突变理论在页岩储层可压性评价中的应用

摘要

There are many methods to evaluate the fracability of shale reservoirs,but it is unusual to apply the catastrophe theory to the fracability evaluation of shale reservoirs.Therefore,firstly based on the analysis of the catastrophe theory,considering the reservoir factors and geological factors,and according to the principle of analytic hierarchy process (AHP),a multilevel structural model composed of target layer,criterion layer and index layer for evaluation of shale reservoirs was established,which determines the fracability catastrophe model of shale reservoirs.And then,based on the data of five wells,their fracability were evaluated by the catastrophe theory,whose order were determined and compared with the results calculated by the method of determining the weight of the analytic hierarchy process.Finally,the applicability,feasibility and limitations of the catastrophe theory were discussed.The results show that the evaluation method of catastrophe theory is consistent with the traditional analytic hierarchy process,which reduces the human subjectivity in the previous evaluation model;the evaluation method is simpler,and the evaluation result is more reliable,which provides a new approach for the fracability of shale reservoir and has certain guiding significance for the pre-pressure evaluation of shale reservoir.%页岩储层可压性评价方法较多,但是将突变理论应用于页岩储层可压性评价则比较少见.为此,首先在分析突变理论的基础上,综合考虑储层因素和地质因素,根据层次分析法原理建立了由目标层、准则层和指标层组成的页岩储层可压性评价多层次结构模型,确定了页岩储层可压性评价突变模型.然后,基于5口井的数据,运用突变理论对其可压性进行了评价,确定了其可压性优劣程度及其顺序,并与利用层次分析法确定权重所计算的结果进行了对比.最后,讨论了突变理论的适用性、可行性以及局限性研究结果表明,突变理论评价方法与传统的层次分析法结果一致.该方法减少了以往评价模型的人为主观性,评价方法更为简单,评价结果更加可靠,为页岩储层可压性评价提供了一条新途径,对于页岩气开发的压前评价具有一定的指导意义.