Worldwide Review Of Petroleum Exploration
Authors: Weeks Lewis G. 
Published: December 2007

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Introduction
A worldwide review of petroleum exploration published 16 years ago showed an active interest in 56 countries. The number has since doubled. A very much longer version of this paper to be published by the Sixth World Petroleum Congress summarizes the highlights of recent exploration in 110 countries. This presentation will touch on only a very few of these, after which we shall examine the progress we are making in our exploration methods, and some of the important problems that need to be resolved.

SOME PRINCIPAL DEVELOPMENTS
The one observation that stands out with greatest emphasis today is the rapid growth of interest in offshore exploration. Scarcely six years ago one could count the countries with offshore activity on the fingers of one hand. Today, at least 58, or fully half of the countries have offshore exploration or development activities in some stage. About 12 per cent of the world's proved oil reserves lie offshore. Only a few years ago depth of water was more seriously considered than geology and the facts of oil occurrence. The situation is being rapidly reversed. Engineering problems have a way of disappearing quickly, as is shown by the fantastic growth in the development of offshore equipment.
There has been a much greater percentage discovery offshore than on land. An important reason is that about 87 per cent of the world's oil and gas reserves has been found in young, that is, Mesozoic - Tertiary sediments. Average per acre yields of these young sediments worldwide are several times those of the Paleozoic. Because of the manner in which the continents have developed, these young sediments are largely in coastal basins. Many of these basins have their best development offshore. And the areas present virgin conditions. Geological, geophysical and transportation costs are normally less offshore. Actual drilling rates in the soft sediments are among the highest.
Some operators have been inclined to measure the chances for profitable offshore operations by the U. S. Gulf Coast. The difficulty here with regard to profits lies mainly with proration and the exhorbitant bonuses paid for leases. It is certainly not due to finding costs. The records show that some of the lowest cost reserves in the United States are being found off the Louisiana Coast.
Another notable development is the worldwide increase in gas reserves. Outside of the U. S., these have doubled or tripled in recent years through very large discoveries in many countries. World figures of cumulative production, recent production rates, and reserves as of 1–1–1962 are shown in Table 10. World gas reserves as of today are estimated at 750 trillion cu ft, equal in energy value to 125 billion bbl of oil, or 40 per cent of that of the oil reserves. The world ratio of gas to oil reserves is now about 2300 cu ft/bbl. This ratio will continue to increase.
With the large growth in gas reserves, interest is growing in the liquefaction of gas at low temperatures and its transport in tankers, and also for more convenient storage during slack seasons. The first large tanker shipment of liquefied gas was made from Saudi Arabia to Japan in late 1961.
World production of crude oil doubled in the last ten years, as shown by Table 8. World demand is currently increasing at a rate of 6.5 to 7 per cent annually. In the United States the annual increase is running at 2 to 2.5 per cent, as against an over-all 10 to 11 per cent abroad.