The OOIP evaluation for Archaean metamorphic reservoir of buried hill is introduced in this paper. Coexistence of pores and fractures, severe heterogeneity are the main features of this kind of reservoirs. Compare to clastic reservoir, it is extremely difficult to determine the minimum effective thickness for metamorphic reservoir through conventional methods. Furthermore, the accurate defination of other petrophysical parameters such as porosity and oil/gas saturation is another challenge. In order to improve the definition of OOIP calculation parameters for unconventional reservoirs, hence get more accurate number for the original oil in place (OOIP) in metamorphic reservoir, a new method integrating resistivity-based image log (FMI), production log tool (PLT), side wall core (SWC) and whole core analysis (WCA) is introduced. The application of this method achieved satisfying results.