Publications

An integrated reservoir characterization case study is presented for the North Belut Gas Field located in Block B, South Natuna Sea, Indonesia. The North Belut productive reservoirs consist of approximately 1700 gross feet of stacked sands deposited in fluviodeltaic environments within the Oligo-Miocene Udang and Gabus formations. This study focuses on reservoir characterization of the Gabus 1 sand involving the integration of 3D seismic data together with petrophysical and core data from six exploratory wells and a number of development wells. Integration of these data types facilitated defining sand body geometries and resolving the challenges of vertical and lateral reservoir heterogeneity and seismic resolution limitations.Interpretation of well log patterns supported by core descriptions enabled the Gabus 1 interval to be divided into two major sequences bounded by a sharp erosional base and on top by shale deposition. Consistent blocky patterns were observed in the well log data and utilized as the basis for the Gabus 1 sand mapping. Overlying the erosional base, thick blocky channel patterns are observed, indicating a stacked body of fluvial sands.Seismic forward modeling demonstrated that the Gabus-1 sands and shales can be optimally differentiated using the elastic parameter lambdarho. Analysis of Lambda-Rho seismic inversion data provided controls for the lateral extent of the Gabus 1 sand. Further investigation suggests that neural networks seismic wave form classification could constrain interpretation of the fluvial system lateral distribution.Integration of the seismic and well data resulted in a more robust description of the fluvial reservoir systems and enabled more optimum well placements and better constraints for reservoir models.