储层应力敏感性评价实验方法与评价指标探讨

应力敏感性评价参数是设计储层保护方案、确定合理工作制度的重要依据.前人对评价实验方法、渗透率与有效应力的关系做了许多探索,但在实验方法、数据处理及评价指标方面仍存在较大争议.利用四川盆地中部致密砂岩气层、油层及松辽盆地低渗透砂岩油层共计70块岩样的应力敏感性实验数据,分析了应力敏感性系数与不同初始条件下渗透率损害率的关系,探讨了不同评价方法的优缺点.结果表明,应力敏感性系数与渗透率损害率相关性强,应力敏感性系数可用于进行不同区块储层的应力敏感程度对比.推荐使用应力敏感性系数来度量储层的应力敏感程度.

Discussion on evaluation methods for stress sensitivities of low permeability and tight sandstone reservoirs

It is of importance for formation damage control and determination of appropriate exploitation means to evaluate stress-sensitivity. Many work have been done in regard to experimental method and relations between permeability and effective stress, however, there are much argument on experimental method, data analysis and evaluation criterion. Data from the analysis of 70 core plugs are used in the study, which are chosen from tight sand gas and oil layers in center of Sichuan Basin, and low permeability sand oil layers in Songliao Basin. Relation between stress sensitive coefficient and permeability damage ratio under different original conditions was analyzed. Advantages and disadvantages of different assessment method were discussed. Results demonstrate that there have strong correlation between stress sensitive coefficient and permeability damage ratio, and stress sensitive coefficient can be used as an index to stress-sensitivity of reservoir rock. We state to use stress sensitive coefficient to characterize stress-sensitivity of different reservoirs.