Non-Seismic Detection of Hydrocarbons: From Overview

Dietmar Schumacher
Terralliance, Mora, NM

The surface expression of hydrocarbon seepage and hydrocarbon-induced alteration of soils and sediments can take many forms including (1) anomalous hydrocarbon concentrations in soils, sediments, and waters; (2) microbiological anomalies and the formation of “paraffin dirt”; (3) mineralogic changes such as formation of calcite, pyrite, uranium, elemental sulfur, and certain magnetic iron oxides and sulfides; (4) bleaching of redbeds; (5) clay mineral alteration; (6) electrochemical changes; (7) electromagnetic and telluric changes, (8) radiation anomalies; and (9) biogeochemical and geobotanical anomalies.These different manifestations have led to development of an equally varied number of geochemical and non-seismic geophysical exploration techniques. These include direct and indirect geochemical methods, magnetic and electrical methods, radioactivity-based methods, and remote sensing methods.

What are the benefits of using geochemical and non-seismic hydrocarbon detection methods in conjunction with conventional exploration methods? In a review of more than 1100 US and International wildcat wells - all drilled after completion of geochemical or non-seismic hydrocarbon detection surveys - more than 80% of wells drilled on prospects associated with positive hydrocarbon anomalies resulted in commercial discoveries; in contrast, only 13% of wells drilled on prospects not associated with such anomalies resulted in discoveries. Although these methods cannot replace conventional exploration methods, they can be a powerful complement to them. The need for such an integrated exploration strategy cannot be overemphasized. This presentation will be illustrated with examples from geochemical surveys, aeromagnetic-micromagnetic surveys, passive and active electromagnetic surveys, and remote sensing data.

AAPG International Conference and Exhibition, Cape Town, South Africa 2008 © AAPG Search and Discovery