中文摘要：

基于塔里木油田大北地区砂岩酸化后测试过程中出现的井壁垮塌问题,研究了酸化过程中酸蚀区内岩石力学参数变化规律,建立了酸蚀区酸化过程中的岩石力学参数变化模型。根据酸化后考虑塑性的井周围岩应力分布规律,建立酸化后试油井壁稳定性评价方法。研究表明,酸化会引起岩层弹性模量、泊松比、黏聚力及内摩擦角变化,酸化过程中,弹性模量和泊松比可以通过孔隙度变化计算;岩石黏聚力与内摩擦角随时间的衰减关系可以通过实验数据拟合;酸化会引起近井应力的衰减,衰减程度与酸化时间及酸化半径有关;酸化后试油过程中井壁稳定性由衰减后的应力及强度参数共同决定;通常酸化前期对试油井壁稳定性的影响比酸化后期严重。

英文摘要：

In the DB Block,Tarim,wellbores collapsed during well test after sandstone matrix acidizing.Aimed at this issue,the parameter variation rule of rock mechanics are studied through experiments.The models of mechanics parameters during acidizing are established.The stress distribution around wellbore with acid treatment is described taking plastic zone into consideration.The evaluation method of wellbore stability with acid treatment is established.The research indicates that,the acidizing treatment would bring into changes in Young＇s modulus,Poisson＇s ratio,cohesion and internal friction angle.During the acidizing,the change of Young＇s modulus and Poisson＇s ratio can be worked out through variation of porosity.Decrease of cohesion and internal friction angle can be fitted through experimental data.The acidizing treatment could lead to stress decrease,which is determined by acidizing time and effective acidizing radius.The wellbore stability is determined by the decreased stress and rock strength.In general,the effect of acidizing treatment at an earlier period on wellbore stability is greater than that at a later period.