Jordanov J., Darakchiev І., Belogushev V. Oil and gas resource assessment methodologies: implementation in national balance estimation and company’s exploration policy

Annual of the university of mining and geology “st. ivan rilski”, Vol. 49, Part I, Geology and Geophysics, 2006.рр 1030109, fig 2, tables 4,ref.24, appendix 1. University of Mining and Geology “St. Ivan Rilski”, Sofia 1700, 2 Ministry of Economy and Energy, Sofia, 3 Ministry of Environment and Waters, Sofia, Bolgaria.Resource assessment methodology has been discussed in many papers during the last 10-15 years and has been described as key issues in national balance estimation, as well as in national exploration and production policy making. Geologic prospect and play assessment procedure involves two basic steps: play existence and delineation, in terms of number and size of prospects included; and second - if the constructed model is riskier than certain level. The bases of the process lie on the concept of hydrocarbon systems, in conjunction with play concept as developed by number of authors (Dow, Perrodon, Demaison, Magoon). The main instrument to decide this problem is implementing the exploration probability analysis, which requires an evaluation of those geological factors that are critical to the discovery of recoverable quantities of hydrocarbons in traced prospects. Following factors are defined as critical and must be evaluated with respect to the resource assessment • presence and quality of reservoir rocks;
presence and quality of mature source rocks, as well as hydrocarbon expulsion, migration and charge processes;
presence and trap mechanism;
retention of hydrocarbons after accumulation;
Implementing a widely known probability techniques, many petroleum companies all over the work) registered remarkable growth ю their proved reserves. These results encourage authors to believe that this is the only way to reduce the geologic risk in Bulgarian exploration practice.Common Questions of companies and natural policy makers
Petroleum system-play-prospect concept in resource assessment
Risk and uncertainty in exploration
Prospect resource assessment procedure
Prospect resources assessment procedure(fig)
Play resource assessment procedure
Play Hydrocarbon volume (in bbl) = Numbers of prospects * Success ratios (potential fields from all the prospects) * Potential field size (in bbl)
Play chance assessment procedure