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  | isbn    = 0-89181-602-X

  | isbn    = 0-89181-602-X

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From a linear rate standpoint, the least efficient process along the migration path is the rate-limiting step that controls the overall rate of the process. In a sequence of sands and shales, the rate limiter is the least permeable shale and the expulsion rate of hydrocarbons in the source. However, the migration rate of a nonwetting separate phase through barriers like shales is self-adjusting. This is accomplished by enlarging the area through which the process operates. For example, in traps, hydrocarbons are accumulated and spread laterally until the accumulation size causes the rate of migration into the structure to equal that going out of the structure. This accumulation process increases the hydrocarbon flux rate through the overlying shale by increasing the contact area of the hydrocarbons with the shale. Any weaknesses in the shale, such as fractures, will eventually be reached by the accumulating hydrocarbons, increasing the [[leakage]] from the trap. Accumulation size is also limited by the spill point.

From a linear rate standpoint, the least efficient process along the migration path is the rate-limiting step that controls the overall rate of the process. In a sequence of sands and shales, the rate limiter is the least permeable shale and the expulsion rate of hydrocarbons in the source. However, the migration rate of a nonwetting separate phase through barriers like shales is self-adjusting. This is accomplished by enlarging the area through which the process operates. For example, in traps, hydrocarbons are accumulated and spread laterally until the accumulation size causes the rate of migration into the structure to equal that going out of the structure. This accumulation process increases the hydrocarbon flux rate through the overlying shale by increasing the contact area of the hydrocarbons with the shale. Any weaknesses in the shale, such as fractures, will eventually be reached by the accumulating hydrocarbons, increasing the [[leakage]] from the trap. [[Accumulation]] size is also limited by the spill point.

==Parallel and serial processes==

==Parallel and serial processes==