Application of Probabilistic Reserves Estimation in Oversea Low Exploration New Venture

Overseas low-degree exploration new ventures are often faced with limited data and time, the geological knowledge also insufficient. Oil-bearing area are not very clear, the thickness, properties and distribution characteristics of the net pay can not to be precise described. Deterministic method only takes the best estimate of each parameter and the evaluation of uncertainty are more subjective, the accuracy of the results is limited by the geological knowledge, and it is easy to cause large deviation. Probability method is a kind of risk analysis method to quantify the uncertainty of the independent variables, and give the probability distribution of the reserves. For structure field, probabilistic reserves estimation is carried out in the case of pre-discovery stage, one well drilled stage, three well drilled stage, and development stage. The results show that when we know little about the pool boundary, net pay thickness distribution, physical property, and other parameters, compared with the deterministic method, probabilistic method significantly narrowed the reserve range, and closer to the true reserves. Probabilistic method considering more about the uncertainty, which can take more advantage of experts and big data, and carry out calculation based on multi parameter scenarios, and the risk and potential can be determined quantitatively, shows a good prospect application in the overseas low degree exploration new venture.