WFSD-4孔深部流体分析和多组分地球化学特征

Fluid Analysis and Multi-component Geochemical Features in the Depth of Drill Hole WFSD-4

采用场内钻探流体实时分析和场外钻探泥浆分析的方法,获得汶川地震断裂带科学钻探工程4号钻孔(WFSD-4)中深部井段流体多组分分析结果。研究钻孔深部井段的流体剖面地球化学特征,认为来自地下深部流体在钻探过程中会保存在钻探循环泥浆中,随钻流体实时分析可记录明显的组分变化信号。钻孔岩心的岩性变化易引起钻探泥浆气体的变化,特别是钻探泥浆气体中的多组分变化,在钻孔岩性裂隙较为丰富的井段,是钻探泥浆气体组分变化强度较大区间。通过比较钻探泥浆的多组分和岩心岩性的弱相关性,可以推测钻探流体与余震相关性较强的区域和周期,更可能获得钻探流体与余震的相关程度。

Both in-site real-time fluid analysis and off-site drilling mud analysis were used to detect the multi-components in the depth of drill hole WFSD and the profiles of multi-components in the drilling mud and other media during drilling. Through the comparison of fluid profile in the depth of the drill hole, the underground fluid geochemistry was discussed in the paper. The fluid from deep underground would be kept in the cycling mud during the drilling process. The further study of drilling mud gas, liquid and solid samples would be helpful to the determination of invasion of underground fluids in various ways. At the same time, the real-time fluid analysis during drilling would record the distinct signal change of components in the cycling mud. The lithologic variation of drilling core would easily cause the change of drilling mud gas, especially the change of multi-components in drilling mud gas. The lithologic section of relatively abundant fissures in the drill hole is the interval of greater drilling mud gas change. The indistinct correlation between multi-components of drilling mud gas and lithology of drilling core was comparatively studied, and the result could indicate the exact region and period in which the correlation of drilling fluid and aftershock was stronger, and this could be helpful to achieving the real degree of correlation between drilling fluid and aftershock.