柴达木盆地北缘中段侏罗系页岩气关键参数研究及资源前景评价

Study on Jurassic Shale Gas Key Parameters and Resource Prospect Assessment in Middle Sector of Northern Qaidam Basin

通过对柴北缘中部侏罗系泥页岩样品进行系统采样和测试分析,综合评价影响页岩气形成和富集的关键参数,认为柴北缘中部主要发育下侏罗统小煤沟组二段和中侏罗统石门沟组上段两套页岩气有利层段,以石门沟组上段最为有利,具有泥页岩有效厚度大、横向展布连续、有机碳平均含量大于4.0%、有机质类型以I-II型为主等有利页岩气形成的物质条件。同时泥页岩中多样储集空间类型和微裂缝为页岩气存储提供了有利场所,而矿物组成中30%左右的石英、长石等脆性矿物的存在,为后期压裂提供了有利条件。研究表明,柴达木盆地北缘具有一定的页岩气资源前景,但研究区的样品成熟度并不高,建议在页岩气研究的同时兼顾页岩油的调查评价。该项目的研究成果为今后柴达木盆地页岩油气的勘探开发提供了基础资料。

Relying on systematic sampling,testing and analysis of Jurassic argillutite samples from coal exploration boreholes in the middle sector of northern Qaidam Basin,comprehensively analyzed and assessed key factors impacting shale gas formation and enrichment. The study has considered that in the area developed lower Jurassic Xiaomeigou Formation Second Member and Shimengou Formation Upper Member two sets of shale gas favorable intervals,while the later is the most favorable. The member has material conditions propitious to shale gas formation including large argillutite effective thickness,continuous lateral extension,average content of organic carbon 4. 0%,and organic matter types mainly category I-II. Moreover,diversified reservoir space types and microfissures provide favorable lieu for shale gas storage. While the existence of about 30% quartz,feldspar brittle minerals have provided favorable condition to later period hydraulic fracturing. The analysis by synthesis has considered that the area has certain shale gas resource prospect,but in allusion to low sample maturity,considered that during the study on shale gas should give consideration to the shale oil. The study has provided important data basis for shale gas and oil exploration,exploitation in the basin henceforth.