Quality Assurance Tests for Reservoir Modeling & Simulation

The objective of these tests is to improve the reliability of forecasts derived from reservoir modeling and simulation studies by:

  • Applying systematic review methods for the early identification of potentially unreliable forecasts.
  • Improving awareness of how to build forecast reliability into reservoir and simulation models.

Models Honor Well Control Test Group:

  • Well Data Consistency: Maps should be consistent with well data values.

This test checks the consistency between actual well data values for key reservoir properties (HCPT, porosity, etc.) and maps representing the subsurface distribution of these properties in the reservoir models used as the basis for production forecasting.

  • Reservoir Property Trends: Maps should exhibit reservoir property trends away from well control that are consistent with reliable interpretations calibrated to well data.

This test examines reservoir property maps (e.g., net sand, average porosity, HCPT, etc.) to ensure that extrapolations of reservoir properties away from well control are supported by hard data and interpreted geologic trends. Reservoir property trends should be derived from geological and geophysical interpretations or from production mapping, if available.

  • Reservoir Property Histograms: Representative average reservoir property histograms should demonstrate consistency between wells, reservoir models, and maps.

This test verifies that histograms of averaged or summed reservoir properties from wells are consistent


Material Balance Consistency Test Group:

  • Aquifer Strength Consistency: Aquifer strength is consistent with material balance analysis and geology.

This test compares analysis of aquifer strength from material balance methods and geological interpretations with the aquifer strength assumed in the simulation models to ensure consistency and that all available data on aquifer strength are incorporated into the reservoir simulation models.

  • HCIP Consistency: Hydrocarbon-in-place is consistent with material balance and other volumetric estimates.

This test ensures that Hydrocarbon-In-Place (HCIP) estimates from simulation models are checked against available data from other methods (e.g., material balance, static reservoir model, map-based volumetrics) and any differences are reconciled and explained.

  • Multiple-Tank Consistency: Multiple-tank compartmentalization criteria are understood, reasonable, and consistent with performance and geology.

The purpose of this test is to ensure that tank definitions are appropriate and consistent with the regions in the reservoir simulation models.

  • Fluid Properties and Compressibility: Fluid properties and rock compressibility are supported by available reservoir data and are consistent between simulation and material balance.

This test validates consistency between fluid properties and rock compressibility assumptions used in the material balance analysis and the reservoir simulation models by ensuring that fluid properties, rock compressibility, water compressibility, and water saturations used in the material balance analysis and the reservoir simulation model are reasonable, consistent, and agree with available data.


Well Forecast Benchmarking Test Group:

  • Existing Wells Production Trends: Forecasts for existing wells honor historical production trends.

This test compares forecasts of production from existing wells derived from history-matched (HM) reservoir simulation with the results obtained using one or more decline curve analysis (DCA) methods.

  • Future Wells Portfolio Trends: Forecasts for future wells honor portfolio trends over time.

This test compares forecasted performance of future wells with the observed portfolio trends, such as a typical trend of declining well production performance over time resulting from well sequencing decisions.

  • Geological and Engineering Trends: Forecasts for future wells are consistent with geological and reservoir engineering trends established from existing wells.

This test verifies that forecasts of productivity, flow rates, decline, and cumulative production for future wells are consistent with the range of performance of actual field wells situated in similar reservoir settings with regards to geology, well spacing, pressure and fluid type, etc.

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