Geological Evaluation Of Singe Well Changshen17

Well Changshen 17 located in the rift basin in the southern central bulge Chagnling belt Daqingzijing North structure. The area is long-term development of paleo-uplift where is the point of North and South sub-depression oil and gas long-term migration to. Because of frequently volcanic activity at rift period this area is advantageous to searching for volcanic rock Gas pool. In this paper, single well geological evaluation on well Changshen 17, major to depict deep zone development of hydrocarbon source, reservoir and seal rocks, knowledge of source-reservoir-seal combinations features and their time-space matching relation, and to summarize gas reservoir-forming conditions and their controlling factors which is of a significance for guiding prospecting in the Changling Fault Depression in next stage.According to core, logging, seismic and paleontological data, the well area is carried out stratigraphic classification and correlation. The research on the structural evolution show that locally developed Volcanic uplift of well Changshen 17 area formed in the late deposition of Denglouku, that is before Quantou sedimentary the structures has been basically finalized.The Study of hydrocarbon source rock qualitative evaluation indicates that the gas was mainly generated of the deep source rocks in the well Changshen 17 area. The organic matter abundance is higher of Huoshiling formation, and its types of organic matter dominated byⅡ2 andⅢ; However, Denglouku formation is lowest, the majority were non-, poor source rocks; The types of organic matter of Yingcheng and Denglouku dominated byⅡ. The Study of hydrocarbon source rock in Qianbei and Qianshenzijing Subdepression shows that the types of organic matter dominated by 112. The organic matter abundance is lower Yingchen Formation in Qianbei subdepression, however, Shahezi Formation is higher. The organic matter abundance is higher Huoshiling Formation in Qianshenzijing subdepression, but Yingchen Formation is lower. The research of quantitative evaluation of hydrocarbon source rocks shows that by 2%～5% of the migration coefficient the total amount of resources of Shahezi and Yingchen Formation in Qianbei Subdepression is 1684×108～4210×108m3, and Shahezi Formation in Qianshenzijing Subdepression is 392×108～980×108m3. Therefore, the two Subdepressions have significant potential for gas exploration. Gas-source correlation using lingh hydrocarbon fingerprints technique shows that It verified from correlation of gas soure that the main gas source of deep gas for well Changshen 17 is Huoshiling Formation source rocks in the well area and Qianshenzijing Subdepression source rocks, however Qianbei Subdepression's contribution is small, or even no contribution to.General lithology identification chart board are established for well Changshen 17 by means of comprehensive explanation of utilization of core photographs,cast sheets,logging, conventional logging and ECS element logging, and determine the lithology is mainly andesite and basalt. Combined with seismic data, the main volcanic facies are explosive facies, effusive facies and volcanic sedimentary facies. Through the research on reservoir characteristics, the porosity of well Changshen 17 is small, secondary porosity is not developed. In addition to individual fractures, volcanic section of the overall permeability is poor. Applying T2 spectrum to construct capillary pressure curves, research on the gas reservoir microscopic characteristics shows that the reservoir propertyis of test gas reservoir is moderate deviation. Comprehensive evaluation of the reservoir revealed that class I of all reservoir ratio of the reservoir are 5%. Statistics by lithology, Class I reservoir lithology is basalt, tuff, tuffaceous sandstone and volcanic breccia, in which the majority of basalt,68% of the total thickness. Statistics by facies, upper subfacies of effusive facies is better, followed by lower subfacies of effusive facies and airfall subfacies of explosive facies.Direct cap rocks of well Changshen 17 gas reservoirs is dense basic extrusive rock, with a low effective porosity and poor physical, not destroyed by crack and fracture, and its horizontal distribution is more stable, so the cap rocks have relatively good sealing capacity. View from the formation period, the cap rock over sediments in the early Yingcheng which much earlier than the main formation period of gas, so it can be the effective seal rock for gas reservoir.General of the study, the main gas formation period of well Changshen 17 well matched with reservoir and seal rock, trap with high efficiency formed before main expulsion hudrocarbon of hydrocarbon source rock, also later tectonic activity has less affected on deep, so preservation conditions are favorable. These factors are key to the formation of gas reservoirs in the area.