All three of the principal indicators of oil and gas activity fell significantly in onshore south Louisiana in 1989 after posting modest gains in 1988.

Drilling activity in 1989 decreased 28% from the 1988 level of 696 wells to 500 wells. As in 1988, this drop was largely at the expense of development wells; a larger proportion of extension wells and a similar number of wildcat wells were drilled in each year. Operators drilled 56 new-field wildcats, 100 other exploratory wells, and 344 development wells. Overall success rate declined from 51% to 47% due to the decreased emphasis on development drilling. Six new-field discoveries were completed: 2 each in the Miocene and Eocene trends, and 1 each in the Oligocene and Cretaceous trends. There were 25 significant extension wells with 6, 14, 4, and 1 successful tests in Miocene, Oligocene, Eocene, and Cretaceous rocks, respectively.

Land acquisition declined 20% relative to 1988 activity from 336,136 ac leased to 267,276 ac. The preferred leasing sites were Vermilion, Terrebonne, Calcasieu, St. Martin, East Feliciana, and Acadia Parishes. The Oligocene trend had the most leasing activity with more than 45% of industry activity, followed by the Miocene trend with 28%.

Geophysical acquisition also dropped from 436.5 crew-weeks in 1988 to 327 crew-weeks in 1989, a decrease of 25%. Favored locales were Cameron, Vermilion, Calcasieu, Plaquemines, and Lafourche Parishes. Geophysical prospecting in the Miocene and Oligocene trends predominated, capturing 48% and 37% of industry interest, respectively.