CHALLENGE FOR THE DEVELOPMENT OF FULL PETROLEUM SYSTEM MODEL -INTEGRATION OF THREE-DIMENSIONAL PETROLEUM MIGRATION MODEL, GEOMECHANICAL MODEL AND SOURCE ROCK DEPOSITIONAL MODEL -

Basin modeling technique was started in 70fs as zero-dimensional source rock maturity model, has evolved to one-dimensional model introducing compaction, heat transfer and kinetic model, and to two-dimensional model with multi-phase fluid flow. Even three-dimensional petroleum migration model has been developed in late 90fs and started using in actual exploration and production projects of oil industry. However, present three-dimensional petroleum migration model is not perfect and lacking enough capability to model essential phenomena in petroleum system such as petroleum migration through faults and fractures, and source rock development. Our solution is to develop additional computer models to simulate these phenomena and establish the linkage among these models. In order to model petroleum migration through faults and fractures, we have developed forward geomechanical model which calculates stress-strain condition and plastic-elastic deformation. We adapted cam-clay model developed in civil engineering. Our case study indicated that this model can simulate work-softening and work-hardening effects, which corresponds to the fault acting as leakage and as seal, respectively. It was also modeled that one fault has both work-softening and hardening portions at the same time according to stress-strain condition. Source-rock distribution and its properties are important and sensitive input data for petroleum migration model. However, at this moment, users have to specify them with limited information and in some cases, it is difficult to do it. Therefore, source-rock depositional model, which calculates water circulation, organic matter production and preservation, has been also developed. Our case study in present Lake Tanganyika indicated that modeled water circulation and organic matter production and concentration are consistent with observed ones. We have just started to include the function to model the formation of methane hydrate into petroleum migration model, which would be additional evolution of petroleum system modeling.