Method for exploiting gravel pore type brine under water replenishing condition

Abstract

The invention provides a gravel pore type brine exploitation method under the water supplementing condition, and belongs to the technical field of brine exploitation. The method comprises the steps that an extraction well and a gas injection well are constructed and built, gas is injected into the gas injection well through gas injection equipment, the injected gas forms a gas wall in a brine layer, and the gas wall is formed in the brine layer through water pumping equipment at the extraction well; the method comprises the following steps: firstly, extracting brine, located at the section of an extraction well and a gas injection well, of a brine layer, then closing gas injection equipment and water pumping equipment to recover the concentration of the brine to the concentration meeting the requirement, and then circulating the steps to carry out the whole brine extraction process. The problems that after brine is extracted from a brine layer at the same position for a long time, underground water in the section has no time to fully absorb underground mineral ions into water to form brine with the concentration meeting the requirement, the concentration of the brine extracted from the section is reduced, and the exploitation requirement is not met are solved.

Description

Technical Field

[0001] The invention belongs to the technical field of brine exploitation, and in particular relates to a method for exploiting gravel porous brine under water replenishment conditions. Background Art

[0002] Brine is highly mineralized water, which often contains ions such as K, Na+, Ca, Mg, Cl, B, Li, Br, I, Sr, Rb, and Cs. Brine or salt brine is classified according to its burial location into shallow brine and deep brine. Deep brine is generally located more than 200m deep in the stratum and is a highly mineralized groundwater. This type of brine is buried deep and is highly closed. Its formation is mainly determined by geological, climatic and hydrogeological conditions.

[0003] Deep lithium-rich brine is an important mineral resource, and lithium resources are an important raw material for the new energy industry. With the rapid development of the new energy industry, my country's lithium carbonate consumption has climbed to 52.5% of the world's total, but the import dependence of lithium products exceeds 70%. 85% of my country's lithium resources exist in salt lake brine. The huge demand for lithium products has made the extraction of lithium from salt lake brine a key proposition of national strategy, which is of great significance to the development and utilization of underground lithium-potassium-rich brine.

[0004] There are two common deep brine storage types. One is the fissure-porous brine, which is mainly affected by tectonic action and usually belongs to ancient brine without obvious recharge sources. The other is the gravel-porous brine, which is mainly affected by sedimentation and is usually closely related to the modern water circulation system. At present, the exploitation of gravel-porous brine will cause obvious drop funnels during the exploitation process, causing the surrounding water resources to quickly flow toward the extraction well. Therefore, after long-term extraction of brine from the brine layer at the same location, the original recharge balance of the groundwater in the area is destroyed, and there is no time to fully absorb the underground mineral ions into the water to form brine with a concentration that meets the demand, resulting in a decrease in the concentration of brine extracted from the area, which does not meet the demand. Therefore, a gravel-porous brine exploitation method under water replenishment conditions is needed to solve this problem. Summary of the invention

[0005] To achieve the above object, the present invention provides a method for exploiting gravel porous brine under water replenishment conditions, comprising the following steps:

[0006] S1: First, explore and select the mining site for brine, then select the area where the brine layer concentration meets the requirements to construct extraction wells and several gas injection wells. The extraction wells are set up downstream in the direction of brine runoff, and several gas injection wells are set up upstream in the direction of brine runoff. The brine ion concentration is lower than the boundary grade, and the several gas injection wells are arranged in a row with intervals;

[0007] S2: Inject gas into several gas injection wells through gas injection equipment, so that the injected gas forms a gas isolation wall in the brine layer, which is used to enhance the seepage power of the brine downstream in the runoff direction and accelerate the flow rate, so that it flows quickly to the extraction well, and at the same time blocks the brine upstream in the runoff direction;

[0008] S3: After the upstream is blocked, the brine in the brine layer between the extraction well and a row of gas injection wells is extracted by pumping equipment at the extraction well;

[0009] S4: After the extraction is completed, the gas injection equipment is first closed and the hole is temporarily sealed. Then the pumping well is closed and the orifice pressure of the pumping well is monitored in real time. Combined with the drilling stability requirements, the orifice pressure is regularly relieved. During this period, the brine flow direction is such that the upstream brine flows normally to the downstream, and the mineral components in the rock formation are dissolved and filtered, so that the brine concentration is restored to the concentration that meets the requirements;

[0010] S5: Monitor the brine ion concentration generated when the pumping port is depressurized. When the concentration of the brine mining area selected for exploration is restored to a concentration that meets the requirements, repeat steps S2 to S4 in sequence, and the entire brine extraction process can be repeated repeatedly.

[0011] Furthermore, the pressure of the extraction wells and the plurality of gas injection wells established in step S1 is 0.8-1.2 Mpa every 100 m of penetration.

[0012] Furthermore, the gas injected into the gas injection well is air, nitrogen, or carbon dioxide.

[0013] The advantages of the present invention are as follows: the present invention provides a method for exploiting gravel porous brine under water replenishment conditions, which solves the problem that after long-term extraction of brine from the brine layer at the same location, the groundwater in the area does not have time to fully absorb the underground mineral ions into the water to form brine with a concentration that meets the requirements, resulting in a decrease in the concentration of the brine extracted from the area, which does not meet the exploitation requirements.

[0014] The present invention is described in detail below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 The present invention is a flow chart of gravel porous brine mining. DETAILED DESCRIPTION

[0016] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined purpose, the specific implementation methods, structural features and effects of the present invention are described in detail below in conjunction with the accompanying drawings and embodiments.

[0017] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] In the description of the present invention, it is necessary to understand that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "aligned", "overlap", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0019] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features; in the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0020] Example 1

[0021] This embodiment provides Figure 1 A method for exploiting gravel porous brine under water replenishment conditions is shown, comprising the following steps:

[0022] S1: First, explore and select the mining site for brine, then select the area where the brine layer concentration meets the requirements to construct extraction wells and several gas injection wells. The extraction wells are set up downstream in the direction of brine runoff, and several gas injection wells are set up upstream in the direction of brine runoff. The brine ion concentration is lower than the boundary grade, and the several gas injection wells are arranged in a row with intervals;

[0023] S2: Inject gas into several gas injection wells through gas injection equipment, so that the injected gas forms a gas isolation wall in the brine layer, which is used to enhance the seepage power of the brine downstream in the runoff direction and accelerate the flow rate, so that it flows quickly to the extraction well, and at the same time blocks the brine upstream in the runoff direction;

[0024] S3: After the upstream is blocked, the brine in the brine layer between the extraction well and a row of gas injection wells is extracted by pumping equipment at the extraction well;

[0025] S4: After the extraction is completed, the gas injection equipment is first closed and the hole is temporarily sealed. Then the pumping well is closed and the orifice pressure of the pumping well is monitored in real time. Combined with the drilling stability requirements, the orifice pressure is regularly relieved. During this period, the brine flow direction is such that the upstream brine flows normally to the downstream, and the mineral components in the rock formation are dissolved and filtered, so that the brine concentration is restored to the concentration that meets the requirements;

[0026] S5: Monitor the brine ion concentration generated when the pumping port is depressurized. When the concentration of the brine mining area selected for exploration is restored to a concentration that meets the requirements, repeat steps S2 to S4 in sequence, and the entire brine extraction process can be repeated repeatedly.

[0027] Furthermore, the pressure of the extraction wells and the plurality of gas injection wells established in step S1 is 0.8-1.2 Mpa every 100 m of penetration.

[0028] Furthermore, the gas injected into the gas injection well is air, nitrogen, or carbon dioxide.

[0029] When in use, first explore and select the mining site of brine, then select the section where the brine layer concentration meets the requirements to construct extraction wells and several gas injection wells. The extraction wells are set up downstream in the direction of brine runoff, and several gas injection wells are set up upstream in the direction of brine runoff. The brine ion concentration is lower than the boundary grade, and the several gas injection wells are arranged in a row with intervals.

[0030] Among them, the established extraction wells and several gas injection wells have a pressure of 0.8-1.2Mpa every 100m down. The spacing between the wells is obtained based on the influence radius obtained from the pumping test, and the spacing should not be less than the influence radius. The gas injected into the gas injection wells can be air, nitrogen, carbon dioxide, etc.;

[0031] In addition, the concentration of the brine layer that meets the requirements varies according to the different brine types. For example, when the target ion is K+ ion, the brine concentration should be no less than 0.6g / L according to KCl calculation. When the target ion is Li+ ion, the concentration should be no less than 150mg / L according to LiCl calculation. The specific brine concentration may vary due to fluctuations in market factors and needs to be determined based on the market conditions of different target ion mineral target products.

[0032] After it is established, gas is injected into several gas injection wells through gas injection equipment, so that the injected gas forms a gas isolation wall in the brine layer, which is used to enhance the seepage power of the brine in the downstream direction of the runoff and accelerate the flow rate, so that it flows quickly to the extraction well, and at the same time blocks the brine in the upstream direction of the runoff; after blocking the upstream, the brine in the brine layer between the extraction well and a row of gas injection wells is extracted at the extraction well through the pumping equipment;

[0033] After the extraction is completed, the gas injection equipment is first closed and the hole is temporarily sealed. Then the pumping well is closed and the orifice pressure of the pumping well is monitored in real time. Combined with the requirements of drilling stability, the orifice pressure is regularly relieved. During this period, the brine flow direction is such that the upstream brine flows normally to the downstream, and the mineral components in the rock formation are dissolved and filtered, so that the brine concentration is restored to the concentration that meets the requirements.

[0034] Finally, monitor the brine ion concentration generated when the pumping port is depressurized. When the concentration of the brine mining area selected for exploration is restored to a concentration that meets the requirements, repeat the above method steps in sequence. The entire brine extraction process can be repeated over and over again, so that the concentration of brine extracted from the brine reservoir reaches a level that meets the requirements.

[0035] In summary, the present invention provides a method for exploiting gravel porous brine under water replenishment conditions, which solves the problem that after long-term extraction of brine from the brine layer at the same location, the groundwater in the area does not have time to fully absorb the underground mineral ions into the water to form brine with a concentration that meets the requirements, resulting in the concentration of brine extracted from the area being reduced and not meeting the exploitation requirements.

[0036] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the protection scope of the present invention.

Claims

1. A method for exploiting gravel porous brine under water replenishment conditions, characterized by: The steps include: S1: First, explore and select the mining site for brine, then select the area where the brine layer concentration meets the requirements to construct extraction wells and several gas injection wells. The extraction wells are set up downstream in the direction of brine runoff, and several gas injection wells are set up upstream in the direction of brine runoff. The brine ion concentration is lower than the boundary grade, and the several gas injection wells are arranged in a row with intervals; S2: Inject gas into several gas injection wells through gas injection equipment, so that the injected gas forms a gas isolation wall in the brine layer, which is used to enhance the seepage power of the brine downstream in the runoff direction and accelerate the flow rate, so that it flows quickly to the extraction well, and at the same time blocks the brine upstream in the runoff direction; S3: After the upstream is blocked, the brine in the brine layer between the extraction well and a row of gas injection wells is extracted by pumping equipment at the extraction well; S4: After the extraction is completed, the gas injection equipment is first closed and the hole is temporarily sealed. Then the pumping well is closed and the orifice pressure of the pumping well is monitored in real time. Combined with the drilling stability requirements, the orifice pressure is regularly relieved. During this period, the brine flow direction is such that the upstream brine flows normally to the downstream, and the mineral components in the rock formation are dissolved and filtered, so that the brine concentration is restored to the concentration that meets the requirements; S5: Monitor the brine ion concentration generated when the pumping port is depressurized. When the concentration of the brine mining area selected for exploration is restored to a concentration that meets the requirements, repeat steps S2 to S4 in sequence, and the entire brine extraction process can be repeated repeatedly.

2. A method for exploiting gravel porous brine under water replenishment conditions as claimed in claim 1, characterized in that: The pressure of the extraction wells and several gas injection wells established in step S1 increases by 0.8-1.2 Mpa for every 100 m of penetration.

3. A method for exploiting gravel porous brine under water replenishment conditions as claimed in claim 1, characterized in that: The gas injected into the gas injection well is air, nitrogen, or carbon dioxide.

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