Abstract: Primary Migration Agents

Kingi Magara

Four possible causes of primary hydrocarbon migration are: (a) forces resulting from sediment compaction (movement of compaction water); (b) aquathermal effect (water expansion owing to increasing temperature); (c) osmotic effect because of variation of formation-water salinity caused by ion filtration by shales; and (d) montmorillonite-illite conversion (montmorillonite dehydration). The relative importance of these causes may be related to another problem--the form of oil and gas at primary migration stage, that is, whether it is in solution in water or in its own phase.

A larger proportion of migrating oil must be in its own phase because of the relatively low solubility; most of the migrating gas must be in solution in water.

AAPG Search and Discovery Article #90961©1978 AAPG Annual Convention and Exhibition, Oklahoma City, Oklahoma