Study On Palaeo-Rock-Solution Of Carbonate Rock Of Ordovician And Its Reservoir

The thesis aims at the practical demand of hydrocarbon exploration of marine carbonate rock in China. Taking the west Tazhong Area, Tarim Basin and the west Ordos Basin as examples, combining various kinds of techniques based on theories and methods of the carbonate rock sedimentology and petrology, karst geology and geomorphology, carbonate rock reservoirs geochemistry, carbonate rock sequence stratigraphy and carbonate rock reservoirs geology together, carbonate rock palaeo-rock-solution of Ordovician and its reservoirs have been studied systemically. Palaeo-rock-solution of Ordovician and its reservoirs of the two study areas have been predicted planely in this thesis. The main conclusions of this thesis are as follows:(1) Palaeo-rock-solution of carbonate rock of Ordovician are divided into three main types according to diagenetic stage and diagenetic environment, that are, syngenesis solution, epidiagenesis solution and burial solution. â‘ According to facies, syngenesis solution is firstly divided into bank and reef of platform margin type, bank and tide flat of intra-platform type and evaporation tide flat type. Through a comprehensive analysis of core and thin-section, recognition symbols of syngenesis solution of bank and reef of platform margin type and bank and tide flat of intra-platform type are summarized. Development pattern of bank and reef of platform margin type and bank and tide flat of intra-platform type belongs to atmospheric fresh water lens. Fresh water and salt water lens form mainly in evaporation tide flat type. â‘¡ On the basis of structural shape of region, epidiagenesis solution of the study areas are classified into two main types. One is gently folded type, like in west Tazhong area and its adjacent areas, the other is block-faulted type, like in west Ordos Basin. The epidiagenesis solution development pattern in the west Tazhong area and its adjacent areas is similar to "A" type autogenetic solution pattern, of which the middle Caledonian epidiagenesis solution and the early Hercynian epidiagenesis solution are relatively sweeping. By means of observing core and thin-section carefully and studying drilling display and geophysical respondence systemically, the main recognition symbols of carbonate rock epidiagenesis solution are put forward. â‘¢Burial solution is considered as all the solution effect and solution phenomena of carbonate rock, which occurred in the burial diagenetic environment in the early and late diagenetic phase. Through an analysis of rock-solution types of the carbonate rock of Ordovician in the two study areas, the types of the burial solution are synthesized into three main types in this thesis, that are, burial organic solution, compaction-released water solution and hydrothermal solution. Burial organic solution...