The study of dolomite reservoirs in qixia formationin the northwest of sichuan region

Based on the macro, micro and geochemical characteristics of the drilling core and field of Qixian formation in the northwest of Sichuan region and combined with routine petrophysical data, the basic features and the main controlling factors of the dolomite reservoirs within the types of strata are studied and the spatial evolution and distribution pattern of this kind of reservoirs are summarized in this paper. It is concluded that the dolomite reservoirs of Qixia formation consist of fine dolostone, mid-wide-crystal dolostone and grain dolostone, the pore space is predominated by secondary solution vugs. Fractures not only posses a certain capacity of storage, but also mainly play the role of connecting the pores. Fracture-vug and fracture-pore are the two of main types of reservoir pore space. The spatial evolution of this kind of reservoirs are mainly controlled by the effect of the sedimentation and diagenesis.