Michel T. Halbouty¹

(1) Michel T. Halbouty Energy, Houston, TX

ABSTRACT: Giant Oil and Gas Fields of the Decade 1990-2000: An Introduction

The two sessions titled Giant Oil and Gas Fields of the Decade 1990-2000 represent the fourth of a four-decade series, each commemorating important giant discoveries, and resulting in the publication of AAPG memoirs, rich in their geologic detail.

During the last thirty years, major trends involving giant fields have occurred, including a steady shift of giant discoveries into deeper waters off continental slopes. Case histories to be presented include those from offshore Brazil, Angola, and the Gulf of Mexico.

The present inventory of giant fields (i.e., 500 million bbl of recoverable oil and/or 3 tcf of gas reserves) is larger than it ever has been. Giant oil field discoveries have contributed significantly to the almost doubling of proven world oil reserves from 560 billion barrels in 1970 to over a trillion barrels at the present time. There has been over a 100 percent gain in giant gas fields during the past thirty years. Important giant gas field case histories presented in these sessions include those found in Pakistan, Indonesia, and Australia. We also include as part of the conference important contributions from North American coalbed methane deposits.

A subtle but very real trend over the past forty years has been the increase of giant fields discovered as a result of their stratigraphic emplacement, as opposed to a strictly structural trap environment. The data also record a pronounced shift of giant field discoveries away from the United States. The countries gaining the most numbers of giant fields during the nineties were Russia, Saudi Arabia, Norway, Iraq, Angola, Australia, Indonesia, Kazakhstan, Nigeria and UAE-Abu Dhabi.

The deliberate solicitation of a group of papers on giant fields to be presented at a convention of the world's largest geological society is an important event.

AAPG Search and Discovery Article #90906©2001 AAPG Annual Convention, Denver, Colorado