Isatoil Workflow

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Overview

ISATOIL is an advanced 2D modeling technique to construct a consistent 3D, stacked sequence, layered model. It applies a consistent multi-layer global approach as opposed to a sequential approach, whose weakness consists in the propagation of errors from top to bottom.

Benefits

• Rely on a true geostatistical risk analysis
• Efficiently update your model when new wells or revised seismic interpretations become available
• Make decisions based on accurate volume calculations
• Handle deviated wells and normal faults

ISATOIL Workflow

Data Loading
The layered reservoir model is stored in a masterfile.

• Deviated wells:
   intersection with geological
  surfaces (TVD)
   petrophysical properties
  (porosity-N/G-saturations)
• Seismic TWT horizons
• A reference depth converted surface
• Unconformity or major fault surfaces
• Fault polygons

Base Case
The layered reservoir model is created in 3 steps:

• Define the reservoir layers by depth converting, simultaneously, all seismic time horizons using a multivariate geostatistical model, constrained by interval thickness or interval velocities and external drifts to impose trends
• Divide seismic layers into geological sublayers
   sublayers thickness consistency is guaranteed using
  collocated cokriging
   fault planes are constructed for accurate sublayer
  intersections
• Populate each reservoir interval with the petrophysical properties

Volumetrics
The oil and gas volumes of each reservoir are calculated from stochastic simulations:

• Same geostatistical models as in the base case
• Contacts can be defined and possibly randomised per segment over the field (GOC, WOC) in order to produce:
   volume distribution and risk curve per polygon (GRV, HCPV, STOIIP, GIP)
   reservoir probability and quantile maps
   uncertainty map for surfaces

Refer to Multi-Layer Reservoir Modeling (PDF - 165.6 kb).