doc-extraction-drilling-riser-viv-parameters

name	doc-extraction-drilling-riser-viv-parameters
description	Sub-skill of doc-extraction-drilling-riser: VIV Parameters (+3).
version	1.0.0
category	engineering
type	reference
scripts_exempt	true

VIV Parameters (+3)

VIV Parameters

Vortex-induced vibration parameters for riser fatigue assessment.

Detection heuristics:

• Keywords: "vortex-induced vibration", "VIV", "Strouhal number", "reduced velocity", "lock-in", "mode shape", "vortex shedding"
• Symbols: St, V_r, f_s, f_n, A/D
• Units: Hz, m/s, dimensionless
• Often in sections titled "VIV Assessment" or "Fatigue from VIV"

Key extraction fields:

- content_type: constants
  domain: drilling_riser
  sub_type: viv_parameter
  data:
    name: "Strouhal number — smooth cylinder"
    symbol: "St"
    value: 0.2
    units: dimensionless
    applicability:
      surface: "smooth"
      reynolds_range: "subcritical"
    source: "DNV-RP-C205 Section 9.3"

VIV parameter reference values:

Parameter	Typical value	Source
Strouhal number (smooth)	0.2	DNV-RP-C205
Strouhal number (rough)	0.21	DNV-RP-C205
Cross-flow VIV onset V_r	4–8	DNV-RP-C205
In-line VIV onset V_r	1–3.5	DNV-RP-C205
Lock-in V_r range	5–7	DNV-RP-C205
Max cross-flow A/D (screening heuristic)	1.0–1.5	Empirical, non-normative

Mode shape extraction:

• Detect mode number, natural frequency, wavelength
• Boundary conditions: tension-controlled, pinned-pinned, fixed-fixed
• Added mass coefficient (C_a) by proximity to seabed

Kill and Choke Line Specifications

Auxiliary line properties for well control.

Detection heuristics:

• Keywords: "kill line", "choke line", "auxiliary line", "bore"
• Pattern: table with ID, OD, pressure rating, material grade columns
• Units: inches (ID/OD), psi or MPa (pressure), ksi (yield)
• Often in riser stack-up tables or well control equipment specs
• Note: values are edition- and vendor-dependent; always capture source edition

Key extraction fields:

- content_type: tables
  domain: drilling_riser
  sub_type: kill_choke_line
  data:
    title: "Kill/choke line specifications"
    columns:
      - {name: line_type, units: null}
      - {name: ID, units: inches}
      - {name: OD, units: inches}
      - {name: working_pressure, units: psi}
      - {name: burst_pressure, units: psi}
      - {name: collapse_pressure, units: psi}
      - {name: material_grade, units: null}
    source: "API RP 16Q Table 4"

Typical kill/choke line parameters:

Parameter	Kill line	Choke line
Nominal bore	3" – 4.5"	3" – 4.5"
Working pressure	10,000 – 15,000 psi	10,000 – 15,000 psi
Material	AISI 4130, 4140	AISI 4130, 4140
Connection	Integral flanged	Integral flanged

BOP Stack Configurations

Blowout preventer stack layout and component specifications.

Detection heuristics:

• Keywords: "BOP", "blowout preventer", "annular preventer", "pipe ram", "blind ram", "shear ram", "stack height", "wellhead connector"
• Pattern: vertical stack-up diagram or table listing components top-to-bottom
• Units: inches (bore), feet or meters (height), tons (weight)
• Often accompanied by schematic drawings

Key extraction fields:

- content_type: tables
  domain: drilling_riser
  sub_type: bop_configuration
  data:
    title: "BOP stack configuration — 18-3/4 inch, 15K"
    components:
      - {position: 1, type: "annular preventer", bore: "18.75 in", rating: "10,000 psi"}
      - {position: 2, type: "annular preventer", bore: "18.75 in", rating: "10,000 psi"}
      - {position: 3, type: "pipe ram", bore: "18.75 in", rating: "15,000 psi"}
      - {position: 4, type: "blind/shear ram", bore: "18.75 in", rating: "15,000 psi"}
      - {position: 5, type: "pipe ram", bore: "18.75 in", rating: "15,000 psi"}
       { ,  ,  ,  }
     { ,  }
     { ,  }
       

BOP component types:

Component	Function
Annular preventer	Seals around any tubular or open hole
Pipe ram	Seals around specific pipe OD
Blind ram	Seals open hole (no pipe)
Shear ram	Cuts pipe and seals
Casing shear ram	Cuts casing strings
Wellhead connector	Connects BOP to wellhead

Riser Stack-Up Data

Joint-by-joint riser assembly data.

Detection heuristics:

• Keywords: "stack-up", "riser joint", "pup joint", "flex joint", "telescopic joint"
• Pattern: table with component name, length, weight, buoyancy columns
• Units: feet or meters (length), kips or tonnes (weight)
• Sequential ordering from mudline to surface

Key extraction fields:

- content_type: tables
  domain: drilling_riser
  sub_type: riser_stack_up
  data:
    title: "Drilling riser stack-up"
    columns:
      - {name: component, units: null}
      - {name: length, units: ft}
      - {name: dry_weight, units: kips}
      - {name: buoyant_weight, units: kips}
      - {name: OD, units: inches}
      - {name: ID, units: inches}
    source: "Riser analysis report Section 3"