The Fuzzy Evaluation Based on Entropy Method for Heavy Oil Reservoir Horizontal Well CO<sub>2</sub> Huff and Puff Well Selection

Abstract

Due to its high viscosity, it is very difficult to develop heavy oil cost-effectively. Currently, CO2 huff and puff method is a better choice to develop heavy oil reservoir. The key to this method is to choose the suitable candidate target wells. However, it is now very difficult to judge the suitability of the horizontal target wells’ heavy oil reservoirs’ CO2 huff and puff. In according to such issue, this paper, based on the entropy weight method of fuzzy comprehensive evaluation, and used the established horizontal wells’ index in heavy oil reservoir CO2 huff and puff, evaluates the suitability of candidate wells comprehensively. Moreover, this paper presents a set of indicator system that suits the choice of horizontal wells with regard to its heavy oil reservoir CO2 huff and puff, and proposes a specific method and procedures to evaluate an individual candidate well. This project uses such method to calculate 19 horizontal wells in area G, and the evaluation results are consistent with the actual situations. Therefore, it proves that such proposed evaluation method and evaluation index system are feasible to a certain extent. Keyword:heavy oil reservoir;horizontal well;CO2 huff and puff;Well selection; entropy method;Fuzzy comprehensive evaluation。