It is demonstrated that the Paleogene reservoir came through compaction, cementation and other diagenesis by the analysis of lab data.The mechanical compaction was main one, not the compaction-dissolution. The cementaion involved quartz growth, carbonate and clay mineral formation.The carbonate cements formed in two fifferent phases,the clay calcite was developed in the early phase on the shallow strata, but the crystal calcite on the middle-deep strata.The dissolution of calcite and feldspar was obvious.The pore evolution went through primary to secondary pores.The pore size was affected by the dissolution of calcite and feldspar,as well as cementation of carbonate.The early cementation of calcite was favorable for the late the development of secondary pores.There was a different depth of secondary pore development in different regions in Jiyang sag.From the west to the east in Jiyang sag, the depth of secondary pore growth was increased,that was 1500-2400m in western Huimin depression, 1650-2450m in middle Dongying depression,then 2200-2700m in Chezhen depression and 2300-3500m in Zhanhua depression ,the characteristics of secondary pore distribution was influnced by the migration of sedimentation center.
The Kuco-Gamba basin with east-west direction of apical axis is located at the Nyalam and Gamba Counties in Southern Tibet. This area belongs to the northern Himalayas tectonic district. The major sedimentary materials were clastics in Lower Cretaceous and black shale mainly concentrates to the Fourth-Fifth Kuco Formation and Dongshan Formation. The sedimentary materials of black shale were very fine-clastic and they were mainly composed of argillaceous and douke sedimentary. The ratio of sand/mud when the sedimentary process finished was low. There were some rhythmic layering which was composed by fine grained sandstone and siltite in submarine fan. The black shale richly contains lot of siderite and calcareous aerites produced under a reduction special marine condition. There are a few ammonite fossils and so on in it. The sedimentary face changed slowly and the seawater was in a low-energy and strong reduction environment. The rare earth assemblage pattern of douke in black shale extremely approach the basalt standard pattern and this demonstrated that the sedimentary possibly accompanied by the volcanic activity even involved with mantle materials. The thickness of Lower Cretaceous black shale in this basin is huge and the structure is simple. Its comprehensive geological characteristic demonstrated there are good conditions for hydrocarbon producing. Some positive factors will be worth taken in the future potential appraisal of oil gas resources in northern Himalayas.
Deep-water traction current research is a comparative new domain of sedimentology. China scholars did contribution in this domain and have advantage and peculiarity in it. Deep-water traction current deposits mainly include two types, contour current deposits, internal-wave and internal-tide deposits. Contour current has been studied since the early and middle part of 1960’s. Early research was mainly refers to fine, lamina and small-scale contour current deposits. Now the advanced development have related to broad scale contour lithohermic body of lithoherms research. Internal-wave and internal-tide research began in 1990’s. Early research start with discriminating internal wave and internal tide deposits of small magnitude and now is the stage of study of large-scale sediment waves on deep-sea bottom. The main effort of future contour current research should put on the contour lithoherms in the stratigraphic record, particularly discovering and studying of contour lithoherms made of clasolite. The geologic body of inter-wave and inter-tide that have most mineral value is made of large sedimentary-waves. The first large sedimentary-wave has been discriminated in middle Ordovician system in Tarim Basin and find out it is hydrocarbon potential. View the situation of internal-wave and internal tide, China is likely keep leading in international in this domain.
Donghe Sandstone was deposited in the early stage of sea transgression from the end of Devonian to the early stage of Carboniferous, Donghe sandstone is not an isochronous stratum with various depositional ages in different areas. As a kind of broadly-developed deposits in the early stage of transgress, Donghe sandstone has an outstanding feature of fill and level up. The important controls of the development of depositional facies are the transgress speed, the sediment supply and the pre-transgression paleo-relief. In northern Tarim Basin, blocked by the Tabei paleo-uplift, seawater stayed around the paleo-uplift for a long period, which, combined with the coarse-grained sediment supply, promoted the development of shore beach deposits. In central Tarim Basin, however, the deposit types are diversiform with the complex topography background. Fluvial deposits developed in the bottom conglomerate section, and estuary and shore beach deposits in the massive sandstone section and the sandy conglomerate section. Different section has its own characteristics of grain component, grain selectivity and grain size. While in the other gently-slope and flat areas, rapidly-deposited shore and shelf sediments developed during the transgressive period. Controlled by the depositional environment, the effective reservoir of Donghe Sandstone distribute regionally. Beside the depositional factor, the low paleo-geothermal gradient and the short-term deep-burial history are the other two crucial controls of the development of the high-quality Donghe Sandstone reservoir.
Palaeogeography is a branch of geosciences that studies natural geographical features in the geological history. The research targets are the variance history of ocean and continent, and the distribution and characteristics of the internal palaeogeographic unit. Palaeogeography research in China mainly comes from stratigraphy, tectonics, palaeontology, sedimentary petrology, Quaternary geology, etc. Thus branch disciplines are originated and developed. There are many types of palaeogeographic maps, including tectonic palaeogeographic maps, palaeonotological palaeogeographic maps, lithofacies palaeogeographic maps, qualitative palaeogeographic maps, quantitative palaeogeographic maps, palaeogeographic maps in different geological time and on different scale, etc. maps are the concentrated expression of the study of palaeogeography. The development of modern computer and information technology provides a series new method for palaeogeography research. Palaeogeography database can be established with various information acquisition and management methods. Palaeogeography information of multi-source and multi-scale can be organized with spatial data model. Palaeogeography environment can be reconstructed with 3D modeling and virtual reality technique. Palaeogeography research achievements can also offer better service with Internet development. The syncretism of palaeogeography research and information technology can advance the research method and level, also can supply effective technology supports for sedimentary mineral deposits in geological history.