Research and application of wire-line coring drilling tools for shallow hole in heterogeneous layers

For existing single core barrel drilling tools is simple in structure, there are many problems when it comes to shallow hole with heterogeneous layers, such as low coring rate, collapse of hole wall without protecting, confusing soil sample, bad water resisting and ineffective coring protection, we develop a kind of wire-line coring drilling tools for shallow hole in heterogeneous layers. It consists of outer tube assembly, inner tube assembly and fisher. The paper described its structure characteristics and working principle in detail. The theoretical formula for falling velocity of inner tube was deduced, ABAQUS was adopted to analyze the damage mechanism and breaking reason for damageable parts-hanging ring and seat ring in wire-line coring drilling tools. Adding weighting mechanism to the fisher, the theoretical formula for weighting mass was deduced. Field test shows that this φ110 wire-line coring drilling tools can accomplish shallow hole drilling work, protect the hole wall effectively and improve the core recovery.