Changes

==Reconnaissance objectives==

==Reconnaissance objectives==

The objective of a reconnaissance survey is to find seeps and microseeps that provide direct evidence that thermogenic hydrocarbons have been generated, i.e., they document the presence of a working [[petroleum system]]. Additionally, the composition of these seeps can indicate whether a basin or play is oil prone or gas prone.<ref name=ch18r17>Jones, V., T., Drozd, R., J., 1983, Predictions of oil or gas potential by near-surface geochemistry: AAPG Bulletin, vol. 67, p. 932–952.</ref> Hydrocarbons from surface and seafloor seeps can be correlated with known oils and gases to identify the specific petroleum system(s) present. Seepage data allow the explorationist to screen large areas quickly and economically, determining where additional and more costly exploration is warranted. For example, results of preseismic geochemical surveys can guide the location and extent of subsequent seismic acquisition by ensuring that areas with significant hydrocarbon anomalies are covered by seismic data.

The objective of a reconnaissance survey is to find seeps and microseeps that provide direct evidence that thermogenic hydrocarbons have been generated, i.e., they document the presence of a working [[petroleum system]]. Additionally, the composition of these seeps can indicate whether a basin or play is oil prone or gas prone.<ref name=ch18r17>Jones, V., T., Drozd, R., J., 1983, [http://archives.datapages.com/data/bulletns/1982-83/data/pg/0067/0006/0900/0932.htm Predictions of oil or gas potential by near-surface geochemistry]: AAPG Bulletin, vol. 67, p. 932–952.</ref> Hydrocarbons from surface and seafloor seeps can be correlated with known oils and gases to identify the specific petroleum system(s) present. Seepage data allow the explorationist to screen large areas quickly and economically, determining where additional and more costly exploration is warranted. For example, results of preseismic geochemical surveys can guide the location and extent of subsequent seismic acquisition by ensuring that areas with significant hydrocarbon anomalies are covered by seismic data.

Published examples of reconnaissance surface geochemical surveys include Abrams<ref name=ch18r1>Abrams, M., A., 1992, Geophysical and geochemical evidence for subsurface hydrocarbon leakage in the Bering Sea, Alaska: Marine and Petroleum Geology Bulletin, vol. 9, p. 208–221., 10., 1016/0264-8172(92)90092-S</ref> Piggot and Abrams<ref name=ch18r28>Piggott, N., Abrams, M., A., 1996, Near-surface coring in the Beaufort and Chukchi Seas, northern Alaska, in Schumacher, D., Abrams, M., A., eds., Hydrocarbon Migration and Its Near-Surface Expression: AAPG Memoir 66, p. 385–399.</ref> Schiemer et al. (1995), Thrasher et al.<ref name=ch18r45>Thrasher, J., A., Strait, D., Lugo, R., A., 1996a, Surface geochemistry as an exploration tool in the South Caribbean, in Schumacher, D., Abrams, M., A., eds., Hydrocarbon Migration and Its Near-Surface Expression: AAPG Memoir 66, p. 373–384.</ref> and Williams et al.<ref name=ch18r49>Williams, A., Kloster, A., Duckworth, R., Piggott, N., 1995, The role of the Airborne Laser Fluorosensor (ALF) and other seepage detection methods in exploring frontier basins, in Hansjien, S., ed., Petroleum Exploration and Exploitation in Norway: NPF Special Publication 4, p. 421–431.</ref>

Published examples of reconnaissance surface geochemical surveys include Abrams<ref name=ch18r1>Abrams, M., A., 1992, Geophysical and geochemical evidence for subsurface hydrocarbon leakage in the Bering Sea, Alaska: Marine and Petroleum Geology Bulletin, vol. 9, p. 208–221., 10., 1016/0264-8172(92)90092-S</ref> Piggot and Abrams<ref name=ch18r28>Piggott, N., Abrams, M., A., 1996, Near-surface coring in the Beaufort and Chukchi Seas, northern Alaska, in Schumacher, D., Abrams, M., A., eds., Hydrocarbon Migration and Its Near-Surface Expression: AAPG Memoir 66, p. 385–399.</ref> Schiemer et al. (1995), Thrasher et al.<ref name=ch18r45>Thrasher, J., A., Strait, D., Lugo, R., A., 1996a, Surface geochemistry as an exploration tool in the South Caribbean, in Schumacher, D., Abrams, M., A., eds., Hydrocarbon Migration and Its Near-Surface Expression: AAPG Memoir 66, p. 373–384.</ref> and Williams et al.<ref name=ch18r49>Williams, A., Kloster, A., Duckworth, R., Piggott, N., 1995, The role of the Airborne Laser Fluorosensor (ALF) and other seepage detection methods in exploring frontier basins, in Hansjien, S., ed., Petroleum Exploration and Exploitation in Norway: NPF Special Publication 4, p. 421–431.</ref>