M.K. Verma | USGS Science

USGS2003

Modified Arrington method for calculating reserve growth; a new model for United States oil and gas fields

Reserve (or field) growth is an appreciation of total ultimate reserves through time and is observed throughout the productive lives of oil and gas fields in all petroleum provinces? but most especially in mature petroleum provinces (like many in the United States) when the rate of finding new discoveries reduces to a low level. The importance of forecasting reserve growth accurately in a mature petroleum province made it necessary to develop improved growth functions, and a critical review of the original Arrington method was undertaken. A modification of the pioneering Arrington (1960) method for estimating reserve growth suggests that, as a basis for optimum reserve growth functions, cumulative growth factor smoothing produces a better match with known volume data than does annual growth factor smoothing. Cumulative growth factor smoothing is thus the basis for the building of reserve growth functions in this study. Estimates of oil and gas growth during 1992?1996 based on the modified Arrington method are closer to the actual volumes than those based on the functions from 1995 National Assessment. The new growth functions predict an average annual reserve growth of 0.42 percent per year for oil and 0.90 percent per year for gas over a 30-year (1996?2026) period.

Bulletin↗

USGS2000

Oil and gas reserve growth-a model for the Volga-Ural Province, Russia

An understanding of reserve growth in known oil and gas fields has become a critical component of energy resource analysis. Significant statistical studies of reserve growth have been published in the U.S., whereas little information is available on other regions of the world. It may be expected that in many countries the magnitude of reserve growth is different from that in the U.S. because of differences in reporting systems and in exploration and production practices. This paper describes the results of a reserve growth study in a group of largest oil and gas fields of the Volga-Ural petroleum province, Russia. The dynamics of reserve growth in these fields shows rapid reserve additions during the first 5 years of field exploration and development, which results from intensive step-out and delineation drilling. Later reserve growth is slow and is related to improvements in recovery technologies and discoveries of new pools and extensions. These two stages of reserve growth are described by two different groups of empirical models. A comparison of these models with the models developed for the lower 48 states and Gulf Coast offshore of the U.S. demonstrates that the reserve growth in the Volga-Ural province is significantly lower than in the U.S. The proposed models may be used for assessment of future reserve additions in known fields of countries that presently have or recently had a centrally-planned economic system.

Conference Paper↗