The Relationship Of Structural Features And Hydrocarbon Accumulation Of Yang Dake Oil-gas Field In Tarim Basin

Yang Dake oil-gas field is located in the Yang Dake tectonic belt of the western margin of Luntai arch, Northern uplift in Tarim basin. With the appropriate source-reservoir-cap assemblage, it possesses rich natural gas resource which has been already developed. Due to the complicated structures, its control function to gas reservoir is quite remarkable. To meet the needs of oil-gas field exploration and development, the paper made a scrutiny into the structural features of this region by analyzing the effects of tectonic activities on gas resource so as to conduct a favorable zone assessment and trap prediction.Firstly, using well log and seismic data to carry out thin layer division and contrast for the objective intervals of Yang Dake gas-oil field. According to the rules that ‘starting from the core standards well, core calibration logging, looking for auxiliary marker layer, cycle comparison and hierarchical controlling’, the intercalations were identified and contrasted, which were classed as the same sedimentary cycle. The thin layer boundary was determined with relatively stable intercalations. Then divided and contrasted them based upon ‘vicinity and equal thickness’ principle.Systematically analyzed sedimentary microfacies types and vertical phase sequence of the reservoir within the study area, and then analyzed effects of structural features and evolutionary process to formation thickness, sedimentary facies belts distribution and their migration as well as sand body distribution in stratum framework to further concluded the planer distribution characteristics of sedimentary microfacies and distribution regularities of sand body.In addition, through analyzing control action of structures to reservoir-cap assemblage, it was found that the fault played an important role in blocking effect to the trap. It is also a decisive factor during the process of oil-gas migration and its matching relation with sand body is a key factor of accumulation. Lastly, it was confirmed that the later structure has no obvious damage to gas reservoir, and identified the favorable zone within Yang Dake oil-gas field.Based on the previous studies in geology, the research continued to improve and deepen the gas reservoir geological characteristics, focused on the research of structural features. The paper integrated with geological thinking, studied the effects of structural features to sedimentation and the relationship between structural features and accumulation especially through analysis of tectonics, sedimentology,logging and petroleum geology, to conduct a favorable belt assessment and trap prediction.