RU2198261C1 - Method of erection of marine platform - Google Patents

Abstract

FIELD: erection of technological platforms for performing jobs in offing; installation of derricks in river beds, swampy areas, under permafrost conditions or on quick sands. SUBSTANCE: method includes transportation of base and deck with technological equipment to area of their installation in above-water position, placing the base on bottom and securing it by means of piles followed by mounting the deck on said base. Then, technological wells are drilled and annulus space is filled with cement mortar. Cementable piles are mounted in stepped pile wells drilled preliminarily. At least one casing pipe is mounted in each step of well at spaced relation to its surface; said clearances and clearances between casing pipe and cementable piles mounted coaxially, as well as its inner cavity are filled with cement mortar. Length of casing pipe is dictated by condition of overlapping unsteady rock. Then, deck with technological equipment is mounted on base. Cementable piles and technological wells may be combined when technological well or production casing string may be located inside cementable pile (performing function of conductor) at spaced relation. In drilling stepped pile wells, mounting cementable piles and technological wells, use is made of self-elevating floating drilling platform; for performing assembly jobs, at least two self-elevating floating transport platforms are used. After leveling the horizontal surfaces of deck and platform, they are coupled together and technological equipment is shifted from one platform to other platform. EFFECT: enhanced operational reliability of platforms due to their enhanced stability. 5 cl, 7 dwg

Description

 The invention relates to the development of underwater mineral deposits, mainly liquid and gaseous, to the construction of technological platforms that provide both exploratory and operational work on the shelf of the open sea, as well as when installing derricks in riverbeds, on marshy terrain, in conditions permafrost or quicksand.

 A technical solution is known, which is characterized in that the base of the platform, designed to operate in the Arctic region, is made in the form of a caisson formed by the upper and lower bases and two shells - the outer and the inner, rigidly interconnected by vertical partitions / 1 /.

 The design of the base - the shells of the caisson and partitions provides for interaction with the ice cover. If it is necessary to install the offshore platform at a sufficiently large depth, this design can withstand sufficiently large loads due to the design of the outer shell in the form of a closed broken curve in cross section. However, it does not allow sufficient resistance to the overturning moment, since clogged piles into the ground quite easily exit from the ground.

 Known offshore platform, which contains installed on the seabed base with the upper deck, the technological equipment on which has the ability to alternately connect with the mouths of the technological wells located in the respective directions of the Central part of the base, the base is equipped with rigidly connected conductors in which are installed piles connecting base of the platform with soil / 2 /.

 In a known technical solution, the foundation plate, the conical and cylindrical parts of the base are a protective structure that allows you to perceive external wave loads and loads from the ice sheet.

 However, despite the presence of a foundation plate, the well-known technical solution also does not solve the problem of reliable fastening of the foundation plate to the ground, since there are no means that prevent the shear and capsizing forces of the structure as a whole.

 There is a method of constructing an offshore platform in which the base and the upper deck are transported with the processing equipment in the water position to the place of their installation, the base is mounted on the bottom and fixed to the bottom using piles, the upper deck with the processing equipment is installed on the base, and technological wells are drilled , fill the annular space of technological wells with cement mortar / 3 / - prototype.

 The construction of the offshore platform by a known method allows us to solve the problem of modular manufacturing of individual functional parts at different shipyards. At the same time, fixing the base to the ground is carried out by the method of driving piles with a copra.

 In hard soils, such a fastening is practically difficult to accomplish, and in soft soils, such fastening cannot be effective by itself due to the small resistance to external influences, in particular, overturning moment. Therefore, the known method provides for the use of the gravitational method to achieve the stability of the platform structure by partially filling the space between the sheathing of the protective structure with cement mortar. Gravity installation methods for offshore platforms, i.e. platforms with a large mass, on the one hand, require very large dimensions of the structure and, as a consequence, large investments, on the other hand, large dimensions of the structure cause large external cyclic loads on the offshore platform from sea currents and wave loads, as well as vibration loads, arising from the destruction of the ice cover. The large weight of such offshore platforms generally limits their use in areas of increased seismic activity.

 The present invention is aimed at solving the problem of increasing the economic efficiency of the construction of the offshore platform, regardless of the characteristics of the soil and weather conditions, increasing the reliability of its operation by increasing the resistance to both tipping moment and shear forces, taking into account cyclic wave loads and interaction with ice cover, as well as providing the possibility of their use in areas of high seismicity.

 The indicated unified technical result is achieved by the fact that a method of constructing an offshore platform is implemented, in which the base and deck with technological equipment are transported in an elevated position to the place of their installation, the base is installed at the bottom and fastened to the bottom with piles, the deck with technological equipment is installed on the base, carry out drilling for technological wells, fill the annular space of technological wells with cement mortar, and the piles are cemented, with This installation of cemented piles is carried out in pre-drilled stepped pile wells, at least one casing pipe is installed in each step of the well with a gap relative to its surface, the mentioned gaps and gaps between the coaxially installed casing pipes and the cemented pile, and also fill the internal cavity of the latter cement mortar, and the length of the casing pipe is selected from the condition of overlapping unstable rocks, after which the deck with technological equipment is installed on warping.

 In a preferred embodiment, the cemented piles and production wells are combined, wherein the production well or production casing is placed inside the cemented pile acting as a conductor with a gap, and said gap is also filled with cement mortar.

 When drilling stepped pile wells, installing cemented piles and technological wells, a self-elevating floating drilling platform is used with the appropriate technological equipment and with retractable supports that ensure interaction with the soil during technological operations.

 When carrying out installation work on the installation of technological equipment, at least two self-elevating floating transport platforms with retractable supports are used that provide interaction with the ground during technological operations, while moving the necessary operational equipment from one platform to another and connecting the elements of technological equipment to each other carried out with the help of hoisting vehicles, which are placed on one of the floating self-lifting vehicles nsportny platforms.

 In addition, they level the horizontal surface of the deck and the floating self-elevating transport platform with retractable supports, dock them and, for example, use hydraulic jacks, carry out horizontal movement of technological equipment along the respective rails from one platform to another.

 The analysis of the prior art by the applicant, including a search by patent and scientific and technical sources of information and the identification of sources containing information about analogues for the method object, made it possible to establish that the applicant did not find analogues characterized by signs that are identical to all the essential signs for the claimed method.

 The definition from the list of identified analogues of the prototype, as the closest in the aggregate of essential features, allows you to identify the set of essential distinguishing features for the claimed object, as set out in the claims, as seen by the applicant.

 Therefore, the claimed invention meets the requirement of "novelty" under applicable law.

 To verify the conformity of the claimed invention to the requirements of the inventive step, the applicant conducted an additional search for known solutions in order to identify features that match the distinctive features of the claimed prototype of the claimed subject matter, the results of which show that the claimed invention does not explicitly follow from the prior art.

 Therefore, the claimed invention meets the requirement of "inventive step" under applicable law.

 The invention is illustrated in figures 1-7.

 Figure 1 shows a design variant of an offshore platform with separate execution of cemented piles and technological wells and section AA, showing the separate arrangement of pile and technological wells.

 Figure 2 presents an embodiment of a cemented pile.

 Figure 3 is an embodiment of the design of the offshore platform with the combined implementation of cemented piles and technological wells and section AA, showing the combined arrangement of pile and technological wells.

 In FIG. 4 shows a possible embodiment of a cemented pile in conjunction with a production well.

 Figures 5 and 6 are drawings explaining the method in terms of options for separate or combined structural design of a cemented pile with a production well using a self-lifting floating drilling platform with retractable supports and location in terms of processing equipment, respectively.

 In FIG. 7 is a drawing explaining a method in terms of mounting process equipment on an offshore platform using floating transport platforms with retractable supports. In this case, FIG. 7a shows a sea platform onto which the processing equipment is being loaded, FIG. 7b shows a floating transport platform with retractable supports on which the handling equipment is located, FIG. 7b shows a floating transport platform with retractable supports, which is intended for transportation of technological equipment.

 The offshore platform in the general case (Fig. 1) contains a base 1 installed on the seabed, consisting of an outer 2 and an inner shell 3, a deck 4 on which technological equipment is installed 5. The base 1 is attached to the ground using cemented piles 6. The cavity formed by the outer 2 and inner 3 shells of the base 1 can be filled with cement mortar 7, or serve, in whole or in part, to collect sludge during drilling.

 In the considered embodiment of the offshore platform with an average ice load (ice thickness up to 2 m), a central part 8 is installed inside the base 1 with a gap, inside of which are the technological wells 9. Here, cemented piles 6 and technological wells 9 are installed separately. Technological equipment 5 has the ability to interact with technological wells in turn 9. In particularly difficult ice conditions, the base of the platform 1 and the central part 8 are installed separately, i.e. with a gap relative to each other, thereby eliminating the effect of external loads on the technological wells 9.

 The design of the cemented pile 6 (Fig. 2) is mainly performed stepwise in the form of two casing pipes 10 and 11 coaxially installed with a gap relative to each other (in the particular case, one casing pipe), which serve to prevent crumbling of unstable rocks and each of which performs the function of direction and conductor. The surface of the casing strings 10, 11, the cemented pile 6 and the surface of the corresponding step of the pile well 12 are rigidly interconnected with cement mortar 7. The internal cavity of the cemented pile 6 is also filled with cement mortar 7.

 In another embodiment (Fig.6), the installation of which is justified at low ice load (ice thickness up to 0.5 m), cemented pile 6 and production well 9 are performed combined.

 At the same time, the stepped pile well 12 (Fig. 4) has an additional step for installing a cemented casing 6 of the technological casing string 13 in its cavity (the production string is not shown).

 Drilling for technological wells 9 and stepped pile wells 12 (Fig. 5 - Fig. 6), as well as the installation of technological equipment 5 (Fig. 7), is preferably carried out using floating self-lifting drilling platforms 14 with retractable supports 15 interacting with the soil.

 When installing process equipment 5 (Fig. 7), floating self-elevating transport platforms 16 are used, on one of which hoisting-and-transport equipment 17 is located.

 The proposed method is implemented as follows.

 The base 1 is transported in a surface position to the installation site. Set the base 1 to the bottom and fix it to the bottom using cemented piles 6. Carry out drilling for technological wells 9, fill the annular space of technological wells 9 with cement mortar 7. Installation of cemented piles 6, casing 10 and 11 is carried out in pre-drilled stepped pile wells 12. In each step of the well 12 with a gap relative to its surface, a corresponding casing 10 and 11 is installed. Moreover, the said gaps, as well as the gaps between the casing 10 and 11, between the casing the bottom pipe 11 and the cemented pile 6 are filled with cement mortar 7 (FIG. 2). The length of the casing 10 and 11 is selected from the condition of overlapping unstable rocks. Then on the base 1 set the upper deck 4 with technological equipment 5.

 In some embodiments, stepped pile 12 and production wells 9 are combined (FIG. 3, FIG. 4). In this case, the technological casing 13 of the technological well 9 is located in the cavity of the casing 11 of the cemented pile 6, which acts as a conductor, with a gap, and the said gap is also filled with cement mortar 7.

 When drilling stepped pile wells 12, installing cemented piles 6 and drilling wells for technological wells 9, a floating self-elevating drilling platform 14 is used with the corresponding technological equipment 5 and with retractable supports 15, which interact with the soil during technological operations (Fig. 5 and Fig. 6). For the specific implementation of the offshore platform, depending on the external conditions, an appropriate ratio of the number of combined and not combined cemented piles 6 and technological wells 9 is selected, as well as their depth and relative layout.

 When carrying out installation work on the installation of technological equipment, at least two floating self-lifting transport platforms 16 with retractable supports 15 are used, which, when performing technological operations, interact with the soil, while moving the necessary operational equipment from one platform to another and connecting elements of production equipment between themselves is carried out using lifting and handling equipment 17 located on one of the floating self-lifting tr import platforms 16 (Fig.7).

 In addition, according to the proposed method, it is possible to level the horizontal surfaces of deck 4 and the floating self-lifting transport platform 16 with retractable supports 15, to dock them and, for example, using hydraulic jacks (not shown), to carry out horizontal movement of the technological equipment along the respective rails with one platforms to another.

 This method of installation of technological equipment can reduce the impact of sea waves on the productivity and quality of work, i.e. essentially allows you to ensure installation work regardless of weather conditions.

 The proposed technical solution allows to increase the reliability of the structures under construction, namely, to increase the resistance to the tipping moment when installing on unstable rocks, to use the construction of step cemented piles when installing drilling platforms in river beds, in marshy terrain, in permafrost or in quicksand.

 The proposed method, which is essentially universal, allows you to perform the whole offshore platform with small dimensions, with a lower weight in comparison with the known technical solutions and, therefore, with great economic efficiency. At the same time, the small dimensions of its upper part minimize vibration loads acting on the offshore platform from the ice cover, and the low weight and reliable attachment of the platform to the ground allows the construction of platforms in seismically hazardous areas.

 In addition, the proposed method c can be used with great economic effect in the construction of offshore platforms with tension supporting structures by replacing ballast cargo with cemented piles.

 Thus, for the claimed technical solution in the form as described in the independent clause of the claims below, the possibility of its implementation using the means and methods described above and known prior to the priority date with the expected technical result is confirmed.

 Therefore, the claimed facility meets the requirement of "industrial applicability" under applicable law.

Literature
1. Application of France 2615217, CL E 02 B 17/00, 1988.

 2. RF patent 2089704, cl. E 02 B 17/00, 1997.

 3. RF patent 2090699, cl. E 02 B 17/00, 1997.

Claims (5)

 1. The method of constructing an offshore platform, in which the base and the deck with the processing equipment are transported in an elevated position to the place of their installation, the base is installed at the bottom and fastened to the bottom using piles, the deck with the processing equipment is installed on the base, drilling is carried out for technological wells fill the annular space of technological wells with cement mortar, characterized in that the piles are cemented, while the installation of cemented piles is carried out in advance at least one casing pipe, said gaps and gaps between the coaxially installed casing pipes and the cemented pile, and also the internal cavity of the latter are filled with cement mortar, and the length of the casing pipes is selected from the condition of overlapping unstable rocks, after which they install a deck with technological equipment on the base.  2. The method according to claim 1, characterized in that the cemented piles and technological wells are combined, while the technological well or production casing is placed inside the cemented pile, which performs the function of a conductor, with a gap, and said gap is also filled with cement mortar.  3. The method according to claim 1 or 2, characterized in that when drilling stepped piles, installing cemented piles and technological wells, use a self-floating floating drilling platform with appropriate processing equipment and with retractable supports that provide interaction with the soil when performing technological operations.  4. The method according to claim 1, or 2, or 3, characterized in that when carrying out installation work on the installation of technological equipment, at least two self-elevating floating transport platforms with retractable supports are used that provide interaction with the ground during technological operations, while the movement of the necessary operational equipment from one platform to another and the connection of the elements of technological equipment among themselves is carried out using hoisting vehicles that are burghers on one of the floating jack-transport platforms.  5. The method according to any one of claims 1 to 4, characterized in that the horizontal surfaces of the deck and the floating self-lifting transport platform with retractable supports are aligned, they are docked and, for example, hydraulic jacks carry out horizontal movement of the processing equipment along the respective guides with one platform to another.

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