CN107461175A - A kind of method and apparatus of advance reinforcement deep-sea gas hydrates reservoir - Google Patents

Abstract

The present invention provides a method for strengthening deep-sea natural gas hydrate reservoir in advance. The natural gas hydrate reservoir includes an upper overburden layer and a lower overburden layer, and a hydrate zone is formed between the upper overburden layer and the lower overburden layer, comprising the following steps: Step 1 : Utilize deep-sea drilling technology to carry out drilling construction from the seabed to the upper overburden to form a well; Step 2: set reinforcement piles in the well so that the lower end of the reinforcement piles stretches into the lower overburden; Step 3: draw some The tubing, using tubing directional drilling technology to form a number of channels, so that some channels are meandering with the corresponding tubing to the hydrate area, and some channels are meandering with the corresponding tubing to the lower overburden, and then inject filling materials into the tubing, and then While the oil pipe is retreating along the channel, the oil pipe is sprayed out with filling material so that the filling material forms a reinforcement in the channel, and the natural gas hydration is strengthened by making the reinforcement and the reinforcement pile form the internal reinforcement of the natural gas hydrate reservoir. reservoir structure.

Description

A method and device for advanced reinforcement of deep sea gas hydrate reservoirs

technical field

The invention relates to the technical field of marine resources and basic engineering, in particular to a method for advanced reinforcement of deep-sea natural gas hydrate reservoirs.

Background technique

Natural gas hydrate is stored in the sediment pores of the overburden under low temperature and high pressure environment. When the temperature rises or the pressure decreases, the natural gas hydrate decomposes into a gas-water mixture, and the released gas-water mixture forms in the overburden Overpressure, so that the degree of sediment consolidation is greatly reduced. Especially in the process of deep-sea gas hydrate exploitation, if the temperature or pressure of gas hydrate in the seabed overburden changes beyond the equilibrium condition, the overpressure generated by the decomposition of gas hydrate will inevitably affect the stability of the overburden. This may further reduce the stability of the submarine slope and lead to submarine landslides. Large-scale submarine landslides will not only cause damage to deep-sea oil and gas drilling, oil pipelines, submarine cables and other submarine engineering facilities, but also cause tsunamis, which greatly endanger the safety of human life and property.

Contents of the invention

In view of this, the embodiment of the present invention provides an advanced method to solve the problem that the gas hydrate reservoir may be destroyed due to the instability of the seabed and the loss of human life and property may be caused by deep-sea gas hydrate exploitation. Methods for consolidating deep-sea gas hydrate reservoirs.

An embodiment of the present invention provides a method for strengthening deep-sea gas hydrate reservoirs in advance. The gas hydrate reservoirs include an upper overburden and a lower overburden. A hydrate zone for natural gas hydrates, the method comprising the steps of:

Step 1: using deep-sea drilling technology to carry out drilling construction from the seabed to the upper overburden to form a well;

Step 2: setting reinforcement piles in the well so that the lower ends of the reinforcement piles extend into the lower covering layer;

Step 3: Draw out several oil pipes from the wells in the upper overburden layer, and form several channels by using oil pipe directional drilling technology, so that some of the channels meander along with the corresponding oil pipes to the hydrate area, and some of the channels Drilling the corresponding oil pipe meanderingly to the lower overburden, then injecting filling material into the oil pipe, and then making the oil pipe eject the filling material while retreating the oil pipe along the channel. making the filling material form a reinforcement in the channel until the tubing exits the corresponding channel, by making the reinforcement and the reinforcement pile form the inner reinforcement of the natural gas hydrate reservoir Strengthening the gas hydrate reservoir structure.

Further, the oil pipe is a flexible pipe.

Further, the filling material is a material with anti-permeation capability.

Further, the filling material in the channel drilled into the hydrate zone is ceramsite, and the filling material in the channel drilled into the lower covering layer is high-strength concrete.

Further, several reinforcement layers are distributed on the outer wall of the well, two adjacent reinforcement layers are arranged at intervals, each reinforcement layer has a plurality of reinforcements, and the reinforcement layers located in the same reinforcement layer A plurality of the reinforcing bodies are distributed on the outer wall of the well in a ring shape, and extend in a divergent shape and bend around.

Further, there are three reinforcement piles, and the three reinforcement piles are parallel to each other and distributed in a triangle.

Further, two of the three reinforcement piles are in close contact.

Further, the bottom of the well is located in the middle area of the upper overburden.

Further, the reinforcement pile is a drainage pile.

An embodiment of the present invention provides a device for strengthening deep-sea gas hydrate reservoirs in advance. The gas hydrate reservoirs include an upper overburden and a lower overburden. The hydrate zone of natural gas hydrate is characterized in that: the device includes a well opened in the upper overburden layer, the upper end of a reinforcement pile is located in the well, and the lower end passes through the hydrate zone downwards and extends into the lower overburden, the lower end of the well is connected with a number of reinforcements, some of the reinforcements meander down to the hydrate zone, and some of the reinforcements meander down to the lower overlay.

The beneficial effect brought by the technical solution provided by the embodiments of the present invention is: through the method and device for strengthening the deep-sea gas hydrate reservoir in advance of the present invention, the reinforcement pile and the reinforcement pile can be built in the gas hydrate reservoir. Solid, the connection of the upper overburden, the hydrate zone and the lower overburden is referred to as a whole, when the natural gas hydrate decomposes, the degree of consolidation of the hydrate zone decreases, and the force generated will be determined by the The upper overburden, the hydrate zone and the lower overburden are shared, thereby reducing the possibility of destabilization of the natural gas hydrate reservoir; (2) the reinforcement pile adopts a drainage pile, in addition to connecting In addition to the role of reinforcement, it can also serve to reduce the damage to the permeability of the hydrate zone.

Description of drawings

Fig. 1 is the schematic diagram of the device for strengthening the deep sea gas hydrate reservoir in advance according to the present invention;

Fig. 2 is a cross-sectional view of the oil pipe drilled into the hydrate zone in the device for advanced reinforcement of deep-sea natural gas hydrate reservoirs according to the present invention;

Fig. 3 is a step diagram of the method for advanced reinforcement of deep-sea gas hydrate reservoirs according to the present invention.

detailed description

In order to make the purpose, technical solution and advantages of the present invention clearer, the embodiments of the present invention will be further described below in conjunction with the accompanying drawings.

The embodiment of the present invention provides a device and method for strengthening deep-sea gas hydrate reservoirs in advance, with the purpose of solving the problem of gas hydrate reservoirs being destroyed due to seabed instability, Problems that cause loss of human life and property.

Please refer to FIG. 1 , the gas hydrate reservoir includes an upper overburden 4 and a lower overburden 5 , and between the upper overburden 4 and the lower overburden 5 is a hydrate zone 6 for storing gas hydrate. Among the present embodiment, the upper covering layer 4 is located at a sea depth of 1500m, the thickness of the upper covering layer 4 is 400m, the thickness of the hydrate zone 6 is 200m, the seabed temperature is about 10°, and the seabed pressure is about 15Mpa. But it is not limited to the data listed in this embodiment.

A well 1 is opened on the upper covering layer 4. In this embodiment, the diameter of the upper opening of the well 1 is 1.5m, and the diameter of the bottom of the well is about 0.8m. The well 1 does not penetrate the upper covering layer 4 , and the well bottom is located in the upper covering layer 4 at a distance of 50 m from the bottom surface of the upper covering layer 4 .

The upper end of a reinforcement pile 2 is located in the well 1, and its lower end passes through the hydrate zone 6 and extends into the lower cover layer 5. The reinforcement pile 2 is a drainage pile. In addition to connecting the upper overburden layer 4 and the lower overburden layer 5 and strengthening the natural gas hydrate reservoir, it can also reduce the damage to the permeability of the hydrate zone 6 .

Please refer to Fig. 1 and Fig. 2, the lower end area of the well 1 is connected with several reinforcement bodies 31, 32, part of the reinforcement body 31 meanders downwards to the hydrate zone 6, and part of the reinforcement body 32 The lower meandering drill reaches the lower cover layer 5 . The building material of the reinforcing body 31 is mainly ceramsite, and the building material of the reinforcing body 32 is mainly high-strength concrete. The ceramsite 7 is a material with superior penetration resistance, and the high-strength concrete is C60 high-strength concrete. The C60 high-strength concrete not only has strong penetration resistance, but also has the advantages of light weight and good compactness. Inject the ceramsite 7 or inject the high-strength concrete into the channel through the oil pipe to form the reinforcements 31, 32, which not only increases the penetration channel, but also does not affect the flexibility of the oil pipe. Increased the strength of the channel. Preferably, the diameter of the ceramsite 7 is 1 cm.

The reinforcements 31 and 32 are bent from the well 1 at an angle α, 10°≤α≤20°, preferably α=15°. Several reinforcement layers are distributed on the outer wall of the well 1, and two adjacent reinforcement layers are arranged at intervals. In this embodiment, the maximum interval between two adjacent reinforcement layers is 20m. Each reinforcement layer has a plurality of reinforcements 31, 32, and the plurality of reinforcements 31, 32 located in the same reinforcement layer are annularly distributed on the outer wall of the well 1, and It diverges and bends to extend around, so that it is in contact with the gas hydrate in the hydrate zone 6 and the lower overburden layer 6 like a tree root, that is, the gas hydrate storage layers are more stable.

There are three reinforcement piles 2, and the three reinforcement piles 2 are parallel to each other, and at the same time, the three reinforcement piles 2 are in close contact with each other, so that the three reinforcement piles 2 are in a stable triangular distribution. In this embodiment, the reinforcement piles The pile 2 is 300 m long and has a diameter of 0.3 m.

Please refer to FIG. 3 , an embodiment of the present invention provides a method for advanced reinforcement of deep-sea gas hydrate reservoirs, including the following steps:

Step 1: Drilling from the seabed to the upper overburden layer 4 using deep-sea drilling technology to form a well 1 . Due to the complexity of deep-sea sediments and the difficulty of drilling, multi-layer casing drilling technology is used, preferably 5-layer casing drilling technology for drilling operations.

Step 2: setting reinforcement piles 2 in the well 1 of the upper covering layer 4 , so that the lower ends of the reinforcing piles 2 extend into the lower covering layer 5 . In this way, the upper covering layer 4 and the lower covering layer 5 are preliminarily connected as a whole, and the reinforcement pile 2 is an internal reinforcement of the whole with a strengthening effect.

Step 3: lead out several oil pipes from the well 1 of the upper overburden layer 4, and form several channels by using oil pipe directional drilling technology, so that part of the channels 31 meander along with the corresponding oil pipes to drill to the hydrate zone 6 1. Part of the passage 32 is meanderingly drilled to the lower cover layer 5 along with the corresponding oil pipe, then inject filling material into the oil pipe, and then make the oil pipe retreat along the passage while making the oil pipe spraying out the filling material so that the filling material forms reinforcements 31, 32 in the channel until the oil pipe is withdrawn from the corresponding channel, by making the reinforcements 31, 32 and the reinforcement pile 2 forming internal reinforcement of the natural gas hydrate reservoir to strengthen the structure of the natural gas hydrate reservoir. Then carry out the gas hydrate reservoir stability test, and then carry out other work such as pre-exploitation. Preferably said oil pipe is a flexible pipe.

The beneficial effect brought by the technical solution provided by the embodiments of the present invention is: through the method and device for strengthening the deep-sea natural gas hydrate reservoir in advance of the present invention, the reinforcement pile and the oil pipe are built in the natural gas hydrate reservoir , the connection of the upper overburden, the hydrate zone and the lower overburden is referred to as a whole, when the natural gas hydrate decomposes, the degree of consolidation of the hydrate zone decreases, and the force generated will be generated by the upper Overburden, the hydrate zone and the lower overburden share the responsibility, thereby reducing the possibility of instability of the natural gas hydrate reservoir; (2) the reinforcement piles use drainage piles, in addition to connecting and reinforcing In addition to the role of hydration, it can also play a role in reducing the damage to the permeability of the hydrate zone.

In this article, the orientation words such as front, rear, upper, and lower involved are defined by the parts in the drawings and the positions between the parts in the drawings, just for the clarity and convenience of expressing the technical solution. It should be understood that the use of the location words should not limit the scope of protection claimed in this application.

In the case of no conflict, the above-mentioned embodiments and features in the embodiments herein may be combined with each other.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection of the present invention. within range.

Claims (10)

1. a kind of method of advance reinforcement deep-sea gas hydrates reservoir, the gas hydrates reservoir include upper caldding layer And lower caldding layer, it is the hydrate formation region of storing natural gas hydrate, its feature between the upper caldding layer and the lower caldding layer It is, the described method comprises the following steps：

Step 1：Carry out forming well from seabed to the wellbore construction of the upper caldding layer using deep sea drilling technology；

Step 2：Reinforcing pile is set in the well, the lower end of the reinforcing pile is stretched into the lower caldding layer；

Step 3：Some oil pipes are drawn from the well of the upper caldding layer, if forming dry passage using oil pipe Technology of Directional Drilling, The part passage is wriggled with the corresponding oil pipe and be drilled into the hydrate formation region, the part passage with the corresponding oil Pipe, which wriggles, is drilled into the lower caldding layer, then toward injection packing material in the oil pipe, then while making the oil pipe described in Passage retreats, while making the oil pipe spray the packing material and the packing material is formed reinforcing in the passage Body, until make the oil pipe exit the corresponding passage, by make the reinforcing body and the reinforcing pile formed it is described natural The interior muscle of gas hydrate reservoir and to strengthen the gas hydrates reservoir structure.

2. the method for advance reinforcement deep-sea gas hydrates reservoir as claimed in claim 1, it is characterised in that：The oil pipe For flexible pipe.

3. the method for advance reinforcement deep-sea gas hydrates reservoir as claimed in claim 1, it is characterised in that：The filling Material is the material with impermeabilisation ability.

4. the method for advance reinforcement deep-sea gas hydrates reservoir as claimed in claim 3, it is characterised in that：It is drilled into described Packing material in the passage of hydrate formation region is haydite, and the packing material being drilled into the passage of the lower caldding layer is high-strength coagulation Soil.

5. the method for advance reinforcement deep-sea gas hydrates reservoir as claimed in claim 1, it is characterised in that：The well Outer wall has some reinforcing body layers, and the adjacent two reinforcing body layer is arranged at intervals, and each reinforcing body layer has multiple The reinforcing body, the lateral wall that is distributed in the well annular in shape positioned at multiple reinforcing bodies of the same reinforcing body layer, And bend and extend to surrounding in divergent shape.

6. the method for advance reinforcement deep-sea gas hydrates reservoir as claimed in claim 1, it is characterised in that：The reinforcing Stake has three, and three reinforcing piles are parallel to each other and distribution triangular in shape.

7. the method for advance reinforcement deep-sea gas hydrates reservoir as claimed in claim 6, it is characterised in that：Described in three Reinforcing pile is in close contact two-by-two.

8. the method for advance reinforcement deep-sea gas hydrates reservoir as claimed in claim 1, it is characterised in that：The well Shaft bottom is located at the intermediate region of the upper caldding layer.

9. the method for advance reinforcement deep-sea gas hydrates reservoir as claimed in claim 1, it is characterised in that：The reinforcing Stake is drainage pile.

10. a kind of device of advance reinforcement deep-sea gas hydrates reservoir, the gas hydrates reservoir include upper covering Layer and lower caldding layer, are the hydrate formation region of storing natural gas hydrate between the upper caldding layer and the lower caldding layer, and it is special Sign is：Described device includes being opened in the well of the upper caldding layer, and the upper end of a reinforcing pile is located at the well, and its lower end to Under through the hydrate formation region and stretch into the lower caldding layer, the lower end area of the well is connected with some reinforcing bodies, part institute State downward wriggle of reinforcing body and be drilled into the hydrate formation region, the part reinforcing body, which wriggles downwards, is drilled into the lower caldding layer.