| The carbonatite has a wide distribution area in the world, There is rich in oil andgas resources. Dolomite reservoir and weathering crust karst reservoirs have a largeproportion in the four types of carbonate reservoir (reefs, grain beach, dolomite, karstweathering crust). Dolomite diagenesis play a crucial role on the two reservoir’sformation.In this paper, O n the basis of predecessors’ research and understanding，TheOrdovician Majiagou Formation Ma5Submember of Daniudi area In the north ordosbasin as the research object. Through the analysis of core observation, Casting thinsections and scanning electron microscope, X-ray diffraction and orderly degree,carbon and oxygen isotope analysis and so on. system analyzed the type andcharacteristics of sedimentary facies, the origin of dolomite. The main results achievedand understanding are as follows:1. Through the observation of field section and core, with reference to thestratigraphic classification plan of changqing oilfield, north China branch ofSinopec.The ordovician Ma5Formation are divided into five subcategories ma51~ma55from top to down and14small layer2. On the basis of sedimentology and paleontological logo, and through study onthe typical drilling core observation, inside casting thin sections identification,sectional structure analysis.The tcarbonate Sedimentary environment of Ma5Formation in Daniudi area is considered a tidal flat deposits, ncluding: supratidal zone,intertidal zone and subtidal zone. Based on fieldobservation and microscopic research,including:carbonatite composition, texture, structure and fossil character.The researched region be Divided into15kinds of rock microfacies3.useing the "three vertical three horizontal" controlled the skeleton section,completed The sedimentary sections of facies comparing in the study region,andplotted sedimentary microfacies of different sub-member of Ma5Formation.Meanwhile build its depositional model of Ma51-2sub-memberand Ma55sub-member4. This paper identified various types of diagenesisprocess in the researchedarea by analytic determination methods such as The casting thin sections,scanningelectron microscope. Including: compaction and dissolution, filling and cementation,recrystallization, metasomatism, Fracturing etc. summarizes the diagenetic sequence ofOrdovician Majiagou Formation Ma5Submember in Daniudi area... |
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