JP5643012B2 - Recovery method of crude oil erupted on the seabed - Google Patents

Description

  The present invention relates to a method of recovering crude oil that is considered so that the crude oil ejected from the seabed can be efficiently recovered after being guided to the sea surface without being diffused.

  As a technique for preventing leakage of crude oil in a submarine oil field, an ejection prevention device called BOP is adopted. This device is equipped with a valve function installed at the crude oil outlet at the bottom of the sea, and its own weight is several hundred tons or more, and it is said that it can contain up to a jet pressure as high as about 1,000 atmospheres.

  Further, although not a technique for collecting crude oil ejected from the seabed, Patent Document 1 proposes a method for collecting methane hydrate gas from the seabed as a similar technique. In the technique described in Patent Document 1, a sheet covering a predetermined range of the seabed is set and deployed, and methane hydrate gas is captured in the sheet by ascending / moving due to buoyancy of methane gasified in the development area of the sheet. It is what I did.

Japanese Patent No. 3305280

  In the former technique described above, for example, when the BOP does not function effectively in the deep sea where the water depth reaches as much as 1500 m, all countermeasures for the trouble must be relied upon by remote control. For this reason, it takes a long time to recover, and as a result, there is a risk of massive marine pollution due to crude oil spills. In fact, on April 20, 2010, a major oil spill occurred in the Gulf of Mexico.

  On the other hand, in the latter technique described above, the weight is suspended from the sea by a rope because the sheet is settled and set by only the weight of a plurality of weights connected to the sheet. However, there is no restriction on the distance between adjacent weights during the subsidence process in the sea. For this reason, the mutual positional relationship between the weights may change during the sedimentation process or at the time of bottoming, which means that the sheet cannot be fully developed at the time of bottoming. I mean. In particular, when trying to apply the latter technique to the collection of crude oil ejected from the seabed, in the case of a seafloor oil field, the depth of the crude oil outlet is approximately 1500 m. It will not be able to achieve its intended purpose without being able to deploy.

  For this reason, there is a strong demand for the realization of an effective crude oil recovery technique in case the crude oil is ejected without the BOP, which is the former technique, functioning effectively.

  The present invention has been made paying attention to such a problem, and a method for recovering crude oil that can efficiently recover the crude oil ejected from the crude oil outlet on the seabed without being diffused. Is to provide.

The invention described in claim 1 is a method for collecting and collecting crude oil from the crude oil outlet on the seabed while suppressing the diffusion of the crude oil to the sea surface. Of the dome assembly consisting of a stretched curtain and a transport pipe connected to the curtain , the frame is subjected to a primary high specific gravity treatment and the frame surrounds the crude oil outlet. In this way, the dome assembly is sunk on the seabed, and a secondary high specific gravity treatment is applied to the frame of the bottomed dome assembly, and the dome assembly is fixed to the seabed using the frame as an anchor and ejected. The curtain is expanded into a dome shape by the buoyancy of crude oil, and the crude oil is collected in the dome-shaped curtain body. It collects.

As the primary and secondary high specific gravity processing for the frame of the dome assembly, it is assumed that a substance for high specific gravity processing is injected into the frame itself as described later. Further, as the above-described offshore crude oil recovery means, for example, a crude oil recovery ship is assumed.

  Here, since the deep sea bottom has a low temperature, the crude oil may harden, or the gas contained in the crude oil may freeze and block the transportation pipe. As a countermeasure, as described in claim 2, injecting air, particularly air raised in temperature by adjusting the temperature, near the top of the dome swelled in the dome shape or in the vicinity of the curtain body side of the transport pipe. Is desirable. More preferably, as described in claim 3, a transport pipe blockage preventive agent such as an emulsifier and warm water is injected together with air. It is also effective to intermittently inject the air.

The closed-loop frame in the dome assembly mentioned here is, for example, a pipe-like and flexible as described in claim 4 , and the primary and secondary high specific gravity treatment is In this case, a substance for increasing the specific gravity is injected into the frame body itself.

More specifically, as described in claim 5, the substance for the secondary high specific gravity treatment has a higher specific gravity than the material for the primary high specific gravity treatment, The next high specific gravity treatment is performed while discharging the material for the primary high specific gravity treatment in parallel with the injection of the material for the secondary high specific gravity treatment.

  In addition, for example, water is assumed as a material for primary high specific gravity treatment, and mortar, cement milk, or the like is assumed as a material for secondary high specific gravity treatment.

The invention according to claim 6 is a method for collecting the crude oil by guiding it to the sea surface while suppressing the diffusion of the crude oil ejected from the crude oil outlet on the seabed, and extending the curtain inside the closed-loop frame. A plurality of dome assemblies that are connected at a predetermined distance in the depth direction are submerged on the sea floor, and a hole is formed in the center of each curtain so as to surround the crude oil outlet. By applying a high specific gravity treatment to the bottom frame of the bottom dome assembly, the bottom dome assembly is fixed on the sea floor using the frame as an anchor, and each dome assembly floats from below. The curtain body bulges into a dome shape due to the buoyancy of the crude oil, and once the crude oil is collected in the dome-shaped curtain body, the crude oil floats upward from the hole in the curtain body, Crude oil collected in a three-dimensional curtain Characterized in that it recovered in the oil recovery means.

Therefore, in at least the invention described in claim 1, for example, after preparing a curtain body to which a transport pipe is connected and a closed loop frame body, the curtain body to which the transport pipe is connected is connected to the closed loop frame body. Tension inside and assemble the dome assembly at sea. Next, the dome assembly is suspended while controlling its posture and position, for example, by a work boat, and after the primary high specific gravity treatment is applied to the frame of the dome assembly, the closed loop frame is made of crude oil. Sink on the ocean floor to surround the spout. If the dome assembly has landed on the seabed, a secondary high specific gravity treatment is applied to the frame of the dome assembly, and the dome assembly is fixed or moored on the seabed using the frame as an anchor. To do.

  If the frame surrounds the crude oil outlet on the seabed, crude oil with a specific gravity smaller than that of seawater is taken inside the curtain with the frame as an anchor and guided to the center of the crude oil. Due to this buoyancy, the curtain body bulges toward the sea surface side so as to have a convex shape, and the crude oil collected by the curtain body rises through the transport pipe and moves up to the sea surface side. As a result, the crude oil can be converged to a certain area on the sea surface while minimizing the spread of the crude oil in the sea. It is possible to collect with a recovery ship.

According to invention of Claim 1, 6, it becomes possible to collect | recover efficiently on the sea, without diffusing the crude oil which ejected from the crude oil outlet of the seabed. In addition, the high specific gravity processing of the frame constituting the dome assembly is divided into primary high specific gravity processing before settling and secondary high specific gravity processing after landing on the seabed. Therefore, it is possible to achieve both the ease of assembly and set-up of the dome assembly and the stronger anchor effect for fixing or mooring after landing.

  According to the second and third aspects of the present invention, air is injected alone or together with an anti-blocking agent into the interior of the curtain swelled in a dome shape, so that blocking of the transport pipe is prevented in advance. It is possible to transport crude oil to the sea side more efficiently and stably.

According to the invention described in claim 4, since each specific gravity increasing process is performed by injecting a material for increasing the specific gravity into the pipe-shaped frame itself, the high specific gravity is increased. Easy to process.

According to the invention described in claim 5, since the substance injected into the pipe-shaped frame body is replaced in the secondary high specific gravity treatment, the fixing or mooring after the bottom of the dome assembly is settled. A stronger anchoring effect for can be expected.

BRIEF DESCRIPTION OF THE DRAWINGS Schematic explanatory drawing which shows 1st Embodiment of the collection | recovery method of the crude oil based on this invention. (A) is explanatory drawing only of the anchor ring shown in FIG. 1, (B) is explanatory drawing which shows the state which combined the curtain with the anchor ring of the same figure (A). Explanatory drawing at the time of sinking the dome assembly shown in FIG. FIG. 4 is an explanatory diagram when fixing the dome assembly submerged on the seabed, following FIG. 3. FIG. 5 is an explanatory diagram when recovering crude oil following FIG. 4. Schematic explanatory drawing which shows 2nd Embodiment of the collection | recovery method of the crude oil which concerns on this invention. Schematic explanatory drawing which shows 3rd Embodiment of the collection | recovery method of the crude oil based on this invention. The schematic explanatory drawing which shows 4th Embodiment of the collection | recovery method of the crude oil which concerns on this invention.

  1 to 5 are diagrams showing a more specific first embodiment of a crude oil recovery method according to the present invention. FIG. 1 shows a state during a crude oil recovery operation, and FIGS. The installation procedure of the dome assembly 4 for this is shown.

  In FIG. 1, 1 indicates the sea surface, 2 indicates the sea bottom, and 3 indicates a crude oil spout drilled on the sea bottom 2 by, for example, boring. As described above, the crude oil outlet 3 employs an ejection prevention device called BOP, but the illustration is omitted here. A dome assembly 4 is covered so as to surround the crude oil outlet 3 on the seabed 2, and a flexible transport pipe 5 extends from the dome assembly 4 to the sea surface 1. Further, a crude oil recovery ship 6 as a crude oil recovery means stands by on the sea surface 1, and a recovery pipe 7 extends from the crude oil recovery ship 6 toward the upper end opening of the transport pipe 5.

  The dome assembly 4 includes an annular or closed loop anchor ring 8 as a frame, and a curtain body 9 that is stretched inside the anchor ring 8 and is expanded or bulged into a hemispherical dome shape. Composed. As will be described later, the anchor ring 8 has a pipe shape in which a large number of short steel pipes 8a are connected in a closed loop shape through a flexible joint sleeve made of rubber or the like, and can follow the undulations of the seabed as a whole. Flexible. The anchor ring 8 has a function as an anchor as its name indicates by injecting a material having a high specific gravity into the inner space, for example, a material having a large specific gravity and fluidity such as mortar. It supports the curtain body 9 that has developed into a dome shape after having settled and settled on the seabed by its own weight. The flexible transport pipe 5 described above is connected to the top of the curtain body 9, and this transport pipe 5 extends to the sea surface 1.

  The crude oil G ejected from the crude oil ejection port 3 on the seabed 2 is collected inside the dome-shaped curtain body 9. Since the specific gravity of the crude oil G is smaller than that of seawater, the crude oil G is led to the top of the dome-shaped curtain body 9 by buoyancy, and further floats toward the sea surface 1 through the transport pipe 5. Then, the recovery pipe 7 faces the opening of the upper end of the transport pipe 5 opened on the sea surface 1 from the side of the crude oil recovery ship 6, and the crude oil G is put into the ship of the crude oil recovery ship 6 by a pump not shown. to recover. By carrying out like this, spreading | diffusion of the crude oil G in the sea containing a deep sea part is suppressed, and the crude oil G can be efficiently collect | recovered on the sea.

  Here, in the deep sea where the water depth reaches 1000 m or more, since the temperature is low, the crude oil G may solidify or the gas contained therein may freeze and cause clogging or blockage in the transport pipe 5. Therefore, an emulsifier, hot water, or air (compressed air) heated by temperature adjustment is injected from the crude oil recovery ship 6 on the sea surface 1 toward the curtain body 9 developed in a dome shape. More specifically, air is blocked with an anti-blocking agent from the crude oil recovery ship 6 side through the air injection pipe 10 in the vicinity of the top of the curtain body 9 bulging in a dome shape or in the immediate vicinity of the curtain body 9 side of the transport pipe 5. Inject with some emulsifier. By doing so, in addition to the above-described clogging prevention effect, an agitation and mixing effect with the crude oil G can also be expected, and furthermore, the maintenance of the dome shape of the curtain body 9 can be contributed by the injection of air.

  For example, in the deep sea where the water depth is about 1500 m, the volume of air is compressed to about 1/150 than that on the sea surface according to Boyle's law. Therefore, when air is led to the seabed, it is necessary to use a pipe (hose) having a pressure strength of 15 MPa or more. On the other hand, the air injected into the transport pipe 5 on the seabed with a water depth of about 1500 m expands simultaneously in the process of rising through the transport pipe 5 and has a volume 150 times on the sea surface 1. For this reason, the pressure in the transport pipe 5 increases, and as a result, the rising of the crude oil G also helps.

  Furthermore, by intermittently injecting an air amount adjusted according to the pipe diameter of the transport pipe 5, a space of only air is created in the transport pipe 5 at a predetermined pitch. As a result, a water pressure difference is generated, which further helps the crude oil G to rise and rise.

  In addition to the floating of the crude oil G to the sea surface 1 side using such air pressure and the buoyancy of the crude oil G itself, the recovery of the crude oil G can be further facilitated by connecting a pump to the transport pipe 5 on the sea surface 1 upper side. . For example, when a rubber hose is used as the transport pipe 5 having a diameter of 20 cm, assuming that the amount of ejected crude oil is 60,000 barrels a day, the flow rate in the rubber hose, which is the transport pipe 5, is 3.5 m for continuously collecting the crude oil G. / S. This can be appropriately designed depending on the viscosity of the crude oil G and the pumping capacity. In addition, the negative suction pressure of the pump acts, so that the inside of the dome-shaped curtain body 9 can be set to a negative pressure, and the outflow of the crude oil G from the gap between the connecting portion and the two sea bottom surfaces is prevented. Can do.

  2 and the subsequent drawings show the installation procedure of the dome assembly 4 described above. First, an anchor ring 8 as shown in FIG. 2A is assembled on the sea surface 1. The anchor ring 8 is a closed loop shape having a diameter of, for example, about 50 m as a whole by connecting a number of short steel pipes 8a, 8a having a diameter of about 800 mm prepared in advance by a flexible joint sleeve 8b made of rubber or the like. And finished in a flexible pipe-like structure. Such an anchor ring 8 has a deformation follow-up property due to the influence of waves on the sea surface 1, and has a follow-up property to the undulations of the sea bottom 2 on the sea bottom 2. In addition, as the steel pipe 8a, an existing sand pipe or the like can be used.

  Next, a circular curtain body 9 is prepared in a folded state as shown in FIG. 2 (B), and the anchor ring 8 and the anchor ring 8 are floated on the sea surface 1. The periphery is firmly fixed using a flat bar, rope or wire. Further, the flexible transport pipe 5 is connected to the connection port 9a at the position corresponding to the top in the center of the curtain body 9 (see FIG. 1). As shown in FIG. 3, the transport pipe 5 is mounted in advance on the pipe deployment ship 11 and is sequentially delivered from the pipe deployment ship 11. Thus, the assembly of the dome assembly 4 is completed.

  Thereafter, as shown in FIG. 3, the dome assembly 4 is suspended in the sea by a plurality of crane ships (work ships) 12 using the anchor ring 8 as a support portion, and not shown as a primary high specific gravity treatment. Water is poured completely into the anchor ring 8 from the water mouth. If water is confined inside the anchor ring 8, the crane ship 12 gradually descends while controlling the position and posture of the dome assembly 4, and as shown in FIG. The dome assembly 4 is attached to the seabed so as to surround the crude oil outlet 3 (see FIG. 1).

  In this case, as shown in FIG. 4, the mortar ship 13 is kept waiting on the sea surface 1, while the mortar injection pipe 14 is connected in advance to a part of the anchor ring 8 to set the dome assembly 4. In addition, the mortar injection pipe 14 is fed out from the mortar ship 13. When the delivery of the transport pipe 5 from the pipe deployment ship 11 of FIG. 3 is finished, the valve 15 at the upper opening of the transport pipe 5 is closed and kept on the sea surface 1 with the buoy 16.

  Although not shown in FIG. 4, it is assumed that an air injection pipe 10 is connected to the transport pipe 5 as shown in FIG.

  When the dome assembly 4 has landed on the seabed 2, a secondary high specific gravity treatment is performed to land the anchor ring 8 of the dome assembly 4 on the seabed. That is, by injecting mortar from the mortar ship 13 on the sea surface 1 into the anchor ring 8 through the mortar injection pipe 14 and draining the water previously injected into the anchor ring 8 in parallel therewith, The weight (specific gravity) of the anchor ring 8 is increased. In this way, the anchor ring 8 to which the weight of the mortar is added in addition to its own weight is fixed on the seabed 2 and is not easily affected by tidal currents. Note that cement milk or the like can be used instead of mortar as necessary.

  Here, the diameter required for the anchor ring 8 formed by connecting a large number of steel pipes 8a, 8a, and the diameter of the curtain body 9 will be verified.

For example, if it is assumed that 60,000 barrels / day of crude oil G is ejected, this will be 0.11 m ³ / s when converted into the amount of ejection per second. It is assumed that the scale can be stored at the top of the curtain 9. Since the amount of crude oil G ejected per hour is 396 m ³ , when the specific gravity of seawater is 1.025 and the specific gravity of crude oil G is 0.8, the buoyancy of crude oil G is expressed by the following equation (1) become.

U = (1.025−0.8) × 396 = 89.1 tf (1)
The weight in water when assuming that the inner space (volume is about 0.5 m ³ / m) of the anchor ring 8 formed by connecting the steel pipes 8a and 8a having a diameter of 800 mm is filled with mortar is expressed by the following formula (2 )become that way.

W = (2.2−1.025) × 0.5 = 0.59 tf / m (2)
Therefore, the required length (circumferential length) L of the anchor ring 8 is L = 89.1 / 0.59 = 151 m, which is about 48 m when converted to the diameter of the anchor ring 8. Therefore, the anchor ring 8 having a closed loop-like and flexible pipe-like structure with a diameter of about 50 m satisfies the above condition.

  When the dome assembly 4 placed on the crude oil outlet 3 is fixed on the sea floor in this way, as shown in FIG. 1 in addition to FIG. 5, the crude oil G ejected from the crude oil outlet 3 is collected in the curtain body 9, The curtain 9 itself expands or bulges in a dome shape, and the crude oil G is guided to the top of the dome-like curtain body 9 by its own buoyancy because the specific gravity is smaller than seawater, and further passes through the transport pipe 5. It will rise to the sea surface.

  Therefore, as shown in the figure, the transport pipe 5 and the recovery pipe 7 extending from the heavy oil recovery ship 6 are connected via a pump or the like, and the crude oil G floating on the sea surface 1 side through the transport pipe 5 is transferred to the inside of the crude oil recovery ship 6. To recover.

  In this case, as described above, air is injected alone or together with an emulsifier near the top of the curtain body 9 bulging in a dome shape or in the vicinity of the transport pipe 5 on the curtain body 9 side. Thereby, the floating of the crude oil G to the sea surface 1 side through the transport pipe 5 is further promoted. It is desirable that the air to be injected is heated by temperature adjustment, and hot water may be injected as necessary.

  As described above, the crude oil G ejected from the crude oil ejection port 3 on the seabed 2 can be continuously collected by the crude oil recovery ship 6 on the sea surface 1 without being diffused in the sea or on the sea surface 1.

  FIG. 6 shows a second embodiment of the present invention. In this second embodiment, the expansion or bulging shape of the curtain body 19 that forms the dome assembly 4 together with the anchor ring 8 is conical or funnel-shaped. It is what.

  FIG. 7 shows a third embodiment of the present invention. In this third embodiment, a conical shape that is a developed or bulged shape of the curtain body 29 that forms the dome assembly 4 together with the anchor ring 8 is shown. Or the distance of the change of funnel shape is made extremely long, and the curtain body 29 and the transport pipe 5 are substantially integrated.

  Note that, in these second and third embodiments, the same reference numerals are given to portions common to FIG. 1, and overlapping description will be omitted. However, in these second and third embodiments, the same air injection pipe 10 as that in FIG. 1 is attached, but the illustration is omitted in FIGS.

  In these second and third embodiments, it goes without saying that the same functions as those of the first embodiment are exhibited.

  FIG. 8 is a diagram showing a fourth embodiment of the present invention, and the same reference numerals are given to the parts common to FIG. 1 which is the first embodiment.

  In the fourth embodiment, a plurality of dome assemblies 4 each composed of an anchor ring 8 and a curtain body 39 that expands or bulges into a dome shape are connected to form a so-called multiple-unit structure. The transportation pipe 5 is abolished. More specifically, the respective dome assemblies 4 are connected to each other by a plurality of wire ropes 17, and the specific gravity of the anchor ring 8 is adjusted so that the respective postures and water depth positions in FIG. 8 can be maintained. A hole 18 is formed at the top of the curtain body 39 of each dome assembly 4, and a recovery pipe 7 extending from the crude oil recovery ship 6 is directly inserted or connected to the hole 18 of the uppermost curtain body 39. Will be.

  In the fourth embodiment, the dome assembly 4 is assembled in order from the lower stage side, and is set in the sea, and the upper dome assembly 4 is assembled while being connected by a wire rope. When all the dome assemblies 4 are completed, each dome assembly 4 is sunk on the seabed, and anchoring of the anchor ring 8 to the seabed 2 in the lowermost dome assembly 4 is the same as in the first embodiment. The same procedure is used.

  The crude oil G is once collected near the top of each curtain body 39 expanded or bulged in a dome shape, but the collected crude oil G leaks out of the hole 18 due to self-levitation force and rises. become. However, the crude oil G leaking from the hole 18 is collected again by the upper curtain 39 before it diffuses, and this behavior is repeated by the number of curtains 39. Finally, the crude oil G collected by the uppermost curtain body 39 is recovered by the offshore crude oil recovery ship 6.

  This fourth embodiment also exhibits substantially the same function as the previous embodiments.

DESCRIPTION OF SYMBOLS 2 ... Submarine 3 ... Crude oil outlet 4 ... Dome assembly 5 ... Transport pipe 6 ... Crude oil recovery ship 8 ... Anchor ring 8a ... Steel pipe 8b ... Joint sleeve 9 ... Curtain body 10 ... Air injection pipe 14 ... Mortar injection pipe 19 ... Curtain Body 29 ... Curtain 39 ... Curtain G ... Crude oil

Claims (6)

A method of collecting the crude oil by guiding it to the sea surface while suppressing the diffusion of the crude oil ejected from the crude oil outlet on the seabed,
Of the dome assembly consisting of a closed-loop frame, a curtain stretched inside the frame, and a transport pipe connected to the curtain, the frame is subjected to a primary high specific gravity treatment. Then , the dome assembly was submerged on the sea floor so that the frame body surrounded the crude oil outlet.
By applying a secondary high specific gravity treatment to the frame of the dome assembly that has landed, the dome assembly is fixed to the sea floor using the frame as an anchor,
The buoyancy of the ejected crude oil causes the curtain body to bulge into a dome shape and collects the crude oil within the dome-shaped curtain body,
A method for recovering crude oil squirted on the seabed, characterized in that the collected crude oil is levitated to the sea surface side through a transport pipe and then recovered by a crude oil recovery means on the sea.   2. The method for recovering crude oil ejected to the seabed according to claim 1, wherein air is injected into the vicinity of the top of the curtain body bulging in a dome shape or the position closest to the curtain body side of the transport pipe.   The method for recovering crude oil ejected to the seabed according to claim 2, wherein an anti-blocking agent for the transport pipe is injected together with air. The closed-loop frame is pipe-like and flexible, and the primary and secondary high specific gravity treatments inject a substance for high specific gravity into the frame itself. The method for recovering crude oil ejected to the seabed according to any one of claims 1 to 3, wherein: The material for the secondary high specific gravity treatment has a higher specific gravity than the material for the primary high specific gravity treatment,
The secondary high specific gravity treatment is performed while discharging the material for the primary high specific gravity treatment in parallel with the injection of the material for the secondary high specific gravity treatment. The method for recovering crude oil ejected to the seabed according to claim 4. A method of collecting the crude oil by guiding it to the sea surface while suppressing the diffusion of the crude oil ejected from the crude oil outlet on the seabed,
A plurality of dome assemblies, each of which is connected with a predetermined distance in the depth direction, are submerged on the sea floor, and a hole is previously formed in the center of each curtain body. Formed,
By applying a high specific gravity treatment to the frame of the lowermost dome assembly that is bottomed so as to surround the crude oil outlet, the lowermost dome assembly is fixed to the sea floor using the frame as an anchor,
In each dome assembly, the curtain body bulges into a dome shape due to the buoyancy of crude oil rising from below, and once the crude oil is collected in the dome-shaped curtain body, the crude oil is moved upward from the hole in the curtain body. To surface
A method of recovering crude oil ejected to the seabed , characterized in that the crude oil collected by the curtain of the uppermost dome assembly is recovered by means of an oil recovery means at sea .

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