ELECTROMAGNETICS RESPONSE OF EM ANTENNA FOR DEEP TARGET MARINE CSEM SURVEY

Deep sea hydrocarbon exploration is still challenging and expensive. Due to the
unreliability for the detection of direct hydrocarbon indicators (DH!s) using seismic
data, new methods have been investigated. Seabed logging (SBL) is a new technique
for detection of deep target hydrocarbon and has the potential to reduce the risks of
DH!s in a deep sea environment. The magnitude of the electromagnetic (EM) waves
is very important for the detection of deep target hydrocarbon reservoirs below 4000m
from the sea floor. Ferrite magnetic materials play an important role in many
applications due to their versatile magnetic properties. EM antenna is developed and
NiZn, YIG ferrite with multiwall carbon nano tubes (MWCNT) as magnetic feeders
are used to increase the field strength of EM antenna. Nano crystalline NiZn
(Ni08Zn02Fe20 4) was encapsulated in MWCNTs composites, and Y3Fe50 12-
MWCNTs composites were prepared by non-conventional methods. NiZn with and
without MWCNTs samples were sintered at 750°C and 950°C where as YIG
(Y3Fe50 12) samples with and without MWCNTs were sintered at 750°C, 1050°C,
1150°C and 1350°C. All samples were characterized by the XRD, FESEM, HRTEM
and Raman spectroscopy. A single phase ofNi08Zno 2Fe20 4 having [311]a major peak
and a single phase of Y1Fe50 12 with [420] a major peak was obtained at the sintering
temperatures of 1050°C, 1150°C and 1350°C by the sol gel-self combustion method.
FESEM images show that grain size increases with the increase of the sintering
temperature and ranges from 24 nm to 60 nm for NiZn with and without MWCNTs
where as grain size increases from 35 nm to 110 nm for Y1Fes0 12 samples with and
without MWCNTs. TEM studies revealed that encapsulation of single crystals of
NiZn has been done at the sintering temperature of 550°C and 750°C.