Some petrological, geochemical and geophysical studies were conducted on the high-quality reservoirs of marine carbonate rocks as the main gas producers in Sichuan Basin and the common origin of each quality reservoir was discussed in an effort to broaden petroleum domains. Results show that (i) there exists an exclusive sedimentation named as rock fragmentation in these carbonate reservoirs, which the early diagenetic carbonate mud may be transported once more under poor concretion; (ii) controlled longitudinally by sedimentation cycles, this fragmentation has a certain periodicity and fundamentally extends into the mid-late highstand system tract of the cycles. While laterally by paleogeomorphology, especially syndepositional faults or slope break; (iii) this fragmentation mechanism stems from the difference of sedimentation rate among various depositional settings. When there is an obvious division between two kinds of adjacent setting, massive carbonate sediments at the higher position with larger calcareous space cannot accumulate in place. Being transported in low-lying zones towards the sea and following the principle of sedimentary differentiation, weakly consolidated carbonate rocks suffer from fracturing and collapse under the influence of paleogeography, gravity, and hydropower; and (iv) the quality reservoirs are closely related to fragments. The fragmentation may alter the mud’s physical composition and generate numerous original intergranular pores and vugs to enlarge the fragments’ surface area. And some unstable mineral within the fragments are fully dissolved by undersaturated fluid in low-lying zones, further having much extension in reservoir space. And carbonate sediments change apparently in their physical properties under the effect of both fragmentation and submarine karstification. In conclusion, for the rock fragmentation, the mechanism to form the beach, reservoir and trap can make traditional theories more colorful. Being conducive to broadening exploration domains, this innovative model provides a new exploiting idea in low-energy facies belts, structural slope or low-lying areas in Sichuan Basin.