Sedimentary Characteristics of Pliocene Slope Channel Complexes in the Rakhine Basin, Offshore Myanmar

Key words: 
• Rakhine Basin /
• Pliocene

Abstract: Slope channel complex is one of the most important sedimentary architecture elements in Pliocene in Rakhine Basin, offshore Myanmar. This study is carried out under the guidance of the relationship between the seismic response and deepwater reservoir. The strong amplitude attributes on 2D and 3D seismic data are applied to deduce coarse sediment existing in slope channel complexes. Technologies that include coherence slice analysis, geoanomaly processing and 3D visualization are used for distinguishing slope channel complexes from background. Detailed descriptions, involving the external geometric shape, the nature of internal fill and reservoir characters are executed.
Three kinds of slope channel complexes have been observed and identified based on the 3D seismic data. Multiple phase aggradational confined channel complexes have been detected in Pliocene in Rakhine Basin. Several large sand bodies, ranging from 7 km to 16 km in the downcurrent direction and usually no more than 10 km in width, have been indentified. These sands comprised 3~5 layers vertically and are related with each other. 
Channel complexes analysis and characterization in this research area result in the recognitions that the confined channel complexes with complicated shapes and sustainable change on morphology and packing characteristics downstream in lower Pliocene are developed. The confined channel complexes in Pliocene can be characterized by three major categories of erosional confined channel complexes, erosional/external aggradational confined channel complexes and aggradational confined channel complexes according to the difference of sedimentary fill. This study reveals that aggradational channel complexes are richer in reservoir than other two types. They are composite features made up of smaller various sandrich subenvironments, such as inside channels, frontal splays, crevasse splays and overbanks that can be identified by seismic anomaly process method. It is inferred that some sands with larger thickness and high vertical continuity probably exit in aggradational confined channel complexes according to the data measured by previous researchers. It is hoped to become Highrate, highultimaterecovery reservoirs and be considered as the most beneficial targets in the Rakhine Basin.