气藏含束缚水储层岩石应力敏感性实验研究

AN EXPERIMENTAL STUDY ON STRESS SENSITIVITY OF GAS RESERVOIR ROCK WITH IRREDUCIBLE WATER

实验研究表明,不管是干燥岩石还是含束缚水岩石,低渗透砂岩储层的应力敏感性是客观存在的,而且这种应力敏感性对储层渗透率造成的伤害不可忽视。随着有效压力的升高,渗透率是逐渐降低的,并且在有效压力升高的早期降低的幅度最明显,在后期则趋于平缓。而在有效压力恢复过程中,渗透率不能恢复到原来大小,即应力敏感对渗透率的伤害具有永久性。通过干燥样品与含束缚水样品的对照实验数据及分析表明,含束缚水样品的应力敏感性更明显,即应力造成含束缚水样品的渗透率降低幅度更大、伤害程度更大。

By the experiment study, the stress-sensitivity of low-permeability gas reservoirs is being existed objectively. And the hurt for reservoir's permeability can't be ignored. The permeability descend by the effective stress ascend, and descend range in earlier period is most significantly and gently in later period. But the permeability can not restore by descend the effective stress, so the hurt for permeability is permanence. Compare to the dry rock samples, the samples with irreducible water have more significantly stress sensitivity, or more seriously hurt for permeability.