3D Facies Modeling of J Reservoirs of Tinggi Field, Offshore Peninsula Malaysia

This paper presents workflows and methods were adopted in constructing 3D-stochastic facies model of tide-dominated estuarine and tidal marine reservoirs within Group J of Tinggi field (Fig. 1). The Tinggi field is a mature oil field situated in the southeastern part of the Malay Basin, approximately 280 kms offshore east of Kerteh, Trengganu (Fig. 2). The 3D facies model built was conditioned to well observation, and conceptual facies model (Fig.3). A combination of RMS Facies:Belt and Facies:Composite methods were performed in the modeling (Fig. 4). During the modeling process, great efforts were made to optimise the workflow, and input parameters for each depositional system. This is to ensure that the input data were honoured, and the facies architecture and its characteristics are preserved (Figs. 5 & 6). Geological framework study was conducted in order to generate input for 3D facies modeling. This study, covering seven depositional sequences, was based on well logs, core data and 3D seismic attribute, revealed detailed reservoir facies architecture of tide-dominated estuarine and tidal marine<br>environments (Fig. 7). Sedimentological reservoir facies include tidal sand bars, tidal sand flats, highand moderate-energy subtidals. Distinctive sedimentological features for each reservoir facies can be observed from well data. Seismic attribute image extracted for the upper reservoirs provide important information about the distribution pattern of the subtidal facies (Fig. 8). Conceptual sedimentological facies model was built by integrating both well and seismic attribute data, as well as modern analogues, and a complete facies interpretation was performed at each well. Depositional model and paleogeographic history were constructed in order to have better understanding on reservoir sand-body geometry and orientation (Fig. 9). Prior to the facies modeling, a 3D structural/stratigraphic model was generated based on depth structure surfaces and fault polygons from two seismic horizons, subsequently was adjusted to well markers during stratigraphic modeling. The 3D model consists of eleven sub grids with 116 layers and about two millions cells (Fig. 10). In conclusion, better-defined facies distribution offered a realistic 3D static model and enhanced the understanding of reservoir properties distribution.