Electric well logging was invented in 1926 and has been used in the oil & gas industry since that time. Over the years numerous other downhole measurements have been applied in the energy exploration and production community. Mount Sopris manufactures many of the classical tools used to characterize oil & gas reservoirs, and more recently, shale gas zones.
New drilling and well development technologies have enhanced the possibility of utilizing standard Mount Sopris geophysical logging tools at shale gas and oil basins around the world. Production from shale gas reservoirs is happening nowadays because of horizontal well drilling and fracturing (fracking); however, efficient use of these technologies requires a solid understanding of the subsurface. Shale lithologies are heterogeneous and geophysical logs are necessary to characterize the formations of interest. Four basic logs help determine whether a shale is a reservoir gas, or a non-reservoir shale.
– QL40-GR, Natural gamma
– QL40-ELOG, True formation resistivity
– QL40-FWS, Vp/Vs ratios
– QL40-DEN, Quantitative formation density
These logs can be run through formations of interest. Cross-plotting the data in WellCAD may help determine or discriminate reservoir shale gas and non-reservoir shale. P-Impedance (product of density and P-wave velocity), and Vp/Vs ratio are easily presented in WellCAD using the formula parser. Since variations in anisotropy, mineral composition, TOC (total organic carbon), and porosity of shale gas greatly influence geophysical log response, using this data allows us to estimate variations in these rock properties. The basic relationship can be show with a couple crossplots.
Energy Crossplot 1
Energy Crossplot 2
QL40-BMR, Borehole Magnetic Resonance can also be used to determine total in situ gas content and distinguish between adsorbed and free gas.
Other tools provided by Mount Sopris are used in shale gas applications, including neutron-thermal-neutron, acoustic televiewer, and EM induction. Contact Us for details on this application, or check the Library Page.
