharge method, wherein a steady flow tank is arranged to convert unstable pressure at a geothermal tail water inlet into controllable pressure in the steady flow tank, and a nitrogen compensation device is used for adjusting the pressure balance between the steady flow tank and a geothermal recharge well, so that the steady operation of the recharge system is ensured.

In order to solve the technical problems, the technical scheme adopted by the invention is as follows: a negative-pressure-free geothermal recharging system comprises a steady flow tank and a nitrogen compensating device which are arranged on the ground, wherein a steady flow tank pressure gauge is arranged at the upper part of the steady flow tank, the inlet of the steady flow tank is connected with a geothermal tail water inlet through a recharging pipeline, a first flowmeter is arranged on the recharging pipeline between the geothermal tail water inlet and the inlet of the steady flow tank, the outlet of the steady flow tank is connected with a geothermal recharging well through a recharging pipeline, a sealed recharging well head device and a well head pressure gauge are arranged at the well head of the geothermal recharging well, a mounting hole of the well head pressure gauge and a mounting hole of the recharging pipeline are arranged on the recharging well head device, a first electric control valve and a second flowmeter are sequentially arranged on the recharging pipeline between the outlet of the steady flow tank and the geothermal recharging well, the nitrogen compensating device is respectively connected into the steady flow tank and the geothermal recharging well through a nitrogen compensating pipeline, and a second electric control valve is arranged on a nitrogen compensation pipeline between the nitrogen compensation device and the flow stabilization tank, a third electric control valve is arranged on the nitrogen compensation pipeline between the nitrogen compensation device and the geothermal recharge well, and the nitrogen compensation device, the flow stabilization tank pressure gauge, the first flowmeter, the wellhead pressure gauge, the first electric control valve, the second flowmeter, the second electric control valve and the third electric control valve are respectively and electrically connected with the PLC central controller.

The technical scheme of the invention is further improved as follows: the sealed recharging wellhead device is connected with a wellhead of the geothermal recharging well by a flange, and the joint is sealed.

The technical scheme of the invention is further improved as follows: a geothermal recharging method without negative pressure comprises the following steps:

s1: geothermal tail water enters the flow stabilizing tank through an inlet of the flow stabilizing tank after entering the geothermal tail water through an inlet of the geothermal tail water, and the inlet flow of the flow stabilizing tank is measured to be Q through the first flowmeter₁；

S2: geothermy tail water is gathered at the lower part of the flow stabilizing tank and is recharged to the geothermy recharging well through the outlet of the flow stabilizing tank, the first electric control valve and the second flow meter in sequence, and the outlet flow of the flow stabilizing tank is measured by the second flow meter to be Q₂；

S3: judgment of Q₁And Q₂The size of (d); when Q is₁≠Q₂In time, the PLC central controller controls the Q by adjusting the opening of the first electric control valve₁＝Q₂；

S4: the pressure in the steady flow tank measured by the steady flow tank pressure gauge is marked as P₁The pressure value in the geothermal recharge well measured by a wellhead pressure gauge is P₂Setting the rated pressure value of the system to be P₀；

S5: judgment of P₁And P₂Are respectively connected with P₀If P is the size of₁<P₀When the nitrogen compensation device and the second electric valve are controlled to be opened by the PLC central controller, the third electric valve is closed at the same time, and nitrogen is supplemented into the flow stabilization tank until P₁＝P₀(ii) a When P is present₂<P₀When the system is used, the PLC central controller controls the nitrogen compensation device and the third electric valve to be opened, and simultaneously the second electric valve is closed to supplement nitrogen into the geothermal recharge well until P₂＝P₀。

The technical scheme of the invention is further improved as follows: the calculation formula of the opening degree of the first electronic control valve in the step S3 is as follows:

let Q₁＝Q₂，

Then

Where φ is the opening of the first electrically controlled valve, Qmax is the maximum rated flow of the first electrically controlled valve.

Due to the adoption of the technical scheme, the invention has the technical progress that:

1. the stable flow tank is arranged to convert unstable pressure at the inlet of the geothermal tail water into controllable pressure in the stable flow tank, and the nitrogen compensation device is used for adjusting the pressure balance between the stable flow tank and the geothermal recharge well, so that the steady-state operation of the recharge system is ensured; the nitrogen compensation device is arranged to adjust the pressure balance between the inside of the flow stabilizing tank and the inside of the geothermal recharging well on one hand, and on the other hand, the stable chemical property of the nitrogen can protect the shaft of the geothermal recharging well from chemical corrosion and prolong the service life of the geothermal recharging well on the other hand.

2. According to the invention, the opening degree of the first electric control valve is adjusted through the PLC central controller, so that the inlet flow of the steady flow tank is ensured to be Q₁And steady flow tank outlet flow Q₂Keep consistent, ensure the stable operation of the system, when Q₁>Q₂The liquid level in the flow stabilizing tank continuously rises, and when the liquid level exceeds the inlet of the flow stabilizing tank, the system fails; when Q is₁<Q₂When the liquid level reaches the outlet of the steady flow tank, the system generates negative pressure, and nitrogen in the steady flow tank enters the geothermal recharging well through the first electric control valve to form a gas column, so that the monitoring of the geothermal recharging well is influenced.

Drawings

FIG. 1 is a flow chart of the system of the present invention;

the system comprises a flow stabilizing tank, a nitrogen compensating device, a flow stabilizing tank pressure gauge, a recharge pipeline, a geothermal tail water inlet, a first flowmeter, a geothermal recharge well, a sealed recharge wellhead device, a wellhead pressure gauge, a first electric control valve, a second flowmeter, a nitrogen compensating pipeline, a second electric control valve, a third electric control valve, a PLC (programmable logic controller) and a central controller, wherein the flow stabilizing tank 1, the nitrogen compensating device 3, the flow stabilizing tank pressure gauge 4, the recharge pipeline 5, the geothermal tail water inlet 6, the first flowmeter, the geothermal recharge well, the sealed recharge wellhead device 9, the wellhead pressure gauge 10, the.

Detailed Description

The present invention will be described in further detail with reference to the following examples:

as shown in fig. 1, a negative-pressure-free geothermal recharging system comprises a steady flow tank 1 and a nitrogen compensation device 2 which are arranged on the ground, wherein a steady flow tank pressure gauge 3 is arranged on the upper portion of the steady flow tank 1, the inlet of the steady flow tank 1 is connected with a geothermal tail water inlet 5 through a recharging pipeline 4, a first flowmeter 6 is arranged on the recharging pipeline 4 between the geothermal tail water inlet 5 and the inlet of the steady flow tank 1, the outlet of the steady flow tank 1 is connected with a geothermal recharging well 7 which is arranged underground through the recharging pipeline 4, a sealing recharging wellhead device 8 and a wellhead pressure gauge 9 are arranged at the wellhead of the geothermal recharging well 7, and the sealing recharging wellhead device 8 adopts the wellhead connection of a flange and the geothermal recharging well 7 and the sealing treatment of the connection. The recharging wellhead device 8 is provided with a mounting port of a wellhead pressure gauge 9 and a mounting port of a recharging pipeline 4, a first electric control valve 10 and a second flowmeter 11 are sequentially arranged on the recharge pipeline 4 between the outlet of the steady flow tank 1 and the geothermal recharge well 7, the nitrogen compensation device 2 is respectively connected into the flow stabilization tank 1 and the geothermal recharging well 7 through a nitrogen compensation pipeline 12, a second electric control valve 13 is arranged on a nitrogen compensation pipeline 12 between the nitrogen compensation device 2 and the steady flow tank 1, a third electric control valve 14 is arranged on the nitrogen compensation pipeline 12 between the nitrogen compensation device 2 and the geothermal recharging well 7, the nitrogen compensation device 2, the steady flow tank pressure gauge 3, the first flowmeter 6, the wellhead pressure gauge 9, the first electric control valve 10, the second flowmeter 11, the second electric control valve 13 and the third electric control valve 14 are respectively and electrically connected with the PLC central controller 15.

The specific implementation mode is as follows:

a geothermal recharging method without negative pressure comprises the following steps:

s1: terrestrial heat tail water enters the flow stabilizing tank 1 through the inlet of the flow stabilizing tank 1 after entering the terrestrial heat tail water inlet 5, and the inlet flow of the flow stabilizing tank 1 is measured to be Q through the first flow meter 6₁；

S2: the geothermal tail water is gathered at the lower part of the flow stabilizing tank 1 and is recharged to the geothermal recharging well 7 through the outlet of the flow stabilizing tank 1, the first electric control valve 10 and the second flow meter 11 in sequence, and the outlet flow of the flow stabilizing tank 1 is measured to be Q through the second flow meter 11₂；

S3; judgment of Q₁And Q₂The size of (d); when Q is₁≠Q₂Meanwhile, the PLC central controller 15 controls Q by adjusting the opening degree of the first electrically controlled valve 10₁＝Q₂Ensuring stable operation of the system when Q is₁>Q₂The liquid level in the flow stabilizing tank 1 continuously rises, and when the liquid level exceeds the inlet of the flow stabilizing tank 1, the system fails; when Q is₁<Q₂The liquid level in the steady flow tank 1 continuously drops, and when the liquid level reaches the outlet of the steady flow tank 1, the system generatesUnder negative pressure, nitrogen in the steady flow tank 1 enters the geothermal recharging well 7 through the first electric control valve 10 to form an air column, so that monitoring of the geothermal recharging well 7 is influenced;

the calculation formula of the opening degree of the first electronic control valve 10 in the step S3 is as follows:

let Q₁＝Q₂，

ThenWhere φ is the opening of the first electrically controlled valve 10, and Qmax is the maximum rated flow of the first electrically controlled valve 10.

S4: the pressure in the steady flow tank 1 measured by the steady flow tank pressure gauge 3 is marked as P₁The pressure value in the geothermal recharging well 7 measured by the wellhead pressure gauge 9 is P₂Setting the rated pressure value of the system to be P₀；

S5: judgment of P₁And P₂Are respectively connected with P₀If P is the size of₁<P₀Meanwhile, the PLC central controller 15 controls the nitrogen compensation device 2 and the second electric valve 13 to be opened, simultaneously the third electric valve 14 is closed, and nitrogen is supplemented into the flow stabilizing tank 1 until P₁＝P₀(ii) a When P is present₂<P₀When the system is used, the PLC central controller 15 controls the nitrogen compensation device 2 and the third electric valve 14 to be opened, simultaneously the second electric valve 13 is closed, and nitrogen is supplemented into the geothermal recharge well 7 until P₂＝P₀The nitrogen compensation device 2 is arranged to adjust the pressure balance between the inside of the flow stabilizing tank 1 and the inside of the geothermal recharging well 7, and to protect the shaft of the geothermal recharging well 7 from chemical corrosion and prolong the service life of the geothermal recharging well 7 due to the stable chemical property of nitrogen.