Evaluation Technology on Permeability of Thin Interbedded Sand Shale Layers in Western Part of South China Sea

The thin interbedded sand-shale layers are highly heterogeneous, and the relationship between porosity and permeability is complex, especially some lamina of centimeter level, far lower than the conventional logging resolution. Therefore, there is great challenge in formation evaluation, which might bring risk to offshore oil gas well testing and well completion. Thus the formation evaluation is facing the challenges. For the oilfields in the western part of South China Sea, by analyzing the rock type and the percolation characteristics, a new kind of method has been developed by using nuclear magnetic resonance imaging data and electric imaging logging data to get the effective reservoir thickness, distinguish reservoir types and calculate intrinsic permeability. It has been confirmed that this kind of method is reliable by analyzing the logging, formation test and DST formation test data. This method can be used for rapid productivity evaluation after the open whole logging, and can be used for making testing decision and perforating strategy with the lowest cost.