Time Domain Controlled Source Electromagnetics for Hydrocarbon Applications

During the past 10 years, marine electromagnetics has developed from infancy into a sizable geophysical industry. While this is feasible in the time and the frequency domains, most of the commercial marine hydrocarbon applications operate in frequency domain, i.e. Controlled-Source Electromagnetic (fCSEM). Until 5 years ago, it was generally assumed that time domain (tCSEMTM) methods would not be of any use in oil exploration. Since then, however, many such measurements have been recorded with several independent tCSEMTM systems that already exist or under development. Time domain measurements can be used everywhere and more suitable for shallow water. They have large anomalous responses than those in fCSEM. From the physical viewpoint, time domain measurements are complementary to frequency domain measurements, as they focus on different spatial regions. With recent advances in electronics time-domain CSEM data can reliably be acquired in an offshore environment. Multiple surveys using autonomous receiver nodes have successfully acquired marine time domain CSEM data. Our work takes the technology a step further, by developing a high-density marine cabled system with novel 5-component sensor package.

[1]  Brian R. Spies,et al.  Depth of investigation in electromagnetic sounding methods , 1989 .

[2]  R. N. Edwards.  On the resource evaluation of marine gas hydrate deposits using sea‐floor transient electric dipole‐dipole methods , 1997 .

[3]  G. Newman,et al.  Three-dimensional magnetotelluric inversion using non-linear conjugate gradients , 2000 .

[4]  Alan D. Chave,et al.  On the theory of sea-floor conductivity mapping using transient electromagnetic systems , 1987 .

[5]  C. S. Cox,et al.  Controlled-source electromagnetic sounding of the oceanic lithosphere , 1986, Nature.

[6]  H. Passalacqua.  Electromagnetic fields due to a thin resistive layer , 1983 .

[7]  Steven Constable,et al.  Marine electromagnetic methods—A new tool for offshore exploration , 2006 .

[8]  Chester J. Weiss.  The fallacy of the “shallow-water problem” in marine CSEM exploration , 2007 .

[9]  P. Weidelt,et al.  Guided waves in marine CSEM , 2007 .

[10]  C. S. Cox,et al.  Marine controlled-source electromagnetic sounding. 2. The PEGASUS experiment , 1996 .

[11]  Lucy MacGregor,et al.  Sea Bed Logging (SBL), a new method for remote and direct identification of hydrocarbon filled layers in deepwater areas , 2002 .

[12]  Charles S. Cox,et al.  The Electrical Conductivity of the Oceanic Lithosphere , 2013 .

[13]  R. N. Edwards,et al.  First measurements from a deep-tow transient electromagnetic sounding system , 1993 .

[14]  G. W. Hohmann,et al.  4. Electromagnetic Theory for Geophysical Applications , 1987 .

[15]  Hydrocarbon Reservoir Detectability Study For Marine CSEM Methods: Time-domain Versus Frequency-domain , 2007 .

[16]  Vertical source, vertical receiver, electromagnetic technique for offshore hydrocarbon exploration , 2009 .

[17]  K. Vozoff,et al.  Case histories of LOTEM surveys in hydrocarbon prospective area , 1989 .

[18]  R. N. Edwards,et al.  12. Electrical Exploration Methods for the Seafloor , 1991 .

[19]  R. N. Edwards,et al.  First results of the MOSES experiment: Sea sediment conductivity and thickness determination, Bute Inlet, British Columbia, by magnetometric offshore electrical sounding , 1985 .

[20]  K. Vozoff,et al.  The joint use of coincident loop transient electromagnetic and Schlumberger sounding to resolve layered structures , 1985 .

[21]  P. Veeken,et al.  Benefits of the induced polarization geoelectric method to hydrocarbon exploration , 2009 .

[22]  K. Strack,et al.  LOTEM data processing for areas with high cultural noise levels , 1989 .

[23]  G. Keller,et al.  Frequency and transient soundings , 1983 .

[24]  W Hohmann Gerald,et al.  Numerical modeling for electromagnetic methods of geophysics , 1987 .

[25]  Bruce Hobbs,et al.  Hydrocarbon detection and monitoring with a multicomponent transient electromagnetic (MTEM) survey , 2002 .

[26]  Sofia Davydycheva,et al.  An efficient finite‐difference scheme for electromagnetic logging in 3D anisotropic inhomogeneous media , 2003 .

[27]  Full frequency-range transient solution for compressional waves in a fluid-saturated viscoacoustic porous medium , 1996 .

[28]  K. Vozoff,et al.  Integrating long‐offset transient electromagnetics (LOTEM) with seismics in an exploration environment1 , 1996 .

[30]  L. Knizhnerman,et al.  Spectral approach to solving three-dimensional Maxwell's diffusion equations in the time and frequency domains , 1994 .

[31]  M. Unsworth,et al.  An active source electromagnetic sounding system for marine use , 1990 .