The Preliminary Study On Mesozoic Hydrocarbon Character In The Eastern Part Of Qaidam Basin

The Papers in full collect, collate and digest the results of previous studies, by the geological survey in field, the system sampling, geochemical analysis and interpretation of seismic data, focus to sequence stratigraphy, sedimentary and tectonic evolution of the reservoir,construction Characteristics,look oil and gas accumulation and exploration target selection as a core,we will preliminary evaluate and study on Mesozoic hydrocarbon character in the eastern part of Qaidam basin.Through above work and research, we obtain a preliminary understanding, As follows:1.We initial establish sequence stratigraphic framework in the Eastern Part of the Qaidam Basin, found that the Jurassic source rocks exist in the southern margin of the basin,pointed out that there are the two sets of source rocks of the Carboniferous, Jurassic in the southern,north-east and northern margin in the Eastern Part of Qaidam basin.2.We more detailed study the source rocks in the Eastern Part of Qaidam basin. Carboniferous organic carbon content is low,but parent source type is good, have a certain degree of hydrocarbon generation capacity early; middle-Lower Jurassic oil shale and black carbonaceous is the main mudstone source rocks in the study region.3.Through the regional geological structure characteristics and evolution analysis, we think that the Qaidam basin is the Late Paleozoic, Mesozoic and Cenozoic superimposed basin. It is stable platform in Late Paleozoic , is main rift basin in Mesozoic Jurassic and mainly developed in the northern part of study area. It is depression basin from the Late Mesozoic to Cenozoic,and basin subsidence center gradually eastward, to gradually shift Quaternary subsidence center Nuomuhong North. The study area that is in the northern part of the northern uplift area is the Jurassic development of the district; Quaternary Cenozoic southern depression area. the eastern Part of Qaidam basin is the former two superimposed basin area, the southern Part of Qaidam basin and may be the first phase and the third period superimposed basin area.4.Through the analysis of seismic profiles,there are Jurassic fault depressions in Dachaidan block, Cenozoic depressions in Nuomuhong block. a large area east of lacustrine facies layer have bio-gas accumulation conditions.5.Based on Investigation and sampling test analysis in the field,we think that there are reservoir in middle-Lower Jurassic of the eastern part of Qaidam basin and they have a certain degree of self-accumulation and self-storage conditions.6.We Pointed out that Dachaidan block is Jurassic favorable exploration area, the Northern and eastern part of Nuomuhong block is the Quaternary biogas exploration favorable long-ranged prospective blocks.