The low permeability reservoir is greatly affected by the well storage effects, the planar radial flow time is longer during the pressure recovery test, which seriously affects the oil production. The theoretical method for reducing the planar radial flow time in the pressure recovery test well is studied. The results show that the well storage effect is the main factor. It is necessary to adopt the downhole shut-in test technology to shorten the shutin time. To overcome the insufficiency of the downhole shut-in pressure test in the past, the pressure measurement process of the underground shut-in is studied. The key of the process is the developed test cylinder and the matching pressure test tool, the comparative experiments on 5 wells have been carried out. The experiments show that the test cylinder and the ABSTRACT 4 DRILLING & PRODUCTION TECHNOLOGY Vol. 42 No. 1 Jan. 2019 pressure measuring tool fit each other very well, the working cylinder is stable and with a long working cycle. The comparison of five wells shows that the downhole shut-in pressure test process can greatly reduce the effects of well storage, the time of the plane radial flow in the test well significantly shortened, and the impact on the yield during the shut-in period greatly reduced.