1、Derivation of Metocean Design and Operating ConditionsANSI/API RECOMMENDED PRACTICE 2METFIRST EDITION, NOVEMBER 2014ISO 19901-1:2005 (Modified), Petroleum and natural gas industriesSpecific requirements for offshore structuresPart 1: Metocean design and operating considerationsSpecial NotesAPI publi
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17、dsapi.org.iiiv Contents Page API Foreword iii Foreword vii Introduction viii 1 Scope. 1 2 Normative references 2 3 Terms and definitions 2 4 Symbols and abbreviated terms . 9 4.1 Main symbols . 9 4.2 Abbreviated terms 11 5 Determining the relevant metocean parameters 12 5.1 General 12 5.2 Expert int
18、erpretation of the metocean database 12 5.3 Selecting appropriate parameters for determining design actions or action effects . 13 5.4 The metocean database 13 5.5 Storm types in a region . 14 5.6 Directionality 14 5.7 Extrapolation to rare conditions . 14 5.8 Metocean parameters for fatigue assessm
19、ents 15 5.9 Metocean parameters for short-term activities . 15 6 Water depth, tides and storm surges . 16 6.1 General 16 6.2 Tides 17 6.3 Storm surge 18 7 Wind . 18 7.1 General 18 7.2 Wind actions and action effects . 19 7.3 Wind profile and time-averaged wind speed . 19 7.4 Wind spectra . 19 8 Wave
20、s 20 8.1 General 20 8.2 Wave actions and action effects 20 8.3 Intrinsic, apparent and encounter wave periods 21 8.4 Two-dimensional wave kinematics 21 8.5 Maximum height of an individual wave for long return periods . 22 8.6 Wave spectra 22 8.7 Wave directional spreading function and spreading fact
21、or 22 8.8 Wave crest elevation 22 9 Currents 23 9.1 General 23 9.2 Current velocities . 23 9.3 Current profile 24 9.4 Current profile stretching 24 9.5 Current blockage 24 10 Other environmental factors . 24 10.1 Marine growth . 24 10.2 Tsunamis 25 10.3 Seiches 25 vi 10.4 Sea ice and icebergs 25 10.
22、5 Snow and ice accretion . 26 10.6 Miscellaneous . 26 Annex A (informative) Additional information and guidance 27 Annex B (informative) Discussion of wave frequency spectra . 66 Annex C (informative) Regional information . 76 Bibliography 160 vii Foreword ISO (the International Organization for Sta
23、ndardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the righ
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26、 International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 1
27、9901-1 was prepared by Technical Committee ISO/TC 67, Materials, equipment and offshore structures for petroleum, petrochemical and natural gas industries, Subcommittee SC 7, Offshore structures. ISO 19901 consists of the following parts, under the general title Petroleum and natural gas industries
28、Specific requirements for offshore structures: Part 1: Metocean design and operating considerations Part 2: Seismic design procedures and criteria Part 3: Topsides structure Part 4: Geotechnical and foundation design considerations Part 5: Weight control during engineering and construction Part 6: M
29、arine operations Part 7: Stationkeeping systems for floating offshore structures and mobile offshore units The following parts are under preparation: Part 8: Marine soil investigations Part 9: Structural integrity management ISO 19901 is one of a series of standards for offshore structures. The full
30、 series consists of the following International Standards. ISO 19900, Petroleum and natural gas industries General requirements for offshore structures ISO 19901 (all parts), Petroleum and natural gas industries Specific requirements for offshore structures ISO 19902, Petroleum and natural gas indus
31、tries Fixed steel offshore structures ISO 19903, Petroleum and natural gas industries Fixed concrete offshore structures ISO 19904, Petroleum and natural gas industries Floating offshore structures ISO 19905, Petroleum and natural gas industries Site-specific assessment of mobile offshore units ISO
32、19906, Petroleum and natural gas industries Arctic offshore structures viii Introduction The series of International Standards applicable to types of offshore structure, ISO 19900 to ISO 19906, constitutes a common basis covering those aspects that address design requirements and assessments of all
33、offshore structures used by the petroleum and natural gas industries worldwide. Through their application the intention is to achieve reliability levels appropriate for manned and unmanned offshore structures, whatever the type of structure and the nature or combination of the materials used. It is
34、important to recognize that structural integrity is an overall concept comprising models for describing actions, structural analyses, design rules, safety elements, workmanship, quality control procedures and national requirements, all of which are mutually dependent. The modification of one aspect
35、of design in isolation can disturb the balance of reliability inherent in the overall concept or structural system. The implications involved in modifications, therefore, need to be considered in relation to the overall reliability of all offshore structural systems. The series of International Stan
36、dards applicable to types of offshore structure is intended to provide a wide latitude in the choice of structural configurations, materials and techniques without hindering innovation. Sound engineering judgment is therefore necessary in the use of these International Standards. The overall concept
37、 of structural integrity is described above. Some additional considerations apply for metocean design and operating conditions. The term “metocean” is short for “meteorological and oceanographic” and refers to the discipline concerned with the establishment of relevant environmental conditions for t
38、he design and operation of offshore structures. A major consideration in the design and operation of such a structure is the determination of actions on, and the behavior of, the structure as a result of winds, waves and currents. Environmental conditions vary widely around the world. For the majori
39、ty of offshore locations there are little numerical data from historic conditions; comprehensive data often only start being collected when there is a specific need, for example, when exploration for hydrocarbons is being considered. Despite the usually short duration for which data are available, d
40、esigners of offshore structures need estimates of extreme and abnormal environmental conditions (with an individual or joint probability of the order of 1 102/ year and 1 103to 1 104/ year, respectively). Even for areas like the Gulf of Mexico, offshore Indonesia and the North Sea, where there are u
41、p to 30 years of fairly reliable measurements available, the data are insufficient for rigorous statistical determination of appropriate extreme and abnormal environmental conditions. The determination of relevant design parameters has therefore to rely on the interpretation of the available data by
42、 specialists, together with an assessment of any other information, such as prevailing weather systems, ocean wave creation and regional and local bathymetry, coupled with consideration of data from comparable locations. It is hence important to employ specialists from both the metocean and structur
43、al communities in the determination of design parameters for offshore structures, particularly since setting of appropriate environmental conditions depends on the chosen option for the offshore structure. This part of ISO 19901 provides procedures and guidance for the determination of environmental
44、 conditions and their relevant parameters. Requirements for the determination of the actions on, and the behavior of, a structure in these environmental conditions are given in ISO 19901-3, ISO 19901-6, ISO 19901-7, ISO 19902, ISO 19903, ISO 19904, ISO 19905 and ISO 19906. Some background to, and gu
45、idance on, the use of this part of ISO 19901 is provided in informative Annex A. The clause numbering in Annex A is the same as in the normative text to facilitate cross-referencing. A discussion on wave spectra is provided in informative Annex B. Regional information, where available, is provided i
46、n informative Annex C. ANSI/API Recommended Practice 2MET/ISO 19901-1:20051 Petroleum and natural gas industries Specific requirements for offshore structures Part 1: Metocean design and operating considerations 1 Scope This part of ISO 19901 gives general requirements for the determination and use
47、of meteorological and oceanographic (metocean) conditions for the design, construction and operation of offshore structures of all types used in the petroleum and natural gas industries. The requirements are divided into two broad types: 1) those that relate to the determination of environmental con
48、ditions in general, together with the metocean parameters that are required to adequately describe them; 2) those that relate to the characterization and use of metocean parameters for the design, the construction activities or the operation of offshore structures. The environmental conditions and m
49、etocean parameters discussed comprise extreme and abnormal values of metocean parameters that recur with given return periods that are considerably longer than the design service life of the structure, long-term distributions of metocean parameters, in the form of cumulative, conditional, marginal or joint statistics of metocean parameters, and normal environmental conditions that are expected to occur frequently during the design service life of the structure. Metocean parameters are applicable to the determinatio
