Research and application of ocean adaptive telescopic rope core drilling technology

Abstract:

When marine coring drilling encounters soft hard interaction formations， it is often necessary to lift the drill and replace it with a matching coring tool to cope with formations of different hardness. The cost of offshore operations is high， and frequent replacement of drilling tools takes a long time. Faced with the interaction of soft and hard geological conditions， an adaptive telescopic rope coring drilling technology has been designed. When encountering soft formations during drilling， the inner pipe extends ahead and the drill bit installed on the inner pipe performs coring drilling； When encountering hard formations， the inner tube will compress its internal spring under the reaction force of the formation on the drilling pressure， and then retract into the outer assembly of the drilling tool. The core drilling is carried out by the outer assembly drill bit， and under the adjustment of the compression spring， the core drilling method can be automatically adjusted according to the change in formation hardness. Through engineering application testing， the average core recovery rate of this process is high， achieving the goal of ensuring core quality and extending the working life of the inner pipe drill bit， improving operational efficiency and safety， and providing certain reference significance for marine engineering investigation.

Key words:ocean drilling;wire-line coring;soft and hard strata;self-adaptive expand and contract;engineering investigation