吐哈盆地致密砂岩气地质条件、资源潜力与勘探方向OA

The Lower-Middle Jurassic tight sandstone gas reservoirs in the Turpan-Hami Basin exhibit substantial resource potential,representing a crucial exploration field for natural gas reserve growth and production enhancement.However,due to complex geological conditions,the hydrocarbon accumulation mechanisms remain unclear,which hinders resource potential evaluation and the optimization of exploration directions.Through systematic analysis of source rock characteristics,reservoir characteristics,and preservation conditions,this paper establishes an accumulation model and identifies three key controlling factors for tight sandstone gas accumulation:(1)effective hydrocarbon kitchens control the lateral distribution of hydrocarbons;(2)high-quality reservoir facies belts determine the degree of hydrocarbon enrichment;(3)stable tectonic settings are conducive to the preservation of large-scale gas reservoirs.Integrated resource evaluation employing the small-bin volume method,resource abundance analogy,and Monte Carlo simulation was conducted for three main target intervals:the third member(J₂x³)and first member(J₂x¹)of the Xishanyao Formation,and the second member(J1s2)of the Sangonghe Formation.Results show that the total geological resource of tight gas in Taibei Sag amounts to 6 793.02×10 ⁸ m³,exhibiting stepwise increase with burial depth.Specifically,the J ₂x³,J₂x¹,and J ₁s² members contain 1 783.51×10⁸ m³,1 923.53×10⁸ m³,and 3 085.98×10⁸ m³,respectively.Resource classification reveals:Type Ⅰ resources(1 596.36×10⁸ m³)are concentrated in the northeastern slope of the Shengbei Sag,Baka structural belt,southern slope of the Qiudong Sag,and southern slope of the Xiaocaohu Sag,serving as priority targets for near-term exploration breakthroughs;Type Ⅱ resources(2 560.97×10⁸ m³)are mainly distributed in the Gedatai-Hongtai structural belt and Qiudong-Xiaocaohu piedmont zones,representing favorable directions for medium-and long-term exploration expansion.These findings provide a scientific basis for efficient tight gas exploration in the basin.