Abstract: The reservoir in Bohai is characterized by high formation-saturation pressure difference and large variation of reservoir pressure. In order to clarify the influence of stress sensitivity on productivity of such reservoirs, this study uses the W group reservoir in the Q oilfield as an example and obtains the change patterns of core permeability and effective stress by changing the effective stress of the core on the basis of gas-logging permeability experiment. The experiment result shows that the relationship between permeability change and the effective stress appears to be exponential. This change pattern was applied to the productivity analysis. The steady-state productivity formula considering the stress sensitivity was derived, and the productivity chart was established for comparative analysis. Considering that the stress sensitivity leads to the obvious overall decrease in productivity, there is a corresponding optimal pressure difference limit of production under different reservoir permeabilities. This is of guiding significance for the formulation of a rational production strategy for reservoirs with high formation-saturation pressure difference in Bohai.

Key words: high formation-saturation pressure difference, stress sensitivity, productivity, evaluation method, optimal production
pressure difference of production