Depth-Based Well Log Analysis & Petrophysical Evaluation Console

1. Subsurface Formation Evaluation & Depth-Indexed Well Logs

In petroleum geoscience and reservoir evaluation, wireline logs and Logging-While-Drilling (LWD) suites are indexed strictly by depth. Displaying borehole physical measurements against vertical depth reveals the stratigraphic succession of formations, identifies fluid contacts (gas-oil, oil-water), evaluates reservoir porosity, and quantifies hydrocarbon saturation.

The WDA Depth Analysis Console (accessed directly from the Databases Explorer tree by right-clicking any Channelset and selecting Analyze Depth Data) provides an interactive petrophysical interpretation environment combining an SQL-driven Depth Data Panel (compound criteria builder, unit converter, and virtualized log grid) with a 60-FPS hardware-accelerated Depth Graph Panel featuring an inverted vertical depth axis and up to 15 simultaneous parameter channels.

2. Inverted Vertical Depth Coordinate System

Conventional scientific charts plot values with the vertical axis ascending upwards. In oilfield geoscience, however, the industry standard requires depth to increase downwards (simulating penetration deeper into the subsurface). WDA implements an authentic petrophysical inverted coordinate system:

• Flexible Depth Index Selection:

  Choose which depth channel drives the vertical scale from the top toolbar dropdown: Measured Depth (MD), Bit Depth (DBIT), or True Vertical Depth (TVD).

• Synchronized Depth Units:

  The vertical scale dynamically calibrates to active unit profiles (Meters m vs Feet ft).

• Vertical Zoom & Navigation:

  Scroll the mouse wheel to zoom into thin-bed laminated reservoirs with centimeter precision, or click Fit All to encompass the complete wellbore trajectory from surface casing shoe to Total Depth (TD).

• Snap Inspection Tooltip:

  Hovering over any curve activates an interactive crosshair marker showing the exact Measured Depth, channel mnemonic, and calibrated reading.

3. Multi-Track Curve Overlays & Scaling Geometries

Petrophysical logging curves exhibit vastly different mathematical ranges. WDA provides independent scaling geometry per parameter slot:

• Linear Scaling Tracks:

  Applied to bounded variables including Gamma Ray (GR, 0–150 API) for shale seal vs reservoir sand discrimination, Spontaneous Potential (SP, mV), Caliper (CALI, 6–16 in) for borehole washout detection, and Sonic Slowness (DT, 40–140 µs/ft).

• Multi-Decade Logarithmic Scaling:

  Essential for Deep, Medium, and Micro-Resistivity curves (RT, ILD, AT90). Spans up to 4 logarithmic decades (0.2 to 2,000 Ω·m), cleanly separating conductive formation brine (< 2 Ω·m) from highly resistive hydrocarbon-saturated pay zones (> 20 Ω·m).

• Porosity & Density Evaluation:

  Overlay Bulk Density (RHOB, 1.95–2.95 g/cm³) and Compensated Neutron Porosity (NPHI, -0.15–0.45 v/v) on standard compatible scales to immediately identify density-neutron crossover indicating gas-bearing intervals.

4. SQL Depth Interval Filtering & Template Persistence

Evaluating deep wellbores requires isolating specific formation members and standardizing displays across offset wells:

• Reservoir Interval Isolation: Use the Between operator on the depth index (e.g. [MD] Between 2,450 m AND 2,620 m) to instantly isolate and render target pay zones without clutter from overburden formations.
• Standardized Petrophysical Templates: Save configured multi-track layouts (e.g., "Triple Combo Standard" or "Drilling Dynamics vs Depth") as reusable JSON template files. Load them with a single click to ensure standardized interpretation across all company assets.
• High-Resolution Graphic Export: Export the depth log canvas directly to publication-ready PNG or JPEG images for composite geological logs and morning management reports.

5. Related WDA Engineering Modules

• WDA: WITSML Compatible Data Analyzer: Explore the WDA platform architecture and high-performance columnar engine.
• Time-to-Depth Conversion Engine: Reconcile sensor time telemetry into depth logs before petrophysical analysis.
• Cross-Well Stratigraphic Correlation: Correlate depth logs across multiple offset wellbores with datum flattening.
• Data Export Console: Stream depth logs directly into standard CWLS LAS 2.0/3.0 or Apache Parquet formats.