Description: Publication date: December 2017 Source: Petroleum Exploration and Development, Volume 44, Issue 6 Author(s): Qiang LAI, Bing XIE, Yuyu WU, Ke HUANG, Xinggang LIU, Yan JIN, Wenjun LUO, Tao LIANG The petrophysical and logging response characteristics of asphaltene carbonate reservoirs were examined based on the measurement of porosity and permeability, density, compressional and shear wave slowness, resistivity and Nuclear Magnetic Resonance transverse relaxation time ( T 2 ) of cores before and after the bitumen dissolving. The results show that (1) the asphalt can damage the pore structure of the reservoir and cause reduction of effective reservoir space and permeability; (2) with the increase of asphalt content, the compression and shear wave slowness generally decrease while the density and resistivity increase; (3) with the increase of asphalt content, the compressional wave slowness and density change less, while the shear wave slowness and resistivity change larger; and (4) the T 2 values of asphalt are generally less than 3 ms, and the higher the maturity of the asphalt, the lower the T 2 value. Based on these experiments, a method based on conventional and special logging methods was presented to evaluate asphalt content, effective porosity and water saturation in asphaltene carbonate reservoirs. The method has already been applied to 80 wells in the Longwangmiao Formation of the Anyue gas field in the Sichuan Basin to pick out zones rich in asphalt on the plane, which has effectively guided the selection of well location in the gas reservoir development.