neqsim-surf-field-layout-design

name	neqsim-surf-field-layout-design
calculation_basis	screening
version	0.1.0
description	Design a screening subsea (SURF) field layout and place the host from open map, bathymetry and licence-block data: group wells into drill centres, place Xmas trees, templates, manifolds, PLEMs and riser bases, position an FPSO or fixed host, route and size every production, injection, service, umbilical and riser line, and export the result as georeferenced GeoJSON and a map. USE WHEN: a task needs a field layout designed rather than an existing one screened - deciding how many drill centres and templates are needed, where the host should sit, which flowline architecture to use (loop, single line or daisy chain), what size the flowlines and risers should be, how long the umbilicals are, or a georeferenced layout to hand to flow assurance, cost estimation or a NeqSim production-network model.
last_verified	2026-08-12
requires	{"python_packages":[],"java_packages":[],"env":[],"network":[]}

SURF Field Layout Design

Use this skill to turn a well count, a reservoir footprint and a water depth into a placed and routed subsea layout: drill centres, wells, Xmas trees, templates and manifolds, PLEMs, riser bases, the host, and every flowline, riser and umbilical between them — each line sized on velocity and each item carrying a latitude and longitude so the result drops straight into a map or a GIS.

It is the design counterpart to neqsim-subsea-layout-geometry, which screens a layout that already exists. Use this skill first to create the layout, then that skill to screen step-outs, and neqsim-pipe-route-profile to put the routes on a real seabed profile.

When to Use

• A concept study needs a subsea architecture before any layout drawing exists.
• The number of drill centres, templates and Xmas trees must follow from the well count and the slots per template.
• The host has to be placed relative to the field, and the riser base with it.
• A flowline architecture must be chosen: a round-trip-piggable dual loop, one dedicated line per drill centre, or a daisy chain.
• Flowline, riser and injection-line sizes are needed at a screening level.
• Total flowline, riser and umbilical lengths are needed for a SURF cost estimate.
• The layout must be georeferenced — on a licence block, on a map, as GeoJSON.
• A production-network or flow-assurance model needs node positions and segment lengths.

Do not use it for detailed routing, crossing design, on-bottom stability, free-span, expansion, installation or mooring analysis.

Inputs

Group	Fields
Identity and position	field_name, centre_latitude_deg, centre_longitude_deg, water_depth_m
Wells	producers, water_injectors, gas_injectors, slots_per_template, slot_spacing_m
Footprint	reservoir_length_km, reservoir_width_km, field_axis_bearing_deg, injector_offset_km, seabed_slope_deg
Host	host_type, host_offset_km, host_bearing_deg, riser_base_offset_m
Architecture	production_architecture (dual_loop, single_line, daisy_chain)
Sizing	design_liquid_rate_m3_per_s, design_water_injection_rate_m3_per_s, design_gas_injection_rate_am3_per_s, densities, target velocities

Rates are actual volumetric rates at the flowing condition, not standard volumes. Convert a standard rate with the formation volume factor before passing it in, or the sizing is wrong by that factor.

Outputs

• nodes — wells, Xmas trees, templates/manifolds, PLEMs, riser base and host, each with a tag, local east/north, latitude, longitude and water depth.
• lines — every flowline, injection line, umbilical and riser, with its service, type, endpoints, length and selected size.
• summary — drill-centre and tree counts, architecture, maximum step-out, and total flowline, umbilical and riser lengths.
• to_geojson() — a WGS84 FeatureCollection of points, lines and the reservoir outline, ready for any map or GIS.
• warnings and assumptions — what was assumed and what a reviewer must check.

Open Map and Sea Data

geodata registers openly licensed sources and plans read-only requests. It never opens a connection of its own: execute returns the plan as a manifest unless the caller supplies its own fetch adapter, so the same code runs in a sandbox and on a connected workstation.

Source	Use	Licence
EMODnet Bathymetry	seabed depth over the field, European seas	CC BY 4.0
GEBCO grid	global bathymetry fallback	free, attribution required
NOAA ETOPO	global relief fallback	public domain
Sodir FactMaps	quadrants, blocks, wellbores, discoveries, fields, facilities, pipelines	NLOD
Sodir FactPages	wellbore coordinates and field records as tables	NLOD
Natural Earth	coastline for a locator map	public domain
Copernicus Marine, MET Norway NORA3	wave, wind and current statistics for the host heading	CC BY 4.0 / open

from surf_field_layout_design import plan_layout_data_package, execute, attribution_block

plan = plan_layout_data_package(west=24.0, south=73.0, east=26.0, north=74.0)
manifest = execute(plan)                       # offline: returns the plan only
manifest = execute(plan, fetch=my_read_only_get)   # connected: retrieves it
print(attribution_block(["emodnet_bathymetry", "sodir_factmaps"]))

Reproduce the attribution lines on any map you publish.

Norwegian blocks

quadrant_bounds("7324") returns the quadrant box, which is exact north of 62 degN: the label is the latitude of the southern edge and the longitude of the western edge, spanning one degree by two. block_bounds("7324/8") divides that into twelve 15-by-40-arc-minute blocks — but the numbering direction is a documented assumption, not a calculation, and the returned dictionary says so. Take the real position from the open Sodir wellbore layer and use the block box only for orientation.

Engineering Method

Drill centres. Wells of each service are grouped into templates of slots_per_template slots, and the resulting drill centres are spaced evenly over 70 % of the reservoir length along the field axis. Water injectors are offset down one flank and gas injectors up the other by injector_offset_km. This is geometry, not a sweep study.

Host and riser base. The host sits host_offset_km from the field centre on host_bearing_deg; the riser base PLEM sits riser_base_offset_m short of it on the reverse bearing. Riser length is the straight riser-base-to-host distance with a 25 % lazy-wave allowance.

Architecture. dual_loop runs two legs through the production drill centres in opposite order, giving a round-trip pigging loop. single_line gives one dedicated line per drill centre. daisy_chain runs one line through them all and is flagged as not round-trip piggable.

Line sizing. The smallest standard nominal size whose velocity stays under both the target velocity and the API RP 14E erosional velocity,

$$ v_e = \frac{1.22,c}{\sqrt{\rho}} $$

with $v_e$ in m/s, $\rho$ in kg/m³ and $c = 100$ for continuous service. Inner diameter follows a fixed diameter-to-wall ratio of 20; that is a screening geometry, not a pressure-containment design.

Python Usage Pattern

from surf_field_layout_design import design_surf_layout, plot_layout_map

layout = design_surf_layout(
    field_name="Example field",
    centre_latitude_deg=73.375,
    centre_longitude_deg=25.0,
    water_depth_m=400.0,
    producers=8,
    water_injectors=6,
    gas_injectors=2,
    slots_per_template=4,
    reservoir_length_km=6.0,
    reservoir_width_km=3.1,
    field_axis_bearing_deg=30.0,
    host_offset_km=2.5,
    host_bearing_deg=270.0,
    production_architecture="dual_loop",
    design_liquid_rate_m3_per_s=28500.0 / 86400.0,
    design_water_injection_rate_m3_per_s=20000.0 / 86400.0,
    design_gas_injection_rate_am3_per_s=0.63e6 * 0.012 / 86400.0,
)

print(layout.summary["drill_centres"], layout.summary["flowline_length_km"], "km")
plot_layout_map(layout, "layout_map.png")
open("layout.geojson", "w").write(json.dumps(layout.to_geojson()))

Handing the layout on

• Flow assurance and hydraulics. Each Line gives the endpoints, length and inner diameter that neqsim.process.equipment.pipeline.PipeBeggsAndBrills needs; take the elevation profile from neqsim-pipe-route-profile or an open bathymetry grid rather than the flat default.
• Production network. Drill centres map to a Mixer manifold and wells to WellFlow inflow, as in neqsim-production-network-routing.
• Cost. flowline_length_km, umbilical_length_km, riser_length_km and the tree, template and PLEM counts are the quantity take-off a SURF cost estimate needs.
• Screening. Feed the node list to neqsim-subsea-layout-geometry for step-out and tie-back distance checks.

Validation Checklist

• The field position comes from an open wellbore or discovery record, not from the block-grid assumption.
• Design rates are actual volumetric rates at the flowing condition.
• Every line size is inside the target velocity and the erosional limit, or the deviation is explained.
• The flowline architecture matches the pigging and shutdown philosophy.
• The seabed is a real bathymetry grid, not the flat default, before any route length or riser length is used for cost or hydraulics.
• The host offset respects the safety zone and the drill-centre envelope.
• Wall thickness has been replaced by a real pressure design.
• A qualified subsea engineer has reviewed the layout.

Common Mistakes

Symptom	Cause	Fix
Flowlines come out far too small	Standard rates passed where actual rates are expected	Multiply by the formation volume factor first
Only one drill centre for many wells	slots_per_template left at a large value	Set the real slot count per template
The reservoir outline does not line up with the drill centres	field_axis_bearing_deg changed but the footprint not re-checked	The outline follows the same axis; check the footprint dimensions
Riser length equals the water depth	Riser configuration allowance ignored	The skill adds 25 % for a lazy wave; replace with a real riser analysis
Umbilical length looks short	Umbilicals are routed host-to-drill-centre in a straight line	Add a routing allowance, or route via the real corridor
The block box does not match the operator's map	The block numbering assumption	Take the position from the Sodir wellbore layer

Limitations

• Screening geometry only: straight-line routes, no obstacle avoidance, no crossings, no corridor or approach design.
• Drill-centre placement is geometric spacing, not a well-placement or sweep optimisation.
• No on-bottom stability, free-span, expansion, buckling, installation, mooring or riser-response analysis.
• Wall thickness follows a fixed D/t ratio and is not a pressure design.
• Line sizing is a velocity check only; no pressure-drop, slugging, erosion-rate or thermal calculation.
• Met-ocean sources are registered but the host heading is not calculated.
• No proprietary or confidential data is used.

Related NeqSim Functionality

• neqsim.process.equipment.pipeline.PipeBeggsAndBrills — flowline and riser hydraulics on the routed segments.
• neqsim.process.equipment.reservoir.WellFlow — well inflow at each tree.
• neqsim.process.equipment.subsea.SubseaWell, SubseaTree — subsea equipment.
• neqsim.process.mechanicaldesign.subsea — SURF mechanical design and cost.
• The NeqSim MCP runPipeline and runFieldEconomics tools.

Related Skills

• neqsim-subsea-layout-geometry — screens step-outs and tie-back distances for the layout produced here.
• neqsim-pipe-route-profile — turns the routes here into an elevation profile.
• neqsim-bathymetry-profile-screening — processes the open bathymetry grid this skill plans the request for.
• neqsim-production-network-routing — takes the drill centres and wells through manifolds and flowlines to an arrival pressure.
• neqsim-step-out-screening — checks the tie-back distance and arrival pressure.
• neqsim-reservoir-model-builder — supplies the well count and the plateau rate.
• neqsim-capex-opex-screening — turns the quantity take-off into a cost.

References

• API RP 14E, Design and Installation of Offshore Production Platform Piping Systems — erosional velocity.
• DNV-ST-F101 Submarine pipeline systems and DNV-RP-F109/F105 for the design checks this skill deliberately does not perform.
• EMODnet Bathymetry: https://emodnet.ec.europa.eu/en/bathymetry
• GEBCO: https://www.gebco.net/
• Norwegian Offshore Directorate FactMaps: https://factmaps.sodir.no/
• Natural Earth: https://www.naturalearthdata.com/
• Copernicus Marine Service: https://marine.copernicus.eu/
• MET Norway NORA3 hindcast: https://thredds.met.no/
• NeqSim: https://github.com/equinor/neqsim