Water-sealed cave depot and water curtain system

Abstract

The invention provides a water-sealed cave depot and a water curtain system, and belongs to the technical field of petroleum storage. The problem that oil leaks due to the fact that natural underground water supply cannot achieve the water seal effect in the excavation stage and the operation stage of an existing underground water seal cave chamber is solved. The water curtain system comprises oil storage hole tanks and water curtain systems, the oil storage hole tanks are arranged at the bottom of the cave depot, the water curtain system is arranged on the upper side of each oil storage hole tank, each water curtain system comprises a transverse water curtain roadway, a vertical water curtain roadway and a water curtain drill hole, and the vertical water curtain roadways are connected with the transverse water curtain roadways. The horizontal water curtain roadway is arranged in the middle of the upper portion of the oil storage hole tank, a plurality of water curtain drill holes are formed in the two sides of the horizontal water curtain roadway in the horizontal direction, a plurality of water curtain drill holes are formed in the lower portion of the horizontal water curtain roadway in the vertical direction, and a plurality of water curtain drill holes are formed in the inclined lower portions of the two sides of the horizontal water curtain roadway. The device is mainly used for underground petroleum storage.

Description

Technical Field

[0001] The invention belongs to the technical field of petroleum storage, and in particular relates to a water-sealed cavern and a water curtain system. Background Art

[0002] At present, a large number of research works on underground water-sealed caverns are mainly focused on the three aspects of "site selection", "water-sealing effect" and "stability of surrounding rock" of underground water-sealed caverns. In terms of site selection of underground water-sealed caverns: because underground water-sealed oil caverns have special storage requirements for the site geology and hydrological environment, once the cavern is unstable or the oil and gas seal fails and leaks, the losses and consequences are difficult to estimate. Therefore, the reasonable selection of the storage site is the basic guarantee for the safe construction and long-term operation of underground water-sealed caverns. In terms of water-sealing effect of underground water-sealed caverns: a reasonable hydraulic gradient is proposed to ensure the sealing of the cavern, and the hydrogeological characteristics of the cavern area are studied through hydrological observation, monitoring, testing and numerical simulation. In terms of surrounding rock stability of underground water-sealed caverns: statistical analysis, analytical solution and numerical simulation are mainly used to study rock quality, surrounding rock stability, fluid-solid coupling and other aspects. However, the natural groundwater recharge in the excavation and operation stages of the existing underground water-sealed caverns cannot achieve the water-sealing effect, which leads to oil leakage. Summary of the invention

[0003] In view of this, the present invention aims to propose a water seal cavern and water curtain system to solve the problem that the natural groundwater replenishment in the existing underground water seal cavern chamber excavation stage and operation stage cannot achieve the water seal effect, thus causing oil leakage.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] An underground water-sealed cavern comprises an oil storage cavern and a water curtain system. The oil storage cavern is arranged at the bottom of the cavern, and the upper side of each oil storage cavern is provided with a water curtain system.

[0006] Furthermore, the water curtain system includes a transverse water curtain tunnel, a vertical water curtain tunnel and water curtain drilling holes. The vertical water curtain tunnel is connected to the transverse water curtain tunnel. The transverse water curtain tunnel is arranged in the upper middle position of the oil storage cave tank. The transverse water curtain tunnel is provided with a plurality of water curtain drilling holes.

[0007] Furthermore, a plurality of water curtain drilling holes are provided in the horizontal direction on both sides of the transverse water curtain tunnel.

[0008] Furthermore, a plurality of water curtain drilling holes are provided in the vertical direction below the transverse water curtain tunnel.

[0009] Furthermore, a plurality of water curtain drilling holes are provided at the oblique lower part of both sides of the transverse water curtain tunnel.

[0010] Furthermore, the inclination angle of the water curtain drilling holes on both sides of the transverse water curtain tunnel is greater than 70°.

[0011] Furthermore, a water injection pipe is connected above the transverse water curtain tunnel.

[0012] Furthermore, a sealing plug is provided on the top of the oil storage cave tank.

[0013] Furthermore, the upper part of the oil storage cave tank is a nitrogen chamber, and the lower part is an oil storage chamber.

[0014] Furthermore, a submersible pump and a submersible oil pump are provided at the bottom of the oil storage cave tank.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] 1. The water curtain system of the present invention uses the water in the rock fissures around the cavern to wrap with oil and gas, and forms a certain pressure difference, so that it cannot penetrate into the rock. The underground water-sealed oil cavern must be built at a certain depth below the stable groundwater level. The burial depth of the oil cavern is related to the pressure of the stored medium. When the pressure of the medium in the cavern is less than the osmotic pressure of the groundwater around the cavern, the groundwater will penetrate into the cavern, and the storage medium cannot penetrate into the surrounding rocks, thereby achieving a water-sealing effect.

[0017] 2. The present invention ensures that there is always a water layer covering the cavern, so that the underground reservoir is always in a water-rich condition, thereby reducing the risk of oil and gas leakage caused by the loss of the surrounding area of ​​the cavern, especially the upper underground due to the natural water level drop. That is, the purpose of setting up the water curtain system is to limit or prevent the leakage of oil and gas from the pressurized underground reservoir by controlling the groundwater. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0019] Figure 1 It is a structural schematic diagram of an underground water-sealed cavern described in the present invention;

[0020] Figure 2 This is a schematic diagram of the internal structure of the oil storage cave tank of the present invention;

[0021] Figure 3 This is a schematic diagram of the horizontal distribution of water curtain drilling holes;

[0022] Figure 4 Schematic diagram of vertical and inclined distribution of water curtain drilling holes;

[0023] Figure 5This is the cavern pressure distribution diagram without water curtain system;

[0024] Figure 6 This is the pressure distribution diagram of the cavern with water curtain system;

[0025] Figure 7 This is the pressure distribution diagram without water curtain system after cave excavation;

[0026] Figure 8 This is the pressure distribution diagram of the water curtain system after the cave excavation.

[0027] 1- oil storage cave tank, 2- horizontal water curtain tunnel, 3- vertical water curtain tunnel, 4- water curtain drilling hole, 5- water injection pipe, 6- sealing plug, 7- nitrogen chamber, 8- oil storage chamber, 9- submersible pump, 10- water curtain system, 11- submersible oil pump. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely explain the technical solutions in the embodiments of the present invention. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict, and the described embodiments are only part of the embodiments of the present invention, not all of the embodiments.

[0029] See also Figure 1-4 To illustrate the present embodiment, an underground water-sealed cavern comprises an oil storage cavern 1 and a water curtain system 10, wherein the oil storage cavern 1 is arranged at the bottom of the cavern, and each oil storage cavern 1 is provided with a water curtain system 10 on its upper side, wherein the water curtain system 10 comprises a transverse water curtain tunnel 2, a vertical water curtain tunnel 3 and water curtain drilling holes 4, wherein the vertical water curtain tunnel 3 is connected to the transverse water curtain tunnel 2, wherein the transverse water curtain tunnel 2 is arranged at the upper middle position of the oil storage cavern 1, and wherein a plurality of water curtain drilling holes 4 are provided on the transverse water curtain tunnel 2.

[0030] The principle of underground water-sealed cavern oil storage is to use the characteristics of oil and water being incompatible and oil being lighter than water. When a water curtain of a certain pressure is formed around the cavern, crude oil can be prevented from escaping and the purpose of storage can be achieved. Therefore, the site selection of underground oil storage caverns must meet two conditions: one is that the surrounding rock integrity of the reservoir area is good and the hardness is good; the second is that there must be good hydrological conditions and a stable groundwater level to meet the "gap storage water replenishment" to ensure that the oil does not leak. Therefore, the water-sealed oil storage cavern is required to have strict water-sealing properties during excavation and operation. The present invention utilizes the rock stratum fissure water around the cavern to wrap with oil and gas, and forms a certain pressure difference, so that it cannot penetrate into the rock. The underground water-sealed oil cavern must be built at a certain depth below the stable groundwater level. The buried depth of the oil cavern is related to the pressure of the stored medium. When the pressure of the medium in the cavern is less than the osmotic pressure of the groundwater around the cavern, the groundwater will penetrate into the cavern, and the storage medium cannot penetrate into the surrounding rocks, thereby achieving a water-sealing effect.

[0031] The underground oil storage depot needs to be built at an appropriate depth below the stable groundwater level line, and the oil storage depot is sealed by the penetration of groundwater into the cave, thereby ensuring that the groundwater pressure around the cave is greater than the pressure of the storage medium in the cave. However, the natural groundwater replenishment during the cave excavation stage and the operation stage may not achieve the water sealing effect. At this time, the artificial water pressure replenishment of the water curtain system 10 in the present invention is particularly important.

[0032] The water curtain system 10 plays a core role in the construction and operation of water-sealed underground storage tanks. It ensures that there is always a water layer covering the top of the cavern, so that the underground storage tank is always in a water-rich condition, thereby reducing the risk of oil and gas leakage caused by the natural water level drop around the cavern, especially the upper underground loss. That is, the purpose of setting up the water curtain system 10 is to limit or prevent oil and gas leakage from the pressurized underground storage tank by controlling groundwater. In the operating state, that is, after the construction tunnel is filled with water, the artificial water seal system should actually include the water curtain system 10 and the construction tunnel in the water-filled state. However, the role of the construction tunnel in the water-filled state is only to provide a stable operating pressure for the water curtain system 10 to ensure that the part between the water curtain system 10 and the oil storage cavern 1 is completely filled with water, thereby ensuring the water seal safety of the reservoir area. For underground water-sealed cavern projects, the artificial water seal function of the water curtain system 10 should be maximized, while the water seal function of the water in the construction tunnel should be reduced to avoid the generation of excessive water seal.

[0033] Furthermore, a plurality of water curtain drilling holes 4 are provided in the horizontal direction on both sides of the transverse water curtain tunnel 2 .

[0034] A plurality of water curtain drilling holes 4 are provided in the vertical direction below the transverse water curtain tunnel 2 .

[0035] A plurality of water curtain drilling holes 4 are provided at the oblique lower part of both sides of the transverse water curtain tunnel 2 .

[0036] The water curtain boreholes 4 on both sides of the transverse water curtain tunnel 2 have an inclination angle greater than 70°.

[0037] The water curtain system 10 can generally be divided into a horizontal water curtain system, a vertical water curtain system and an inclined water curtain system according to the different layout directions of the water curtain drilling holes 4. In order to ensure the water filling efficiency 4 of the water curtain drilling holes and ensure that there is abundant water stored in the cracks, in theory, the water curtain drilling holes 4 should intersect with the structural surface of the rock mass at a large angle, generally greater than 70°. At present, the horizontal water curtain system is a widely used layout method.

[0038] Furthermore, a water injection pipe 5 is connected above the transverse water curtain tunnel 2 for injecting water into the transverse water curtain tunnel 2 .

[0039] Furthermore, a sealing plug 6 is provided on the top of the oil storage cave tank 1 to ensure the sealing of the oil storage cave tank 1 .

[0040] Furthermore, the upper part of the oil storage cave tank 1 is a nitrogen chamber 7 , and the lower part is an oil storage chamber 8 .

[0041] Furthermore, a submersible pump 9 and a submersible oil pump 11 are provided at the bottom of the oil storage cave tank 1 .

[0042] The embodiments of the present invention disclosed above are only used to help illustrate the present invention. The embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. According to the content of this specification, many modifications and changes can be made. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well.

Claims

1. An underground water-sealed cavern, characterized in that: It comprises an oil storage cave tank (1), wherein the oil storage cave tank (1) is arranged at the bottom of the cave, and a plurality of the oil storage cave tanks (1) are arranged and evenly distributed at the bottom of the cave.

2. A water curtain system according to claim 1, characterized in that: A sealing plug (6) is provided on the top of the oil storage cave tank (1).

3. The underground water-sealed cavern according to claim 1, characterized in that: The upper part of the oil storage cave tank (1) is a nitrogen chamber (7), and the lower part is an oil storage chamber (8).

4. The underground water-sealed cavern according to claim 1, characterized in that: A submersible pump (9) and a submersible oil pump (11) are provided at the bottom of the oil storage cave tank (1).

5. A water curtain system installed in an underground water-sealed cavern according to any one of claims 1 to 4, characterized in that: A water curtain system (10) is arranged above a plurality of oil storage caverns (1), the water curtain system (10) comprising a transverse water curtain tunnel (2), a vertical water curtain tunnel (3) and water curtain drilling holes (4), the vertical water curtain tunnel (3) is connected to the transverse water curtain tunnel (2), the transverse water curtain tunnel (2) is arranged at the middle position above the oil storage caverns (1), and the transverse water curtain tunnel (2) is provided with a plurality of water curtain drilling holes (4).

6. The underground water-sealed cavern according to claim 5, characterized in that: A plurality of water curtain drilling holes (4) are provided in the horizontal direction on both sides of the transverse water curtain tunnel (2).

7. The underground water-sealed cavern according to claim 5, characterized in that: A plurality of water curtain drilling holes (4) are arranged in the vertical direction below the transverse water curtain tunnel (2).

8. The underground water-sealed cavern according to claim 7, characterized in that: A plurality of water curtain drilling holes (4) are provided at the oblique lower sides of both sides of the transverse water curtain tunnel (2).

9. The underground water-sealed cavern according to claim 8, characterized in that: The water curtain drill holes (4) on both sides of the transverse water curtain tunnel (2) have an inclination angle greater than 70°.

10. The underground water-sealed cavern according to claim 2, characterized in that: A water injection pipe (5) is connected above the transverse water curtain tunnel (2).

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