Conductivity‐depth imaging of time‐domain EM data based on pseudo‐layer half‐space model

2006 ◽  
Author(s):  
Haoping Huang ◽  
Jonathan Rudd
Keyword(s):  
Half Space ◽  
Time Domain ◽  
Depth Imaging ◽  
Space Model

Conductivity-depth imaging of helicopter-borne TEM data based on a pseudolayer half-space model

Geophysics ◽  
2008 ◽  
Vol 73 (3) ◽  
pp. F115-F120 ◽  
Author(s):  
Haoping Huang ◽  
Jonathan Rudd
Keyword(s):  
Half Space ◽  
Mineral Exploration ◽  
Synthetic Data ◽  
Depth Imaging ◽  
Space Model ◽  
Depth Images ◽  
Homogeneous Half Space ◽  
Time Domain Electromagnetic ◽  
Speed Up ◽  
Effective Depth

Helicopter-borne time-domain electromagnetic (HTEM) systems with a concentric horizontal coil configuration have been used increasingly in mineral exploration. Conductivity-depth imaging (CDI) is a useful tool for mapping the distribution of geologic conductivity and for identifying conductive targets. A CDI algorithm for HTEM systems with a concentric coil configuration is developed based on the pseudolayer half-space model. Primary advantages of this model are immunity to altimeter errors and better resolution of conductive layers than other half-space models. Effective depth is derived empirically from the diffusion depth and apparent thickness of the pseudolayer. A table lookup procedure is established based on the analytic solution of a half-space model to speed up processing. This efficiency makes generation of real-time conductivity-depth images possible. Tests on synthetic data demonstrate that the pseudolayer conductivity-depth-imaging algorithm maps a wider range of conduc-tivities and does a better job of resolving highly conductive layers, compared with that of the homogeneous half-space model. Effective depths are close to true depths in many circumstances. Field examples show stable and geologically meaningful conductivity-depth images.

Analysis of Operating Deflection Shapes Based on Subspace Method

1997 ◽  
Author(s):  
Nobutaka Tsujiuchi ◽  
Yuichi Matsumura ◽  
Takayuki Koizumi
Keyword(s):  
Experimental Data ◽  
Time Domain ◽  
State Space Model ◽  
Measurement Data ◽  
Time Varying ◽  
Subspace Method ◽  
Identification Scheme ◽  
Space Model ◽  
Time Varying Systems ◽  
Frequency Components

Abstract In this paper, we propose the new method to identify the Operating Deflection Shapes (ODSs) from the measurement data of time domain. At first, we present the identification scheme of ODSs based on a state-space model. Then the scheme is extended to identify the ODSs adaptively for the time-varying systems by using the URV Decomposition (URVD). Proposed scheme is able to decompose the deformation of a structure under operating condition into the underlying superposition of well excited frequency components. This paper introduces the algorithm and shows the effectiveness of our proposed scheme applyed for both synthesized and experimental data.

Sign in / Sign up

Export Citation Format

Share Document