低渗透气藏应力敏感性及其变形机制研究

低渗透气藏岩性致密、渗流阻力大、压力传导能力差，地层压力的下降会对渗透率造成伤害而影响气井产能。目前，一般通过室内物理模拟实验评价储层应力敏感性。以吉林油田龙深气藏为研究对象，从储层岩石硬度、裂缝分布、粘土矿物含量以及含水饱和度等方面进行了实验研究，结果表明该气藏具有较强的应力敏感性，储层岩石存在较强的泥化现象，粘土矿物含量高是产生应力敏感的主要原因，形成了储层岩石变形的规律性认识。为了降低应力敏感带来的危害，应用了降低粘土矿物膨胀程度的压裂液进行体积压裂，优化了合理的生产压差，新井试气结果理想。研究结果为该类气藏的合理开发提供了有力的技术支撑。

Study on Stress Sensitivity and Transformation Mechanism of Low Permeability Reservoir

In low-permeability gas reservoir,reservoir pressure decline causes irreversible permeability damages as well as the productivity impairment due mostly to the great lithologic compaction high flow resistance and poor pressure conductivity.At present,the permeability stress sensitivity is evaluated by lab physical simulation experiment.This paper takes Longshen low permeable gas reservoir of Jilin Oilfield as research subject.Based on the experimental research,this paper studies the rock hardness,fracture distribution,clay mineral content and water saturation,and understands the stress sensitivity and rock deformation mechanism of low permeable gas reservoir.The results show that Longshen gas field have strong stress sensitivity and the reason of the phenomenon is that rock of the field have stronger clay grounting.That is high content of clay minerals is the main reason of stress sensitivity.Forming a deformation mechanism regularity understanding of Reservoir.In order to reduce the harm of stress sensitivity,the fracturing fluid of reducing the swelling of the clay minerals has been applied to fracturing and we have optimized the reasonable production pressure difference,and got the desired results.The results provided a powerful theoretical support for establishing the reasonable development techniques of this type of gas reservoir and gas reservoir protection.