Work Packages That Actually Control: A Field Guide for Oil & Gas

Designing evidence-based Work Packages inside Control Accounts for commissioning-grade control

TL;DR
CA = WBS leaf × OBS lane (one CAM).
WP = the executable, evidence-based slice of that WBS leaf, designed for one CAM to plan, earn, and forecast credibly.
Design WPs by evidence first (discipline), then add phase, and add only the boundaries that change acceptance, ownership, logic, EV method, or risk (area, subsystem/MC, test pack/feeder, contractor, etc.).
If evidence doesn’t exist, value isn’t earned.

Mini-Glossary

CAM — Control Account Manager (single owner of a CA)
CA — Control Account: one WBS leaf × one OBS lane
ITR — Inspection & Test Record (discipline-specific evidence form)
MC — Mechanical Completion (end of Pre-Commissioning)
ROC — Rules of Credit: 5–8 proof-backed steps (or units) that sum to 100%
MECE — Mutually Exclusive, Collectively Exhaustive (no overlap, no gaps)
EV/ES — Earned Value / Earned Schedule
FAT/SAT — Factory / Site Acceptance Test

Why this design matters (and what goes wrong if you skip it)

Commissioning-grade “Done”. Why: Turnover succeeds only when evidence matches how Ops/Commissioning accept. If not: “90% done” disputes; dossier rebuilds; late start-up.
Single-point accountability. Why: One CAM per CA eliminates blurred ownership. If not: KPI ping-pong, unowned risks, slow decisions.
Predictive control. Why: Clean WP↔activity mapping + ROC unlocks SPI/CPI, ES and credible ETC/EAC. If not: EV noise; straight-line wishcasting.
Audit/claims defensibility. Why: Evidence-backed progress with reason-coded rebaselines stands up. If not: Reconciliation marathons and weak claim posture.

The design recipe (do this in order)

Start at the product (WHAT). Pick a handover-able WBS leaf (system/subsystem/area) with a clear Definition of Done.
Fix accountability (WHO). Pair that leaf with one OBS lane → that pairing is your CA; name the CAM.
Slice by evidence first (HOW). Make discipline the primary WP boundary (ELE, IST, PIP/MEC, CIV/STR, TLC, HVAC, FFE) because ITRs and artifacts are discipline-grouped.
Add phase when the handshake changes. ENG / PROC / FAB / CONST / PRE-COMM (MC) / COMM / Turnover.
Add the minimum necessary further boundaries (zero, one, or more—no arbitrary cap). Add only if they change: acceptance, ownership, logic, EV method, or risk. Candidates: Area/Location; Subsystem/MC; Test pack/Feeder–circuit; Contractor/PO lot; (sometimes) Procurement lot or Access window. Decision test: If a candidate slice triggers ≥2 of the above, give it its own WP.
Choose one EV method per WP (never mix inside a WP): 0/100, Weighted Milestones, Units, (Apportioned sparingly).
Write the ROC (Rules of Credit). 5–8 steps that sum to 100% (for WM) or a unit logic (for Units). Every step calls a named artifact (ITR form ID, loop folder, weld/NDT report, IR test, FAT/SAT, MC cert, survey set, RFI closure).
Map to the schedule cleanly. WP ↔ activity IDs = 1:1 or 1:few (never many:many). Include procurement milestones where they drive readiness.
MECE check + right size. WPs cover the CA without overlap and give a weekly signal (typically 2–8 weeks).

EV method & ROC examples

PIP / CONST / Test Pack
361-009 • PIP • CONST • TP-361-009-A — Hydrotest & Reinstatement • 0/100
Evidence: Hydro dossier, pressure chart, reinstatement ITRs. Why: Test packs define acceptance and turnover; 0/100 removes “95% hydrotest” fiction.
ELE / PRE-COMM / Feeder
PR-05 • ELE • PRE-COMM • Feeder E1 — Pre-Energization Complete • Units
Evidence: IR tests, settings, pre-energization checklist. Why: Energization boundaries drive genuine readiness.
IST / PRE-COMM / Subsystem
220-001 • IST • PRE-COMM • Subsystem 220-001 — Loops Accepted • WM
ROC: Cold loop 30% → Hot loop 40% → Dossier 20% → Punch-A + MC cert 10%.
Evidence: Loop folders, IR sheets, MC certificate.
MEC / CONST / Area
220-001 • MEC • CONST • A13(310): Shell Courses — Installed & NDT Accepted • WM
ROC: Fit-up 15% → Weld 35% → NDT 25% → Dimensional 15% → As-built + Punch-A 10%.
Evidence: Weld/NDT maps, survey, ITR-MEC-SHELL.

Anti-patterns (and the price you pay)

CA by department (not by product) → mixed leaves, no single DoD → EV noise; turnover fights.
WPs that cross CAs/leaves → fuzzy ownership → double counting; finger-pointing.
Mixed EV inside a WP → incomparable progress → broken SPI/CPI/ES.
“% complete” without artifacts → unverifiable claims → audit exposure; claims risk.
Procurement left outside → invisible LLIs → “ready-to-install” surprises.
Many:many WP↔activity → tracing nightmare → schedule games; fake float.
Overslicing (micro-WPs) → admin drag → planners measuring, not controlling.

Naming pattern (evidence-driven and searchable)

{WBS.Leaf} • {Discipline} • {Phase} • {Boundary1}[ • {Boundary2} …] • {EV}

Want the ROC templates per discipline (ELE/IST/TLC/MEC/CIV) and a 15-point CA/WP audit checklist? Comment “WP” and we’ll share the pack.