大牛地气田储集层应力敏感性研究

大牛地气田具有低渗、低产、低压、低丰度的特征，而低渗透气藏常伴随着应力敏感性影响。为了研究大牛地致密气藏的应力敏感性，特别是多次开井和关井条件下的应力敏感性，开展了闭合回路下的应力敏感实验研究。结果表明，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，渗透率逐渐降低，并且在有效压力升高的早期渗透率降低的幅度最明显，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。研究结论为大牛地气田开发方案的制定提供了依据，也为其它低渗透气田的开发提供参考。

Stress sensitivity study of reservoirs in Daniudi gas field

Low permeability gas reservoirs are often affected by stress sensitivity.Daniudi gas field is characterized by low permeability,low production,low pressure and low abundance.Experiment study of stress sensitivity has been conducted with closed loop for Daniudi tight gas reservoir,especially under the condition of multiple open and shut-in of wells.The result shows that stress sensitivity does exist in low permeability sandstone reservoir,and brings definite harm to reservoir permeability.As the increasing of effective pressure,permeability reduces gradually,and reduces most rapidly in early pressure increasing stage and slowly in late stage;while during effective pressure build-up,permeability can not resume to the initial size,i.e.the harm of stress sensitivity to permeability is permanent.This study has provided basis for preparing development plan of Daniudi gas field and reference for developing other low permeability gas fields.