drillbotics-1-trajectory-planner

name	drillbotics-1-trajectory-planner
description	Sub-skill of drillbotics: 1. Trajectory Planner (+9).
version	1.1.0
category	engineering/drilling
type	reference
scripts_exempt	true

1. Trajectory Planner (+9)

1. Trajectory Planner

3D directional well-path computation from surface to multiple downhole targets. Algorithms used by winning teams: cubic Bezier curves, minimum-curvature method. Constraints: dogleg severity (DLS) limits, survey station uncertainty propagation.

# Key inputs
targets: list[Point3D]     # revealed on competition day
dls_max: float             # deg/100ft — formation / BHA constraint
survey_uncertainty: float  # typical ±0.5° inclination, ±1° azimuth

# Key outputs
planned_path: list[SurveyStation]   # MD, inclination, azimuth at each station

2. Trajectory Control Optimizer (TCO)

Closed-loop steering of the simulated bit along the planned path. Must correct for BHA model uncertainty at each survey station. Reinforcement learning has been used by winning teams (UiS 2021-2022) for generalization to unseen target geometries.

3. BHA Model (RSS and Motor)

Critical constraint: BHA type (Rotary Steerable System vs Adjustable Kick-Off motor) is specified on competition day. Both must be pre-implemented and switchable.

Open-source references:

• MADSim-Wilson-Simple-BHA-Model (Open Source Drilling Community)
• Aarsnes-and-Shor-Torsional-Model (torsional vibration)

4. ROP Optimisation

Real-time, formation-dependent optimisation of WOB and RPM to maximise ROP without causing dysfunctions. Typically a nonlinear constrained optimisation problem.

Bourgoyne-Young model (eight-parameter, industry standard):

ROP = f(WOB, RPM, d_bit, ECD, formation_coefficients, bit_wear, overbalance, compaction)

Warren model (simplified, two-parameter):

ROP = K * (WOB / d_bit)^a * RPM^b

Status in ACE Engineering: NOT YET IMPLEMENTED. Gap identified in WRK-375. Candidate location: digitalmodel/well/drilling/rop_model.py

5. Torque and Drag

Drillstring friction and axial/torque loads along the wellbore trajectory. Used for WOB management and stuck-pipe detection.

Open-source reference: Dixit-Drillstring-Model-2023 (Open Source Drilling Community)

Status in ACE Engineering: NOT YET IMPLEMENTED.

6. Wellbore Hydraulics / ECD

Managed pressure drilling: keep bottomhole pressure inside the mud-weight window.

Parameter	Formula	Purpose
ECD	MW + (annular_ΔP / (0.052 × TVD))	Formation overbalance control
Annular velocity	Q / (d_hole² − d_pipe²) × 0.408	Cuttings transport
Pump pressure	Fanning friction + acceleration components	Surface pump management

Status in ACE Engineering: PARTIAL — CT hydraulics exists at digitalmodel/src/digitalmodel/marine_ops/ct_hydraulics/ct_hydraulics.py (ECD, pressure drop, Reynolds/friction, pump pressure). Needs generalisation to arbitrary pipe/annulus diameters and multi-phase flow. Gap: ~250 lines to extend.

7. Well Control

Kick detection and automated shut-in. Scored as a separate category.

Detection signals:

• Flow-in/out differential > 5% sustained
• Pit volume gain > threshold
• Standpipe pressure anomaly

False-alarm rate is explicitly scored — conservative triggers that shut in unnecessarily count against the team.

8. Formation Classification (ML)

Real-time identification of formation being drilled from surface drilling signals (WOB, ROP, torque, vibration). Enables adaptive control parameter switching.

UMaT (2024 winner) used ensemble ML methods + a Python-based digital-twin architecture.

9. Operator HMI

Human-in-the-loop interface required since 2021. Criteria:

• Alarm management following alarm philosophy standards
• Levels-of-automation design (operator can always intervene)
• Mitigation of automation complacency ("ironies of automation")

10. D-WIS Interoperability (2025-2026 requirement)

All modules must expose data via Drilling Well Information Schema (D-WIS) semantic network protocols. This is a mandatory gate for Phase II entry in the 2025-2026 cycle.

Reference: https://d-wis.org

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