Multi Transient ElectroMagnetics. Table of content: (sorry Add 3 to numbers above 9!) 2-5 What MTEM is. Logging Before Drilling 6-9 MTEM applications 10-11 EM techniques 12-21 MTEM method 22-26 – France test and Reciprocity 27-40 RTA 41-46 Processing and Inversion 47-49 Data Examples 49-50 Recording System 51 Conclusion
Multi-Transient ElectroMagnetics Multi-Transient EM Aug 2007
The structure may reveal a potential reservoir (in general a porous rock bounded by a cap)
The porous rock contains a fluid (water or hydrocarbons, or a mixture) but seismics cannot usually determine the nature of that fluid – drill!
Resistivity – a physical rock property determined through EM – can make that distinction – drill in the right place!
Resistivities of Rocks Diagram courtesy Henri Brasse http://userpage.fu-berlin.de~hbrasse
Fluid saturation and rock properties P-wave velocity is affected only slightly by hydrocarbon saturation in a porous rock. Resistivity can vary by more than an order of magnitude. Picture redrawn from Wilt M. and Alumbaugh D. 1998, The Leading Edge 17, 487-492.
Direct Resistivity Indicator Seismic traces Seismic amplitudes and attributes Logging measurements Logging before drilling MTEM Resistivity