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松辽盆地梨树断陷纵向上发育白垩系沙河子组和营城组两套主力泥页岩烃源岩层系,其沉积环境有利、厚度大、分布广。沙河子组以Ⅱ段页岩气地质条件最好,其w(TOC)分布范围为0.11%~8.20%(平均值1.45%);营城组发育两段优质泥页岩,Ⅰ段w(TOC)为0.26%~12.01%(平均值1.96%),Ⅱ段w(TOC)为0.06%~5.03%(平均值1.06%)。有机质类型以Ⅱ1-Ⅲ型为主,含少量I型。沙河子组Ro普遍较高,断陷西部基本进入过成熟阶段,缓坡带处于成熟-高成熟阶段。营城组Ro变化范围较大,小城子、孤家子和十屋地区Ro达到2.00%以上。两套泥页岩脆性矿物体积分数为32.10%~62.90%,具有较好的储集性能。断陷内有多口探井在沙河子组和营城组的厚层泥页岩段钻遇高气测显示。营城组I段泥页岩含气量为0.62~3.09m3/t。采用概率法初步预测出沙河子组和营城组页岩气资源量为6 645.34×108 m3。秦家屯地区和苏家屯次洼为页岩气勘探的有利目标区,桑树台深洼带为较有利目标区。
Two main shale source rocks of Cretaceous Shahezi Formation and Yingcheng Formation are developed longitudinally in the Lishu Fault Depression, Songliao Basin. The sedimentary environment is favorable, with large thickness and wide distribution. Shahezi Formation has the best geological conditions for shale gas in section Ⅱ, with a distribution of w (TOC) ranging from 0.11% to 8.20% (average 1.45%); two high-quality shale in Yingcheng Formation, ) Was 0.26% ~ 12.01% (mean 1.96%), and the TOC of Ⅱ segment was 0.06% ~ 5.03% (average 1.06%). The type of organic matter is mainly Type II-III, with a small amount of type I. The Shahezi Formation Ro is generally high, the western part of the fault depression has basically entered the over-maturity stage, and the gentle slope belt is in the maturity-high maturity stage. Yingcheng group Ro a larger range of changes, small town, solitary son and ten house area Ro reached more than 2.00%. The volume fraction of two shale brittle minerals is 32.10% -62.90%, which shows good reservoir performance. There are many exploration wells in the fault depression in the Shahezi Formation and Yingcheng Formation thick mud shale section of the high-gas drilling shows. The gas content of shale in Yingcheng Formation I section is 0.62 ~ 3.09m3 / t. Probabilistic method is used to predict shale gas resources in Shahezi and Yingcheng formations are 6 645.34 × 108 m3. The Qinjiatun area and Sujiatun times depression are favorable target areas for shale gas exploration, and the Sanshitai deep depression belt is the more favorable target area.