松辽盆地白垩系青山口组页岩层系非均质地质特征与页岩油甜点评价

Geological heterogeneity of shale sequence and evaluation of shale oil sweet spots in the Qingshankou Formation， Songliao Basin

白斌 戴朝成 侯秀林 杨亮 王瑞 王岚 孟思炜 董若婧 刘羽汐

Bin BAI Chaocheng DAI Xiulin HOU Liang YANG Rui WANG Lan WANG Siwei Meng Ruojing DONG Yuxi LIU

松辽盆地白垩系青山口组湖相沉积发育规模富有机质页岩，古页油平1井实现了深湖区古龙页岩油勘探突破。为进一步精细评价湖盆不同相带页岩层系地质特征，明确陆相湖盆页岩油甜点特征，按青山口组页岩形成环境差异，开展湖盆不同相带页岩层系地质特征非均质性研究。淡水湖盆不同相带页岩层系存在富有机质（总有机碳含量>3 %）纹层状黏土（质）页岩、纹层状黏土（质）页岩、长英（质）页岩、纹层状介壳页岩、块状泥岩、灰岩和白云岩7种类型，分别评价生烃与滞留烃总量差异及烃类流动性、储集性、可压性和产油能力差异，据此提出页岩油资源甜点与工程甜点。根据和（热解烃含量）将青山口组页岩资源甜点划分为Ⅰ，Ⅱ和Ⅲ类，其中Ⅰ类资源甜点大于3.0 %，大于4.0 mg/g；Ⅱ类资源甜点在1.5 %～3.0 %，在1.0～4.0 mg/g；Ⅲ类资源甜点小于1.5 %，小于1.0 mg/g。半深湖-深湖相页岩多为Ⅰ类和Ⅱ类资源甜点，滨浅湖相页岩则以Ⅱ类和Ⅲ类资源甜点为主。通过不同相带岩相含油性、渗流性、可压性、源岩特性和物性等因素分析，优选松辽盆地青山口组页岩油主力靶体。

The lacustrine sediment of the Cretaceous Qingshankou Formation in the Songliao Basin is rich in organic shale， and the well Guye 1 has achieved a breakthrough in oil exploration of Gulong shale of deep lake facies. To further evaluate the geological characteristics of the shale sequence in different facies zones of the lacustrine basin and evaluate the characteristics of shale oil sweet spots in the continental lacustrine basin， we study the geological heterogeneity of shale sequences in different facies zones of the lacustrine basin regarding the environmental difference for lacustrine shale formation in the Qingshankou Formation. It is suggested that the shale sequences deposited in the freshwater lacustrine basin can be divided into seven types according to lithofacies， namely the organic-rich lamellar clayey shale （>3 %）， lamellar clayey shale， felsic shale， lamellar shell shale， massive mudstone， limestone and dolomite respectively， which are evaluated in terms of total hydrocarbon generated and retained， hydrocarbon mobility， reservoir property， compressibility and oil production capacity. The geological and engineering sweet spots of shale oil are thereby proposed. Based on the contents of and （pyrolysis hydrocarbon content）， we group the geological sweet spots of the Qingshankou Formation shale into TypeⅠ，Ⅱ， and Ⅲ. The TypeⅠ sweet spot is generally characterized by content greater than 3 % and greater than 4 mg/g； the Type Ⅱ by content ranging between 1.5 % and 3 %， and between 1.0 and 4 mg/g； the Type Ⅲ by content less than 1.5 % and less than 1.0 mg/g. The semi-deep lacustrine and deep lacustrine facies are dominated by sweet spots of TypeⅠ and Ⅱ， while the shales of shallow lacustrine facies by sweet spots of Type Ⅱ and Ⅲ. The Qingshankou Formation shale in Songliao Basin is selected as the major oil pay zone after a comprehensive analysis of the oil-bearing property， percolation coefficient， compressibility， characteristics of source rocks and physical properties of different facies zones.

10.11743/ogg20230404