Tight Oil Resources Assessment In Tengger Formation And Arshan Formation Of The Lower Cretaceous In Erlian Basin

The Erlian basin is a large,Meso-Cenozoic fault depression basin,characterized by strong separability.Each sag are respectively developed a unique set of sedimentary system,but it is almost the same tectonic and sedimentary evolution process,so the sag is roughly similar strata and tectonic conditions.Sag in the 4th member of Arshan formation and 1th member of Tengger formation developed of the slant oily high-quality hydrocarbon source rocks,the flooding stage of shore shallow lake facies carbonate thickness distribution is stable and good lateral continuity,easy to form structural fractures and bolt,is a good dense oil reservoir,both in the vertical distribution of composite constitutes the favorable dense oil accumulation conditions.According to the assessment sag difference,respectively using the method of small cell capacity and resource abundance analogy method for different sag of tight oil resource is evaluated.Anan sag,Erennaor sag of master data is relatively abundant,so use small cell volume method.According to the results of the small cell volume method to calculate the tight oil in "special lithologic members",the biggest amount of Anan sag,1.07×108 t;Resource abundance is the highest,up to 120~150×104 t/km2.Followed by the forehead Erennaor sags,tight oil resources is 1.02×108 t,the resources abundance of 110~150×104 t/km2.Due to less data in other potential development tight oil sag,use analogy method and select the Jimusar sag of Zhungar basin to be analogy.The evaluation results show that the tight oil resources to Wuliyasitai south subsag is 4.6×108t.Based on results of calculating the volumetric method and analogy method of summary by the Erlian basin tight oil resources is 13.49~30.21×108t.