Abstract: The fracture diagnostic technology of micro-seismic mapping is widely applied in the U. S. shale gas wells. A number of research results from abroad show that the larger the stimulated reservoir volume, the better the well performance; fractures are no longer shaped in a two-wing structure but in a complex network, from which a technical term of stimulated reservoir volume (SRV) has come into being . However, present studies abroad are still at the lev- el of how to improve the SRV. In order to make the SRV being correctly and widely accepted in China, we introduce a new concept of volume fracturing, give its definition in both broad sense and narrow sense, and put forward the reservoir condition, key technical points, and main techniques of forming fracture network. Moreover, based on a comparison analysis of traditional fracturing and volume fracturing, a net pressure determination equation is studied for shear fracture propagation, and their difference in seepage mechanism is emphasized. The shortest-distance seepage all-round from matrix to fracture is first presented herein. Finally, breaking with the traditional way of avoiding the fracture interference, the induced stress model of a single cluster fracture is established to obtain the optimal fracture spacing, providing guidance to the multi-stage and multi-cluster fracturing design and laying the foundation for technical development, completion and wide application of volume fracturing in China.
Key words: volume fracturing; horizontal well; shale gas; fracture network; multi-stage and multi-cluster; shortest seepage;  fracture interference