Granite to Grass Roots: Understanding the Geologic History of Unconventional Resource Basins from Bottom to Top

Harris Cander
BP America, Houston, Texas

The competition for unconventional resources in North America has resulted, in some cases, to acquisition of acreage prior to thorough understanding of subsurface technical risks or identification of fairway boundaries and sweet spots. Indeed, the term “resource play” implies to some that subsurface risks are either minimized or irreducible. As well, the term “unconventional gas” connotes that little is to be gained from application of conventional principles of basin evolution and petroleum generation, migration, and entrapment. Under these circumstances, the value of regional geologic understanding of an entire basin prior to acreage capture can be overlooked and the focus turned to completions technology and post-well analysis.

This lecture will discuss the importance of understanding a basin from basement to surface – granite to grass roots – in the search for unconventional fairways. The lecture will include a holistic integration of data and interpretations from basin modeling, petroleum migration modeling, gas isotope data, pressure history, seismic, and reservoir quality. Linkages will be made from microscopic scale observations to tectonic-scale processes. Examples will be given from various North American basins that illustrate how mega-scale features such as basement architecture and Precambrian rift history have a first order and transcendent effect on the evolution and occurrence of unconventional resource fairways, including a strong influence on petroleum generation and entrapment as well as changes in reservoir rock during post-orogenic uplift.

AAPG Search and Discovery Article #90101 © 2010 AAPG Foundation Distinguished Lecturer Series 2009-2010