Unconventional Geophysics for Hydrocarbon Exploration: An Example From the Michigan Basin
An example of the application of magnetotellurics (MT), DC resistivity and IP chargeability to define a gas pool in the mature and challenging environment of the Michigan Basin of Southwestern Ontario is presented. The results of the survey illustrate the potential applicability of non-seismic and hence unconventional geophysical methods in being able to define not only the gas pool, but areas within the pool potentially containing elevated amounts of gas. The application of DC resisitivity and MT methods in a culturally noisy environment illustrates the utility and additional targeting parameters that can be used to guide exploration programs in areas where the acquisition of seismic data is of little additional value, is no longer economically feasible, may not be ecologically acceptable or is no longer a culturally acceptable form of exploration.
The current study measured magneto-tellurics, DC resistivity and IP using a high resolution multi-channel, multi-parameter, distributed acquisition system (DAS), recording broad band tensor audio magnetotelluric resistivity (MT), D.C. resistivity (DC) and Induced Polarization (IP) data. The system utilized a fixed receiver array in combination with multiple current injections and highly accurate 24-bit sampling to achieve great depth of penetration, data quality and detectability.
First used in mineral exploration applications, the system has been applied to exploration for a wide variety of commodities, including gold, copper, base metals, diamonds, in addition to hydrocarbons. The data is processed using a full-waveform, digital signal processing platform and interpreted using 2D and 3D inversion techniques. Currently system acquisition can be in 2D or full 3D mode (similar to 3D seismic).
Results and Conclusions
The results of the survey illustrate the potential of being able to define the electrical properties of the gas pool. The application of these methods in a high resolution survey in a electrically noisy environment illustrates the utility and additional targeting parameters that can be used to guide exploration programs in areas where acquiring additional seismic data is of little value, not economically feasible or not culturally acceptable.
1) applicability of MT and DCIP methods to hydrocarbon exploration.
2) ability to define the structural controls
3) utility of complementary geophysical techniques in defining properties of the hydrocarbon target.
AAPG Datapages/Search and Discovery Article #90323 ©2018 AAPG Annual Convention and Exhibition, Salt Lake City, Utah, May 20-23, 2018