Study about Quantitative Identification of Deep Reservoir Fluid by Logging Method in Xihu Sag

Due to complex logging responses and fluids distribution of deep reservoirs, especially low permeability reservoirs, it is quite difficult to evaluate reservoirs. The logging evaluating difficulties are identification of fluid property and calculation of fluid saturation. Rock-electro parameters and irreducible water saturation model are gained according to logging responses and rock-electro and nuclear magnetic experiments for the deep reservoirs cores in Xihu Sag of East China Sea. Reservoir parameters are calculated by using the principle of optimization through using the analysis program of formation components, and refined models are established for each block. On this basis, double-saturation method has been used for identification of deep oil-gas layer and water layer for the first time, and the effect is preferable and identification standard has been established. The gas-oil ratio calculated by well logging information has been used for the first to identify fluid property of deep reservoirs, and it can effectively distinguish oil layer from gas layer quantitatively combining with gas saturation. Thus, deep oil layer, gas layer and water layer can be well identified and distinguished.