UK Oil & Gas Investments (UKOG) has said its estimation of a potential 100 billion barrels of oil near Gatwick airport was untested.
The “clarification” came after its oil discovery in Horse Hill last week.
But the company now says it has “not undertaken work sufficient to comment” on the Weald Basin potential.
It said that further well testing will be required to prove the commerciality of extracting the oil.
UKOG does however maintain its estimation of the new Horse Hill discovery at 158 million barrels of oil per sq mile.