Research and application of key technologies for long-distance wire-line core drilling in horizontal boreholes

Abstract:

With the upgrading and transformation of the national energy strategy， the western region has become a key carrier for hydropower project construction. There is an urgent need for detailed exploration of the geological characteristics in the construction areas to support the efficient planning and construction of hydropower projects. Aiming at issues in this region such as unclear lateral lithological and geological characteristics， and inaccurate description of fault distribution， the long-distance horizontal wire-line coring drilling technology was adopted for detailed exploration of the construction areas. By selecting advanced equipment and tools， formulating reasonable and efficient drilling process technologies， and establishing a set of key technologies for long-distance horizontal wire-line coring， the goal of detailed investigation of the geological characteristics and structures in the exploration area was achieved. Taking the engineering geological exploration of a project in the western region as an example， the key technology system for long-distance horizontal wire-line coring was applied. The results showed that the average drilling speed of the hole was 3.61 m/h， the monthly efficiency per rig reached 422.42 m/rig-month， the core recovery rate of the whole hole was as high as 94.92%， the error between the drilled hole angle and the designed value was only 0.1%， and the azimuth of the hole fluctuated within ±1° of the designed value. Field application indicates that the key technology of long-distance horizontal wire-line coring directional drilling proposed in this study has good application value for engineering exploration in the western region and can provide technical support for the exploration and development of complex geological areas.