ABSTRACT
After overcoming the difficulties of the rugged topography and harsh climate, a field survey of the Long Window Transient Electromagnetic (LOWTEM) method was successfully carried out for the first time in southern China for oil and gas exploration. To make better use of these data, some new methods for data processing and interpretation have been searched. Based on the studies of transient electromagnetic fields over a conducting half space and a conducting thin sheet, two parameters for data interpretation are put forward, one is the all-time apparent resistivity, and the other one is all-time apparent vertical conductance. Pseudo-seismic profiling and 1-D inversion methods are developed also. By using the above methods, the LOWTEM data can trace conducting layers and identify small structures, such as reef buildups quite well. The field trials in rugged areas illustrate that the LOWTEM method is productive and has higher resolution than Magnetotelluric (MT) method, so it has excellent prospects in oil and gas exploration.
