In recent years, major exploration breakthroughs and subsequent booming development of marine shale gas in both Upper Ordovician Wufeng and Lower Silurian Longmaxi Fms in the Sichuan Basin and its surroundings highlight the strategic importance for the theoretical innovation and technological advances of natural gas in China. A number of key theories and technologies, such as continuous hydrocarbon accumulation and horizontal well volume fracturing, and so on, have contributed to the large-scale development of shale gas fields such as Shunan, Fuling, etc., in Sichuan Basin. Based on China's geological conditions, industrial practices and current limitations in executing the full-scale development of shale gas, a new concept called "volume development (VD)" has been proposed. Under the framework of this theory, man-made volumetric fracture network systems are established through the combination of horizontal well drilling and transverse hydraulic fracturing through which gas flow become much more efficient due to the lateral flow superimposed by vertical fracture flow. VD has become a very efficient development model for shale gas because it can make natural gas in the volume affected by the man-made fracture network system become commercial reserves, and be produced more cost-effectively. VD includes five core technologies, i.e. integrated evaluation of "sweet areas", "optimization design of well patterns for volume development", "optimization and trajectory design of horizontal well drilling in target window", "massive fracturing technology for horizontal wellbores", "design of production system and platform-based well factory-like management". The VD theory and technology provides important theoretical basis and technical support not only for the present three-dimensional development of shale gas in Changning, Fuling and other nearby blocks, but for the overall utilization of unconventional oil and gas resources such as continental, transitional marine and continental facies shale gas. It is believed that VD will have broad application prospects in shale gas development.