Service

Depth Conversion & Velocity Modelling

Robust velocity models and quantified depth uncertainty.

Overview

Robust velocity models and quantified depth uncertainty.

Depth conversion is often the single largest source of volumetric uncertainty in a prospect or field. We deliver velocity models built from check shots, sonic logs, stacking velocities and FWI velocities, combined with geostatistical and probabilistic depth-conversion methods to quantify uncertainty rigorously and translate it directly into volumetric ranges.

  • Velocity-model buildingIntegration of check shots, sonic logs, well markers, stacking velocities and FWI velocities into a coherent layered velocity model.
  • Layer-cake & instantaneous modelsV0/k models, layer-cake interval-velocity models and instantaneous velocity grids tuned to the structural style of the area.
  • Geostatistical depth conversionKriging with external drift, collocated co-kriging and stochastic simulation to capture spatial uncertainty between wells.
  • Probabilistic depth uncertaintyMonte-Carlo realisations of depth surfaces feeding directly into volumetric uncertainty workflows.
  • Time-depth conversion of horizonsConversion of time-domain horizons to depth, with consistent handling of well-tie residuals and tie-point selection.
  • Pre-stack depth migration QCIndependent QC of vendor PSDM velocity models, including focusing analysis, residual-curvature QC and well-tie reconciliation.
  • Well prognosis & calibrationPre-drill depth prognosis with uncertainty bars, and post-drill calibration with structured velocity-model updates.
  • FWI & high-resolution velocity useIntegration of full-waveform-inversion velocities into shallow and overburden velocity models for improved imaging.
  • Time-shift / 4D depth updatesVelocity-model updating for repeat surveys to support 4D time-shift to depth-shift conversion.
  • Independent technical auditIndependent third-party audit of in-house or vendor depth-conversion workflows, with clear recommendations.

Tools & Platforms

Petrel VelPak Kingdom Python (numpy scipy geostatspy)

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