Commencing from sedimentation, according to core, cast liquid photo, scan electron microscope etc., combining the geology setting in the area, this study thinks
that the high quality reservoirs of Carboniferous bioclastic limestone member in the western Maigaiti slope is silt crystal dolomite and clay\|silt crystal dol
omite; and the pore space is mostly pores (intercrystalline pore, intercrystalline emposieu, and birdeye pore) and tectonic dissolution fractures; the pore stru
cture is chick flexure and wellsorted, with drainage pressure less than 0.5 MPa, and most pore throats of 1.5~20 μm, and with average pore throats more than
0.5 μm, most pore throats 7 μm; and the porosity is 8~29.6% with the average of 10.4%, permeability is (0.1~68.4)×10\+\{-3\} μm\+2 with the average of 2.6×
10\+\{-3\} μm\+2, the reservoirs are of medium porosity and medium permeability to high porosity and medium permeability. Epilittoral zone dolomite of evapora
tion tableland and eulittoral zone limy dolomite are the primary factors controlling the development of the high quality reservoirs, and dolomitization, air fre
sh water dissolution, and tectonic fractures and hydrocarbon infusion of late Hercynian play the most important constructive roles in the development, connectio
n and preservation of pores. Vertically, the high quality reservoirs are controlled by depositional setting and mostly developed in evaporation tableland on the
upper and top of the bioclastic limestone member, with the thickness of 1~5 m; horizontally, they are controlled by the Qunkuqiake palaeohigh of late Early Car
boniferous, and along the palaeohigh are not only favorable diagenetic facies (syngenetic dolomitization, air fresh water dissolution) of good quality reservoir, but also important target areas for exploration.
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