Patent Publication Number: US-11396351-B2

Title: Platform for floating type offshore structure having protrusion member and semi-submersible offshore structure including the same

Description:
TECHNICAL FIELD 
     Exemplary embodiments of the present invention relate to a platform for a floating type offshore structure having a protrusion member which minimizes influence by a seawater flow to improve stability at sea and a semi-submersible offshore structure including the same. 
     BACKGROUND ART 
     Generally, a semi-submersible offshore structure, such as a hybrid power-generation structure on the sea is equipped with an expensive drilling system or riser equipment for perforation on an upper deck and floats on the sea and moored at a fixed position to be used. 
     For example, in the case of a semi-submersible offshore structure such as a drilling rig ship, various devices extend from the upper deck of the drilling rig ship to a sea floor during the drilling operation so that the devices may be significantly affected by an up and down movement of the drilling rig ship. 
     That is, the semi-submersible offshore structure is used while floating on the sea so that movement is inevitably caused by the flow of the seawater. 
     When the offshore structure consistently moves due to the flow of the seawater such as wave, it greatly affects the performance of various drilling devices installed in the offshore structure and moreover, drilling devices may be damaged. 
     As a prior art document, there is Korean Unexamined Patent Application Publication No. 10-2010-0090991 (published on Aug. 18, 2010). 
     DISCLOSURE 
     Technical Problem 
     An exemplary embodiment of the present invention provides a platform for an offshore structure having a protrusion member which minimizes influence by flow of seawater to stably moor the offshore structure with improved stability on the sea and a semi-submersible offshore structure including the same. 
     Technical problems to be solved by the present invention are not limited to the above-mentioned technical problem(s), and other technical problem(s), which is (are) not mentioned above, can be clearly understood by those skilled in the art from the following descriptions. 
     Technical Solution 
     A platform for a floating type offshore structure having a protrusion member according to an exemplary embodiment of the present invention includes: a main body which is installed on the sea and has an arrangement structure in which a plurality of pontoons is combined to form a plurality of polygonal shapes, a protrusion member which extends from each corner of the main body and outwardly protrudes from the main body, and a protrusion member connecting unit which connects the protrusion member to the main body. 
     The platform for a floating type offshore structure may further include a protrusion member on which a tower is installed and the protrusion member is located at an end of the protrusion member connecting unit. 
     The tower may be a wind tower for wind power generation. 
     A mooring line fastening unit for connecting a mooring line may be installed at a side pontoon of the main body. 
     The mooring line fastening units may be installed on both sides of the corner. 
     The mooring line fastening units may be disposed to be symmetrical to each other with respect to a length direction of the protrusion member connecting unit. 
     The main body may include an upper horizontal connecting unit and a lower horizontal connecting unit which have an arrangement structure in which a plurality of pontoons is coupled in a horizontal direction and spaced apart from each other to be parallel and a vertical connecting unit which is disposed between the upper horizontal connecting unit and the lower horizontal connecting unit to be perpendicular thereto. 
     The platform for a floating type offshore structure may further include a protrusion member reinforcing unit which connects the side pontoon of the main body and the protrusion member and extends from the vertical connecting unit of the main body to be inclined. 
     The protrusion member reinforcing unit may be formed to be downwardly inclined from an upper portion of the vertical connecting unit of the main body. 
     The protrusion member reinforcing unit may be formed to be upwardly inclined from a lower portion of the vertical connecting unit of the main body. 
     The protrusion member reinforcing unit may include a first protrusion member reinforcing unit which is formed to be downwardly inclined from an upper portion of the vertical connecting unit of the main body; and a second protrusion member reinforcing unit which is formed to be upwardly inclined from a lower portion of the vertical connecting unit of the main body. A semi-submersible offshore structure according to an exemplary embodiment of the present invention includes the above-described platform for a floating type offshore structure. Specific items of other embodiments are included in the detailed description and the drawings. 
     Advantageous Effects 
     According to an exemplary embodiment of the present invention, a protrusion member connecting unit is formed to outwardly protrude from a main body so that an external force caused by waves while being moored on the sea may be dispersed and the influence by the wake may be reduced. 
     According to an exemplary embodiment of the present invention, unlike a platform for a floating type offshore structure of the related art, a reach distance limit of a crane for installing a structure is reduced and thus accessibility and operability of the crane may be greatly improved. According to an exemplary embodiment of the present invention, the semi-submersible offshore structure stably floats by a mooring line which is connected to a mooring line fastening unit and the mooring line fastening unit is installed at a corner of the main body so that the influence of the load of a mooring line which is applied to a connecting member of the protruding unit and the main body is reduced, thereby structurally stabilizing the connecting member. According to an exemplary embodiment of the present invention, a protrusion member reinforcing unit is installed to disperse the load generated from the protrusion member so that the load which is concentrated on the protrusion member is dispersed to improve durability of the platform. 
    
    
     
       DESCRIPTION OF DRAWINGS 
         FIG. 1  is a front view of a platform for a floating type offshore structure according to an exemplary embodiment of the present invention. 
         FIG. 2  is a plan view of a platform for a floating type offshore structure according to another exemplary embodiment of the present invention. 
         FIG. 3  is a view illustrating a crane which operates on a platform for a floating type offshore structure according to an exemplary embodiment of the present invention. 
         FIG. 4  is a view illustrating a crane which operates on a platform for a floating type offshore structure according to another exemplary embodiment of the present invention. 
         FIG. 5  is a plan view of a platform for a floating type offshore structure according to an exemplary embodiment of the present invention in which a mooring line fastening unit is installed. 
         FIG. 6  is a plan view of a platform for a floating type offshore structure according to another exemplary embodiment of the present invention in which a mooring line fastening unit is installed. 
         FIG. 7  is a front view of a platform for a floating type offshore structure according to an exemplary embodiment of the present invention. 
         FIG. 8  is a front view of a platform for a floating type offshore structure according to another exemplary embodiment of the present invention. 
         FIG. 9  is a front view of a platform for a floating type offshore structure according to still another exemplary embodiment of the present invention. 
     
    
    
     BEST MODE 
     Advantages and characteristics of the present invention and/or a method of achieving the advantages and characteristics will be clear by referring to exemplary embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the following exemplary embodiments but may be implemented in various different forms. The exemplary embodiments are provided only to complete the disclosure of the present invention and to fully provide a person having ordinary skill in the art to which the present invention pertains with the category of the disclosure, and the present invention will be defined by the appended claims. Like reference numerals indicate like elements throughout the specification. 
     Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. 
     An offshore structure of the present invention is a semi-submersible offshore structure such as an oil and gas production facility or an offshore wind power generation facility, and is a facility which floats or is moored on the sea to produce oil or gas or perform hybrid power generation.  FIG. 1  is a front view of a platform for a floating type offshore structure according to an exemplary embodiment of the present invention and  FIG. 2  is a plan view of a platform for a floating type offshore structure according to another exemplary embodiment of the present invention. 
     Referring to  FIGS. 1 and 2 , a floating type offshore structure according to an exemplary embodiment of the present invention has a platform for an offshore structure having a protrusion member  210  with an improved stability. The platform  10  for a floating type offshore structure includes a main body  100  and a protrusion member connecting unit  200 . 
     The main body  100  is installed on the sea and has an arrangement structure in which a plurality of pontoons is combined to form a plurality of polygonal shapes. 
     For example, as illustrated in  FIG. 1 , the main body  100  may have an arrangement structure in which a side pontoon  110  forms a rectangular shape, a diamond-shaped pontoon is coupled inside the side pontoon  110 , and a cross-shaped pontoon is coupled inside the diamond shape to divide the diamond shape into four parts. 
     As another example, as illustrated in  FIG. 2 , the main body  100  may have an arrangement structure in which a side pontoon  110  forms a triangular shape, a X-shaped pontoon is coupled inside the side pontoon  110  to divide the side pontoon into three parts. 
     As described above, the main body  100  may be formed by connecting a plurality of pontoons to disperse the load and improve the durability. In this case, the pontoons located at the outside of the main body  100  are connected so that the side pontoon  110  which determines a planar outer appearance of the main body  100  may have a polygonal shape and include a corner  111  which forms an angled portion of the polygon. 
     Even though in  FIGS. 1 and 2 , it is illustrated that the shapes formed by the side pontoon  110  of the main body  100  are a rectangle and a triangle, respectively, the shape of the main body is not limited thereto and the main body  100  may have an arrangement structure with various polygonal shapes. 
     The protrusion member connecting unit  200  extends from each corner  111  of the main body and connects the protrusion member  210  which outwardly protrudes from the main body  100  to the main body  100 . 
     Specifically, since the protrusion member connecting unit  200  serves to connect the protrusion member  210  or a tower installed in the platform  10  for a floating type offshore structure to the main body  100 , the protrusion member connecting unit may be a tower connecting unit and formed to outwardly protrude with respect to a center of the main body  100 . 
     Even though the number of protrusion member connecting units  200  is not specifically limited, since the protrusion member connecting units are formed at all corners  111  of the main body  100 , the number of protrusion member connecting units  200  may be desirably equal to the number of corners  111 . Further, an extending direction of the protrusion member connecting unit  200 , that is, a length direction or an extending length direction of the protrusion member connecting unit  200  may be more desirably located on the same line as the center of the main body  100 . 
     In this case, since the protrusion member connecting unit  200  is formed to outwardly protrude from the main body  100 , the platform  10  for a floating type offshore structure according to an exemplary embodiment of the present invention may disperse the external force by waves generated while being moored on the sea and reduce the influence of wakes. 
     That is, the protrusion member connecting unit  200  also serves as a sort of breakwater which protects the platform  10  for a floating type offshore structure according to the present invention from waves of the outside sea. 
     Further, the extending length of the protrusion member connecting unit  200  may be appropriately determined to be proportional to the size of the main body  100  equipped in the platform  10  for a floating type offshore structure. 
     The platform  10  for a floating type offshore structure according to an exemplary embodiment of the present invention may further include a protrusion member  210  for installing a tower and the protrusion member  210  is located at an end of the protrusion member connecting unit  200 . 
     The tower may be a wind tower for wind power generation, but is not limited thereto and may include all structures which are installed in the existing offshore structure or can be installed in the existing offshore structure. 
       FIG. 3  is a view illustrating a crane which operates on a platform for a floating type offshore structure according to an exemplary embodiment of the present invention and  FIG. 4  is a view illustrating a crane which operates on a platform for a floating type offshore structure according to another exemplary embodiment of the present invention. 
     In the existing platform for an offshore structure, an upper structure which mostly occupies the load is located inside the platform for an offshore structure, specifically, in a center portion, so that a crane having a long reach distance is required to install the structure. 
     Therefore, in the related art, there is a limitation of a size of the platform for a floating type offshore structure which can be manufactured in accordance with the realistic reach distance limit of the crane. 
     However, the protrusion member  210  according to the present invention is located at an end of the protrusion member connection unit  200  which is formed to outwardly protrude from the main body  100  so that unlike the platform for a floating type offshore structure of the related art, a reach distance limit of the crane  300  for installation of the structure is reduced, thereby greatly improving accessibility and operability of the crane  300 . 
     In  FIGS. 3 and 4 , for the purpose of description, the size of the crane  300  is exaggerated, but actually the size of the platform for a floating type offshore structure is much larger than the crane  300 . Therefore, the effect of improving the accessibility and the operability of the crane  300  due to the location of the protrusion member  210  may be more dramatic. 
       FIG. 5  is a plan view of a platform for a floating type offshore structure according to an exemplary embodiment of the present invention in which a mooring line fastening unit is installed and  FIG. 6  is a plan view of a platform for a floating type offshore structure according to another exemplary embodiment of the present invention in which a mooring line fastening unit is installed. 
     Referring to  FIGS. 5 and 6 , the side pontoon  110  of the main body  100  may be equipped with a mooring line fastening unit  120  to connect the mooring line  130 . 
     Generally, a large load is applied to the mooring line fastening unit  120 . However, in the platform  10  for a floating type offshore structure according to the present invention, the mooring line fastening unit  120  is installed not in the protrusion member connecting unit  200 , but in the main body  100 , specifically, at a corner of the main body  100  so that a structure stability of the protrusion member connecting unit  200  is significantly improved. 
     Specifically, the mooring line fastening units  120  may be installed to be adjacent to both sides of the corner  111  to which the protrusion member connecting unit  200  extends and a tower which mostly occupies the load is installed in the protrusion member connecting unit  200 . The mooring line fastening units  120  are desirably disposed to be symmetrical with respect to a length direction of the protrusion member connecting unit  200  to disperse the force which is applied to the mooring line fastening unit  120 . 
     By doing this, the platform  10  for a floating type offshore structure may stably float through the mooring line  130  connected to the mooring line fastening unit  120  and is installed at the corner of the main body so that the influence of the load of the mooring line which is applied to the connecting member of the protrusion member and the main body is reduced. Therefore, the connecting member has a stable structure. 
       FIG. 7  is a front view of a platform for a floating type offshore structure according to an exemplary embodiment of the present invention,  FIG. 8  is a front view of a platform for a floating type offshore structure according to another exemplary embodiment of the present invention, and  FIG. 9  is a front view of a platform for a floating type offshore structure according to still another exemplary embodiment of the present invention. 
     The platform  10  for a floating type offshore structure according to the present invention may include a main body  100  and a protrusion member connecting unit  200  and the main body  100  includes a horizontal connecting unit  140  having an arrangement structure in which a plurality of pontoons is coupled in a horizontal direction and a vertical connecting unit  150  configured by columns having a shape of a vertical frame. 
     Specifically, the horizontal connecting unit  140  is disposed such that an upper horizontal connecting unit  141  and a lower horizontal connecting unit  142  are spaced apart from each other with a predetermined interval to be parallel and the vertical connecting unit  150  is disposed between the upper horizontal connecting unit  141  and the lower horizontal connecting unit  142  to be perpendicular thereto to support the horizontal connecting units  140 . 
     Here, “horizontal” means a width direction in  FIGS. 7 to 9  and “vertical” means a length direction in  FIGS. 7 to 9 . 
     Referring to  FIGS. 7 to 9 , the platform  10  for a floating type offshore structure according to the present invention may further include a protrusion member reinforcing unit  220  which connects a side pontoon  110  of the main body  100  and the protrusion member  210  and extends from the vertical connecting unit  150  of the main body  100  to be inclined. 
     That is, since the protrusion member  210  is formed at an end of the protrusion member connecting unit  200  in the platform  10  for a floating type offshore structure according to the present invention, the load may be concentrated on the protrusion member  210 . Therefore, the protrusion member reinforcing unit  220  may be added to disperse the load. 
     Referring to  FIG. 7 , the protrusion member reinforcing unit  220  according to an exemplary embodiment of the present invention is downwardly inclined from the upper portion of the vertical connecting unit  150  of the main body  100  and disperses the load which is applied to the protrusion member  210 . 
     Referring to  FIG. 8 , the protrusion member reinforcing unit  220  according to another exemplary embodiment of the present invention is upwardly inclined from the lower portion of the vertical connecting unit  150  of the main body  100  and disperses the load which is applied to the protrusion member  210 . 
     Referring to  FIG. 9 , the protrusion member reinforcing unit  220  according to still another exemplary embodiment of the present invention includes a first protrusion member reinforcing unit  221  which is downwardly inclined from the upper portion of the vertical connecting unit  150  of the main body  100  and a second protrusion member reinforcing unit  222  which is upwardly inclined from the lower portion of the vertical connecting unit  150  of the main body  100  and more efficiently disperses the load applied to the protrusion member  210 . 
     Although a specific exemplary embodiment of the present invention has been described, it should be understood that various modifications may be made therein without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiment, but should be determined by the claims to be described below and equivalents thereof. 
     As described above, although the present invention has been described by limited embodiments and drawings, the present invention is not limited to the embodiments, and it will be apparent to those skilled in the art to which the present invention pertains that various modifications and variations may be made from the description. Therefore, the spirit of the present invention needs to be interpreted by the appended claims and all equivalent modifications are included within the spirit of the present invention.