During well tests on producing wells in oil and gas reservoirs on non-stationary flow regimes, the most common technology used is shutting a well on a wellhead, due to little technical and economic resources needed. Using these techniques however willingly implies a range of complicating factors, which have a direct influence on quality of the data on hydrodynamic properties of a reservoir, necessary for further production engineering.
This paper describes the physical-chemical mechanism and diagnostics of such complicating factors as segregation processes in the wellbore, which substantially distort the real pressure response of studied reservoir hydrodynamic system. The paper proposes a method of phase redistribution diagnostic, gives assumptions of causes of complicating segregation effects. In addition, the study suggests some technical and interpretational solutions aimed at improvement of quality and productivity of well tests.