THE GEOLOGIC CONTEXT OF HYDRAULIC FRACTURING: AN OVERVIEW OF CONTINUOUS OIL AND GAS RESOURCE PLAY TYPES

Two fundamental innovations underlie the emergence of continuous oil and gas plays in the United States over the past 10-15 years: (1) New exploration concepts that allow for a broad distribution of the resources in low-permeability reservoirs in close proximity to the source rocks; and (2) Engineering advances in hydraulic fracturing (HF) that have facilitated gas and oil production from these low-permeability reservoirs. Fundamental petroleum geology principles provide an understanding of the nature and distribution of continuous oil and gas play types such as shale gas, shale oil, tight gas and oil, and also of the geographic distribution of HF practices in the U.S. Unlike conventional hydrocarbon accumulations, continuous oil and gas are not confined to well-defined structural and stratigraphic traps, so the impacts of its production by HF techniques have the potential to affect broad areas. Innovations in directional drilling associated with HF have served to lessen the surface impacts. This overview presentation provides the geologic context for hydraulic fracturing, based on the development of continuous oil and gas plays in the U.S.