基于综合权重法的页岩气储量评价方法探讨

Shale gas reserve quality evaluation based on a comprehensive weighting method

针对页岩气地质特征和开采技术的特殊性,提出一种基于综合权重法的评价方法。通过综合考虑影响页岩气开发效果的各种因素,构建了页岩气储量综合评价指标体系;分别利用层次分析法和最大熵值法,求取主观权重和客观权重系数,综合主/客观权重的影响确定综合指标权重系数,结合储量级别与所掌握资料的可靠性分析,进而确定考虑风险的储量综合评价值。利用该方法对7个页岩气储量区块进行综合评价,给出储量品质的差异以及储量的升级动用排序。研究结果表明,对页岩气储量进行评价时,应综合考虑影响页岩气地质、开发、经济等多种因素,并且通过引入风险系数,确保评估结果更为合理,可为页岩气储量区块优选提供决策建议。

A shale gas reserve quality evaluation approach based on the comprehensive weighting method was proposed according to geological characteristics and special development processes. Some key factors which have great impacts on shale gas production were selected to build an evaluation system. A hierarchical analytical method was used to calculate the subjective weighting factors and a maximum entropy method was used to calculate the objective weighting factors. A comprehensive evaluation model was built based on subjective and objective weight-ing factors. A development risk factor was determined after analyzing the completion and match with existing reserves data. Grades with or without a risk factor can be provided simultaneously. With the proposed method, the quality of seven shale gas reserves was compared and their development order was determined according to the ranking for undeveloped reserves. The results indicated that many factors including geological, development and economic factors should be taken into consideration for shale gas reserve evaluation. Meanwhile, risk factors should be introduced as an evaluation factor. The evaluation results considering comprehensive relevant factors are reasonable and effective and can provide useful suggestions for future shale gas reserve management.