伊犁盆地石炭-二叠系石油地质特征

PETROLEUM GEOLOGICAL PROPERTIES OF PERMOCARBONIFEROUS IN ILI BASIN

伊犁盆地阿克沙克组(C_1a)、铁木里克组(P_2t)的有机质丰度较高,有机质类型以腐殖型为主,均已成熟,生储盖条件匹配合理,各类圈闭发育,有希望找到油气田。

Ili Basin is a Permo-Carboniferous basin that developed on Proterozoic basementwith an area of 2.3×10~4 km^2 and the maximum thickness of 10000m and over.The Lower Carboniferous Aksak Formation is composed of clastic and carbonaterocks that deposited in shallow sea shelf and shallow sea platform environment,the sourcerocks of which are 200-700m thick.Organic carbon contents:limestone is 0.56%,mud-stone 0.99%;chloroform extract “A”:the limestone is 32 ppm,the mudstone 92.8ppm.The organic matter is mainly humic type and the ratio of vitrinite reflectance1.99%-2.74%.The Upper Permian Timulik Formation is mainly clastic rocks of riverand lacustrine facies,the source rocks of which is 80-100m thick.Organic carbon contents:mudstone-shale is 1.38%,limestone 0.65%;chloroform extract“A”:mudstone-shaleis 358 ppm,limestone 91 ppm.The organic matter is generally humic type and the ratio ofvitrinite reflectance 0.75%.Light oil and bitumen showings have been found in two for-mations.The above mentioned two sets of source rocks occurred in Qapqal and K(?)nes Sags with extensive distrioution and great thickness.Besides,they have fine source-reservoir-cap rock assemblages and various trap types,thus the two sags are most potential in hy-drocarbon exploration.