Abstract: In order to scientifically select optimal oil and gas field development plans, this paper presents improved TOPSIS (Technique for Order Preference by Similarity to Ideal Solution) method. The improved method can be used to solve the problem of the conventional TOPSIS that short distance may be coinstantaneous between the schemes to ideal solution and to opposite ideal solution. Vertical distance is proposed to replace Euclid distance by the improved TOPSIS method and the order of priority of all plans is given according to the vertical distance. The effectiveness of the improved TOPSIS is illustrated by applying it to an oil reservoir. The illustration builds TOPSIS evaluation model based on synthetically taking into account of the developmental and economical indexes. Compared with the results of fuzzy comprehensive evaluation method, the calculating results of the improved method is less complex and easily operated.

Key words: TOPSIS, vertical distance, oil and gas field, development plan, optimization