|
Mr. R. G. W. BRUNSTROM asked why the hydrocarbons which escaped vertically should be expected to be concentrated around the edge of the oil-field. One of Professor Evans’s illustrations had shown an oil-field with a cap rock co-extensive with the oil accumulation, but this was a misconception; in Nottinghamshire the various cap rocks were of infinite extent when compared with the areas of the oil accumulations, and it was hard to see why leakage, if any, should take place only at the edges.
Professor Evans had recorded traces of hydrocarbons in the Keuper near the surface in the area of the Egmanton oil-field when that oilfield had just been discovered (in 1955), and had found no such traces in the Keuper near the surface at Eakring, where the oil-wells had been pumping since 1939. He had deduced from this that the pumping, by altering the pressures, had disturbed the equilibrium of the system and stopped further leakage to surface. The speaker asked why any oil had remained in the
...
This 250-word extract was created in the absence of an abstract.
