库车坳陷克深井区白垩系巴什基奇克组孔缝充填特征及流体来源

塔里木盆地库车坳陷白垩系巴什基奇克组为典型的超深层裂缝-孔隙型砂岩储层。通过岩石薄片观察和阴极发光分析对裂缝内充填的碳酸盐脉体和孔隙内赋存的碳酸盐胶结物进行了分析研究，结合微区原位元素测试等技术手段，对比分析了库车坳陷克深井区白垩系巴什基奇克组孔缝碳酸盐流体性质、期次和来源等。研究结果表明：①库车坳陷克深井区白垩系巴什基奇克组孔隙中赋存2期方解石胶结物和2期白云石胶结物；裂缝中充填2期方解石脉体和1期白云石脉体。②研究区白垩系巴什基奇克组孔隙中赋存的第Ⅱ期方解石胶结物与裂缝中充填的第Ⅰ期方解石脉体阴极发光均呈橙黄色，且具有相似的稀土配分模式（轻稀土富集，重稀土亏损，δCe弱负异常，δEu明显正异常），显示孔隙和裂缝中存在着同期同源流体，且该期流体的胶结倾向于发生在裂缝内，对裂缝周边孔隙的保存具有建设作用。

Characteristics of pore-fracture filling and fluid source of Cretaceous Bashijiqike Formation in Keshen well block，Kuqa Depression

The Cretaceous Bashijiqike Formation in Kuqa Depression of Tarim Basin is a typical ultra-deep fracture-pore sandstone reservoir. The properties，stages and sources of pore-fracture carbonate fluid in Cretaceous Bashijiqike Formation in Keshen well block of Kuqa Depression were comparatively analyzed by means of observation of thin sections and cathode-luminescence analysis of carbonate veins and carbonate cements in pores. The results show that：（1）There were two-stage calcite cements and two-stage dolomite cements in the pores of Cretaceous Bashijiqike Formation in Keshen well block，Kuqa Depression. The fractures were filled with two-stage calcite veins and one-stage dolomite veins.（2）The phase Ⅱ calcite cements existed in the pores and the phase Ⅰ calcite veins filled in the fractures of Cretaceous Bashijiqike Formation in the study area are orange-yellow in cathodoluminescence，and they have similar REE distribution patterns（LREE enrichment, HREE loss， weak negative δCe anomaly，positive δEu anomaly），indicating that there are simultaneous homologous fluids in the pores and fractures. The fluid cementation at that stage tends to occur in fractures，which plays a constructive role in the preservation of pores around the fractures.