Research on cement capping technique of progressive plugging

For the purpose of secondary infill development of original area of oilfield, some low-efficiency wells shall be plugged, while the low success rate of general plugging cannot meet the demand for development of original area. To solve this problem, the cement capping technique of progressive plugging is developed. Y441-112 packer, release sub and cement injector are developed to realize the function of plugging in layers and progress release and ensure that the cement slurry is injected into the process pipe string efficiently and safely. This technique solves the problems of uneven cement injection and bad plugging effect caused by interlayer pressure difference resulting from general squeeze and injection for shut-in. Currently, this technique has been applied in 34 wells and the success rate is 100%, with good plugging effect and meeting the demand for secondary reconstruction of original area.