Triassic Reservoir Characteristics And Resource Estimates In Muli Depression Of Qinghai Province

The study of South Qilian basin has a long history. However, the study mainly focuses on theEarly Palaeozoic Era and Kainozoic era and we lack study on Cenozoic era. In recent years, thenature gas hydrate discovered in south qilian basin shows that trias of the south qilian basin has arather prospective future for petroleum resources. The study on the features of oil-gas storage ofMuri depression in the south qilian basin and the further evaluation of its oil-gas resource potentialwill be of great significance for the future oil exploration in the south qilian basin.This dissertation chooses the Muri depression of the south qilian basin as the research object.It will firstly evaluate the source rock of the Muri depression by applying the Geochemistry oforganic matter. Secondly, it will evaluate the storage properties，feature of pore structure and theinfluencing factors，using the petrological, Reservoir and geological methods and Reservoirevaluation theory，so as to make a overall evaluation the Reservoir characteristics of Muridepression. In addition，in this dissertation, organic geochemistry, Probability and statistics andother mathematical theory and methods will be applied to measure out the best scheme for theevaluation of estimating the amount of resources under different exploration degree. Here, thisdissertation aims to achieve the following Results and cognition:The source rock of Temple Group in the Muri depression of south qilian basin is typeⅠ-Ⅱ,while that ofDajialian group is typeⅡ.The abundance of organic matter is high and the genre isbetter. The heating degree of source rock is higher. The overall development of Muri depression isModerate-good source rock.The reservoir stratumof the basin’s triassic clastic rock show anoverall presentation of low porosity and low permeability. There are differences between east andwest within the basin. The western physical property of reservoir is relatively good, which can bemainly attributed to the fact that shale content in the Sedimentary rock components and theDetrital composition in Effusive rock are higher. However, the Muri depression has gone throughMulti stages of tectonic reconstruction and Fissures of various kinds have fully developed and, toa large extent, have improve the the reservoir performance of the rocks, which belongs to thepore-fracture type of reservoir.Due to limited exploration cost and technology, the traditional resource estimation can nolonger satisfy the needs that is required for the predicting the prospect of oil-gas resources; whilethe statistical method is becoming a mainstream for its low exploration cost and high reliability.Thus the combination of the two will make the evaluation accuracy higher. According to thelimited Sample analysis data, it is acknowledged that accidental errors are rather large byapplying comparative analysis using two traditional Calculation method of reserves. This requiresfurther stronger Exploration and Test data analysis. The accomplishment of Monte Carlo methodin resource estimation has largely lessen the Systematic Error in the process of resource estimation,which has certain enlightening significance in improving the accuracy of the resource estimation.