页岩对甲烷的吸附作用及其固气效应初步研究——以渝东南残留向斜为例  

Methane adsorption and sealing effects of shale:A case study of relict synclines in the southeastern Chongqing

作　　者：鲍云杰[1,2] 邓模[1] 翟常博[1] 刘友祥[1,2] 吕俊祥[1] 俞凌杰[1,2] 曹涛涛[1,2] 

机构地区：[1]中国石化石油勘探开发研究院无锡石油地质研究所,江苏无锡214126 [2]中国石化油气成藏重点实验室,江苏无锡214126

出　　处：《石油实验地质》2016年第4期509-513,共5页Petroleum Geology & Experiment

基　　金：中国石化石油勘探开发研究院院控项目"地层温压条件下页岩吸附能力预测技术与应用"(G5800-15-ZS-YK013)资助

摘　　要：页岩对甲烷的吸附作用既有普遍性,又有差异性,其对页岩气赋存状态、保存、富集成藏影响的研究有待深化。采用等温吸附、扫描电镜、液氮吸附、有机质地球化学等技术手段,对渝东南残留向斜区常压页岩气藏五峰—龙马溪组页岩的吸附作用进行了研究。结果表明,页岩吸附作用受控于页岩的孔隙结构、有机质特征等内在特性,以及其所处的温度和压力等外部环境条件;地层条件下页岩的吸附作用强度可以利用Langmuir模型进行预测,渝东南某残留向斜五峰—龙马溪组页岩吸附作用强度存在临界深度,在临界深度吸附作用强度达到峰值。结合理论分析及三轴应力吸附条件下页岩渗透率测定实验数据,认为页岩的吸附作用致使其渗透率降低,形成一种阻滞页岩气渗流扩散的"固气效应",这种固气效应对残留向斜页岩气保存及富集边界的影响值得进一步研究。Universality and difference both exist in the methane adsorption of shale. This study concerns the influencing factors of shale gas occurrence, preservation and accumulation. The gas adsorption capacity of the Wufeng-Longmaxi shale in the relict synclinal district in the southeastern Chongqing was studied by means of isothermal adsorption, scanning electron microscopy, nitrogen adsorption and organic geochemical methods. The adsorption capacity of shale is controlled by some internal characteristics such as pore structure and organic matter features, and some external environment conditions such as temperature and pressure. The adsorption strength of shale under subsurface conditions can be predicted using a Langmuir model. The adsorption strength of Wufeng-Longmaxi shale from the relict synclinal district in the southeastern Chongqing has a critical depth at which adsorption strength reaches its peak value. Theore-tical analysis and experimental data of shale permeability determination under three axial stress concluded that the ad-sorption effect of shale resulted in the decrease of permeability which blocked the diffusion influences to shale gas flow, which was called as ‘gas sealing effect ’ . The influences from this effect on gas preservation and enrichment boundary should be further studied.

关 键 词：页岩 吸附作用 固气效应 残留向斜 渝东南 

分 类 号：TE132.2[石油与天然气工程—油气勘探]