Stress-sensitivity is one of the main factors that affect single well productivity in low-permeability rese-rvoirs.It is common sense that wells tend to produce less after certain volumes of reservoir fluids were recovered as that would cause drop-down in formation pressure

porosity and permeability and increase of effective stress.The authors modified the previous productivity function of low-permeability oil wells that only considers the influences of permeability decrease by incorporating the influences of stress on porosity

established a new stress-sensitive productivity function with both porosity and permeability being taken into consideration

and proposed the concept of productivity-stress-sensitivity index.Along with the intensifying of stress-sensitivity of low-permeability reservoirs and increase of stress-sensitivity constant

the productivity-stress-sensitivity index also enlarges

and daily oil production quickly shrinks.The new function simplifies the calculation process and improves the accuracy.Practices show that the productivity-stress-sensitivity index exerts a strong influence upon the productivity of wells in low-permeability reservoirs.As the index increases

the decreasing of open flow capacity of oil wells slows down.Compared with the old function

the new one reflects better the actual production of low-permeability reservoirs and therefore could be used to guide their development.