Chapter 8 Petroleum Geology of the Tanintharyi Region, Myanmar

Abstract

The Tanintharyi offshore region as designated by the government is shown in Figure 8.1a. It is subdivided into two broadly north–south-trending structural elements: the Tanintharyi Shelf on which the small Tanintharyi and North and South Mali basins are also present, and the distal, southern, part of the Martaban Basin. Fig. 8.1. ( a ) The Tanintharyi region showing MOGE block numbers, the Martaban Basin and the Yetagun gas field development area. ( b ) Eastern part of the Tanintharyi region showing wells, blocks and bathymetric contours. In the Yetagun area some wells have been omitted for the sake of clarity. The Tanintharyi Shelf (also known as the Mergui Shelf or Mergui Terrace) forms the eastern part of the region and mainly overlies a basement of Palaeozoic–Mesozoic indurated sediments intruded by granites of the Phuket-Slate Belt terrane (see Chapter 2). Its western boundary is marked by the dextral Shan Fault (also known as the Mergui Fault in Thailand), and the shelf is located in an overall back-arc setting on continental crust. This shelf area is designated as shallow-water licence blocks M12 and M13 in the north to M18 in the south. The sediments on this shelf were sourced during much of the Early and Middle Miocene from the Thai-Myanmar Peninsula in the east, and the succession thickens westwards. During the Late Miocene–Pleistocene, sediment input from the north became more dominant representing the distal portion of the Thanlwin/Ayeyarwady depositional system. The Yetagun Field and associated discoveries in and around the SE corner of Block M12 (Fig. 8.1a, b) are close to the present-day shelf edge, which coincides approximately with the more gradational western boundary of the Tanintharyi Shelf. Several early wells in the northern half of the shelf area had hydrocarbon shows, but the structures were generally small and partially breached. In the eastern part of …