Study on sensitivity of siltstone reservoir of Saling formation in Daqing oilfield

The low-porosity and low-permeability siltstone res- ervoir in Daqing oilfield is subject to be damaged by sensitivi- ty.A study was performed to evaluate the sensibility of silt- stone reservoir,and results show that the pressure sensitivi- ty is moderate by weak.The damage ratio of confining pres- sure to permeability is 43.2%.With the better restoration of the confining pressure to reduce the permeability,the resto- ration ratio increases from 70%to 95%.At this kind of geo- logical setting,the reservoir has no or weak velocity sensi- tivity,but the salt sensitivity is apparent and the degree is medium to weak with the threshold salinity as 1800 mg/L, and the water sensitivity is in the medium by intense degree with the index as 56%.The study is of significance to the flood development.