we statistically analyzed the secondary hydrocarbon migration distances of 229 large carbonate oil and gas fields within the major petroliferous basins in the world.It is found that the secondary hydrocarbon migration distances and number of oil/gas fields within carbonate migration systesms show no exponential decay relationship as the clastic migration systems.Carbonate reservoirs are generally proximal to source rocks.However
for reservoirs distal to source rocks
the migration distance has no obvious control on the probability of hydrocarbon accumulation.For reservoirs distal to source rocks
oil and gas distribution are generally controlled by the distribution pattern of faults and the distribution range of carbonate reservoirs of vuggy-cavernous type.Given sufficient hydrocarbon supply
the possibility of hydrocarbon accumulation remains almost consistent with such a range.Therefore
even at a long distance
as long as it is within the distribution range of faults and reservoir rocks of the vuggy-cavernous type
the probability of hydrocarbon accumulation can be relatively high.