特低渗储层应力敏感性及对油井产量的影响

对长6某特低渗储层进行了系统的应力敏感性实验研究.研究表明:该特低渗储层岩石的应力敏感程度在26%~80%的范围,岩石的渗透率越低,应力敏感性越强;原始条件下地下渗透率明显小于地面渗透率,它们之间有较好的线性关系;储层岩石应力敏感伤害后,储层岩石的渗透率不能立即恢复,最终渗透率恢复率在68.6%~100.0%,岩石渗透率越高,渗透率恢复值越大;当岩石的渗透率小于0.5×10-3μm2时,储层岩石的应力敏感性明显增强.模型预测表明,当地层压力降低5MPa时,该储层岩石的应力敏感性对油井产量的影响在8.6%~35.7%,渗透率越低下降幅度越大.

Stress sensitivity of super-low permeability reservoirs and its influence on the productivity of oil well

The stress sensitivity of some Chang-6 super-low permeability reservoir is systemically studied by experiments. The study results show that, the stress sensitivity degree of this super-low permeability reservoir ranges from 26% to 80% , the lower the permeability, the stronger the stress sensitivity; the underground permeability under original formation condition is apparently lower than the permeability under surface condition, there is better linear relationship between them; after the reservoir is injured by stress sensitr/ity, its permeability can't be immediately recovered, the ultimate permeability restoration rate is 68. 60% to 100%, the higher the original permeability, the greater the ultimate permeability restoration rate; when the rock permeability is under 0.5 × 10-3 μm2, the stress sensitivity of reservoir rock apparently increases. The mcdel prediction show that if formation pressure drops to 5MPa, the production of oil well is decreased by 8.6% to 35.7% because of stress-sensitivity damage, the lower the permeability, the greater the drop of the productivity.