The Silurian of Tarim Basin，with area of 236000 km2, oil and gas resources of 598 million tons, and sphalt sandstone area of about 15100 km2, is one of the most important marine clastic rocks exploration object. The paper... [ view full abstract ]
The Silurian of Tarim Basin，with area of 236000 km2, oil and gas resources of 598 million tons, and sphalt sandstone area of about 15100 km2, is one of the most important marine clastic rocks exploration object. The paper was based on the digital outcrop, drilling and seismic data, comprehensive research of lithofacies palaeogeography，and showed that：Lower Silurian Kepingtage formation developed tidal flat-coastal sedimentary system controlled by paleogeomorphy in northern basin, which had nearly thousand kilometers ancient coastline from east to west. Ancient coast outward which had high energy wave action, developed foreshore, flushing and shoreface low angle wash and cross-bedding coastal sand bar, with single sand body thickness of 1.2-4m, high sandstone composition and structure maturity, fine quartz sandstone, silt-fine lithic quartz sandstone, such as YingMaiLi, Hala Ha Tang area. Ancient coast inward，gulf area which had weak energy wave action, developed high mud cuttings or boulder clay content in sandstone, with low composition and structure maturity, single sand body thickness of less than 1m, such as YueNan area. Ancient coast flat area which had tidal action, developed vertical multiphase channel sand body superimposed , with scour surface and bedding boulder at the bottom , Bidirectional, tabular cross bedding in the middle, intertidal mudflat lenticular or ripple bedding in the Upper part, single sand body thickness of 0.6-2.7m, such as KePing area. Coastal sedimentary system with stable sand distribution, large thickness, good reservoir qualities and weak heterogeneity, are favorable for oil and gas accumulation and exploration in the area.
