Abstract: Micro—petroleum seepage and associated surface abnormal physical and/ or chemical fields are the targets that the non—seismic exploratory work, except for high accurate gravity—magnetic measurement, strives to detect .Oil and gas seeps are of obvious significance to exploration. The concept of m icro—seepage, however, differs subsiantia- 11 y from that of well accepted micro —seepage on aspects such as migration mechanism, distribution» phase and componenis etc. Surface oil expecting technique as whole is based on the theory of vertical migration (or micro—seepage ).This theory has nature of hypothesis and guess to some extent. There exist problems such as migration mechanism, migration passage, phase, driving force and interpretation model which need to solve, although some field work has provided supporting evidence. Therefore, the theory requires urgent study and practice—examination.
Employing concept of information net value, this paper applys method of decision tree to determine the maximum expected net value of information, exploring whether or not investment and how much investment should be spent on gathering non—seismic exploratory information in oil exploration. Then, the paper discusses the role that non—seismic work as a supplement and assistant tool can play in conventional exploration technique, suggesting its tasks in the exploration.