Geology

Abstract

The Bakken Formation in the Williston Basin, North Dakota, USA, is an unconventional reservoir that has been one of the major producers of oil for almost 50 years. Recently with new advancements in horizontal drilling, hydraulic fracturing and Enhanced Oil Recovery (EOR) techniques, this formation is considered one of the most prolific oil shale plays in the U.S. and around the globe. The combination of all these technologies have highly increased oil production from the Bakken, resulting the state of North Dakota becoming one of the largest oil producers in America. Innovative production technologies in the Bakken has introduced new challenges to the oil industry which can jeopardize successful stimulation, horizontal drilling operations, EOR and hydraulic fracturing. Considering the fact that unconventional shale plays are becoming a major source of energy recently along with shales being the main constituent of all sedimentary basins around the world, we need to address the problems that would encounter in tight shale oil formations for better field operations. Geomechanical modeling, which plays a significant role for a successful field operation, is one of the major concerns which is notably based on a good understanding of various components within any formation. We need to characterize different shale components and their elastic parameters to input them in different rock physics models to improve mechanical earth modeling (MEM). These formations have a large total organic carbon (TOC) content which is not common in conventional reservoirs. Organic matter which is the reason for high TOC has totally a different physio-chemical properties than other rock forming components. Neglecting to include these properties in our modeling will lead to failure and costly operation. Although the importance of such information organic matter characteristics still requires major investigations. Additionally, the pore spaces where hydrocarbons are stored are very small scale compared to conventional reservoirs which makes the permeability or the flow pathways abnormal. Therefore, we have to expand more in-depth studies in various scales of measurements from nano to macro and mega, to examine how production from this reservoirs can be enhanced from 3% to recovery factor levels of conventional reservoirs. In order to focus our studies in a very small scale, more advanced analytical techniques should be developed and employed.