地质岩心钻孔人工造斜方法实践

Practice of Artificial Deflecting Method in Geological Core Drilling

摘要:

在岩心钻探施工过程中，钻遇岩（矿）心脱落需要补取岩心，或钻具脱落、埋钻和烧钻需要绕障时，人工造斜方法是解决问题的有效手段。钻孔较浅，造斜孔段刚好在变径后的位置，且上部孔壁稳定，易于扩孔和下套管，宜选用异径偏心楔人工造斜；钻孔较深，不能改变口径，造斜孔段岩层硬度较大，宜选用同径偏心楔人工造斜；钻孔较深，造斜孔段岩层硬度不大（如煤系地层中的煤层、泥岩等），宜选用同径自然造斜。选用偏斜楔造斜时，偏斜楔长度、偏斜角大小和导斜槽直径的合理选择，偏斜楔下入钻孔过程中的正确操作；选用同径自然造斜，水泥浆灌注孔段位置确定、水泥浆凝固后达到一定的强度和造斜过程中合理的钻进参数，是造斜成功的关键。

关键词:地质岩心钻探;偏心楔;人工造斜（侧钻）;造斜角

Abstract:

In the process of core drilling, the artificial deflecting method is an effective means to make up coring for core falling off and bypass obstacles while drilling tool breaking-off and drill bit being buried or burned. For shallow borehole, the inclined section is just under the stepped-diameter position, the stable upper hole wall is convenient for reaming and casing putting, it is advisable to choose the different diameter eccentric wedge for artificial deflecting; for deep borehole, due to the unchangeablehole diameter and hard rocks in deflecting section, the same diameter eccentric wedge is the proper selection for artificial deflecting; for deep borehole with low-hardness rocks in deflecting section, such as coal seam in coal measure strata and mudstone, etc., the same diameter natural deflecting is optimum. When choosing eccentric wedge, the rational determination of its length, deflection angle degree and the diameter of deviation groove, as well as proper operation are the key points; for the same diameter natural deflecting, the determination of the cement slurry filling section, solidification strength of cement slurry and drilling parameters are the key factors.

Key words:geological core drilling; eccentric wedge; artificial deflecting (side tracking); deflection angle