Petroleum Resource Assessments in the Arctic - the Benefits of Proven Methodologies from the North Slope of Alaska

Bjorn Wygrala¹, Kenneth Peters², and Oliver Schenk^1
1Schlumberger, Aachen, Germany.
²Schlumberger, Mill Valley, CA.

Petroleum Resource Assessments are used to quantify undiscovered oil and gas that is technically and economically recoverable within a certain time frame (e.g. 30 years) from a basin or area. Unlike Petroleum Reserves which are based on data from drilling and fields which can be assessed according to well-defined industry accepted standards, Petroleum Resource Assessments have in the past been less well defined. General guidelines are available such as those in the SPE/WPC/AAPG/SPEE Petroleum Resources Management System, but these do not specify assessment procedures. The value of many resource assessments is therefore limited as they are not based on a rigorously applied methodology, they do not directly take the underlying geoscience data into account, and the effects of uncertainties are not assessed and quantified.

The application of Petroleum Systems Modeling to petroleum resource assessments however provides significant benefits, especially concerning the quantification of results and the effects of uncertainties, and is for example supported by the US Geological Survey (USGS). Resource assessments using Petroleum Systems Modeling are based on the construction of 3D geological models of areas of interest which use all of the available G&G data. These can range from mega-regional studies to play fairway analysis to charge catchment areas for specific prospects. Data handling is scalable to enable very low-density data from frontier areas to be integrated with higher-density data from more explored areas if available.

Key benefits of the Petroleum Systems Modeling approach are that: a rigorous and structured synthesis of the data is performed: an integrated and consistent basin stratigraphy is developed: all of the available surface and subsurface geology can be visualized and related: the assessment units are defined as volumes, and the data can be modeled to acquire quantified and risked data. Additional and unique benefits are assessments of processes through geologic time such as petroleum migration and re-migration, and their relationship to the structural history, as well as petroleum product and property predictions such as oil vs. gas distributions. The inclusion of unconventional hydrocarbons such as gas hydrates is also possible, as their existence is controlled by pressures and temperatures which are an inherent part of the petroleum systems modeling process.

AAPG Search and Discover Article #90096©2009 AAPG 3-P Arctic Conference and Exhibition, Moscow, Russia