| Early Paleozoic development a thick marine carbonate rocks in Tarim Basin, almost covered the entire basin, sediments thickness generally in the 3000m or more. However, because of greater burial depth and the limitations of exploration conditions, the exploration of marine carbonate rocks mainly concentrated in the Ordovician in the past, and found a number of large oil and gas reservoirs. With the increase of exploration efforts in recent years, the majority of drilling drilled the Cambrian, more and more scholars began to study the Cambrian in Tarim Basin, the The results show that Cambrian has a good exploration prospects. Therefore, this paper based on the results of previous studies, guided theoretically by sedimentology, stratigraphic paleontology, stratigraphy, geochemistry, geophysics, petroleum geology and based on outcrop, logging data, seismic data and sample analysis data, the sedimentary facies, sequence stratigraphy, sequence characteristics and evolution of lithofacies paleogeography, reservoir characteristics and controlling factors of development, reservoir-cap combination of characteristics of development of Cambrian in Tarim Basin were researched, has made some progress in the following:1 Based on system research of rock types in outcrop and drill, and combine with reflection characteristics of seismic facies, characteristics of electrofacies and paleontologic evidence, six type of sedimentary facies were identified in Cambrian of Tarim Basin. They are evaporation platform, restricted platform, open platform, platform margin, shelf and basin. And discuss the evolution of sedimentary facies through its correlation diagram. Through the above study, the depositional model of Cambrian in Tarim Basin has been established, one depositional model is mainly of evaporation platform in Early Middle Cambrian, another depositional model is mainly of restricted platform in Late Cambrian.2 Based on the observations of outcrops and combined with the drilling data, log data, seismic interpretation data and other relevant information of the study area, the types and characteristics of sequence boundaries of Cambrian in Tarim Basin were analyzed. There are 6 types of sequence boundaries, which are weathering crust, slag-like layer, ancient karst active surface, lithologic facies transition surface, erosion surface and overlying surface erosion. Based on the above research , the sequence stratigraphy of Cambrian in Tarim basin is divided into three 2nd-order sequences(SS1,SS2,SS3) and fourteen 3rd-order sequences. The 2nd-order sequences belong to the type I sequence, constituted by TST and HST. Finally, the development of sequence stratigraphic characteristics were compared, and established the stratigraphic framework of Tarim Basin Cambrian.3 Based on the research of sedimentary facies and sequence stratigraphy, six Sequence-based lithofacies paleogeographic maps of Cambrian were compiled with mapping units of sedimentary system tracts. The results show that the Tarim Basin has experienced three large-scale sea level changes in Cambrian. The first large-scale transgression occurred in the early Early Cambrian and formed the deposition pattern which is restricted platform-open platform developed in the central and western basin and shelf-basin developed in eastern and northwestern edge of the basin. After a brief transgression, the sea level began to decline slowly, the decline of sea level led to changes of depositional environment in central and western basin is turned into evaporation platform and depositional environment remains shelf-basin in eastern basin. The second large-scale transgression occurred in the early Middle Cambrian, it is a rapid transgression. Affected by rising sea levels, the depositional environment in central and western basin is turned into restricted platform-open platform, platform margin developed in northwestern edge of the basin, and depositional environment keeps shelf-basin in eastern basin. After a brief transgression, the sea level began to decline slowly, the decline of sea level led to changes of depositional environment in central and western basin is turned into evaporation platform and depositional environment remains shelf-basin in eastern basin. The third large-scale transgression occurred in the early Late Cambrian, the rising of sea level is slowly and experienced a longer time. The depositional environment in central and western basin is turned into restricted platform-open platform and depositional environment remains shelf-basin in eastern basin. The sea level began to decline slowly in the middle and late Late Cambrian, the depositional environment in central and western basin remains restricted platform-open platform, and open platform developed in eastern basin because of the decline of sea level.4 By the macro and microscopic observation of Cambrian dolomite reservoir and combined with the test and analysis of sample and other related information, found the Cambrian reservoir rock types are mainly grain dolomite, algal dolomite and micritic dolomite. The primary pores, intergranular pores, secondary pores and cracks are mainly pores of reservoir, secondary solution pores and cracks are more common. Through the research of dolomitization of Tarim Basin Cambrian found that there are 3 types of dolomitization, they are syngenetic dolomitization, buried dolomitization and hydrothermal dolomitization. On the basis of the above research, the controlling factors of reservoir development in Tarim Basin Cambrian have been analysised. The results show that the dolomitization and hydrothermal dissolution are the mainly controlling factors of reservoir development, and last the model of reservoir evolution has been established.5 Based on the research of sedimentary facies, sequence stratigraphy, reservoir development characteristics and controlling factors, the development characteristics of reservoir cap has been systemic researched. The results show that, the reservoir developed in SS1 HST , SS2 TST , SS3 TST and HST in central and western basin and developed in SS3 HST in eastern basin, the cap rock developed in SS1 HST and SS2 HST, the source bed developed in SS1 TST and HST and SS2 HST in central and western basin and developed in SS1, SS2,SS3 in eastern basin. There are 2 sets of reservoir-caprock developed in central and western basin, and 1 set of reservoir-caprock developed in eastern basin. Reservoirs in SS3 of central and western basin and SS3 HST in eastern basin can be formed a better reservoir-caprock with overlying strata.6 Based on the research of above, the favorable areas of oil and gas resources accumulation and preservation in Tarim Basin Cambrian has been forecasted. There are 3 areas benefit for oil and gas resources accumulation and preservation, they are Bachu prospect area, Central prospect area and East prospect area.
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