This thesis summarizes the preliminary design work of a new subsurface safety valve (SSSV) for extreme high pressure (30,000 psi) and high temperature (450°F) (XHPHT) applications. Current SSSV designs are not reliable in current production environments and certainly will not be qualified to fail-safe under XHPHT conditions. In this design stage, a quasi-static study on the fluid structure interactions of a flapper SSSV is conducted. A parametric 3D CAD model of a flapper SSSV is built in Solidworks. Then computational fluid dynamics (CFD) analysis is conducted in AnsysRTM CFX. CFD results and the water hammer pressure surge calculated are successfully imported into AnsysRTM Workbench followed by a finite element analysis (FEA) of the stresses. Flappers with different sealing types are compared and summarized. This study is a necessary step for the next design stage, which supplies information that might result in a technical step change in the SSSV design.