The goal of this project is to quantify how well an in-situ measurement of bulk electrical resistivity using the new method of Depth to Surface Electromagnetic (DSEM) imaging can be related to the changes in rock properties and fluid propagation that occur as a result of hydraulic fracturing.
GroundMetrics, Inc. (GMI), San Diego, CA, 92123
Global Microseismic Services, Inc. (GMS)
Berkeley Geophysics Associates, Ltd.
Encana Oil & Gas, USA
Approximately 45 percent of the world’s recoverable natural gas reserves are classified as unconventional. Worldwide, the share of unconventional gas production is projected to increase from the current 14 percent to 32 percent. Increasing production from new, tight shale resources is projected to result in the U.S. overtaking Saudi Arabia as the world’s largest producer of liquid fuels (oil, natural gas, and biofuels) as early as 20131.
Hydraulic fracturing (fracking) has enabled commercial production from unconventional formations. However, fracking is more expensive than the conventional methods used to produce gas and oil, and fracked wells exhibit a much faster decline in production than conventional wells. Furthermore, there are environmental concerns with the amount of water required, pollution of groundwater reservoirs, triggering of earthquakes, and release of methane into the atmosphere. A key concern of the general public is hydrofracturing out of the formation and into the groundwater table.
Unconventional wells exhibit highly variable production in a given area, and often the majority of gas or oil produced comes from only a few of the fracturing stages, resulting in more extensive fracturing operations than are really needed and excess proppant being pumped into the formation. These inefficiencies indicate that the eventual destination of the injected fluids used in reservoir stimulation is poorly understood.
1BP Energy Outlook 2030 https://www.bp.com/en/global/corporate/news-and-insights/press-releases/bp-energy-outlook-2030-shows-increasing-impact-of-unconventional-oil-and-gas-on-global-energy-markets.html.
Seismic methods are used to locate hypocenters and, via the tomographic fracture image method, produce images of entire fracture networks. However, the underlying data represent the fracture of the host rock. In contrast, if successful, the proposed DSEM method will image the presence of hydrofracturing fluid in the new pore spaces and quantify the resulting increase in porosity. The following project impacts and benefits are anticipated:
The project has ended with GroundMetrics meeting their objectives. Please see attached Final Technical Report for project related details.
Final Technical Report [PDF-3.46MB] October 1, 2013 - July 1, 2016