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The USGS World Previous HitOilNext Hit and Previous HitGasNext Hit Assessment*

Thomas S. Ahlbrandt, United States Geological Survey, Denver, CO

Search and Discovery Article #10006 (2000)

*Slight revision of abstract of paper presented at AAPG Convention, April, 2000, in New Orleans, together with parts of article, World Previous HitOilNext Hit Resource Forecast Increases, in AAPG Explorer, June, 2000.

A new assessment by the U.S. Geological Survey of the technically recoverable undiscovered Previous HitoilNext Hit and Previous HitgasNext Hit resources of the world was released at the World Petroleum Congress in Calgary in June 2000. Assessments were made by a team of over 30 geoscientists at the end of the calendar year 1999. Petroleum systems are identified and assessed using a probabilistic methodology coupled with geologic analysis. Nearly 1,000 provinces were defined; they in turn were grouped into eight regions roughly comparable to the eight economic regions defined by the U.S. State Department. Petroleum resources are allocated to 409 of these (refer to Figures 1, 2). A total of 76 priority provinces containing 95% of the world’s known Previous HitoilNext Hit and Previous HitgasNext Hit and 26 boutique, or highly prospective, provinces are assessed. Based upon our initial analyses, several observations are clear. First, our estimates of undiscovered technically recoverable Previous HitoilNext Hit resources will not differ greatly from those of the 1994 USGS assessment; however, estimates of both natural Previous HitgasNext Hit and natural Previous HitgasNext Hit liquid resources will be larger than previous estimates (refer to Figures 3, 4). In addition, field growth estimates** of known fields will likely be large and several algorithms are utilized to encompass uncertainty  associated with this critical component of any analysis of world Previous HitoilNext Hit and Previous HitgasNext Hit supply. A production plateau concept of reserve development rather than a bell shaped (or  Hubbert) production profile is advocated and is linked to the concept of field growth. Continuous or unconventional Previous HitoilNext Hit and Previous HitgasNext Hit resources have been captured digitally for a future assessment effort and represent a significant future resource. A series of digital products including geologic maps of the world as well as petroleum system write-ups have been made available via the CD-ROM and the internet. These digital products and the methodology employed in the assessment have been favorably reviewed by the National Academy of Science (NRC), AAPG and GIS World.

**Estimates of reserve growth at the world level were made for the first time in Assessment 2000. Reserve growth estimates nearly equal those of undiscovered resources. Reserve growth results from the following:

  • As drilling and production within discovered fields progresses, new pools or reservoirs are found that were not previously known.

  • Advances in exploration technology make it possible to identify new targets within existing fields.

  • Advances in drilling technology make it possible to recover Previous HitoilNext Hit, and Previous HitgasNext Hit not previously considered recoverable in the initial reserve estimates.

  • Enhanced Previous HitoilNext Hit recovery techniques increase the recovery factor for Previous HitoilNext Hit and thereby increase the reserves within existing fields.

Other highlights of the assessment:

  • A 20 percent increase in undiscovered Previous HitoilNext Hit and a slight decrease in undiscovered natural Previous HitgasNext Hit.

  • More Previous HitoilNext Hit and Previous HitgasNext Hit in the Middle East and in the offshore areas of western Africa and eastern South America than previously reported.

  • Less Previous HitoilNext Hit and Previous HitgasNext Hit in Canada and Mexico.

  • Significantly lower volumes of natural Previous HitgasNext Hit in the Former Soviet Union.

Notable Quotes:

Thomas S. Ahlbrandt: “There is still an abundance of Previous HitoilNext Hit and Previous HitgasNext Hit in the world. Since Previous HitoilNext Hit became a major energy source about 100 years ago, about 539 billion barrels of Previous HitoilNext Hit have been produced outside of the United States. We now estimate the total amount of future technically recoverable Previous HitoilNext Hit, outside the U.S., to be about 2,120 billion barrels.”

Gene Whitney, USGS: “These assessments provide a snapshot of current information about the location and abundance of undiscovered Previous HitoilNext Hit and Previous HitgasNext Hit resources at a point in history, Such an overview provides exploration geologists, economists and investors a general picture of where Previous HitoilNext Hit and Previous HitgasNext Hit resources are likely to be developed in the future.”

 

Figure 1.  Conventional Previous HitoilNext Hit endowment of the world.

 

 

Figure 2.  Conventional natural Previous HitgasNext Hit endowment of the world.

 

 

  Figure 3.  Estimates of Previous HitoilNext Hit and Previous HitgasNext Hit resources, including conventional reserve growth, in Assessment 2000.

 

  Figure 4.  Estimates of undiscovered Previous HitoilNext Hit and natural Previous HitgasNext Hit, together with reserve growth, Assessment 2000 in comparison to assessment in 1994.