Research On Transportation System In Southern Slop Of Dongying Sag

Based on the exploration practice in southern slop of Dongying Sag and previous studies, this paper summarized the distribution features of the reservoirs,analyzed the influencing factors and mechanism of transportation system,discussed the hydrocarbon accumulation process and the transportation system controlling hydrocarbon model , by applying the reservoir forming assemblage theory.The results show that the reservoir distributions in different series of strata in southern slop of Dongying Sag are of comparability and combination, and they are obviously controlled by the constitution mode of transportation system. The transportation system is of zoning laterally and combination vertically, and is different in different tectonic zones. The similar sedimentary system assemblage leads to the vertical combination of transportation system. The types and distribution of the transportation system determine the types and spatial combinations of the reservoirs. The fault, sand body and unconformity have effects on the migration and accumulation of oil and gas. The same type transportation body but of different origins has different transportation ability. Different transportation system combinations have different transportation mechanisms as well as migration and accumulation efficiencies.The transportation system of the indisde slope and the middle slope are constituted of faults and sands. The preferred migration pathway in delta skeletal sand body is mainly controlled by the top surface depth of the buried sand body. The difference of migrating capability in fault along lateral and vertical are controlled by the fault structure. From the analysis, it is found that in different pool-forming periods, the spatial relationship between the top relief of skeletal sand body and the fault determined the hydrocarbon migration paths; during the same forming period, different skeletal sand bodies have different top relief having the independent migration paths. One oil-gas trap was formed by the hydrocarbon migrating and accumulating through different migration paths of different skeletal sand bodies during different periods.The transportation system of the outdisde slope and the platfood are constituted of unconformity and sands. The heterogeneous migration of petroleum in unconformity systems is closely associated with classification of unconformity systems and their vertical texture. The mechanism of strata reservoirs forming was mainly discussed, concluding that first their reservoir forming dynamic is buoyancy and the second the structure stress. The buoyancy is the main dynamic for the oil and gas migration in strata reservoirs and the abruptly releasing of stress is the spring mechanism of the oil and gas episodic migration. The strata reservoirs forming shows a relative continuous process with episode.According to these research,the major controlling factors of the transportation system are scalar quantization,the quantitative evaluation method of the transportation system in southern slop of Dongying sag is established,which is a foundation for comparing the transportation ability of different transportation system assemblage. The mainly oil-gas migration paths can be found through the up-building of the macro transportation frame. The transportation system being principal line, the reservoir forming assemblage can be divided. Using this method, not only the distribution of the proved reservoirs can be well interpreted, but the prediction for exploration potentiality and prospects can be performed effectively, which is an effective method for zonal oil and gas exploration in continental downfaulted basin.