Hydrocarbons Accumulations & Uncertainties


Who should attend?

  • This course provides a practical understanding of hydrocarbon accumulations estimation and the methods to assess related uncertainties.
Audience :
  • Geoscientists, petroleum and reservoir engineers interested or involved in hydrocarbon accumulations estimation.

Level : Proficiency

Course Content


      • Definitions of accumulations and reserves.
      • Resources and reserves classification - PRMS.
      • Review of methods for estimating reserves: volumetrics, material balance, decline curves analysis, simulation models.

      • Overview of volumetric method.
      • Gross Rock Volume estimation from isobaths and/or geological models; contacts determination from logs and formation testing (RFT/MDT).
      • Porosity and Net-to-Gross estimation from logs; notion of cut off.
      • Saturation estimation from logs and cores.
      • Formation volume factor.
      • Exercises.

      • Definitions of risk and uncertainty.
      • Notion of probability and probability distribution.
      • Statistical description of data:
      • Histograms and quantiles.
      • Theoretical models: population, samples, probability density functions.
      • Common statistical distributions.

      • Correlation of reservoir layers in order to visualize the reservoir units.
      • Qualitative log interpretation of several wells.
      • Evaluation of Ht, Hu, ф and Swi on each well for each sub-reservoir unit.
      • Review of the available PVT studies (reports) and selection of the most reliable one to give the main characteristics of the reservoir fluids.
      • Calculation of the probable (P50) hydrocarbon volumes in place (calculation of rock volumes by using isobath maps).
      • Evaluation of the range of hydrocarbons in place (min & max) taking uncertainties into account with both deterministic and probabilistic methods (Monte-Carlo).
      • Synthesis and wrap-up.

Learning Objectives

  • Upon completion of the course, participants will be able to:
  • define and discuss the difference between hydrocarbon accumulations and reserves,
  • estimate hydrocarbon accumulations using the volumetric method,
  • define the main concepts of risks and uncertainties and related main assessment techniques,
  • apply both deterministic and probabilistic methods for estimating volumes in place and gain a thorough understanding of various uncertainties levels,

Ways & Means

  • Interactive presentations and practical exercises
  • Real case study using a complete data set and a spread sheet for uncertainties assessment