Deep Panuke Project Description - Encana

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is much more weather-dependent than using a floating hull type installation and requires a calmer seastate. This could impact the project by adding cost and time for schedule impacts due to unfavorableweather. The cost of the jack-deck is also more expensive than other solutions and leasing options werenot available. As a result of the economic disadvantages compared to the jack-up solution, this optionwas rejected.Two approaches for executing the jack-up concept were investigated: 1) build a new jack up-hull to a‘harsh environment’ drill rig specification to accommodate a new purpose-built topsides or 2)refit/modify an existing harsh environment MODU to accommodate a new purpose built topsides. Thejack-up structure was selected as the best option for the Project, the final concept of a new build or refittedjack-up structure will be confirmed during the MOPU bid competition.2.10.2.3 Topsides TypeThe type of topsides for the revised Deep Panuke Project has not yet been confirmed. It will be largelydependent on the hull design of the jack-up structure. This design will be conducted by the MOPUcontractor, selected through a competitive bid process, who will engineer all elements of the MOPU,including the topsides.2.10.2.4 Total Number of PlatformsOffshore installations are generally designed to be built as the largest components possible to maximizeconstruction, hookup and commissioning activities onshore, which greatly reduces cost. Multiplestructures are used when the size of the structure exceeds lifting capabilities for heavy lift vessels orthere are other specific requirements that dictate the use of multiple platforms. As per the Project designbasis for the approved 2002 CSR, the preferred development alternative for number of platforms wasthree separate platforms for wellheads, processing, and living quarters/utilities based on conceptdeliverability criteria, reduced drilling and installation flexibility, as well as safety.For the revised Project, the size of the topsides required for the revised 8.5 x 10 6 m 3 /d [300 MMscfd]production capacity is well within the weight and size limitations for placement on one jack-up typestructure. However, EnCana had specific concerns regarding personnel safety offshore because of thepresence of H 2 S in the fluids stream. A twin-platform arrangement employing a production platform andseparate bridge-linked accommodations and control room platform was investigated, but was found toincrease capital cost significantly.Deep Panuke Volume 4 (Environmental Assessment Report) • November 2006 2-66
A single platform solution was investigated on a single jack-up type structure. Target levels of safetywere identified that are consistent for offshore installations within the industry. All types of hazards forthe installation were identified, including fire, explosion, ship collision, helicopter crashes, and sour gasleaks. The work concluded that the Project facilities could be safely placed on one platform offshore,provided additional special measures are put in place to protect workers against the effects of a potentialsour gas leak. The special measures include a combination of infrastructure, such as portable breathingair apparatus, and work procedures for personnel offshore. Thus, the Project has selected a singleplatformsolution to support the topsides facilities.2.10.2.5 Re-Use of Existing PlatformIn the approved 2002 CSR, re-use of the existing Panuke platform, which was installed as part of theCohasset Project was examined and rejected as a Project option. In any event, the Panuke jacket wasremoved during the decommissioning of the Cohasset Project in 2005, and therefore, re-use of the Panukeplatform is no longer a valid alternative that can be assessed.2.10.2.6 Processing LocationOnshore versus offshore processing was reviewed to determine which alternative provided the bestoption for the evaluation criteria noted above. Onshore versus offshore processing was assessed in 2002with the following cases considered:• full offshore processing;• onshore processing with minimal offshore processing to allow transportation only; and• split onshore/offshore processing (intermediate case).Between 2002 and 2006, the following additional alternative was considered:• full onshore processing via a long subsea tie-back.The alternatives are summarized in Table 2.11 and are discussed below.Full Offshore ProcessingFull offshore processing involves gas sweetening, acid gas injection, TEG dehydration, gas dewpointing,gas compression, produced water treatment and disposal, and condensate treatment/usage for platformfuel offshore. Market-ready natural gas is shipped to shore in a subsea pipeline.Deep Panuke Volume 4 (Environmental Assessment Report) • November 2006 2-67
Page 1 and 2:
2 PROJECT DESCRIPTIONThis section p
Page 3 and 4:
Potential Radioactive Components: T
Page 5 and 6:
2.2.2 Subsea Wells and FlowlinesThe
Page 10 and 11:
2.2.3.1 M&NP OptionThe proposed pip
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The onshore portion of the pipeline
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2.3 Construction and Installation2.
Page 16 and 17: 2.3.2 Export PipelineA proposed pip
Page 18 and 19: A dedicated subsea umbilical will b
Page 20 and 21: Table 2.2 Construction MethodsCateg
Page 22 and 23: These subsea structures may be fast
Page 24 and 25: For the new production and injectio
Page 26 and 27: Figure 2.8Typical Production Well S
Page 28 and 29: 2.3.8.1 Drilling Fluid ProgramWater
Page 30 and 31: Table 2.4 Hydrostatic Fluid Dischar
Page 32 and 33: Acid GasInjectionFeed GasCompressio
Page 34 and 35: Although the M&NP Option is the onl
Page 36 and 37: Spent TEG has no measurable H 2 S a
Page 38 and 39: Table 2.7 Water CompositionComponen
Page 40 and 41: 2.4.2 Utilities2.4.2.1 Electrical P
Page 42 and 43: will be designed considering emerge
Page 44 and 45: zones over the pipeline although th
Page 46 and 47: 2.7 Emissions and DischargesEnCana
Page 48 and 49: Table 2.8 Routine Project Emissions
Page 50 and 51: 2.7.1.1 Air PollutantsThe following
Page 52 and 53: esult in eye irritation, respirator
Page 54 and 55: Typically, a re-entry and completio
Page 56 and 57: 2.7.5.3 Deck DrainageDuring constru
Page 58 and 59: 2.9.2 Pipeline Leak PreventionThe p
Page 60 and 61: 2.9.5 Subsea Protection StructuresT
Page 62 and 63: • consider concept alternatives f
Page 64 and 65: Table 2.10Centre Substructure Type
Page 68 and 69: Table 2.11 Processing Location Alte
Page 70 and 71: After carefully considering the con
Page 72 and 73: Flaring acid gas consists of direct
Page 74 and 75: Table 2.13Produced Water Disposal A
Page 76 and 77: Therefore, injection into an annula
Page 78 and 79: Use of a dedicated condensate pipel
Page 80 and 81: is taken offshore on a special lay
Page 82: Table 2.15Acid Gas Injection Locati
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Deep Panuke Project Description - Encana

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