Abstract: The application of PreFrac technology and analysis of acquired data is important to determine design principle and job size of the fracturing.Through PreFrac evaluation，stress characteristics of the reservoir can be acquired，filtration characteristics and fracture height extension feature can be recognized，and the fracture height and vertical extension also can be verified with software models.In this paper，MFO test，Step Rate test，MiniFrac test and temperature logging technology are implemented in X2S which is located in Rub Al Khali Basin in Saudi Arabia，reservoir parameters are evaluated，the physical property，rock stress property，leak off coefficient and fracture extension character are recognized，fracturing technology is optimized，and the fracturing job is improved and implemented successfully.PreFrac testing is useful for acquiring reservoir parameters and important for safety of oilfield job implementation，also gives good advisements for similar condition well′s stimulation in domestic.

Key words: injection/pressure drop test, step rate test, minifrac test, temperature logging, tight sandstone gas reservoir, pressure decline analysis