ResInsight/docs/diagrams/msw-export/04-fishbones-model.md

Fishbones MSW Model

Well path layout

Each fishbones "sub" position on the main bore spawns one ICD branch and one lateral branch per installed tube. All segments belong to RigMswBranch structs; connectivity is expressed through outletSegmentNumber.

Heel (seg 1)
  |
  |  Branch 1 — main bore
  |
  o--[seg 2]--[seg 3]--[seg 4]--[seg 5]--[seg 6]-- ... --[seg N]-- Toe
                 |                  |
             Sub position       Sub position
                 |                  |
            [ICD seg]           [ICD seg]        <- Branch 2, 5, ...  (one per sub)
            (WSEGVALV)          (WSEGVALV)
             /     \             /     \
       [lat seg] [lat seg]  [lat seg] [lat seg]  <- Branch 3/4, 6/7, ... (one per lateral)
       COMPSEGS  COMPSEGS   COMPSEGS  COMPSEGS

Branch and segment hierarchy

graph LR
    classDef mainBore fill:#4a90d9,color:#fff,stroke:#2c6fad
    classDef icd      fill:#e8a838,color:#fff,stroke:#b07e1e
    classDef lateral  fill:#5cb85c,color:#fff,stroke:#3d7a3d
    classDef heel     fill:#888,color:#fff,stroke:#555

    HEEL(["Heel<br/>seg 1"]):::heel

    HEEL --> S2["seg 2"]:::mainBore
    S2   --> S3["seg 3"]:::mainBore
    S3   --> S4["seg 4<br/>(sub A position)"]:::mainBore
    S4   --> S5["seg 5"]:::mainBore
    S5   --> S6["seg 6<br/>(sub B position)"]:::mainBore
    S6   --> TOE(["Toe<br/>seg N"]):::mainBore

    S4 --> ICD_A["ICD seg<br/>Branch 2<br/>WSEGVALV"]:::icd
    ICD_A --> LA1["Lateral 1<br/>Branch 3<br/>COMPSEGS"]:::lateral
    ICD_A --> LA2["Lateral 2<br/>Branch 4<br/>COMPSEGS"]:::lateral

    S6 --> ICD_B["ICD seg<br/>Branch 5<br/>WSEGVALV"]:::icd
    ICD_B --> LB1["Lateral 1<br/>Branch 6<br/>COMPSEGS"]:::lateral
    ICD_B --> LB2["Lateral 2<br/>Branch 7<br/>COMPSEGS"]:::lateral

Per-sub data structure

flowchart TD
    SUB["RimFishbones sub<br/>(subIndex, measuredDepth)"]

    SUB --> ICD_SEG["RigMswSegment — ICD<br/>- segmentNumber = icdSegNum<br/>- outletSegmentNumber = main-bore seg at sub MD<br/>- wsegvalvData: cv, area (from icdCount + orifice diameter)<br/>- intersections: cells closest to sub (COMPSEGS)"]

    ICD_SEG --> LAT_BR["RigMswBranch per lateral<br/>(one branch per installed tube)"]

    LAT_BR --> LAT_SEG["RigMswSegment per grid-cell intersection<br/>- outletSegmentNumber chains along lateral<br/>  (first seg -> icdSegNum)<br/>- diameter = equivalentDiameter<br/>- roughness = openHoleRoughnessFactor<br/>- intersections: COMPSEGS (deduplicated<br/>  against cells already used by ICD or<br/>  other laterals on same sub)"]

Outlet segment lookup

The ICD segment outlet is found with findOutletSegmentForMD:

cellSegMap (built during main-bore pass):

  [startMD ---- midpoint ---- endMD] -> lastSubSegmentNumber
  [  200.0 ---- 212.5 ----  225.0 ] -> seg 3
  [  225.0 ---- 237.5 ----  250.0 ] -> seg 4   <- sub A at MD 243 connects here
  [  250.0 ---- 262.5 ----  275.0 ] -> seg 5
  [  275.0 ---- 287.5 ----  300.0 ] -> seg 6   <- sub B at MD 290 connects here

Rule: pick the entry whose midpoint is closest to, but not greater than, the sub MD.