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AAPG Annual Convention and Exhibition

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Petroleum Systems Modeling Applied to Unconventional Resource Plays


Since 2010, we have applied Petroleum Systems Modeling (PSM) to many unconventional resource plays on multiple continents. Experience shows PSM studies need different design for conventional, unconventional, mixed, or hybrid plays. Workflows and data vary for model input and calibration to assess these different types of plays. Examples of workflows and methods will be shown from Canada, the Middle East and Europe. A key requirement for successful play evaluation is understanding a basin's petroleum systems and its generation, expulsion, migration, and accumulation history. This initial phase of assessment uses geochemical interpretation of oils, source rocks and known accumulations to document the origins of fluids and to assess to what extent they may have migrated or remained in situ. Calibration of porosity, pressure, temperature, and maturity, are important for all models. Hydrocarbon fluid composition, phase, and saturation can provide additional calibration. Models targeting unconventional plays can require different input or calibration: selection of mapped surfaces, better stratigraphic definition within the target intervals, advanced primary and secondary cracking kinetics to predict fluid composition, shale mineralogical and textural analyses, lab-derived Langmuir adsorption measurements, and combined use of advanced petrophysics, geomechanics, and additional geochemical data, to locate the most prospective zones. The PSM needs to focus on the geological processes that have the most meaningful impact on exploration success. A study that targets the right processes and illustrates the resulting impact on exploration outcomes will deliver the best risk assessment. Petroleum system studies for the assessment of unconventional resources may have different goals. These include: (1) first-pass asset or play screenings, (2) more rigorous exploration risk assessments (either regional, or targeted, e.g., leading to a pilot well), and (3) regional or national resource assessments. Studies are also constrained by business objectives, budgetary limitations, and deadlines. Cooperative multi-disciplinary teams allow more flexibility to examine geological processes from multiple perspectives. A multi-disciplinary approach, combined with an integrated workflow sequence of geologic model building, PSM simulations, Play Chance Mapping (PCM) and statistical methods, provides improved assessments of geologic and exploration risk in unconventional resource plays.