基于优化组合赋权的煤层气开发潜能评价

Evaluation on coalbed methane development potential based on optimized combined weighting

为了对煤层气井进行优化布局与经济开发,在对影响煤层气开发潜能主要地质因素分析的基础上,运用离差平方和优化组合熵值法和三角模糊数法求得的权重进行优化,确定最佳权重指标,建立煤层气开发潜能评价模型,并以沁水盆地南部柿庄南区块煤层气井为例进行实证评价。结果显示,影响该区块煤层气开发潜能的主要地质因素影响大小依次为:渗透率、含气量、构造、水文地质、储层压力、孔隙度、埋藏深度和煤层厚度;该模型更能反映关键评价指标的特征,使评价结果更接近于实际。研究表明:模型能优化主观评价和客观评价的赋权比例,最大化地减少主观因素对评价结果的影响,能客观合理地表达多指标间的对比差异,以对煤层气开发潜能进行可靠的定量化评价。

In order to make an optimized arrangement and economic development of the coalbed methane,based on the analysis on the major geological factors affected to the development potential of the coalbed methane,the weighting obtained from the differential square and optimized combined entropy method was applied to determine the optimum weighting of the index.An evaluation model on the development potential of the coalbed methane was established.An empirical evaluation was conducted on the coalbed methane wells in Shizhuang South Block at the south part of Qinshui Basin as a case.The results showed that the major geological factors affected to the development potential of the coalbed methane in the block were including the permeability,gas content,structure,hydrogeology,reservoir pressure,porosity,depth and seam thickness.The model could reflect the features of the key evaluation indexes and could make the evaluation results more closely to the reality.The study showed that the model could optimize the weight percentage between the subjective evaluation and the objective evaluation,could maximally reduce the subjective factors affected to the evaluation results and could objectively and rationally explain the comparison differences between the multi indexes in order to make a reliable and quantitative evaluation on the development potential of the coalbed methane.