吐哈盆地天然气特征及分布

吐哈盆地中下侏罗统煤系烃源岩发育，侏罗系以分布轻质油为特色，绝大多数气藏为凝析气藏，且轻质油藏溶解气油比大，油溶气丰度很高；在台北凹陷，油气并存为油气分布的重要特点，气藏的分布与油气分异有一定的关系；目前发现的气藏层位均为侏罗系，其上的地层中没有气藏分布可能与盖层封闭性差有关。另外，埋深较大的侏罗系及三叠系中与烃源岩互层或很近的砂岩中存在规模很大的致密砂岩气藏；分布广泛的煤层吸附气也是重要的潜在天然气资源。

Characteristics and Distribution of Natural Gas in Turpan-Hami Basin

In Turpan-Hami basin, the hydrocarbon source rock in coal-bearing system of Middle-Lower Jurassic is well develooed Jurassio is characterized by widely distribution of light oil, the majority of most gas-reservoirs are condensate-gas pools. In light-oil reservoirs both solution gas-oil ratio and oil-soluble gas abundance are high. In Taibei depression, the distribution of oil-gas are featured by the coexistence of oil and gas, the distribution of gas-pools are in certain extent related to oil-gas segregation. So far, all the gas reservoirs are located in sequence of Jurassic. Absence of gas reservoir distributed in formation overlap above Jurassic may probably be associated with the undesirable cap-bed condition. Besides, there are large scale of tight sandstone gas-reservoirs occurred in sandstone formations which are interbedded or nearly the hydrocarbon source rock of deep buried Triassic and Jurassic. The widely distributed coal layer adsorbed gas is also an important potential natural gas resource.