Hailar Basin Urxun-Beier Sag’s Jurassic Source Rock Evaluation

Hailar basin is a large oil and gas bearing basin,which is an important potential area of oil and gas in northeastern China. At present, industry reservoir have been discovered in the Hailar basin mainly concentrated in the Cretaceous layer,however,Jurassic layer is one of a Mesozoic sedimentary strata, the exploration degree is low, lack of awareness. With the deepening of exploration, the gradual deepening of geological understanding,and the urgent need for reserve resources, exploration Jurassic layer of Hailar basin began to be taken seriously.Urxun-Beier sag is the main exploration region of the Cretaceous in Hailar basin,and the highest exploration degree sag,There are many wells drilled beneath the Cretaceous strata,and seismic data has covered 2 sags. Under the Cretaceous exsit sedimentary rock has been confirmed,The drilling and seismic for us to study the sedimentary rocks, age,distribution,hydrocarbon potential has provided an important support.The drilling and the surrounding outcrops of Jurassic in Hailar basin’s lithology is mainly mudstone, siltstone, sandstone, glutenite very small volcano rock.According to the drilling and seismic data that Urxun-Beier sag’s Jurassic delta lake sedimentary system main types is fan delta plain, delta front,shallow lake and semi-deep lake to deep lacustrine.Use the existing seismic data reinterpretation show that Urxun-Beier sag’s Jurassic strata thickness up to 800 m, an average about 350 m,Urxun sag is larger than Beier sag.According to the contant of Pr/Ph and gammacerane judge the environment of Jurassic water is freshwater, micro saltwater.The organic matter abundance is not high, and the type of organic matter is also partial humus type,Through the analysis of field sampling and core samples,The source rocks of Jurassic strata are between mature to high maturity.This is the most advantage stage of hydrocarbon generation and expulsion.According to “A”/TOC and S₁+S₂/TOC determined hydrocarbon threshold depth, exhaust hydrocarbon threshold depth and the peak of oil generation depth in proper order is 1450 m, 2250 m, 2300 m.By using the method of volume analogy carried out Urxun-Beier sag’s Jurassic layer and Turpan-Hami basin Urxun-Beier sag’s Jurassic layer,the exploration process of Jurassic in Taipei sag has been evaluated for many times, and its resources should be relatively true.By analogy, deduct the contribution of the resources of the coal part in Taipei sag, two sag have a close organic matter abundance.On mudstone maturity of Urxun-Beier sag is higher, other petroleum geological conditions also have good comparability,By analogy to get the resources reserve of the Urxun-Beier sag, oil 0.51⁰.76 ×10⁸t, gas197²58 ×10⁸ m3.According to the organic matter maturity, thickness of dark mudstone, organic carbon content that three factors form a Jurassic layer’s advantage area distribution chart, the advantage exploration areas were in the middle of the Urxun sag and Beier sag.