Whether deep buried dolomite can form effective reservoirs is the main challenge for petroleum exploration in deep area of Tarim Basin. The cores sampled from Tashen-1 well at the burial-depth of >8000m have revealed that the dolomites are well-developed with vuggy zones, have high porosity and permealbity favorable for forming effective petroleum reservoirs, and revealing the existence of effective dolomite reservoirs in deep part. It has been confirmed vuggy zones are of hot fluid origin. However, the detailed characteristics of vuggy zones including their origin and their distribution in strata need to be disclosed by further studies. Based on field outcrop observation as well as experimental analyses, it was found that solution pores similar with those in Tashen-1 well are widely spread in Upper Sinian and Lower Ordovician dolomite ( which have experienced deep-buried conditions) in Keping area. It was also found that primary saline water inclusions of vug-filling quartz, automorphic dolomite and calcite have homogenization temperature of up to 368 degrees C, 314 degrees C and 303 degrees C respectively, which are much higher than normal formation temperature range (120 similar to 240 degrees C) of corresponding host strata at the maximum burial depth of about 6000m. The salinity of inclusions is respectively 3. 39% similar to 9. 86% NaCleqv, 1. 05% similar to 18. 13% NaCleqv and 4.34% similar to 9. 98% NaCleqv. Moreover, a variety of hydrothermal mineral associations related to pyrite, fluorite, barite, quartz, siderite, dalarnite and saddle dolomite are identified in dolomite samples. In the inclusions of these hydrothermal minerals, CO(2), H(2)S, hydrocarbon gases which may dissolve dolomite are also recognized. It was proposed that dolomite strata in Keping outcrop area experienced large-scaled abnormal hot fluid activities which might be related to extensive magmatic activities in deep part of the basin. It created abundant pore space types, such as bedding dissolution, differential dissolution, cooling fissure and dissolution-slump belt caused by hot fluid. Pore types are mainly characterized by combined type of solution enhanced fracture and vug. Hot fluid activity is mainly controlled by structural fractures and stratigraphical boundary. In this study area, the modification of hot fluid to dolomite reservoirs is mainly represented by the coexistence of constructive and destructive effects, and it is characterized by constructive effect.
