The Borehole-Ground Controlled Source Electromagnetic Signal Transmitter

Electromagnetic logging technique based on borehole radar

An electromagnetic logging technique based on borehole radar is introduced in this paper. The tool consists of one transmitter and two receivers, which can be used to cancel the effect of the antenna characteristics by taking the ratio of two receiver signals. Since receiver signals measured in the time domain can be converted into the frequency domain by Fourier transformation, the amplitude r...

Special Section — Marine Controlled-source Electromagnetic Methods an Introduction to Marine Controlled-source Electromagnetic Methods for Hydrocarbon Exploration

Early development of marine electromagnetic methods, dating back about 80 years, was driven largely by defense/military applications, and use for these purposes continues to this day. Deepwater, frequency-domain, electric dipole-dipole, controlled-source electromagnetic CSEM methods arose from academic studies of the oceanic lithosphere in the 1980s, and although the hydrocarbon exploration ind...

The influence of wellbore inflow on electromagnetic borehole flowmeter measurements.

This paper describes a combined field, laboratory, and numerical study of electromagnetic borehole flowmeter measurements acquired without the use of a packer or skirt to block bypass flow around the flowmeter. The most significant finding is that inflow through the wellbore screen changes the ratio of flow through the flowmeter to wellbore flow. Experiments reveal up to a factor of two differe...

The Risk of Pollution of Ground Water from Borehole Latrines

3-D controlled source electromagnetic interferometry by multidimensional deconvolution

Controlled Source Electromagnetic (CSEM) is an important technique in hydrocarbon exploration, because it uses the large contrast in electrical resistivity to distinguishes between water and hydrocarbons. In a shallow sea environment, the airwave that is refracted from the air-water interface dominates the recorded signal at large offsets. Therefore, the hydrocarbon detection ability of the CSE...