The extension and distribution of hydraulic fractures in stimulated reservoir volume (SRV) after volume fracturing are the key for unconventional oil and gas exploration and development.The artificial fractures created in reservoirs after volume fracturing were identified and characterized based on the actual coring data

logging data and laboratory data of the coring wells completed in the tight oil pilot area of the Ordos Basin.Subsequently

the development characteristics of artificial fractures in the simulated reservoir volume (SRV) were analyzed

and the effective extension and spatial distribution of the hydraulic fractures were discussed.The results show that under volume fracturing

the nearly vertical extensional mirco-fractures of 0.13 m in length were created in the oil-bearing massive sandstones in the Chang 7 of the tight oil pilot zone X233

and many bedding-parallel or -crossing fractures were observed in oil layers about 1.49 m away from the operational area.Hydrocarbon extravasation along these fractures is significant

indicating that they are the artificial fractures generated by fracturing.By comprehensive analysis

we found that a hydraulic fracture network consists of limited number of main fractures

a large number of micro-fractures generated and bedding-parallel fractures extended or expanded by fracturing.Meanwhile

the extension range of macro-fracture network in the SRV is limited

but the micro-fractures are widely developed

and the remaining oil saturation of the reservoir stays high

all of which indicate that there is still room to optimize the volume fracturing technology for tight oil reservoir.