Core drilling technology for complex strata in Yangling iron mine area， Gansu Province

Abstract:

The iron ore body in the Yangling Iron Mine area of Gansu Province is located in the fourth lithological segment of the Pingtoushan Formation of the Jixian system， which is composed of shallow metamorphic clastic rocks interbedded with muddy marble rock layers. The upper part of the strata is complete and has strong abrasiveness， while the lower part is severely fractured and leaked， exhibiting strong ferromagnetism. In response to the construction difficulties caused by the complex geological formations mentioned above， such as low drill bit lifespan， frequent accidents in the hole， and severe magnetic interference， measures such as optimizing drilling structure， selecting drilling equipment reasonably， and improving the use of flushing fluid have been taken to effectively solve the above problems. At the same time， it has played a positive role in accelerating construction progress， improving drilling efficiency， and saving construction costs. This drilling technology experience has certain reference significance for drilling construction in other strong magnetic mining areas.

Key words:strong grinding formation;strong magnetism;drilling leakage;borehole curvature