Abstract: A new assessment method combined catastrophe theory and fuzzy mathematics is established and applied for the first time to determine the development sequence of heavy oil reservoirs, in which subordinate functions of reservoir parameters are derived with the combination of catastrophe theory and fuzzy mathematics. Based on these subordinate functions, comprehensive values of all heavy oil reservoirs are calculated, based on which, the development sequence of all reservoirs is ranked. The greater the evaluation value is, the more prior the development sequence of the reservoir is. Finally, 11 developed heavy oil reservoirs are presented to validate the ranking method. Result shows that the sequence ranked by the method is in accord with the order of benefit very well. The method can ensure the veracity and creditability of the evaluated result and avoid the randomicity and troubling of hierarchy process, factor analysis, fuzzy comprehensive appraisal and other assessment methods. The ranking method has been proved to be practical in the decision of heavy oil development.

Key words: development sequence, catastrophe theory, fuzzy mathematics, heavy oil reservoir, subordinate function