UNCERTAINTIES ANALYSIS OF WELL LOGGING DATA: ACQUISITION AND INTERPRETATION

Every field management is unique and therefore fit-for-purpose data requirements vary from field to field and even from reservoir to reservoir within a field. The knowledge and experience of reservoir team members combined with the budgets and technology available to them at different stages of field life, all contribute to the commercial return on investment. When it is not in our power to follow what is true, we ought to follow what is most probable. In addition to the most likely value of the hydrocarbon in place, the reservoir engineer needs to know the uncertainty about this value. Another source of uncertainty and risk is the use of radioactive elements in logging data acquisition. The lost of these radioactive elements may cause damage to the environment and even the quality of produced oil; this is in addition to economic risk. This paper presents two methods for quantification of uncertainties propagated from log data: the Monte Carlo method, which requires a few lines of programming but a long computation time and an analytical solution, which requires a sophisticated program but short computation time. These analyses provide an estimation of the dispersion of the results caused by random and sampling errors.