Integrated Interpretation of High-Resolution Aeromagnetic Data with High-Frequency Seismic and Landsat Data--Northwest Williston Basin: ABSTRACT

Abstract

A low-altitude (300-ft), close-spaced (4 lines/mi) airborne magnetic gradiometer survey was flown in a 1000-mi/sup 2/ area of northeastern Montana. This area included 31 oil fields, and a modern high-frequency, broad-bandwidth seismic data set was obtained across it. The aeromagnetic survey was designed specifically to study and analyze the short-wavelength, small-amplitude magnetic anomalies associated with near-surface magnetic sources. A secondary objective was a more conventional magnetic basement study. Some of the near-surface magnetic sources may be related to epigenetic changes associated with seepage from hydrocarbon reservoirs. All 31 oil fields displayed a near-surface magnetic anomaly. Other near-surface magnetic anomalies displayed an obvious seismic anomaly visible on the high-frequency, broad-bandwidth seismic data. In addition, the zones that offset and truncate the observed near-surface magnetic anomalies can be seen in the seismic data. This suggests a small, though deep-seated, Quaternary or Holocene wrench-fault system. Many of the magnetic offset zones were also visible in available Landsat data. Some magnetically observed basement faults were also visible on the seismic and Landsat data.