The invention belongs to the technical field of tools for the oil and gas field and particularly provides a sand-out returning fluid stop valve for an
oil well and an application method of the stop valve. The stop valve comprises an upper connector, a baffle, a
pressure balance spring, a stop valve body, a setting ball, a ball seat, an upper oil
pipe male buckle and a lower oil
pipe female buckle.The problems are solved that in the prior art, during sand-out of the
oil well, in the process of replacing a joint, there is still full of water in the well field, the requirement of the
environmental protection act cannot be met, in the reverse-circulation sand-out process, the flow direction of pumped fluid is identical to that of returning fluid during sand-out and
joint replacement, a checkvalve cannot be installed on an in-well
pipe column, if the project is complex in the sand-out process, forward sand-out and reverse sand-out are needed, and installation of the
check valve cannot meet the construction demand. According to the stop valve, overflowing of the returning fluid in the sand-out operation
joint replacement process can be effectively blocked, the environmental
pollution is avoided, site construction is effectively guided, the sand-out operation efficiency of a common oil pipe is improved, and the safety and environment protection risks are reduced.