Keywords: 
• shale gas /
• total organic carbon content /
• volume method /
• reserves evaluation

Abstract: As a kind of unconventional oil and gas resources, shale gas will become an important component of natural gases in the future with the increase in energy demand. This paper introduces to the readers the overall geological conditions, accumulation mechanism and development options of shale gas, as well as the method for shale gas resource assessment. According to regional geological knowledge, basin center and structural slope are the favorable areas for shale gas accumulation. As to the accumulation of shale gas, it requires that the shale sequence, which contains rich organic matter with development value, reaches a certain thickness, and is continuously and steadily distributed. The net pay thickness should not be less than 15m. The total organic content should be higher than 2 percentage, the organic maturity is greater than 1.1 percentage, and the content of brittle mineral is over 30%. Volume method commonly is used on the evaluation of shale gas reserves. The major parameters required include total organic content, porosity, water saturation, adsorption gas content, and reservoir thickness. these parameters generally are calculated with well logging data, combined with drilling core analysis data.