A STUDY OF MARINE CSEM SURVEY GEOMETRY FOR SEABED LOGGING

HUSSAIN, NAZABAT HUSSAIN (2011) A STUDY OF MARINE CSEM SURVEY GEOMETRY FOR SEABED LOGGING. Masters thesis, UNIVERSITI TEKNOLOGI PETRONAS.

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Abstract

In recent years marine Controlled Source Electromagnetic (CSEM) method is
being used for hydrocarbon exploration in deeper water. The marine CSEM is
preferred over seismic due to its ability to differentiate reservoir of resistive
hydrocarbon and conductive saline fluids. In marine CSEM method, however, the
survey data is highly dependent on source-receiver position and orientation.
Furthermore, real geological conditions are extremely varied and it is rarely possible
to turn the survey data into reliable picture of geological structure using virtual
simulation. Consequently, it is important to understand EM field behavior for various
geological models and source-receiver position to improve virtual simulation process.
The aforementioned aspect studied through comprehensive forward modeling is an
alternate to real time geophysical surveys. In this research, a forward modeling
algorithm is employed as a staggered-grid finite difference solution to the totalelectric
field Maxwell’s equations. Solution are achieved through (i) an optimal grid
technique that extends the boundaries of the mesh outward from the region of interest
using a minimal number of nodes, and (ii) a direct matrix solution technique that
allows for simultaneous solution for all sources. The forward modeling algorithm is
applied on 1D and 2D geological models implemented using MATLAB. Results
obtained provide qualitative understanding of electromagnetic signal propagation
through different stratified media with various source positions and orientation. 1D
forward modeling is used to find optimal frequency for specific depth and for
studying effects of speed variation of dipole source. The 2D forward modeling is used
to understand EM field behavior for resistive hydrocarbon and conductive saline fluid
reservoirs. Furthermore, inaccuracy due to improper survey geometry such as dipping
effect is also analyzed and discussed. In essence, forward modeling was applied to
various scenarios and obtained results were accurately matched with previously
published work of real time survey. This is a significant step towards the
improvement in confidence modeling which in turn can potentially help to reduce
surveying cost.

Item Type: Thesis (Masters)
Departments / MOR / COE: Engineering > Electrical and Electronic
Depositing User: Users 6 not found.
Date Deposited: 05 Jun 2012 08:12
Last Modified: 25 Jan 2017 09:41
URI: http://utpedia.utp.edu.my/id/eprint/2808

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