The drilling fluid technology of 3500m extra-deep hole in Xiaoqinling Gold Field

Abstract:

The 3500m extra-deep hole （ZK001 hole） in Xiaoqinling gold mine field is located in Lingbao City， Henan Province. It is the first full-hole continuous coring extra-deep hole in the Xiaoqinling tectonic belt. The formation lithology of this hole is very complicated， with soft， hard and broken strata appearing interactively， and the wall protection is extremely difficult. There are many complicated conditions in drilling， such as hole wall collapse， block loss， hydration decomposition and pulping， high in-situ stress gouge shrinkage and micro-fracture water loss. In this paper， the flushing solution system is adjusted according to the formation changes. The upper part uses low solid phase flushing solution and the lower part uses low solid phase polymer anti-collapsing flushing solution system. The flushing solution formula is constantly optimized， the performance parameters are timely maintained and adjusted， and various problems in the hole are effectively solved. It provides a reliable flushing fluid technology for deep hole core drilling in Xiaoqinling area.