Vertical Geometric Factor of a Two-Coplanar Coils Sonde

A vertical geometric factor of an unconventional two coplanar coils sonde (2C40-Coplanar) is determined and compared with that of the Shlumberger's conventional two coaxial coils sonde (2C40-Coaxial) and the coaxial focusing sonde (6FF40). We recommend the use of 2C40-Coplanar as an auxiliary electromagnetic induction tool in thin bed reservoirs because of its very low shoulder effects permits a good vertical resolution. Besides, presence of a hom in the log profile of a 2C40-Coplanar system against an interface between thick beds help in demarcating accurately the bed-boundaries.