− | A regional exploration program to study a large unexplored area in the Colombian [http://http://www.greatestplaces.org/notes/amazon.htm Amazon basin] was conducted by [http://http://www.britannica.com/EBchecked/topic/21168/Amoco-Corporation Amoco Production Company] in 1987 and 1988.<ref name=ch16r2>Burgett, W., A., Orange, A., Sigal, R., F., 1992, Integration of MT, seismic, gravity, and magnetic data for reconnaissance of the Colombian Amazon: 54th meeting, European Association of Exploration Geophysicists, Expanded Abstracts, p. 428–499.</ref> This study area was very large approximately 300,000 km<sup>2</sup> (115,000 mi<sup>2</sup>) and remote with dense jungle cover, rugged terrain, and limited road access. | + | A regional exploration program to study a large unexplored area in the Colombian [http://http://www.greatestplaces.org/notes/amazon.htm Amazon basin] was conducted by [http://http://www.britannica.com/EBchecked/topic/21168/Amoco-Corporation Amoco Production Company] in 1987 and 1988.<ref name=ch16r2>Burgett, W. A., A. Orange, and R. F. Sigal, 1992, Integration of MT, seismic, gravity, and magnetic data for reconnaissance of the Colombian Amazon: 54th meeting, European Association of Exploration Geophysicists, Expanded Abstracts, p. 428–499.</ref> This study area was very large approximately 300,000 km<sup>2</sup> (115,000 mi<sup>2</sup>) and remote with dense jungle cover, rugged terrain, and limited road access. |
| The first phase of the program consisted of 31,700 km (19,700 mi) of [[Gravity basics|airborne gravity]] and [[magnetics]]. The large-scale structures delineated in these surveys were then further investigated by [[magnetotellurics]] (MT). The MT survey was feasible with a light helicopter because the crew was small and equipment was light and compact. Data were collected from 43 sites, with a typical spacing of 10–20 km (6–12 mi). | | The first phase of the program consisted of 31,700 km (19,700 mi) of [[Gravity basics|airborne gravity]] and [[magnetics]]. The large-scale structures delineated in these surveys were then further investigated by [[magnetotellurics]] (MT). The MT survey was feasible with a light helicopter because the crew was small and equipment was light and compact. Data were collected from 43 sites, with a typical spacing of 10–20 km (6–12 mi). |
| Encouraged by the evidence from the MT survey, Amoco decided to shoot a small seismic program and drill a shallow stratigraphic test. This program was positioned on the edge of a subbasin defined in the MT data. There generally was good agreement between the MT data, the seismic data, and the borehole geology. | | Encouraged by the evidence from the MT survey, Amoco decided to shoot a small seismic program and drill a shallow stratigraphic test. This program was positioned on the edge of a subbasin defined in the MT data. There generally was good agreement between the MT data, the seismic data, and the borehole geology. |
− | The airborne gravity and magnetic data, followed by the surface MT survey, provided a very cost-effective means of regional basin definition and led directly to a well-positioned seismic survey and well site. | + | The airborne [[gravity]] and magnetic data, followed by the surface MT survey, provided a very cost-effective means of regional basin definition and led directly to a well-positioned seismic survey and well site. |