Enhanced HRAM Anomalies Correlate Faults

between 2-D Seismic Lines

Serguei A. Goussev, Lisa A. Griffith, John W. Peirce and Andreas Cordsen 

GEDCO, Calgary 

Summary Correlation of faults between 2-D seismic lines using enhanced magnetic anomalies is illustrated by this example from a High- Resolution AeroMagnetic (HRAM) survey near the Weyburn oil field in south-eastern Saskatchewan as part of the IAE Weyburn CO2

Storage and Monitoring Project. Seismic fault picks, interpreted on 2-D seismic sections, closely correlate with linear magnetic 

anomalies on the filtered HRAM map. These fault-associated magnetic anomalies can be correlated within the 2-D seismic coverage

area and beyond its limits. 

Introduction 

It is always a challenge to correlate faults between 2-D seismic lines which are widely spaced. This task becomes even more 

complicated when the fault offsets are small and seismic lines have different vintages and processing quality.

The ambiguity of this correlation can be significantly reduced by integration with HRAM data. Structural discontinuities such as faults, 

lithological contacts, and depositional edges can create lateral contrasts in magnetization of rocks. Lateral magnetization contrasts

often generate detectable magnetic anomalies (Glenn and Badgery, 1998, Goussev et al, 2003, Grauch et al, 2001, Peirce et al, 

1998), many of which are sourced in the sedimentary section.

Advanced HRAM filtering techniques can enhance these subtle fault-associated magnetic anomalies to make them coherent and 

correlatable over areas covered by 2-D seismic programs and also between 3-D seismic programs. 

HRAM Data

The S.E. Saskatchewan HRAM Survey was flown along orthogonal flight lines of 500 m x 1500 m spacing. This network provides a

dense and even data sampling over the survey area. The processing of observed data included standard corrections (diurnals and 

IGRF), cultural editing, levelling and gridding at 150 m grid cell size. The gridded data were Wiener filtered to remove extreme high- frequency noise and then reduced to the pole to compensate for local inclination and declination of the Earth’s magnetic field and 

center the magnetic anomalies over their sources. 

The enhancement of subtle magnetic anomalies associated with the fault-like structural discontinuities was achieved by application of

the cascaded Goussev filter (Goussev et al, 1998, 2003) as it provides a superior suppression of noise and improved coherency of 

filtered anomalies. For our study, this filter was designed as a 1.6-3.2 km bandpass of a difference between the total and horizontal 

gradients calculated after applying the depth separation (Jacobsen, 1987) to the total magnetic field.

Seismic Data

Three nearly parallel SW-NE oriented 2-D seismic lines (#1, #2 and #3) were chosen in the IEA Weyburn CO2 study area with ~12 km 

spacing between lines #1 and #2, and ~14 km between lines #2 and #3. Seismic lines are from 48 km to 50 km length. The 

interpreted faults have small offsets and are related to both extensional and compressional regional stress regimes at different times.

Two faults on lines #2 and #3 having apparent seismic signatures typical of strike-slip faulting are marked as PFS - “Positive Flower

Structure” and NFS - “Negative Flower Structure” (Fig. 1). In the absence of complementary information, the correlation of interpreted

fault picks from seismic data only is very ambiguous, especially for the strike-slip fault picks. 

Correlation 

Fig. 2 shows the enhanced HRAM anomalies overlain with 2-D seismic lines, interpreted fault picks and correlated faults. Note how 

closely the enhanced magnetic anomalies correlate with fault picks A, B, C, D and “strike-slip” fault picks PFS and NFS. Based on the 

geologically plausible assumption that a continuous (coherent) magnetic anomaly represents the same type of structural discontinuity

over the area of its correlation, we can correlate the fault “A” between and beyond all three seismic lines. The same approach can be 

followed in correlating the faults “B” and “C” between lines #1 and #2. 

Correlation of the fault picks PFS and NFS without reference to the HRAM anomalies is hardly possible at all. Separated by just 14

km, these faults seem to be associated with the opposite deformation styles: extensional NFS and compressional PFS. Both fault 

picks are in perfect correlation with enhanced HRAM anomalies which clearly show that these fault picks represent orthogonally trending strike-slip faults: the PFS fault trends WSW-ENE and the NFS fault trends SSE-NNW (Fig. 2). 

Conclusions 

1. Enhanced HRAM anomalies can be used to correlate faults between 2-D seismic lines. 

2. HRAM data complements 2-D seismic programs, both locally and regionally. 

3. HRAM data can help to establish the structural deformation styles over large areas, especially when combined with seismic 

data. 

Great Explorations – Canada and Beyond 1
Fig. I 

Line I 

Line# 

Line #3 

• 

2-D seismic lines, fault picks and inlerpreled faults 

on top of the filtered HR AM map 

Flg.2 

This work is a part of GEDCO’s contribution to the IEA Weyburn CO2 Monitoring and Storage Project which is coordinated by the 

Petroleum Technology Research Centre (PTRC). 

Acknowledgments 

GEDCO thanks the IEA Weyburn CO2 Monitoring and Storage Project, and Encana Corporation, a major sponsor of this Project, for 

permission to show the seismic images. 

Great Explorations – Canada and Beyond 2
Great Explorations – Canada and Beyond 3

References 

Glenn, W.E., and Badgery, R.A., 1998, High-resolution aeromagnetic surveys for hydrocarbon exploration: prospect scale interpretation: Can. J. Expl. Geoph., 34, 

97-102. 

Goussev, S.A., Charters, R.A., Hassan, H.H., Peirce, J.W., and Genereux, J.A., 1998, HRAM fault interpretation using MagProbeTM depth estimates and nontraditional filtering: Can. J. Expl. Geoph., 34, 30-39. 

Goussev, S.A., Charters, R.A., Peirce, J.W., and Glenn, W.E., 2003, Jackpine Creek magnetic anomaly: Identification of a buried meteorite impact structure: The 

Leading Edge, 22, 740-741. 

Grauch, V.J.S., Hudson, M.R., and Minor, S.A., 2001, Aeromagnetic expression of faults that offset basin fill, Albuquerque basin, New Mexico: Geophysics, 66, 707-

720. 

Jacobsen, B.H., 1987, A case for upward continuation as a standard separation filter for potential field maps, Geophysics, 52, 1138-1148. 

Peirce, J.W., Goussev, S.A., Charters, R.A., Abercrombie, H.J., and DePaoli, G.R., 1998, Intra-sedimentary magnetization by vertical fluid flow and exotic 

geochemistry: The Leading Edge, 17, 89-92.