Development and Evaluation Test of Automatic-Setting Wellhead Plug

The wellhead device is prone to washout in the process of slug sand fracturing or blowing while production， which makes it impossible to address the risk of well control in time， thus imposing a serious potential safety hazard. An innovative automatic-setting wellhead plug and supporting hydraulic fishing tool were developed. In this paper， the main structures， working principles， main technical performance parameters and features of the device and tool were introduced， and the laboratory performance evaluation test was performed on the physical prototype of the automatic-setting wellhead plug. The test results show that under the 15 MPa wellbore pressure， the stop pin of the automatic-setting wellhead plug is pulled to allow the plug to fall into the wellbore freely， so as to realize automatic release and delay automatic setting， and meet the requirement of sealing at 50 MPa. The hydraulic fishing tool can be used to pressurize 10 MPa to realize automatic unsealing and pressure relief for equilibrium before the wellhead plug is safely lifted. The developed plug and tool are ready for field testing， and they have been proved effective for addressing the problem of wellhead washout in a short time. Thus， the plug and tool are prospective for popularization and application.