Changes

==Principles of migration==

==Principles of migration==

* Hydrocarbons migrate as a separate phase, primarily due to buoyancy. This force causes them to move vertically at geologically rapid rates.

* Hydrocarbons migrate as a separate phase, primarily due to [[Buoyancy forces in reservoir fluids|buoyancy]]. This force causes them to move vertically at geologically rapid rates.

* Lithologic layers slow or restrict the vertical movement of hydrocarbons. Seals deflect the hydrocarbons laterally up dip through underlying beds to a trap or spill point. Lateral migration is also facilitated by meteoric groundwater flow. Flow rates for compaction-driven water generally are too slow to significantly affect hydrocarbon flow.

* Lithologic layers slow or restrict the vertical movement of hydrocarbons. [[Seal]]s deflect the hydrocarbons laterally up [[dip]] through underlying beds to a [[trap]] or spill point. Lateral migration is also facilitated by meteoric groundwater flow. Flow rates for compaction-driven water generally are too slow to significantly affect hydrocarbon flow.

* The properties of reservoirs and carrier beds (dip, relative permeability, etc.) control the rate of migration and thus the specific direction of the bulk of hydrocarbons under seals.

* The properties of [[reservoir]]s and carrier beds (dip, [[relative permeability]], etc.) control the rate of migration and thus the specific direction of the bulk of hydrocarbons under seals.

Less is known about migration than any other process involved in the accumulation of hydrocarbons in the subsurface. It is generally described as that unknown process or group of processes that enable petroleum to move from a source to a reservoir.

Less is known about migration than any other process involved in the accumulation of hydrocarbons in the subsurface. It is generally described as that unknown process or group of processes that enable petroleum to move from a source to a reservoir.