| Sanjiang-Middle Amur basin is located at the northeast Asia continental margin, in the territories of Russia and China, which spans the boundary as a unique basin. It is elongated in a NE-direction over 500 km with a width of 200 km from Jiamusi of China to Komsomolsk-na-amure of Russia. The total area of the basin is 90370 km2, in which more than 60% is in Russia. It is necessary to reinforce research as the area in China (Sanjiang basin) is one of the largest sedimentary basins in northeast china, for the purpose of searching for new oil and gas resources. Although much has been done, most of them are concentrated on either the Chinese part or Russian part without correlations between them. So, this thesis carries out the integrated study on stratigraphic sequence, sedimentary character and petroleum geological conditions from the perspective of the entire basin.Its geotectonic position locates at the joint region where Paleo-Asian Ocean structural domain and the littoral Pacific Ocean structural domain connect. The separation and amalgamation of micro-continental block is complicated. The western part of Sanjiang-Middle Amur basin's overlies the Precambrian Bureya-Jiamusi massif, while its central and eastern parts overlie the Sikhote-Alin Mesozoic orogenic belt. The basin's general structure is seen as a system of grabens and horsts. There are three first-order structures in the southwestern sector of the basin (in China): Suibing depression, Fujing uplift, and Qianjin depression. In the northeastern sector (in Russia), the first-order structures are mainly made up of Birofeld,Kur-Urmi fault depression, Uldura-Churkinsk uplift, Vandan-Gorbylyakh uplift, Khekhtsir and Petropaclovsk uplift, Pereyaslavsky-Anyuy fault depression.Middle-upper Jurassic, Cretaceous, Cenozoic sediments are the main deposits of Sanjiang-Middle Amur basin. Based on Mesozoic sequence of the southwestern sector of the basin in China and Cenozoic sequence in the northeastern sector in Russia, the author established an uniform general stratigraphic column. The formational sequence is identified as follows(bottom-up): Suibin formation in middle Jurassic and Dongrong formation in upper Jurassic. Didao formation, Chenzihe formation, Muling formation and Dongshan formation in lower Cretaceous, Houshigou formation, Hailang formation, Qixinghe formation and Yanwo formation in upper Cretaceous. The Cenozoic consist of Chernaya Rechka formation, Birofeld formation, Ushumun formation, Golovin formation, Priamurskaya formation.Southwestern sector of Sanjiang-Middle Amur basin as to Sanjiang area of China is the only Mesozoic sedimentary basin that has marine facies and continental-oceanic interaction facies in northeast China, and a residual basin which reformed by many times tectonic movements. According to the integrative analysis of cores, field sections, utilizing logging data, seismic materials and paleontology datas, it is indicated that the sedimental feature and assemblages in this area are mostly made up of the continental facies, and others are marine-continental transitional and marine facies. There are two major gulfs from Russia to China at the period of Chengzihe Formation. One flows to Bikin basin along the Ussuri River, then comes into Hulin basin as a cove along Dunmi fault, while the other flows along Heilongjiang(Amur River) south into Suibin depression. Sanjiang-Middle Amur basin is considered to be a large submaritime basin in Mesozoic. Cenozoic maily develops fluvial facies, lacustrine facies, paludal facies, etc.According to the sedimentary environment studying, it meets the requirements of source rocks which is rich in organic matrix. Suibin formation and Dongrong formation, middle and upper Chenzihe formation, Muling formation, Chernaya Rechka formation, Birofeld formation are the main source rock.Suibin formation in middle Jurassic and Dongrong formation in upper Jurassic, Chenzihe formation, Muling formation in lower Cretaceous are characterized by low porosity and low permeability and the reservoir physical property is poor. The Cenozoic most potential reservoirs are middle and upper Chernaya Rechka formation, Birofeld formation and Ushumun formation. Comprehensive study on the character of the source rock reservoir and cap cover shows, there are two main types of source reservoir cap assemblage which are self-generating and self-accumulating, bottom source-top reservior.While, whether there is oil or gas shows is the most direct evidence of the petroleum potential in a basin or depression. For the time being there have been several oil and gas occurrences in Sanjiang-Middle Amur basin. The presence of low resistivity zone and deep fault zone in the eastern basin provide a certain basis to find inorganic gas reservoirs.In the end, on the basis of geology and petroleum geology conditions studying, this paper points out that Suibin depression and Qianjin depression which locate at the southwestern sector of the basin (in China) are the most favorable exploration areas. The main exploration layer in Suibin depression is middle and upper Jurassic, in Qianjin depression is upper Cretaceous and Paleogene. The favorable exploration areas in northeastern sector (in Russia) are Birofeld and Pereyaslavsky fault depression, and Paleogene, Ushumun formation of Lower-Middle Miocene is the main exploration layer.By means of large number of real and basic geological documents and petroleum geology materials, stratigraphic sequence, sedimentary characters have been researched in detail from the perspective of unique basin, and petroleum geological conditions evaluation has completed, then favorable exploration areas has put forward. The above study results possess much more important theoretical significance and practical value for further exploration and the exploitation of Sanjaing-Middle Amur basin and other China-Russia transboundary basin.
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