Abstract: In Chad, cement cap technology is often applied to the upward well test of plugged layers in the buried hill reservoirs.The fractures in the buried-hill openhole intervals are well developed, so cement slurry leakage occurs in the process of cementing plug and it is difficult to control the top position of the cement plug. And consequently, the one-trip success rate of cement plug setting is low and its depth is not accurate. In order to solve these problems, a new tool, i.e., drillable openhole bridge plug was developed. And combined with cementing, layer plugging is implemented so that the plugging technology for buried hill openhole well is simplified, the success rate of layer plugging operation is improved and the openhole section is positioned and plugged accurately. The field experiment results show that this tool can meet the needs of field operation, reaching the expected aim of layer plugging.