Reservoir spill point

Petroleum may not remain in the first trap it encounters and spillage can occur the most dense fluids can be displaced past the spill point if less dense fluids, especially gas, continue to reach the trap. This process of displacement—tertiary migration — can significantly affect the composition of hydrocarbons encountered in a sequence of stacked reservoirs, possibly leading to the presence of oil in the most shallow units and gas in the deeper units. 

The vertical interval from the crest of the reservoir to the petrolenm water contact is termed the pay zone. Not ah of this interval may be prodnctive. It may also contain impermeable strata. Thns it is nsnal to differentiate between the gross pay and the net effective pay. The vertical interval from the crest of a reservoir to the lowest closing contour on a trap is termed the closnre. The lowest closing contonr is termed the spill plane. The nadir of the spiU plane is termed the spill point. Depending onthe amount of petroleum available a trap may or may not be full to the spill point. The term field is applied to a petroleum-productive area. An oil field may contain several separate pools. Apool is a petroleum accumulation with a single petroleum-water contact. 

Migration of petroleum within the Chalk reservoirs from its point of entry on the Judy structure is considered to be the most likely mechanism by which the Joanne Chalk reservoirs are charged. At present, there is no structural spill from Judy to Joanne at either Ekofisk or Tor horizons. However, the Top Ekofisk depth map, flattened on an intra-Oligocene event, shows that the Joanne structure developed considerably later than the Judy structure. It is therefore possible that, during growth of the... 

Data on the recovery of cyanide-poisoned ecosystems are scarce. In one case, a large amount of cyanide-containing slag entered a stream from the reservoir of a Japanese gold mine as a result of an earthquake. The slag covered the streambed for about 10 km from the point of rupture, killing all stream biota cyanide was detected in the water column for only 3 d after the spill. Within 1 month, flora was established on the silt covering the abovewater stones, but there was little underwater... 

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