Formation fluid pressure-maintaining sampling device for low-pressure oil reservoir

The utility model relates to a low-pressure oil reservoir formation fluid pressure-maintaining sampling device which comprises a sampling cavity. The top end of the sampling cavity is connected with an oil pipe; the bottom end of the sampling cavity is connected with a sampling device; the sampling cavity is divided into a sampling cavity body and a pressure control end by a horizontally arranged piston; the side wall of the sampling cavity is connected with a one-way valve for fluid to enter, a pressure gauge is also arranged in the sampling cavity, and the bottom end of the sampling cavity is connected with a sampling device; the pressure control end comprises a fixed baffle, the fixed baffle is parallel to the piston and located above the piston, the two ends of the fixed baffle are fixed to the inner wall of the sampling cavity, one side of the fixed baffle is connected with the piston through a spring, and the other side of the fixed baffle is connected with a steel cable; the device further comprises a