Magnetic basement: gravity‐guided magnetic source depth analysis and interpretation |
| |
Authors: | Serguei A Goussev John W Peirce |
| |
Institution: | 1. Fugro Robertson Inc., Gravity & Magnetic Services, 6100 Hillcroft, 5th Floor, PO Box 740010, Houston, TX 77274, USA;2. GEDCO, 815 8th Avenue SW, Suite 1200, Calgary T2P 3P2, Alberta, Canada |
| |
Abstract: | We present a new integrated approach to the interpretation of magnetic basement that is based on recognition of characteristic patterns in distributions and alignments of magnetic source depth solutions above and below the surface of magnetic basement. This approach integrates a quantitative analysis of depth solutions, obtained by 2D Werner deconvolution of the magnetic data, with a qualitative evaluation of the Bouguer gravity anomalies. The crystalline/metamorphic basement and sedimentary cover have different origins, tectonic histories, lithologies and magnetic properties. These differences result in different geometries of magnetic sources associated with faults, fracture zones, igneous intrusions, erosional truncations, subcrop edges and other structural discontinuities. Properly tuned, 2D Werner deconvolution is able to resolve the intra‐sedimentary and intra‐basement magnetic source geometries into distinctly different distributions and alignments of calculated depth solutions. An empirical set of criteria, basement indicators, was developed for identification and correlation of the basement surface. The ambiguity of basement correlation with limited or non‐existent well control, which is common for onshore frontier and offshore explorations, can be reduced by incorporating the Bouguer gravity data into the process of correlation. |
| |
Keywords: | |
|
|