Field Development Plan — Tobago

Generated by the worldenergydata field-development playbook (epic #567). Recommendation is heuristic (Concept Select / FEL-1 fidelity), not a sanctioned design.

Engineering rationale

Tobago is a small, ultra-deepwater accumulation in ~2,925 m of water that could never justify a dedicated floater, so it was developed as a subsea tieback to the regional Perdido spar in AC857, which gathers Great White, Silvertip and Tobago within a ~15 km radius. The Perdido host uses a direct-vertical-access spar with subsea caisson separation and electrical submersible pumping to lift low-energy Lower Tertiary fluids up ~2.4 km of riser; Tobago's wells feed that shared infrastructure rather than carrying their own trees to surface. Reservoir distribution and very low column energy at this depth favored wet-tree subsea wells boosted to the host over any standalone concept. The 2010 Tobago well set a world water-depth record for a subsea oil and gas well at 9,627 ft. Notable: World's deepest offshore oil and gas well at startup (9,627 ft / ~2,934 m), tied to the world's deepest production spar (Perdido).

Field parameters

Water depth
2925.0 m
Concept
subsea_tieback
Fluid
oil
Operator
Shell (operator, 32.5%); partners Chevron 57.5%, Nexen/CNOOC 10%
Wells
4
Plateau
Tieback
13.0 km
First oil
2010

Recommended concept shortlist

ConceptScoreTreesRationale / flags
subsea_tieback ★0.847wethost within 60 km with spare capacity
subsea_to_shore0.734wet
fpso0.688wethurricane regime: FPSO needs a disconnectable turret
flng0.622wet

★ = the concept actually selected for this field (where known).

Economics & execution (engine estimate)

Dev system
subsea20
Est. CAPEX
498.0 $MM
Est. NPV
Install vessels
8
Max crane
5000.0 t
Hardware
RJ-08-HYD-15K

As built (actuals)

Host
Perdido spar (Alaminos Canyon 857)
Play
Lower Tertiary / Paleogene (Wilcox-equivalent) Perdido Fold Belt stratigraphic trap
First oil
2010
BSEE code
AC859
Confidence
high

Architecture & layout (subsea_tieback)

Subsea architecture — Tobago flowline umbilical jumper control jumper control jumper control jumper control export Export Existing Host (tieback) Manifold 1 XT 1 XT 2 XT 3 XT 4
Subsea architecture block diagram
Field layout — Tobago Subsea manifold Manifold 1 Subsea tree (wet XT) XT 1 Subsea tree (wet XT) XT 2 Subsea tree (wet XT) XT 3 Subsea tree (wet XT) XT 4 Existing host (tieback) Existing Host (tieback) Export Export N 1 km
Plan-view field layout (to scale)

Sources: SubseaIQ field catalog (~2014) + BSEE + curated vessel/ subsea catalogs. Schematics are deterministic, generated from the field concept.