1、Pressure Effects on Subsea Hardware During Flowline Pressure Testing in Deep Water API TECHNICAL REPORT 17TR11 FIRST EDITION, SEPTEMBER 2015Special NotesAPI publications necessarily address problems of a general nature. With respect to particular circumstances, local, state, and federal laws and reg
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16、 is published annually by API, 1220 L Street, NW, Washington, DC 20005.Suggested revisions are invited and should be submitted to the Standards Department, API, 1220 L Street, NW, Washington, DC 20005, standardsapi.org.iiiContentsPage1 Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
17、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Normative References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Terms, Definitions, Acronyms,
18、and Abbreviations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.1 Terms and Definitions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.2 Acronyms and Abbreviati
19、ons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 Limitations on Subsea Testing Pressures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34.1 General . . . . . .
20、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34.2 Case 1: Subsea Test Pressures at or Below 1.0 RWPa . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44.3 Case 2: S
21、ubsea Test Pressures Greater than 1.0 RWPa and Not Above 1.0 RWPd . . . . . . . . . . . . . . . 44.4 Case 3: Subsea Test Pressures Greater than 1.0 RWPd (Greater than 1.0 RWPa), but Not Above 1.5 RWPa . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
22、 . . . . . . . . . . . . . . . 64.5 Case 4: Subsea Test Pressures Greater than 1.5 RWPa, but Not Above 1.5 RWPd (or 1.25 MAOP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74.6 Case 5: Subsea Test Pr
23、essure over 1.5 RWPdNot Recommended . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95 Separate Testing of Subsea Flowline and Riser . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96 Recording of Subsea Pressure Tests . . . . . . . . . . . . . .
24、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107 Testing of New vs Old Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10Bibliography . . . . . . . . . . . . . . . . . . . . . . . . .
25、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11Figures1 Commissioning Test of Subsea Flowline with RiserCase 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 Commissioning Test of Subsea Flowline with RiserC
26、ase 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 Commissioning Test of Subsea Flowline with RiserCase 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64 Commissioning Test of Subsea Flowline with RiserCase 4 . . . . . . . . . . . . . . . . .
27、. . . . . . . . . . . . . . . . . . . 8vIntroductionSubsea hydrotesting demonstrates the structural integrity of the flowline system to tolerate the maximum allowable operating pressure (MAOP), and it confirms the sealing integrity of the pipeline system and subsea hardware components to contain hyd
28、rocarbon production. These subsea hardware components may include, but are not limited to, integral and flanged valves; flanged connections and other-end connections (OECs); jumper and flowline connectors and hubs; pressure caps and their vent valves; pressure/temperature sensors; chemical injection
29、 valves and porting; electrical penetrators; tees; crosses; pipe bends; fittings; and any similar items that will be pressurized during the subsea flowline pressure testing operations.For subsea systems where the pressure source is at the wellhead, the MAOP is typically assigned to be equal to the w
30、ellhead shut-in tubing pressure (WHSITP). Present regulations do not allow the owner/operator to consider the gradient of produced fluids to determine a variable design pressure along flowline and riser as a function of elevation if flowline and riser are not separated by physical barriers. For more
31、 details on this issue see: 30 Code of Federal Regulations (CFR) 250 Subpart J, Paragraph 250.1002; Notice to Lessees (NTL) 2009-G28, Alternate Compliance and Departure Requests in Pipeline Applications; OTC Technical Paper 25087, Formulating Guidance on Hydrotesting Deepwater Oil and Gas Pipelines.
32、Pre-commissioning leak testing demonstrates the sealing integrity of the barriers for a fully assembled subsea production system to contain hydrocarbon production fluids (or injection fluids). The leak test pressure is normally applied as internal pressure within the flowline itself, but leak testin
33、g of individual connections may be applied as a backside seal test using test pressure from a remotely operated vehicle (ROV) or other remote pressure source. The preferred use of a backside seal test is a preliminary or cursory test to verify the integrity of a connection joint before an internal p
34、ressure test of the system. The backside pressure test is typically performed with agreement between the operator and manufacturer. The backside seal test port can also be used to monitor an individual connection for leakage during an internal pressure test (during diagnostics or troubleshooting).Th
35、ere is a need to distinguish between surface shut-in tubing pressure (SSITP) and WHSITP. Standard subsea flowline hydrotest pressure typically exposes the flowline system to a differential pressure between 1.25 MAOP and 1.5 MAOP of the flowline at all locations and elevations. In some cases, the sur
36、face test pressure can be based on a calculated SSITP taking into account the hydrostatic head within the riser. In other cases, the surface test pressure may have to be 1.25 (or 1.5) times the full WHSITP at the seabed, with no reduction allowed for density of produced fluids in the riser. Thus, it
37、 is important to confirm whether the surface test pressure must be based on WHSITP or if it can be reduced, based on SSITP, considering density of produced fluids in the riser.vii1Pressure Effects on Subsea Hardware During Flowline Pressure Testing in Deep Water 1 ScopeThis document provides guidanc
38、e to the industry on allowable pressure loading of subsea hardware components that can occur during hydrotesting of subsea flowlines and risers and during pre-commissioning leak testing of these systems. There are potential problems with confusion arising from high hydrostatic pressure in deep water
39、, partially due to the variety of applicable test specifications and partly from the inconsistent use of a variety of acronyms for pressure terminology. With guidance, owner/operators can avoid unexpected loading conditions and the resulting potential for equipment damage, failure, or leakage (eithe
40、r immediate or delayed leaks) or reduced service life.This document and the examples provided give the user guidance for evaluating subsea hydrotesting scenarios where test pressures are often well above maximum allowable operating pressure (MAOP). 2 Normative ReferencesThe following referenced docu
41、ments are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. API Technical Report 17TR8, High-pressure High-temperature Design GuidelinesAP
42、I Technical Report 17TR12, Consideration of External Pressure in the Design and Pressure Rating of Subsea Equipment 3 Terms, Definitions, Acronyms, and Abbreviations3.1 Terms and DefinitionsFor the purposes of this document, the following definitions apply.3.1.1 absolute pressure Absolute pressure i
43、nside the components being tested, measured in “psia.”3.1.2 barrierElement forming part of a pressure-containing envelope that is designed to prevent unintentional flow of produced/injected fluids, particularly to the external environment.3.1.3 differential pressure Difference between the absolute p
44、ressure inside a component and the absolute pressure outside of the component at that location, measured in “psid.”NOTE For the purposes of discussions in this document, “psig” and “psid” are the same if at the same water depth.2 API TECHNICAL REPORT 17TR113.1.4 external pressureExternal pressure ac
45、ting on the subsea equipment due to the ambient seawater pressure at the submerged depth of the equipment being tested (Po).3.1.5 gauge pressure Pressure gauge reading (assuming gauge is referenced to ambient pressure at the subsea depth); for example the differential between the absolute pressure i
46、nside the component being tested subsea and the external ambient pressure at the submerged depth, measured in “psig.”3.1.6 maximum allowable operating pressureMAOPThe single absolute pressure rating assigned, by U.S. regulator, to a flowline system including topsides to seabed limits. NOTE 1 MAOP ma
47、y be the maximum pressure determined by design of a critical section or component pressure rating. NOTE 2 MAOP may also be the lowest design pressure of the maximum design pressures of all pipeline sections and components.3.1.7 rated working pressureRWPMaximum internal pressure a piece of equipment
48、is designed to contain and/or control.NOTE 1 For the purposes of this technical report, rated working pressure is defined as the absolute internal pressure minus 14.7 psia (see API 6A and API 17D).NOTE 2 Typically applies to valves, flanges, hubs, OECs, fittings, etc.3.1.8 rated working pressure, ab
49、soluteRWPaManufacturers rated working pressure rating for the component, expressed in absolute pressure of fluid inside the component (psia).NOTE For the purpose of this technical report, the term RWPa means the manufacturers rated working pressure, measured in “psia.”3.1.9 rated working pressure, differentialRWPdFor valve bore sealing elements, the maximum allowable differential pressure across the closed valve (applies to both testing and operations).NOTE When conducting typical factory acceptance testing (FAT) and fabrication facility pressure tests
