4 links
Canadian Society of Petroleum Geologists
cspg.org
Site includes member information, convention information, news, and publications. Publishes books, a magazine and a technical journal. Has 3500 members.
PGK - Petroleum Geological Circle
pgknet.nl
Dutch professional society of petroleum geologists and engineers. In English.
Society of Petroleum Engineers
spe.org
Serves professional engineers, scientists, and managers in the exploration and production segments of the worldwide oil and gas industry.
Society of Professional Well Log Analysts
spwla.org
Includes member services, well log mnemonics, software directory. Has 2000 members.